From 417bec5b0f25e000866f1be845d44a3ca0690697 Mon Sep 17 00:00:00 2001 From: Takashi Iwai Date: Tue, 13 Jan 2009 17:57:12 +0100 Subject: ALSA: hda - Update model descriptions in patch_sigmatel.c Update models in patch_sigmatel.c, mainly for the last Gateway updates. Signed-off-by: Takashi Iwai --- Documentation/sound/alsa/HD-Audio-Models.txt | 12 ++++++++++-- 1 file changed, 10 insertions(+), 2 deletions(-) (limited to 'Documentation') diff --git a/Documentation/sound/alsa/HD-Audio-Models.txt b/Documentation/sound/alsa/HD-Audio-Models.txt index 4b7ac21ea9e..64eb1100eec 100644 --- a/Documentation/sound/alsa/HD-Audio-Models.txt +++ b/Documentation/sound/alsa/HD-Audio-Models.txt @@ -275,7 +275,8 @@ STAC9200 dell-m25 Dell Inspiron E1505n dell-m26 Dell Inspiron 1501 dell-m27 Dell Inspiron E1705/9400 - gateway Gateway laptops with EAPD control + gateway-m4 Gateway laptops with EAPD control + gateway-m4-2 Gateway laptops with EAPD control panasonic Panasonic CF-74 STAC9205/9254 @@ -302,6 +303,7 @@ STAC9220/9221 macbook-pro Intel Mac Book Pro 2nd generation (eq. type 3) imac-intel Intel iMac (eq. type 2) imac-intel-20 Intel iMac (newer version) (eq. type 3) + ecs202 ECS/PC chips dell-d81 Dell (unknown) dell-d82 Dell (unknown) dell-m81 Dell (unknown) @@ -310,9 +312,13 @@ STAC9220/9221 STAC9202/9250/9251 ================== ref Reference board, base config + m1 Some Gateway MX series laptops (NX560XL) + m1-2 Some Gateway MX series laptops (MX6453) + m2 Some Gateway MX series laptops (M255) m2-2 Some Gateway MX series laptops + m3 Some Gateway MX series laptops + m5 Some Gateway MX series laptops (MP6954) m6 Some Gateway NX series laptops - pa6 Gateway NX860 series STAC9227/9228/9229/927x ======================= @@ -329,6 +335,7 @@ STAC92HD71B* dell-m4-1 Dell desktops dell-m4-2 Dell desktops dell-m4-3 Dell desktops + hp-m4 HP dv laptops STAC92HD73* =========== @@ -337,6 +344,7 @@ STAC92HD73* dell-m6-amic Dell desktops/laptops with analog mics dell-m6-dmic Dell desktops/laptops with digital mics dell-m6 Dell desktops/laptops with both type of mics + dell-eq Dell desktops/laptops STAC92HD83* =========== -- cgit v1.2.3 From e86c1451d3138b4cd0378282b30397d171fa4252 Mon Sep 17 00:00:00 2001 From: Bartlomiej Zolnierkiewicz Date: Wed, 14 Jan 2009 19:19:03 +0100 Subject: ide: remove unused CONFIG_BLK_DEV_IDE_AU1XXX_SEQTS_PER_RQ Acked-by: Sergei Shtylyov Signed-off-by: Bartlomiej Zolnierkiewicz --- Documentation/mips/AU1xxx_IDE.README | 6 +----- 1 file changed, 1 insertion(+), 5 deletions(-) (limited to 'Documentation') diff --git a/Documentation/mips/AU1xxx_IDE.README b/Documentation/mips/AU1xxx_IDE.README index f54962aea84..8ace35ebdcd 100644 --- a/Documentation/mips/AU1xxx_IDE.README +++ b/Documentation/mips/AU1xxx_IDE.README @@ -52,14 +52,12 @@ Two files are introduced: b) 'drivers/ide/mips/au1xxx-ide.c' contains the functionality of the AU1XXX IDE driver -Four configs variables are introduced: +Following extra configs variables are introduced: CONFIG_BLK_DEV_IDE_AU1XXX_PIO_DBDMA - enable the PIO+DBDMA mode CONFIG_BLK_DEV_IDE_AU1XXX_MDMA2_DBDMA - enable the MWDMA mode CONFIG_BLK_DEV_IDE_AU1XXX_BURSTABLE_ON - set Burstable FIFO in DBDMA controller - CONFIG_BLK_DEV_IDE_AU1XXX_SEQTS_PER_RQ - maximum transfer size - per descriptor SUPPORTED IDE MODES @@ -87,7 +85,6 @@ CONFIG_BLK_DEV_IDEDMA_PCI=y CONFIG_IDEDMA_PCI_AUTO=y CONFIG_BLK_DEV_IDE_AU1XXX=y CONFIG_BLK_DEV_IDE_AU1XXX_MDMA2_DBDMA=y -CONFIG_BLK_DEV_IDE_AU1XXX_SEQTS_PER_RQ=128 CONFIG_BLK_DEV_IDEDMA=y CONFIG_IDEDMA_AUTO=y @@ -105,7 +102,6 @@ CONFIG_BLK_DEV_IDEDMA_PCI=y CONFIG_IDEDMA_PCI_AUTO=y CONFIG_BLK_DEV_IDE_AU1XXX=y CONFIG_BLK_DEV_IDE_AU1XXX_MDMA2_DBDMA=y -CONFIG_BLK_DEV_IDE_AU1XXX_SEQTS_PER_RQ=128 CONFIG_BLK_DEV_IDEDMA=y CONFIG_IDEDMA_AUTO=y -- cgit v1.2.3 From df291fa993c506da89a89264ff8166bccd172a14 Mon Sep 17 00:00:00 2001 From: Randy Dunlap Date: Thu, 8 Jan 2009 10:59:34 -0800 Subject: kbuild: fix kbuild.txt typos Fix typos in the new kbuild.txt file. Signed-off-by: Randy Dunlap Signed-off-by: Sam Ravnborg --- Documentation/kbuild/kbuild.txt | 29 +++++++++++++++-------------- 1 file changed, 15 insertions(+), 14 deletions(-) (limited to 'Documentation') diff --git a/Documentation/kbuild/kbuild.txt b/Documentation/kbuild/kbuild.txt index 923f9ddee8f..f3355b6812d 100644 --- a/Documentation/kbuild/kbuild.txt +++ b/Documentation/kbuild/kbuild.txt @@ -3,7 +3,7 @@ Environment variables KCPPFLAGS -------------------------------------------------- Additional options to pass when preprocessing. The preprocessing options -will be used in all cases where kbuild do preprocessing including +will be used in all cases where kbuild does preprocessing including building C files and assembler files. KAFLAGS @@ -16,7 +16,7 @@ Additional options to the C compiler. KBUILD_VERBOSE -------------------------------------------------- -Set the kbuild verbosity. Can be assinged same values as "V=...". +Set the kbuild verbosity. Can be assigned same values as "V=...". See make help for the full list. Setting "V=..." takes precedence over KBUILD_VERBOSE. @@ -35,14 +35,14 @@ KBUILD_OUTPUT -------------------------------------------------- Specify the output directory when building the kernel. The output directory can also be specificed using "O=...". -Setting "O=..." takes precedence over KBUILD_OUTPUT +Setting "O=..." takes precedence over KBUILD_OUTPUT. ARCH -------------------------------------------------- Set ARCH to the architecture to be built. In most cases the name of the architecture is the same as the directory name found in the arch/ directory. -But some architectures suach as x86 and sparc has aliases. +But some architectures such as x86 and sparc have aliases. x86: i386 for 32 bit, x86_64 for 64 bit sparc: sparc for 32 bit, sparc64 for 64 bit @@ -63,7 +63,7 @@ CF is often used on the command-line like this: INSTALL_PATH -------------------------------------------------- INSTALL_PATH specifies where to place the updated kernel and system map -images. Default is /boot, but you can set it to other values +images. Default is /boot, but you can set it to other values. MODLIB @@ -90,7 +90,7 @@ INSTALL_MOD_STRIP will used as the options to the strip command. INSTALL_FW_PATH -------------------------------------------------- -INSTALL_FW_PATH specify where to install the firmware blobs. +INSTALL_FW_PATH specifies where to install the firmware blobs. The default value is: $(INSTALL_MOD_PATH)/lib/firmware @@ -99,7 +99,7 @@ The value can be overridden in which case the default value is ignored. INSTALL_HDR_PATH -------------------------------------------------- -INSTALL_HDR_PATH specify where to install user space headers when +INSTALL_HDR_PATH specifies where to install user space headers when executing "make headers_*". The default value is: @@ -112,22 +112,23 @@ The value can be overridden in which case the default value is ignored. KBUILD_MODPOST_WARN -------------------------------------------------- -KBUILD_MODPOST_WARN can be set to avoid error out in case of undefined -symbols in the final module linking stage. +KBUILD_MODPOST_WARN can be set to avoid errors in case of undefined +symbols in the final module linking stage. It changes such errors +into warnings. -KBUILD_MODPOST_FINAL +KBUILD_MODPOST_NOFINAL -------------------------------------------------- KBUILD_MODPOST_NOFINAL can be set to skip the final link of modules. -This is solely usefull to speed up test compiles. +This is solely useful to speed up test compiles. KBUILD_EXTRA_SYMBOLS -------------------------------------------------- -For modules use symbols from another modules. +For modules that use symbols from other modules. See more details in modules.txt. ALLSOURCE_ARCHS -------------------------------------------------- -For tags/TAGS/cscope targets, you can specify more than one archs -to be included in the databases, separated by blankspace. e.g. +For tags/TAGS/cscope targets, you can specify more than one arch +to be included in the databases, separated by blank space. E.g.: $ make ALLSOURCE_ARCHS="x86 mips arm" tags -- cgit v1.2.3 From 9abf0eea877d6107d3a8a5c6913450e961fb7050 Mon Sep 17 00:00:00 2001 From: Henrique de Moraes Holschuh Date: Sun, 11 Jan 2009 03:00:58 -0200 Subject: ACPI: thinkpad-acpi: update documents for the new location Update documentation to reflect the new location of the thinkpad-acpi driver. Signed-off-by: Henrique de Moraes Holschuh Signed-off-by: Len Brown --- Documentation/laptops/thinkpad-acpi.txt | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) (limited to 'Documentation') diff --git a/Documentation/laptops/thinkpad-acpi.txt b/Documentation/laptops/thinkpad-acpi.txt index 898b4987bb8..ddc371e0a1a 100644 --- a/Documentation/laptops/thinkpad-acpi.txt +++ b/Documentation/laptops/thinkpad-acpi.txt @@ -16,7 +16,8 @@ supported by the generic Linux ACPI drivers. This driver used to be named ibm-acpi until kernel 2.6.21 and release 0.13-20070314. It used to be in the drivers/acpi tree, but it was moved to the drivers/misc tree and renamed to thinkpad-acpi for kernel -2.6.22, and release 0.14. +2.6.22, and release 0.14. It was moved to drivers/platform/x86 for +kernel 2.6.29. The driver is named "thinkpad-acpi". In some places, like module names, "thinkpad_acpi" is used because of userspace issues. -- cgit v1.2.3 From 0045c0aa7d5e787f78938e6a10927b8a516f0b83 Mon Sep 17 00:00:00 2001 From: Henrique de Moraes Holschuh Date: Sun, 11 Jan 2009 03:01:03 -0200 Subject: ACPI: thinkpad-acpi: add UWB radio support Add rfkill support for USB UWB radio devices on very recent ThinkPad laptop models. The new subdriver is moslty a trimmed down copy of the wwan subdriver. Signed-off-by: Henrique de Moraes Holschuh Cc: Ivo van Doorn Signed-off-by: Len Brown --- Documentation/laptops/thinkpad-acpi.txt | 18 ++++++++++++++++++ 1 file changed, 18 insertions(+) (limited to 'Documentation') diff --git a/Documentation/laptops/thinkpad-acpi.txt b/Documentation/laptops/thinkpad-acpi.txt index ddc371e0a1a..91c00010b15 100644 --- a/Documentation/laptops/thinkpad-acpi.txt +++ b/Documentation/laptops/thinkpad-acpi.txt @@ -1413,6 +1413,24 @@ Sysfs notes: rfkill controller switch "tpacpi_wwan_sw": refer to Documentation/rfkill.txt for details. +EXPERIMENTAL: UWB +----------------- + +This feature is marked EXPERIMENTAL because it has not been extensively +tested and validated in various ThinkPad models yet. The feature may not +work as expected. USE WITH CAUTION! To use this feature, you need to supply +the experimental=1 parameter when loading the module. + +sysfs rfkill class: switch "tpacpi_uwb_sw" + +This feature exports an rfkill controller for the UWB device, if one is +present and enabled in the BIOS. + +Sysfs notes: + + rfkill controller switch "tpacpi_uwb_sw": refer to + Documentation/rfkill.txt for details. + Multiple Commands, Module Parameters ------------------------------------ -- cgit v1.2.3 From 175add1981e53d22caba8f42d5f924a4de507b6c Mon Sep 17 00:00:00 2001 From: John Keller Date: Mon, 24 Nov 2008 16:47:17 -0600 Subject: [IA64] SN specific version of dma_get_required_mask() Create a platform specific version of dma_get_required_mask() for ia64 SN Altix. All SN Altix platforms support 64 bit DMA addressing regardless of the size of system memory. Create an ia64 machvec for dma_get_required_mask, with the SN version unconditionally returning DMA_64BIT_MASK. Signed-off-by: John Keller Signed-off-by: Tony Luck --- Documentation/DMA-API.txt | 9 ++++----- 1 file changed, 4 insertions(+), 5 deletions(-) (limited to 'Documentation') diff --git a/Documentation/DMA-API.txt b/Documentation/DMA-API.txt index b462bb14954..52441694fe0 100644 --- a/Documentation/DMA-API.txt +++ b/Documentation/DMA-API.txt @@ -170,16 +170,15 @@ Returns: 0 if successful and a negative error if not. u64 dma_get_required_mask(struct device *dev) -After setting the mask with dma_set_mask(), this API returns the -actual mask (within that already set) that the platform actually -requires to operate efficiently. Usually this means the returned mask +This API returns the mask that the platform requires to +operate efficiently. Usually this means the returned mask is the minimum required to cover all of memory. Examining the required mask gives drivers with variable descriptor sizes the opportunity to use smaller descriptors as necessary. Requesting the required mask does not alter the current mask. If you -wish to take advantage of it, you should issue another dma_set_mask() -call to lower the mask again. +wish to take advantage of it, you should issue a dma_set_mask() +call to set the mask to the value returned. Part Id - Streaming DMA mappings -- cgit v1.2.3 From aa2fbcec07b0d594808bc3058692395d24eba66e Mon Sep 17 00:00:00 2001 From: Henrique de Moraes Holschuh Date: Sun, 11 Jan 2009 03:01:10 -0200 Subject: ACPI: thinkpad-acpi: bump up version to 0.22 It is about time to bump up the version. Features added since 0.21: fan suspend/resume support, preserve radio state across power off (for some radio types), built-in UWB radio rfkill support and thermal alarm events support. Signed-off-by: Henrique de Moraes Holschuh Signed-off-by: Len Brown --- Documentation/laptops/thinkpad-acpi.txt | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) (limited to 'Documentation') diff --git a/Documentation/laptops/thinkpad-acpi.txt b/Documentation/laptops/thinkpad-acpi.txt index 91c00010b15..41bc99fa188 100644 --- a/Documentation/laptops/thinkpad-acpi.txt +++ b/Documentation/laptops/thinkpad-acpi.txt @@ -1,7 +1,7 @@ ThinkPad ACPI Extras Driver - Version 0.21 - May 29th, 2008 + Version 0.22 + November 23rd, 2008 Borislav Deianov Henrique de Moraes Holschuh @@ -17,7 +17,7 @@ This driver used to be named ibm-acpi until kernel 2.6.21 and release 0.13-20070314. It used to be in the drivers/acpi tree, but it was moved to the drivers/misc tree and renamed to thinkpad-acpi for kernel 2.6.22, and release 0.14. It was moved to drivers/platform/x86 for -kernel 2.6.29. +kernel 2.6.29 and release 0.22. The driver is named "thinkpad-acpi". In some places, like module names, "thinkpad_acpi" is used because of userspace issues. -- cgit v1.2.3 From 1c301fc5394f7e1aa4c201e6e03d55d9c08b3bdf Mon Sep 17 00:00:00 2001 From: Jordan Crouse Date: Thu, 15 Jan 2009 22:27:47 +0100 Subject: hwmon: Add a driver for the ADT7475 hardware monitoring chip Hwmon driver for the ADT7475 chip. Signed-off-by: Jordan Crouse Signed-off-by: Hans de Goede Signed-off-by: Jean Delvare --- Documentation/hwmon/adt7475 | 87 +++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 87 insertions(+) create mode 100644 Documentation/hwmon/adt7475 (limited to 'Documentation') diff --git a/Documentation/hwmon/adt7475 b/Documentation/hwmon/adt7475 new file mode 100644 index 00000000000..a2b1abec850 --- /dev/null +++ b/Documentation/hwmon/adt7475 @@ -0,0 +1,87 @@ +This describes the interface for the ADT7475 driver: + +(there are 4 fans, numbered fan1 to fan4): + +fanX_input Read the current speed of the fan (in RPMs) +fanX_min Read/write the minimum speed of the fan. Dropping + below this sets an alarm. + +(there are three PWMs, numbered pwm1 to pwm3): + +pwmX Read/write the current duty cycle of the PWM. Writes + only have effect when auto mode is turned off (see + below). Range is 0 - 255. + +pwmX_enable Fan speed control method: + + 0 - No control (fan at full speed) + 1 - Manual fan speed control (using pwm[1-*]) + 2 - Automatic fan speed control + +pwmX_auto_channels_temp Select which channels affect this PWM + + 1 - TEMP1 controls PWM + 2 - TEMP2 controls PWM + 4 - TEMP3 controls PWM + 6 - TEMP2 and TEMP3 control PWM + 7 - All three inputs control PWM + +pwmX_freq Read/write the PWM frequency in Hz. The number + should be one of the following: + + 11 Hz + 14 Hz + 22 Hz + 29 Hz + 35 Hz + 44 Hz + 58 Hz + 88 Hz + +pwmX_auto_point1_pwm Read/write the minimum PWM duty cycle in automatic mode + +pwmX_auto_point2_pwm Read/write the maximum PWM duty cycle in automatic mode + +(there are three temperature settings numbered temp1 to temp3): + +tempX_input Read the current temperature. The value is in milli + degrees of Celsius. + +tempX_max Read/write the upper temperature limit - exceeding this + will cause an alarm. + +tempX_min Read/write the lower temperature limit - exceeding this + will cause an alarm. + +tempX_offset Read/write the temperature adjustment offset + +tempX_crit Read/write the THERM limit for remote1. + +tempX_crit_hyst Set the temperature value below crit where the + fans will stay on - this helps drive the temperature + low enough so it doesn't stay near the edge and + cause THERM to keep tripping. + +tempX_auto_point1_temp Read/write the minimum temperature where the fans will + turn on in automatic mode. + +tempX_auto_point2_temp Read/write the maximum temperature over which the fans + will run in automatic mode. tempX_auto_point1_temp + and tempX_auto_point2_temp together define the + range of automatic control. + +tempX_alarm Read a 1 if the max/min alarm is set +tempX_fault Read a 1 if either temp1 or temp3 diode has a fault + +(There are two voltage settings, in1 and in2): + +inX_input Read the current voltage on VCC. Value is in + millivolts. + +inX_min read/write the minimum voltage limit. + Dropping below this causes an alarm. + +inX_max read/write the maximum voltage limit. + Exceeding this causes an alarm. + +inX_alarm Read a 1 if the max/min alarm is set. -- cgit v1.2.3 From db0fb1848a645b0b1b033765f3a5244e7afd2e3c Mon Sep 17 00:00:00 2001 From: Peter W Morreale Date: Thu, 15 Jan 2009 13:50:42 -0800 Subject: Update of Documentation: vm.txt and proc.txt Update Documentation/sysctl/vm.txt and Documentation/filesystems/proc.txt. More specifically, the section on /proc/sys/vm in Documentation/filesystems/proc.txt was removed and a link to Documentation/sysctl/vm.txt added. Most of the verbiage from proc.txt was simply moved in vm.txt, with new addtional text for "swappiness" and "stat_interval". Signed-off-by: Peter W Morreale Acked-by: Randy Dunlap Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- Documentation/filesystems/proc.txt | 288 +---------------- Documentation/sysctl/vm.txt | 619 ++++++++++++++++++++++++++----------- 2 files changed, 437 insertions(+), 470 deletions(-) (limited to 'Documentation') diff --git a/Documentation/filesystems/proc.txt b/Documentation/filesystems/proc.txt index d105eb45282..bbebc3a43ac 100644 --- a/Documentation/filesystems/proc.txt +++ b/Documentation/filesystems/proc.txt @@ -1371,292 +1371,8 @@ auto_msgmni default value is 1. 2.4 /proc/sys/vm - The virtual memory subsystem ----------------------------------------------- -The files in this directory can be used to tune the operation of the virtual -memory (VM) subsystem of the Linux kernel. - -vfs_cache_pressure ------------------- - -Controls the tendency of the kernel to reclaim the memory which is used for -caching of directory and inode objects. - -At the default value of vfs_cache_pressure=100 the kernel will attempt to -reclaim dentries and inodes at a "fair" rate with respect to pagecache and -swapcache reclaim. Decreasing vfs_cache_pressure causes the kernel to prefer -to retain dentry and inode caches. Increasing vfs_cache_pressure beyond 100 -causes the kernel to prefer to reclaim dentries and inodes. - -dirty_background_bytes ----------------------- - -Contains the amount of dirty memory at which the pdflush background writeback -daemon will start writeback. - -If dirty_background_bytes is written, dirty_background_ratio becomes a function -of its value (dirty_background_bytes / the amount of dirtyable system memory). - -dirty_background_ratio ----------------------- - -Contains, as a percentage of the dirtyable system memory (free pages + mapped -pages + file cache, not including locked pages and HugePages), the number of -pages at which the pdflush background writeback daemon will start writing out -dirty data. - -If dirty_background_ratio is written, dirty_background_bytes becomes a function -of its value (dirty_background_ratio * the amount of dirtyable system memory). - -dirty_bytes ------------ - -Contains the amount of dirty memory at which a process generating disk writes -will itself start writeback. - -If dirty_bytes is written, dirty_ratio becomes a function of its value -(dirty_bytes / the amount of dirtyable system memory). - -dirty_ratio ------------ - -Contains, as a percentage of the dirtyable system memory (free pages + mapped -pages + file cache, not including locked pages and HugePages), the number of -pages at which a process which is generating disk writes will itself start -writing out dirty data. - -If dirty_ratio is written, dirty_bytes becomes a function of its value -(dirty_ratio * the amount of dirtyable system memory). - -dirty_writeback_centisecs -------------------------- - -The pdflush writeback daemons will periodically wake up and write `old' data -out to disk. This tunable expresses the interval between those wakeups, in -100'ths of a second. - -Setting this to zero disables periodic writeback altogether. - -dirty_expire_centisecs ----------------------- - -This tunable is used to define when dirty data is old enough to be eligible -for writeout by the pdflush daemons. It is expressed in 100'ths of a second. -Data which has been dirty in-memory for longer than this interval will be -written out next time a pdflush daemon wakes up. - -highmem_is_dirtyable --------------------- - -Only present if CONFIG_HIGHMEM is set. - -This defaults to 0 (false), meaning that the ratios set above are calculated -as a percentage of lowmem only. This protects against excessive scanning -in page reclaim, swapping and general VM distress. - -Setting this to 1 can be useful on 32 bit machines where you want to make -random changes within an MMAPed file that is larger than your available -lowmem without causing large quantities of random IO. Is is safe if the -behavior of all programs running on the machine is known and memory will -not be otherwise stressed. - -legacy_va_layout ----------------- - -If non-zero, this sysctl disables the new 32-bit mmap mmap layout - the kernel -will use the legacy (2.4) layout for all processes. - -lowmem_reserve_ratio ---------------------- - -For some specialised workloads on highmem machines it is dangerous for -the kernel to allow process memory to be allocated from the "lowmem" -zone. This is because that memory could then be pinned via the mlock() -system call, or by unavailability of swapspace. - -And on large highmem machines this lack of reclaimable lowmem memory -can be fatal. - -So the Linux page allocator has a mechanism which prevents allocations -which _could_ use highmem from using too much lowmem. This means that -a certain amount of lowmem is defended from the possibility of being -captured into pinned user memory. - -(The same argument applies to the old 16 megabyte ISA DMA region. This -mechanism will also defend that region from allocations which could use -highmem or lowmem). - -The `lowmem_reserve_ratio' tunable determines how aggressive the kernel is -in defending these lower zones. - -If you have a machine which uses highmem or ISA DMA and your -applications are using mlock(), or if you are running with no swap then -you probably should change the lowmem_reserve_ratio setting. - -The lowmem_reserve_ratio is an array. You can see them by reading this file. -- -% cat /proc/sys/vm/lowmem_reserve_ratio -256 256 32 -- -Note: # of this elements is one fewer than number of zones. Because the highest - zone's value is not necessary for following calculation. - -But, these values are not used directly. The kernel calculates # of protection -pages for each zones from them. These are shown as array of protection pages -in /proc/zoneinfo like followings. (This is an example of x86-64 box). -Each zone has an array of protection pages like this. - -- -Node 0, zone DMA - pages free 1355 - min 3 - low 3 - high 4 - : - : - numa_other 0 - protection: (0, 2004, 2004, 2004) - ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ - pagesets - cpu: 0 pcp: 0 - : -- -These protections are added to score to judge whether this zone should be used -for page allocation or should be reclaimed. - -In this example, if normal pages (index=2) are required to this DMA zone and -pages_high is used for watermark, the kernel judges this zone should not be -used because pages_free(1355) is smaller than watermark + protection[2] -(4 + 2004 = 2008). If this protection value is 0, this zone would be used for -normal page requirement. If requirement is DMA zone(index=0), protection[0] -(=0) is used. - -zone[i]'s protection[j] is calculated by following expression. - -(i < j): - zone[i]->protection[j] - = (total sums of present_pages from zone[i+1] to zone[j] on the node) - / lowmem_reserve_ratio[i]; -(i = j): - (should not be protected. = 0; -(i > j): - (not necessary, but looks 0) - -The default values of lowmem_reserve_ratio[i] are - 256 (if zone[i] means DMA or DMA32 zone) - 32 (others). -As above expression, they are reciprocal number of ratio. -256 means 1/256. # of protection pages becomes about "0.39%" of total present -pages of higher zones on the node. - -If you would like to protect more pages, smaller values are effective. -The minimum value is 1 (1/1 -> 100%). - -page-cluster ------------- - -page-cluster controls the number of pages which are written to swap in -a single attempt. The swap I/O size. - -It is a logarithmic value - setting it to zero means "1 page", setting -it to 1 means "2 pages", setting it to 2 means "4 pages", etc. - -The default value is three (eight pages at a time). There may be some -small benefits in tuning this to a different value if your workload is -swap-intensive. - -overcommit_memory ------------------ - -Controls overcommit of system memory, possibly allowing processes -to allocate (but not use) more memory than is actually available. - - -0 - Heuristic overcommit handling. Obvious overcommits of - address space are refused. Used for a typical system. It - ensures a seriously wild allocation fails while allowing - overcommit to reduce swap usage. root is allowed to - allocate slightly more memory in this mode. This is the - default. - -1 - Always overcommit. Appropriate for some scientific - applications. - -2 - Don't overcommit. The total address space commit - for the system is not permitted to exceed swap plus a - configurable percentage (default is 50) of physical RAM. - Depending on the percentage you use, in most situations - this means a process will not be killed while attempting - to use already-allocated memory but will receive errors - on memory allocation as appropriate. - -overcommit_ratio ----------------- - -Percentage of physical memory size to include in overcommit calculations -(see above.) - -Memory allocation limit = swapspace + physmem * (overcommit_ratio / 100) - - swapspace = total size of all swap areas - physmem = size of physical memory in system - -nr_hugepages and hugetlb_shm_group ----------------------------------- - -nr_hugepages configures number of hugetlb page reserved for the system. - -hugetlb_shm_group contains group id that is allowed to create SysV shared -memory segment using hugetlb page. - -hugepages_treat_as_movable --------------------------- - -This parameter is only useful when kernelcore= is specified at boot time to -create ZONE_MOVABLE for pages that may be reclaimed or migrated. Huge pages -are not movable so are not normally allocated from ZONE_MOVABLE. A non-zero -value written to hugepages_treat_as_movable allows huge pages to be allocated -from ZONE_MOVABLE. - -Once enabled, the ZONE_MOVABLE is treated as an area of memory the huge -pages pool can easily grow or shrink within. Assuming that applications are -not running that mlock() a lot of memory, it is likely the huge pages pool -can grow to the size of ZONE_MOVABLE by repeatedly entering the desired value -into nr_hugepages and triggering page reclaim. - -laptop_mode ------------ - -laptop_mode is a knob that controls "laptop mode". All the things that are -controlled by this knob are discussed in Documentation/laptops/laptop-mode.txt. - -block_dump ----------- - -block_dump enables block I/O debugging when set to a nonzero value. More -information on block I/O debugging is in Documentation/laptops/laptop-mode.txt. - -swap_token_timeout ------------------- - -This file contains valid hold time of swap out protection token. The Linux -VM has token based thrashing control mechanism and uses the token to prevent -unnecessary page faults in thrashing situation. The unit of the value is -second. The value would be useful to tune thrashing behavior. - -drop_caches ------------ - -Writing to this will cause the kernel to drop clean caches, dentries and -inodes from memory, causing that memory to become free. - -To free pagecache: - echo 1 > /proc/sys/vm/drop_caches -To free dentries and inodes: - echo 2 > /proc/sys/vm/drop_caches -To free pagecache, dentries and inodes: - echo 3 > /proc/sys/vm/drop_caches - -As this is a non-destructive operation and dirty objects are not freeable, the -user should run `sync' first. +Please see: Documentation/sysctls/vm.txt for a description of these +entries. 2.5 /proc/sys/dev - Device specific parameters diff --git a/Documentation/sysctl/vm.txt b/Documentation/sysctl/vm.txt index a3415070bca..3197fc83bc5 100644 --- a/Documentation/sysctl/vm.txt +++ b/Documentation/sysctl/vm.txt @@ -1,12 +1,13 @@ -Documentation for /proc/sys/vm/* kernel version 2.2.10 +Documentation for /proc/sys/vm/* kernel version 2.6.29 (c) 1998, 1999, Rik van Riel + (c) 2008 Peter W. Morreale For general info and legal blurb, please look in README. ============================================================== This file contains the documentation for the sysctl files in -/proc/sys/vm and is valid for Linux kernel version 2.2. +/proc/sys/vm and is valid for Linux kernel version 2.6.29. The files in this directory can be used to tune the operation of the virtual memory (VM) subsystem of the Linux kernel and @@ -16,180 +17,274 @@ Default values and initialization routines for most of these files can be found in mm/swap.c. Currently, these files are in /proc/sys/vm: -- overcommit_memory -- page-cluster -- dirty_ratio + +- block_dump +- dirty_background_bytes - dirty_background_ratio +- dirty_bytes - dirty_expire_centisecs +- dirty_ratio - dirty_writeback_centisecs -- highmem_is_dirtyable (only if CONFIG_HIGHMEM set) +- drop_caches +- hugepages_treat_as_movable +- hugetlb_shm_group +- laptop_mode +- legacy_va_layout +- lowmem_reserve_ratio - max_map_count - min_free_kbytes -- laptop_mode -- block_dump -- drop-caches -- zone_reclaim_mode -- min_unmapped_ratio - min_slab_ratio -- panic_on_oom -- oom_dump_tasks -- oom_kill_allocating_task -- mmap_min_address -- numa_zonelist_order +- min_unmapped_ratio +- mmap_min_addr - nr_hugepages - nr_overcommit_hugepages -- nr_trim_pages (only if CONFIG_MMU=n) +- nr_pdflush_threads +- nr_trim_pages (only if CONFIG_MMU=n) +- numa_zonelist_order +- oom_dump_tasks +- oom_kill_allocating_task +- overcommit_memory +- overcommit_ratio +- page-cluster +- panic_on_oom +- percpu_pagelist_fraction +- stat_interval +- swappiness +- vfs_cache_pressure +- zone_reclaim_mode + ============================================================== -dirty_bytes, dirty_ratio, dirty_background_bytes, -dirty_background_ratio, dirty_expire_centisecs, -dirty_writeback_centisecs, highmem_is_dirtyable, -vfs_cache_pressure, laptop_mode, block_dump, swap_token_timeout, -drop-caches, hugepages_treat_as_movable: +block_dump -See Documentation/filesystems/proc.txt +block_dump enables block I/O debugging when set to a nonzero value. More +information on block I/O debugging is in Documentation/laptops/laptop-mode.txt. ============================================================== -overcommit_memory: +dirty_background_bytes -This value contains a flag that enables memory overcommitment. +Contains the amount of dirty memory at which the pdflush background writeback +daemon will start writeback. -When this flag is 0, the kernel attempts to estimate the amount -of free memory left when userspace requests more memory. +If dirty_background_bytes is written, dirty_background_ratio becomes a function +of its value (dirty_background_bytes / the amount of dirtyable system memory). -When this flag is 1, the kernel pretends there is always enough -memory until it actually runs out. +============================================================== -When this flag is 2, the kernel uses a "never overcommit" -policy that attempts to prevent any overcommit of memory. +dirty_background_ratio -This feature can be very useful because there are a lot of -programs that malloc() huge amounts of memory "just-in-case" -and don't use much of it. +Contains, as a percentage of total system memory, the number of pages at which +the pdflush background writeback daemon will start writing out dirty data. -The default value is 0. +============================================================== -See Documentation/vm/overcommit-accounting and -security/commoncap.c::cap_vm_enough_memory() for more information. +dirty_bytes + +Contains the amount of dirty memory at which a process generating disk writes +will itself start writeback. + +If dirty_bytes is written, dirty_ratio becomes a function of its value +(dirty_bytes / the amount of dirtyable system memory). ============================================================== -overcommit_ratio: +dirty_expire_centisecs -When overcommit_memory is set to 2, the committed address -space is not permitted to exceed swap plus this percentage -of physical RAM. See above. +This tunable is used to define when dirty data is old enough to be eligible +for writeout by the pdflush daemons. It is expressed in 100'ths of a second. +Data which has been dirty in-memory for longer than this interval will be +written out next time a pdflush daemon wakes up. + +============================================================== + +dirty_ratio + +Contains, as a percentage of total system memory, the number of pages at which +a process which is generating disk writes will itself start writing out dirty +data. ============================================================== -page-cluster: +dirty_writeback_centisecs -The Linux VM subsystem avoids excessive disk seeks by reading -multiple pages on a page fault. The number of pages it reads -is dependent on the amount of memory in your machine. +The pdflush writeback daemons will periodically wake up and write `old' data +out to disk. This tunable expresses the interval between those wakeups, in +100'ths of a second. -The number of pages the kernel reads in at once is equal to -2 ^ page-cluster. Values above 2 ^ 5 don't make much sense -for swap because we only cluster swap data in 32-page groups. +Setting this to zero disables periodic writeback altogether. ============================================================== -max_map_count: +drop_caches -This file contains the maximum number of memory map areas a process -may have. Memory map areas are used as a side-effect of calling -malloc, directly by mmap and mprotect, and also when loading shared -libraries. +Writing to this will cause the kernel to drop clean caches, dentries and +inodes from memory, causing that memory to become free. -While most applications need less than a thousand maps, certain -programs, particularly malloc debuggers, may consume lots of them, -e.g., up to one or two maps per allocation. +To free pagecache: + echo 1 > /proc/sys/vm/drop_caches +To free dentries and inodes: + echo 2 > /proc/sys/vm/drop_caches +To free pagecache, dentries and inodes: + echo 3 > /proc/sys/vm/drop_caches -The default value is 65536. +As this is a non-destructive operation and dirty objects are not freeable, the +user should run `sync' first. ============================================================== -min_free_kbytes: +hugepages_treat_as_movable -This is used to force the Linux VM to keep a minimum number -of kilobytes free. The VM uses this number to compute a pages_min -value for each lowmem zone in the system. Each lowmem zone gets -a number of reserved free pages based proportionally on its size. +This parameter is only useful when kernelcore= is specified at boot time to +create ZONE_MOVABLE for pages that may be reclaimed or migrated. Huge pages +are not movable so are not normally allocated from ZONE_MOVABLE. A non-zero +value written to hugepages_treat_as_movable allows huge pages to be allocated +from ZONE_MOVABLE. -Some minimal amount of memory is needed to satisfy PF_MEMALLOC -allocations; if you set this to lower than 1024KB, your system will -become subtly broken, and prone to deadlock under high loads. - -Setting this too high will OOM your machine instantly. +Once enabled, the ZONE_MOVABLE is treated as an area of memory the huge +pages pool can easily grow or shrink within. Assuming that applications are +not running that mlock() a lot of memory, it is likely the huge pages pool +can grow to the size of ZONE_MOVABLE by repeatedly entering the desired value +into nr_hugepages and triggering page reclaim. ============================================================== -percpu_pagelist_fraction +hugetlb_shm_group -This is the fraction of pages at most (high mark pcp->high) in each zone that -are allocated for each per cpu page list. The min value for this is 8. It -means that we don't allow more than 1/8th of pages in each zone to be -allocated in any single per_cpu_pagelist. This entry only changes the value -of hot per cpu pagelists. User can specify a number like 100 to allocate -1/100th of each zone to each per cpu page list. +hugetlb_shm_group contains group id that is allowed to create SysV +shared memory segment using hugetlb page. -The batch value of each per cpu pagelist is also updated as a result. It is -set to pcp->high/4. The upper limit of batch is (PAGE_SHIFT * 8) +============================================================== -The initial value is zero. Kernel does not use this value at boot time to set -the high water marks for each per cpu page list. +laptop_mode -=============================================================== +laptop_mode is a knob that controls "laptop mode". All the things that are +controlled by this knob are discussed in Documentation/laptops/laptop-mode.txt. -zone_reclaim_mode: +============================================================== -Zone_reclaim_mode allows someone to set more or less aggressive approaches to -reclaim memory when a zone runs out of memory. If it is set to zero then no -zone reclaim occurs. Allocations will be satisfied from other zones / nodes -in the system. +legacy_va_layout -This is value ORed together of +If non-zero, this sysctl disables the new 32-bit mmap mmap layout - the kernel +will use the legacy (2.4) layout for all processes. -1 = Zone reclaim on -2 = Zone reclaim writes dirty pages out -4 = Zone reclaim swaps pages +============================================================== -zone_reclaim_mode is set during bootup to 1 if it is determined that pages -from remote zones will cause a measurable performance reduction. The -page allocator will then reclaim easily reusable pages (those page -cache pages that are currently not used) before allocating off node pages. +lowmem_reserve_ratio + +For some specialised workloads on highmem machines it is dangerous for +the kernel to allow process memory to be allocated from the "lowmem" +zone. This is because that memory could then be pinned via the mlock() +system call, or by unavailability of swapspace. + +And on large highmem machines this lack of reclaimable lowmem memory +can be fatal. + +So the Linux page allocator has a mechanism which prevents allocations +which _could_ use highmem from using too much lowmem. This means that +a certain amount of lowmem is defended from the possibility of being +captured into pinned user memory. + +(The same argument applies to the old 16 megabyte ISA DMA region. This +mechanism will also defend that region from allocations which could use +highmem or lowmem). + +The `lowmem_reserve_ratio' tunable determines how aggressive the kernel is +in defending these lower zones. + +If you have a machine which uses highmem or ISA DMA and your +applications are using mlock(), or if you are running with no swap then +you probably should change the lowmem_reserve_ratio setting. + +The lowmem_reserve_ratio is an array. You can see them by reading this file. +- +% cat /proc/sys/vm/lowmem_reserve_ratio +256 256 32 +- +Note: # of this elements is one fewer than number of zones. Because the highest + zone's value is not necessary for following calculation. + +But, these values are not used directly. The kernel calculates # of protection +pages for each zones from them. These are shown as array of protection pages +in /proc/zoneinfo like followings. (This is an example of x86-64 box). +Each zone has an array of protection pages like this. + +- +Node 0, zone DMA + pages free 1355 + min 3 + low 3 + high 4 + : + : + numa_other 0 + protection: (0, 2004, 2004, 2004) + ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ + pagesets + cpu: 0 pcp: 0 + : +- +These protections are added to score to judge whether this zone should be used +for page allocation or should be reclaimed. + +In this example, if normal pages (index=2) are required to this DMA zone and +pages_high is used for watermark, the kernel judges this zone should not be +used because pages_free(1355) is smaller than watermark + protection[2] +(4 + 2004 = 2008). If this protection value is 0, this zone would be used for +normal page requirement. If requirement is DMA zone(index=0), protection[0] +(=0) is used. + +zone[i]'s protection[j] is calculated by following expression. + +(i < j): + zone[i]->protection[j] + = (total sums of present_pages from zone[i+1] to zone[j] on the node) + / lowmem_reserve_ratio[i]; +(i = j): + (should not be protected. = 0; +(i > j): + (not necessary, but looks 0) + +The default values of lowmem_reserve_ratio[i] are + 256 (if zone[i] means DMA or DMA32 zone) + 32 (others). +As above expression, they are reciprocal number of ratio. +256 means 1/256. # of protection pages becomes about "0.39%" of total present +pages of higher zones on the node. + +If you would like to protect more pages, smaller values are effective. +The minimum value is 1 (1/1 -> 100%). -It may be beneficial to switch off zone reclaim if the system is -used for a file server and all of memory should be used for caching files -from disk. In that case the caching effect is more important than -data locality. +============================================================== -Allowing zone reclaim to write out pages stops processes that are -writing large amounts of data from dirtying pages on other nodes. Zone -reclaim will write out dirty pages if a zone fills up and so effectively -throttle the process. This may decrease the performance of a single process -since it cannot use all of system memory to buffer the outgoing writes -anymore but it preserve the memory on other nodes so that the performance -of other processes running on other nodes will not be affected. +max_map_count: -Allowing regular swap effectively restricts allocations to the local -node unless explicitly overridden by memory policies or cpuset -configurations. +This file contains the maximum number of memory map areas a process +may have. Memory map areas are used as a side-effect of calling +malloc, directly by mmap and mprotect, and also when loading shared +libraries. -============================================================= +While most applications need less than a thousand maps, certain +programs, particularly malloc debuggers, may consume lots of them, +e.g., up to one or two maps per allocation. -min_unmapped_ratio: +The default value is 65536. -This is available only on NUMA kernels. +============================================================== -A percentage of the total pages in each zone. Zone reclaim will only -occur if more than this percentage of pages are file backed and unmapped. -This is to insure that a minimal amount of local pages is still available for -file I/O even if the node is overallocated. +min_free_kbytes: -The default is 1 percent. +This is used to force the Linux VM to keep a minimum number +of kilobytes free. The VM uses this number to compute a pages_min +value for each lowmem zone in the system. Each lowmem zone gets +a number of reserved free pages based proportionally on its size. + +Some minimal amount of memory is needed to satisfy PF_MEMALLOC +allocations; if you set this to lower than 1024KB, your system will +become subtly broken, and prone to deadlock under high loads. + +Setting this too high will OOM your machine instantly. ============================================================= @@ -211,82 +306,73 @@ and may not be fast. ============================================================= -panic_on_oom +min_unmapped_ratio: -This enables or disables panic on out-of-memory feature. +This is available only on NUMA kernels. -If this is set to 0, the kernel will kill some rogue process, -called oom_killer. Usually, oom_killer can kill rogue processes and -system will survive. +A percentage of the total pages in each zone. Zone reclaim will only +occur if more than this percentage of pages are file backed and unmapped. +This is to insure that a minimal amount of local pages is still available for +file I/O even if the node is overallocated. -If this is set to 1, the kernel panics when out-of-memory happens. -However, if a process limits using nodes by mempolicy/cpusets, -and those nodes become memory exhaustion status, one process -may be killed by oom-killer. No panic occurs in this case. -Because other nodes' memory may be free. This means system total status -may be not fatal yet. +The default is 1 percent. -If this is set to 2, the kernel panics compulsorily even on the -above-mentioned. +============================================================== -The default value is 0. -1 and 2 are for failover of clustering. Please select either -according to your policy of failover. +mmap_min_addr -============================================================= +This file indicates the amount of address space which a user process will +be restricted from mmaping. Since kernel null dereference bugs could +accidentally operate based on the information in the first couple of pages +of memory userspace processes should not be allowed to write to them. By +default this value is set to 0 and no protections will be enforced by the +security module. Setting this value to something like 64k will allow the +vast majority of applications to work correctly and provide defense in depth +against future potential kernel bugs. -oom_dump_tasks +============================================================== -Enables a system-wide task dump (excluding kernel threads) to be -produced when the kernel performs an OOM-killing and includes such -information as pid, uid, tgid, vm size, rss, cpu, oom_adj score, and -name. This is helpful to determine why the OOM killer was invoked -and to identify the rogue task that caused it. +nr_hugepages -If this is set to zero, this information is suppressed. On very -large systems with thousands of tasks it may not be feasible to dump -the memory state information for each one. Such systems should not -be forced to incur a performance penalty in OOM conditions when the -information may not be desired. +Change the minimum size of the hugepage pool. -If this is set to non-zero, this information is shown whenever the -OOM killer actually kills a memory-hogging task. +See Documentation/vm/hugetlbpage.txt -The default value is 0. +============================================================== -============================================================= +nr_overcommit_hugepages -oom_kill_allocating_task +Change the maximum size of the hugepage pool. The maximum is +nr_hugepages + nr_overcommit_hugepages. -This enables or disables killing the OOM-triggering task in -out-of-memory situations. +See Documentation/vm/hugetlbpage.txt -If this is set to zero, the OOM killer will scan through the entire -tasklist and select a task based on heuristics to kill. This normally -selects a rogue memory-hogging task that frees up a large amount of -memory when killed. +============================================================== -If this is set to non-zero, the OOM killer simply kills the task that -triggered the out-of-memory condition. This avoids the expensive -tasklist scan. +nr_pdflush_threads -If panic_on_oom is selected, it takes precedence over whatever value -is used in oom_kill_allocating_task. +The current number of pdflush threads. This value is read-only. +The value changes according to the number of dirty pages in the system. -The default value is 0. +When neccessary, additional pdflush threads are created, one per second, up to +nr_pdflush_threads_max. ============================================================== -mmap_min_addr +nr_trim_pages -This file indicates the amount of address space which a user process will -be restricted from mmaping. Since kernel null dereference bugs could -accidentally operate based on the information in the first couple of pages -of memory userspace processes should not be allowed to write to them. By -default this value is set to 0 and no protections will be enforced by the -security module. Setting this value to something like 64k will allow the -vast majority of applications to work correctly and provide defense in depth -against future potential kernel bugs. +This is available only on NOMMU kernels. + +This value adjusts the excess page trimming behaviour of power-of-2 aligned +NOMMU mmap allocations. + +A value of 0 disables trimming of allocations entirely, while a value of 1 +trims excess pages aggressively. Any value >= 1 acts as the watermark where +trimming of allocations is initiated. + +The default value is 1. + +See Documentation/nommu-mmap.txt for more information. ============================================================== @@ -335,34 +421,199 @@ this is causing problems for your system/application. ============================================================== -nr_hugepages +oom_dump_tasks -Change the minimum size of the hugepage pool. +Enables a system-wide task dump (excluding kernel threads) to be +produced when the kernel performs an OOM-killing and includes such +information as pid, uid, tgid, vm size, rss, cpu, oom_adj score, and +name. This is helpful to determine why the OOM killer was invoked +and to identify the rogue task that caused it. -See Documentation/vm/hugetlbpage.txt +If this is set to zero, this information is suppressed. On very +large systems with thousands of tasks it may not be feasible to dump +the memory state information for each one. Such systems should not +be forced to incur a performance penalty in OOM conditions when the +information may not be desired. + +If this is set to non-zero, this information is shown whenever the +OOM killer actually kills a memory-hogging task. + +The default value is 0. ============================================================== -nr_overcommit_hugepages +oom_kill_allocating_task -Change the maximum size of the hugepage pool. The maximum is -nr_hugepages + nr_overcommit_hugepages. +This enables or disables killing the OOM-triggering task in +out-of-memory situations. -See Documentation/vm/hugetlbpage.txt +If this is set to zero, the OOM killer will scan through the entire +tasklist and select a task based on heuristics to kill. This normally +selects a rogue memory-hogging task that frees up a large amount of +memory when killed. + +If this is set to non-zero, the OOM killer simply kills the task that +triggered the out-of-memory condition. This avoids the expensive +tasklist scan. + +If panic_on_oom is selected, it takes precedence over whatever value +is used in oom_kill_allocating_task. + +The default value is 0. ============================================================== -nr_trim_pages +overcommit_memory: -This is available only on NOMMU kernels. +This value contains a flag that enables memory overcommitment. -This value adjusts the excess page trimming behaviour of power-of-2 aligned -NOMMU mmap allocations. +When this flag is 0, the kernel attempts to estimate the amount +of free memory left when userspace requests more memory. -A value of 0 disables trimming of allocations entirely, while a value of 1 -trims excess pages aggressively. Any value >= 1 acts as the watermark where -trimming of allocations is initiated. +When this flag is 1, the kernel pretends there is always enough +memory until it actually runs out. -The default value is 1. +When this flag is 2, the kernel uses a "never overcommit" +policy that attempts to prevent any overcommit of memory. -See Documentation/nommu-mmap.txt for more information. +This feature can be very useful because there are a lot of +programs that malloc() huge amounts of memory "just-in-case" +and don't use much of it. + +The default value is 0. + +See Documentation/vm/overcommit-accounting and +security/commoncap.c::cap_vm_enough_memory() for more information. + +============================================================== + +overcommit_ratio: + +When overcommit_memory is set to 2, the committed address +space is not permitted to exceed swap plus this percentage +of physical RAM. See above. + +============================================================== + +page-cluster + +page-cluster controls the number of pages which are written to swap in +a single attempt. The swap I/O size. + +It is a logarithmic value - setting it to zero means "1 page", setting +it to 1 means "2 pages", setting it to 2 means "4 pages", etc. + +The default value is three (eight pages at a time). There may be some +small benefits in tuning this to a different value if your workload is +swap-intensive. + +============================================================= + +panic_on_oom + +This enables or disables panic on out-of-memory feature. + +If this is set to 0, the kernel will kill some rogue process, +called oom_killer. Usually, oom_killer can kill rogue processes and +system will survive. + +If this is set to 1, the kernel panics when out-of-memory happens. +However, if a process limits using nodes by mempolicy/cpusets, +and those nodes become memory exhaustion status, one process +may be killed by oom-killer. No panic occurs in this case. +Because other nodes' memory may be free. This means system total status +may be not fatal yet. + +If this is set to 2, the kernel panics compulsorily even on the +above-mentioned. + +The default value is 0. +1 and 2 are for failover of clustering. Please select either +according to your policy of failover. + +============================================================= + +percpu_pagelist_fraction + +This is the fraction of pages at most (high mark pcp->high) in each zone that +are allocated for each per cpu page list. The min value for this is 8. It +means that we don't allow more than 1/8th of pages in each zone to be +allocated in any single per_cpu_pagelist. This entry only changes the value +of hot per cpu pagelists. User can specify a number like 100 to allocate +1/100th of each zone to each per cpu page list. + +The batch value of each per cpu pagelist is also updated as a result. It is +set to pcp->high/4. The upper limit of batch is (PAGE_SHIFT * 8) + +The initial value is zero. Kernel does not use this value at boot time to set +the high water marks for each per cpu page list. + +============================================================== + +stat_interval + +The time interval between which vm statistics are updated. The default +is 1 second. + +============================================================== + +swappiness + +This control is used to define how aggressive the kernel will swap +memory pages. Higher values will increase agressiveness, lower values +descrease the amount of swap. + +The default value is 60. + +============================================================== + +vfs_cache_pressure +------------------ + +Controls the tendency of the kernel to reclaim the memory which is used for +caching of directory and inode objects. + +At the default value of vfs_cache_pressure=100 the kernel will attempt to +reclaim dentries and inodes at a "fair" rate with respect to pagecache and +swapcache reclaim. Decreasing vfs_cache_pressure causes the kernel to prefer +to retain dentry and inode caches. Increasing vfs_cache_pressure beyond 100 +causes the kernel to prefer to reclaim dentries and inodes. + +============================================================== + +zone_reclaim_mode: + +Zone_reclaim_mode allows someone to set more or less aggressive approaches to +reclaim memory when a zone runs out of memory. If it is set to zero then no +zone reclaim occurs. Allocations will be satisfied from other zones / nodes +in the system. + +This is value ORed together of + +1 = Zone reclaim on +2 = Zone reclaim writes dirty pages out +4 = Zone reclaim swaps pages + +zone_reclaim_mode is set during bootup to 1 if it is determined that pages +from remote zones will cause a measurable performance reduction. The +page allocator will then reclaim easily reusable pages (those page +cache pages that are currently not used) before allocating off node pages. + +It may be beneficial to switch off zone reclaim if the system is +used for a file server and all of memory should be used for caching files +from disk. In that case the caching effect is more important than +data locality. + +Allowing zone reclaim to write out pages stops processes that are +writing large amounts of data from dirtying pages on other nodes. Zone +reclaim will write out dirty pages if a zone fills up and so effectively +throttle the process. This may decrease the performance of a single process +since it cannot use all of system memory to buffer the outgoing writes +anymore but it preserve the memory on other nodes so that the performance +of other processes running on other nodes will not be affected. + +Allowing regular swap effectively restricts allocations to the local +node unless explicitly overridden by memory policies or cpuset +configurations. + +============ End of Document ================================= -- cgit v1.2.3 From 89365e264104b52da6a61c4e227bb5a934764fa7 Mon Sep 17 00:00:00 2001 From: Andy Whitcroft Date: Thu, 15 Jan 2009 13:50:50 -0800 Subject: sysrq documentation: remove the redundant updated date git is maintaining the last update time much more accuratly than the internal update time. Remove it. Signed-off-by: Andy Whitcroft Cc: Randy Dunlap Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- Documentation/sysrq.txt | 1 - 1 file changed, 1 deletion(-) (limited to 'Documentation') diff --git a/Documentation/sysrq.txt b/Documentation/sysrq.txt index 10a0263ebb3..265f637b97d 100644 --- a/Documentation/sysrq.txt +++ b/Documentation/sysrq.txt @@ -1,6 +1,5 @@ Linux Magic System Request Key Hacks Documentation for sysrq.c -Last update: 2007-AUG-04 * What is the magic SysRq key? ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ -- cgit v1.2.3 From 47c33d9c1984ae4c5bd1f144024eacc14c5bc0c0 Mon Sep 17 00:00:00 2001 From: Andy Whitcroft Date: Thu, 15 Jan 2009 13:50:51 -0800 Subject: sysrq documentation: document why the command header only is shown Document the interactions between loglevel and the sysrq output. Also document how to work round it should output be required on the console. Signed-off-by: Andy Whitcroft Cc: Martin Mares Cc: Randy Dunlap Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- Documentation/sysrq.txt | 18 ++++++++++++++++++ 1 file changed, 18 insertions(+) (limited to 'Documentation') diff --git a/Documentation/sysrq.txt b/Documentation/sysrq.txt index 265f637b97d..9e592c718af 100644 --- a/Documentation/sysrq.txt +++ b/Documentation/sysrq.txt @@ -210,6 +210,24 @@ within a function called by handle_sysrq, you must be aware that you are in a lock (you are also in an interrupt handler, which means don't sleep!), so you must call __handle_sysrq_nolock instead. +* When I hit a SysRq key combination only the header appears on the console? +~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ +Sysrq output is subject to the same console loglevel control as all +other console output. This means that if the kernel was booted 'quiet' +as is common on distro kernels the output may not appear on the actual +console, even though it will appear in the dmesg buffer, and be accessible +via the dmesg command and to the consumers of /proc/kmsg. As a specific +exception the header line from the sysrq command is passed to all console +consumers as if the current loglevel was maximum. If only the header +is emitted it is almost certain that the kernel loglevel is too low. +Should you require the output on the console channel then you will need +to temporarily up the console loglevel using alt-sysrq-8 or: + + echo 8 > /proc/sysrq-trigger + +Remember to return the loglevel to normal after triggering the sysrq +command you are interested in. + * I have more questions, who can I ask? ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ And I'll answer any questions about the registration system you got, also -- cgit v1.2.3 From 45ce80fb6b6f9594d1396d44dd7e7c02d596fef8 Mon Sep 17 00:00:00 2001 From: Li Zefan Date: Thu, 15 Jan 2009 13:50:59 -0800 Subject: cgroups: consolidate cgroup documents Move Documentation/cpusets.txt and Documentation/controllers/* to Documentation/cgroups/ Signed-off-by: Li Zefan Acked-by: KAMEZAWA Hiroyuki Acked-by: Balbir Singh Acked-by: Paul Menage Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- Documentation/cgroups/cgroups.txt | 5 +- Documentation/cgroups/cpuacct.txt | 32 + Documentation/cgroups/cpusets.txt | 808 +++++++++++++++++++++++++ Documentation/cgroups/devices.txt | 52 ++ Documentation/cgroups/memcg_test.txt | 342 +++++++++++ Documentation/cgroups/memory.txt | 399 ++++++++++++ Documentation/cgroups/resource_counter.txt | 181 ++++++ Documentation/controllers/cpuacct.txt | 32 - Documentation/controllers/devices.txt | 52 -- Documentation/controllers/memcg_test.txt | 342 ----------- Documentation/controllers/memory.txt | 399 ------------ Documentation/controllers/resource_counter.txt | 181 ------ Documentation/cpusets.txt | 808 ------------------------- Documentation/scheduler/sched-design-CFS.txt | 2 +- 14 files changed, 1818 insertions(+), 1817 deletions(-) create mode 100644 Documentation/cgroups/cpuacct.txt create mode 100644 Documentation/cgroups/cpusets.txt create mode 100644 Documentation/cgroups/devices.txt create mode 100644 Documentation/cgroups/memcg_test.txt create mode 100644 Documentation/cgroups/memory.txt create mode 100644 Documentation/cgroups/resource_counter.txt delete mode 100644 Documentation/controllers/cpuacct.txt delete mode 100644 Documentation/controllers/devices.txt delete mode 100644 Documentation/controllers/memcg_test.txt delete mode 100644 Documentation/controllers/memory.txt delete mode 100644 Documentation/controllers/resource_counter.txt delete mode 100644 Documentation/cpusets.txt (limited to 'Documentation') diff --git a/Documentation/cgroups/cgroups.txt b/Documentation/cgroups/cgroups.txt index e33ee74eee7..d9e5d6f41b9 100644 --- a/Documentation/cgroups/cgroups.txt +++ b/Documentation/cgroups/cgroups.txt @@ -1,7 +1,8 @@ CGROUPS ------- -Written by Paul Menage based on Documentation/cpusets.txt +Written by Paul Menage based on +Documentation/cgroups/cpusets.txt Original copyright statements from cpusets.txt: Portions Copyright (C) 2004 BULL SA. @@ -68,7 +69,7 @@ On their own, the only use for cgroups is for simple job tracking. The intention is that other subsystems hook into the generic cgroup support to provide new attributes for cgroups, such as accounting/limiting the resources which processes in a cgroup can -access. For example, cpusets (see Documentation/cpusets.txt) allows +access. For example, cpusets (see Documentation/cgroups/cpusets.txt) allows you to associate a set of CPUs and a set of memory nodes with the tasks in each cgroup. diff --git a/Documentation/cgroups/cpuacct.txt b/Documentation/cgroups/cpuacct.txt new file mode 100644 index 00000000000..bb775fbe43d --- /dev/null +++ b/Documentation/cgroups/cpuacct.txt @@ -0,0 +1,32 @@ +CPU Accounting Controller +------------------------- + +The CPU accounting controller is used to group tasks using cgroups and +account the CPU usage of these groups of tasks. + +The CPU accounting controller supports multi-hierarchy groups. An accounting +group accumulates the CPU usage of all of its child groups and the tasks +directly present in its group. + +Accounting groups can be created by first mounting the cgroup filesystem. + +# mkdir /cgroups +# mount -t cgroup -ocpuacct none /cgroups + +With the above step, the initial or the parent accounting group +becomes visible at /cgroups. At bootup, this group includes all the +tasks in the system. /cgroups/tasks lists the tasks in this cgroup. +/cgroups/cpuacct.usage gives the CPU time (in nanoseconds) obtained by +this group which is essentially the CPU time obtained by all the tasks +in the system. + +New accounting groups can be created under the parent group /cgroups. + +# cd /cgroups +# mkdir g1 +# echo $$ > g1 + +The above steps create a new group g1 and move the current shell +process (bash) into it. CPU time consumed by this bash and its children +can be obtained from g1/cpuacct.usage and the same is accumulated in +/cgroups/cpuacct.usage also. diff --git a/Documentation/cgroups/cpusets.txt b/Documentation/cgroups/cpusets.txt new file mode 100644 index 00000000000..5c86c258c79 --- /dev/null +++ b/Documentation/cgroups/cpusets.txt @@ -0,0 +1,808 @@ + CPUSETS + ------- + +Copyright (C) 2004 BULL SA. +Written by Simon.Derr@bull.net + +Portions Copyright (c) 2004-2006 Silicon Graphics, Inc. +Modified by Paul Jackson +Modified by Christoph Lameter +Modified by Paul Menage +Modified by Hidetoshi Seto + +CONTENTS: +========= + +1. Cpusets + 1.1 What are cpusets ? + 1.2 Why are cpusets needed ? + 1.3 How are cpusets implemented ? + 1.4 What are exclusive cpusets ? + 1.5 What is memory_pressure ? + 1.6 What is memory spread ? + 1.7 What is sched_load_balance ? + 1.8 What is sched_relax_domain_level ? + 1.9 How do I use cpusets ? +2. Usage Examples and Syntax + 2.1 Basic Usage + 2.2 Adding/removing cpus + 2.3 Setting flags + 2.4 Attaching processes +3. Questions +4. Contact + +1. Cpusets +========== + +1.1 What are cpusets ? +---------------------- + +Cpusets provide a mechanism for assigning a set of CPUs and Memory +Nodes to a set of tasks. In this document "Memory Node" refers to +an on-line node that contains memory. + +Cpusets constrain the CPU and Memory placement of tasks to only +the resources within a tasks current cpuset. They form a nested +hierarchy visible in a virtual file system. These are the essential +hooks, beyond what is already present, required to manage dynamic +job placement on large systems. + +Cpusets use the generic cgroup subsystem described in +Documentation/cgroups/cgroups.txt. + +Requests by a task, using the sched_setaffinity(2) system call to +include CPUs in its CPU affinity mask, and using the mbind(2) and +set_mempolicy(2) system calls to include Memory Nodes in its memory +policy, are both filtered through that tasks cpuset, filtering out any +CPUs or Memory Nodes not in that cpuset. The scheduler will not +schedule a task on a CPU that is not allowed in its cpus_allowed +vector, and the kernel page allocator will not allocate a page on a +node that is not allowed in the requesting tasks mems_allowed vector. + +User level code may create and destroy cpusets by name in the cgroup +virtual file system, manage the attributes and permissions of these +cpusets and which CPUs and Memory Nodes are assigned to each cpuset, +specify and query to which cpuset a task is assigned, and list the +task pids assigned to a cpuset. + + +1.2 Why are cpusets needed ? +---------------------------- + +The management of large computer systems, with many processors (CPUs), +complex memory cache hierarchies and multiple Memory Nodes having +non-uniform access times (NUMA) presents additional challenges for +the efficient scheduling and memory placement of processes. + +Frequently more modest sized systems can be operated with adequate +efficiency just by letting the operating system automatically share +the available CPU and Memory resources amongst the requesting tasks. + +But larger systems, which benefit more from careful processor and +memory placement to reduce memory access times and contention, +and which typically represent a larger investment for the customer, +can benefit from explicitly placing jobs on properly sized subsets of +the system. + +This can be especially valuable on: + + * Web Servers running multiple instances of the same web application, + * Servers running different applications (for instance, a web server + and a database), or + * NUMA systems running large HPC applications with demanding + performance characteristics. + +These subsets, or "soft partitions" must be able to be dynamically +adjusted, as the job mix changes, without impacting other concurrently +executing jobs. The location of the running jobs pages may also be moved +when the memory locations are changed. + +The kernel cpuset patch provides the minimum essential kernel +mechanisms required to efficiently implement such subsets. It +leverages existing CPU and Memory Placement facilities in the Linux +kernel to avoid any additional impact on the critical scheduler or +memory allocator code. + + +1.3 How are cpusets implemented ? +--------------------------------- + +Cpusets provide a Linux kernel mechanism to constrain which CPUs and +Memory Nodes are used by a process or set of processes. + +The Linux kernel already has a pair of mechanisms to specify on which +CPUs a task may be scheduled (sched_setaffinity) and on which Memory +Nodes it may obtain memory (mbind, set_mempolicy). + +Cpusets extends these two mechanisms as follows: + + - Cpusets are sets of allowed CPUs and Memory Nodes, known to the + kernel. + - Each task in the system is attached to a cpuset, via a pointer + in the task structure to a reference counted cgroup structure. + - Calls to sched_setaffinity are filtered to just those CPUs + allowed in that tasks cpuset. + - Calls to mbind and set_mempolicy are filtered to just + those Memory Nodes allowed in that tasks cpuset. + - The root cpuset contains all the systems CPUs and Memory + Nodes. + - For any cpuset, one can define child cpusets containing a subset + of the parents CPU and Memory Node resources. + - The hierarchy of cpusets can be mounted at /dev/cpuset, for + browsing and manipulation from user space. + - A cpuset may be marked exclusive, which ensures that no other + cpuset (except direct ancestors and descendents) may contain + any overlapping CPUs or Memory Nodes. + - You can list all the tasks (by pid) attached to any cpuset. + +The implementation of cpusets requires a few, simple hooks +into the rest of the kernel, none in performance critical paths: + + - in init/main.c, to initialize the root cpuset at system boot. + - in fork and exit, to attach and detach a task from its cpuset. + - in sched_setaffinity, to mask the requested CPUs by what's + allowed in that tasks cpuset. + - in sched.c migrate_all_tasks(), to keep migrating tasks within + the CPUs allowed by their cpuset, if possible. + - in the mbind and set_mempolicy system calls, to mask the requested + Memory Nodes by what's allowed in that tasks cpuset. + - in page_alloc.c, to restrict memory to allowed nodes. + - in vmscan.c, to restrict page recovery to the current cpuset. + +You should mount the "cgroup" filesystem type in order to enable +browsing and modifying the cpusets presently known to the kernel. No +new system calls are added for cpusets - all support for querying and +modifying cpusets is via this cpuset file system. + +The /proc//status file for each task has four added lines, +displaying the tasks cpus_allowed (on which CPUs it may be scheduled) +and mems_allowed (on which Memory Nodes it may obtain memory), +in the two formats seen in the following example: + + Cpus_allowed: ffffffff,ffffffff,ffffffff,ffffffff + Cpus_allowed_list: 0-127 + Mems_allowed: ffffffff,ffffffff + Mems_allowed_list: 0-63 + +Each cpuset is represented by a directory in the cgroup file system +containing (on top of the standard cgroup files) the following +files describing that cpuset: + + - cpus: list of CPUs in that cpuset + - mems: list of Memory Nodes in that cpuset + - memory_migrate flag: if set, move pages to cpusets nodes + - cpu_exclusive flag: is cpu placement exclusive? + - mem_exclusive flag: is memory placement exclusive? + - mem_hardwall flag: is memory allocation hardwalled + - memory_pressure: measure of how much paging pressure in cpuset + +In addition, the root cpuset only has the following file: + - memory_pressure_enabled flag: compute memory_pressure? + +New cpusets are created using the mkdir system call or shell +command. The properties of a cpuset, such as its flags, allowed +CPUs and Memory Nodes, and attached tasks, are modified by writing +to the appropriate file in that cpusets directory, as listed above. + +The named hierarchical structure of nested cpusets allows partitioning +a large system into nested, dynamically changeable, "soft-partitions". + +The attachment of each task, automatically inherited at fork by any +children of that task, to a cpuset allows organizing the work load +on a system into related sets of tasks such that each set is constrained +to using the CPUs and Memory Nodes of a particular cpuset. A task +may be re-attached to any other cpuset, if allowed by the permissions +on the necessary cpuset file system directories. + +Such management of a system "in the large" integrates smoothly with +the detailed placement done on individual tasks and memory regions +using the sched_setaffinity, mbind and set_mempolicy system calls. + +The following rules apply to each cpuset: + + - Its CPUs and Memory Nodes must be a subset of its parents. + - It can't be marked exclusive unless its parent is. + - If its cpu or memory is exclusive, they may not overlap any sibling. + +These rules, and the natural hierarchy of cpusets, enable efficient +enforcement of the exclusive guarantee, without having to scan all +cpusets every time any of them change to ensure nothing overlaps a +exclusive cpuset. Also, the use of a Linux virtual file system (vfs) +to represent the cpuset hierarchy provides for a familiar permission +and name space for cpusets, with a minimum of additional kernel code. + +The cpus and mems files in the root (top_cpuset) cpuset are +read-only. The cpus file automatically tracks the value of +cpu_online_map using a CPU hotplug notifier, and the mems file +automatically tracks the value of node_states[N_HIGH_MEMORY]--i.e., +nodes with memory--using the cpuset_track_online_nodes() hook. + + +1.4 What are exclusive cpusets ? +-------------------------------- + +If a cpuset is cpu or mem exclusive, no other cpuset, other than +a direct ancestor or descendent, may share any of the same CPUs or +Memory Nodes. + +A cpuset that is mem_exclusive *or* mem_hardwall is "hardwalled", +i.e. it restricts kernel allocations for page, buffer and other data +commonly shared by the kernel across multiple users. All cpusets, +whether hardwalled or not, restrict allocations of memory for user +space. This enables configuring a system so that several independent +jobs can share common kernel data, such as file system pages, while +isolating each job's user allocation in its own cpuset. To do this, +construct a large mem_exclusive cpuset to hold all the jobs, and +construct child, non-mem_exclusive cpusets for each individual job. +Only a small amount of typical kernel memory, such as requests from +interrupt handlers, is allowed to be taken outside even a +mem_exclusive cpuset. + + +1.5 What is memory_pressure ? +----------------------------- +The memory_pressure of a cpuset provides a simple per-cpuset metric +of the rate that the tasks in a cpuset are attempting to free up in +use memory on the nodes of the cpuset to satisfy additional memory +requests. + +This enables batch managers monitoring jobs running in dedicated +cpusets to efficiently detect what level of memory pressure that job +is causing. + +This is useful both on tightly managed systems running a wide mix of +submitted jobs, which may choose to terminate or re-prioritize jobs that +are trying to use more memory than allowed on the nodes assigned them, +and with tightly coupled, long running, massively parallel scientific +computing jobs that will dramatically fail to meet required performance +goals if they start to use more memory than allowed to them. + +This mechanism provides a very economical way for the batch manager +to monitor a cpuset for signs of memory pressure. It's up to the +batch manager or other user code to decide what to do about it and +take action. + +==> Unless this feature is enabled by writing "1" to the special file + /dev/cpuset/memory_pressure_enabled, the hook in the rebalance + code of __alloc_pages() for this metric reduces to simply noticing + that the cpuset_memory_pressure_enabled flag is zero. So only + systems that enable this feature will compute the metric. + +Why a per-cpuset, running average: + + Because this meter is per-cpuset, rather than per-task or mm, + the system load imposed by a batch scheduler monitoring this + metric is sharply reduced on large systems, because a scan of + the tasklist can be avoided on each set of queries. + + Because this meter is a running average, instead of an accumulating + counter, a batch scheduler can detect memory pressure with a + single read, instead of having to read and accumulate results + for a period of time. + + Because this meter is per-cpuset rather than per-task or mm, + the batch scheduler can obtain the key information, memory + pressure in a cpuset, with a single read, rather than having to + query and accumulate results over all the (dynamically changing) + set of tasks in the cpuset. + +A per-cpuset simple digital filter (requires a spinlock and 3 words +of data per-cpuset) is kept, and updated by any task attached to that +cpuset, if it enters the synchronous (direct) page reclaim code. + +A per-cpuset file provides an integer number representing the recent +(half-life of 10 seconds) rate of direct page reclaims caused by +the tasks in the cpuset, in units of reclaims attempted per second, +times 1000. + + +1.6 What is memory spread ? +--------------------------- +There are two boolean flag files per cpuset that control where the +kernel allocates pages for the file system buffers and related in +kernel data structures. They are called 'memory_spread_page' and +'memory_spread_slab'. + +If the per-cpuset boolean flag file 'memory_spread_page' is set, then +the kernel will spread the file system buffers (page cache) evenly +over all the nodes that the faulting task is allowed to use, instead +of preferring to put those pages on the node where the task is running. + +If the per-cpuset boolean flag file 'memory_spread_slab' is set, +then the kernel will spread some file system related slab caches, +such as for inodes and dentries evenly over all the nodes that the +faulting task is allowed to use, instead of preferring to put those +pages on the node where the task is running. + +The setting of these flags does not affect anonymous data segment or +stack segment pages of a task. + +By default, both kinds of memory spreading are off, and memory +pages are allocated on the node local to where the task is running, +except perhaps as modified by the tasks NUMA mempolicy or cpuset +configuration, so long as sufficient free memory pages are available. + +When new cpusets are created, they inherit the memory spread settings +of their parent. + +Setting memory spreading causes allocations for the affected page +or slab caches to ignore the tasks NUMA mempolicy and be spread +instead. Tasks using mbind() or set_mempolicy() calls to set NUMA +mempolicies will not notice any change in these calls as a result of +their containing tasks memory spread settings. If memory spreading +is turned off, then the currently specified NUMA mempolicy once again +applies to memory page allocations. + +Both 'memory_spread_page' and 'memory_spread_slab' are boolean flag +files. By default they contain "0", meaning that the feature is off +for that cpuset. If a "1" is written to that file, then that turns +the named feature on. + +The implementation is simple. + +Setting the flag 'memory_spread_page' turns on a per-process flag +PF_SPREAD_PAGE for each task that is in that cpuset or subsequently +joins that cpuset. The page allocation calls for the page cache +is modified to perform an inline check for this PF_SPREAD_PAGE task +flag, and if set, a call to a new routine cpuset_mem_spread_node() +returns the node to prefer for the allocation. + +Similarly, setting 'memory_spread_slab' turns on the flag +PF_SPREAD_SLAB, and appropriately marked slab caches will allocate +pages from the node returned by cpuset_mem_spread_node(). + +The cpuset_mem_spread_node() routine is also simple. It uses the +value of a per-task rotor cpuset_mem_spread_rotor to select the next +node in the current tasks mems_allowed to prefer for the allocation. + +This memory placement policy is also known (in other contexts) as +round-robin or interleave. + +This policy can provide substantial improvements for jobs that need +to place thread local data on the corresponding node, but that need +to access large file system data sets that need to be spread across +the several nodes in the jobs cpuset in order to fit. Without this +policy, especially for jobs that might have one thread reading in the +data set, the memory allocation across the nodes in the jobs cpuset +can become very uneven. + +1.7 What is sched_load_balance ? +-------------------------------- + +The kernel scheduler (kernel/sched.c) automatically load balances +tasks. If one CPU is underutilized, kernel code running on that +CPU will look for tasks on other more overloaded CPUs and move those +tasks to itself, within the constraints of such placement mechanisms +as cpusets and sched_setaffinity. + +The algorithmic cost of load balancing and its impact on key shared +kernel data structures such as the task list increases more than +linearly with the number of CPUs being balanced. So the scheduler +has support to partition the systems CPUs into a number of sched +domains such that it only load balances within each sched domain. +Each sched domain covers some subset of the CPUs in the system; +no two sched domains overlap; some CPUs might not be in any sched +domain and hence won't be load balanced. + +Put simply, it costs less to balance between two smaller sched domains +than one big one, but doing so means that overloads in one of the +two domains won't be load balanced to the other one. + +By default, there is one sched domain covering all CPUs, except those +marked isolated using the kernel boot time "isolcpus=" argument. + +This default load balancing across all CPUs is not well suited for +the following two situations: + 1) On large systems, load balancing across many CPUs is expensive. + If the system is managed using cpusets to place independent jobs + on separate sets of CPUs, full load balancing is unnecessary. + 2) Systems supporting realtime on some CPUs need to minimize + system overhead on those CPUs, including avoiding task load + balancing if that is not needed. + +When the per-cpuset flag "sched_load_balance" is enabled (the default +setting), it requests that all the CPUs in that cpusets allowed 'cpus' +be contained in a single sched domain, ensuring that load balancing +can move a task (not otherwised pinned, as by sched_setaffinity) +from any CPU in that cpuset to any other. + +When the per-cpuset flag "sched_load_balance" is disabled, then the +scheduler will avoid load balancing across the CPUs in that cpuset, +--except-- in so far as is necessary because some overlapping cpuset +has "sched_load_balance" enabled. + +So, for example, if the top cpuset has the flag "sched_load_balance" +enabled, then the scheduler will have one sched domain covering all +CPUs, and the setting of the "sched_load_balance" flag in any other +cpusets won't matter, as we're already fully load balancing. + +Therefore in the above two situations, the top cpuset flag +"sched_load_balance" should be disabled, and only some of the smaller, +child cpusets have this flag enabled. + +When doing this, you don't usually want to leave any unpinned tasks in +the top cpuset that might use non-trivial amounts of CPU, as such tasks +may be artificially constrained to some subset of CPUs, depending on +the particulars of this flag setting in descendent cpusets. Even if +such a task could use spare CPU cycles in some other CPUs, the kernel +scheduler might not consider the possibility of load balancing that +task to that underused CPU. + +Of course, tasks pinned to a particular CPU can be left in a cpuset +that disables "sched_load_balance" as those tasks aren't going anywhere +else anyway. + +There is an impedance mismatch here, between cpusets and sched domains. +Cpusets are hierarchical and nest. Sched domains are flat; they don't +overlap and each CPU is in at most one sched domain. + +It is necessary for sched domains to be flat because load balancing +across partially overlapping sets of CPUs would risk unstable dynamics +that would be beyond our understanding. So if each of two partially +overlapping cpusets enables the flag 'sched_load_balance', then we +form a single sched domain that is a superset of both. We won't move +a task to a CPU outside it cpuset, but the scheduler load balancing +code might waste some compute cycles considering that possibility. + +This mismatch is why there is not a simple one-to-one relation +between which cpusets have the flag "sched_load_balance" enabled, +and the sched domain configuration. If a cpuset enables the flag, it +will get balancing across all its CPUs, but if it disables the flag, +it will only be assured of no load balancing if no other overlapping +cpuset enables the flag. + +If two cpusets have partially overlapping 'cpus' allowed, and only +one of them has this flag enabled, then the other may find its +tasks only partially load balanced, just on the overlapping CPUs. +This is just the general case of the top_cpuset example given a few +paragraphs above. In the general case, as in the top cpuset case, +don't leave tasks that might use non-trivial amounts of CPU in +such partially load balanced cpusets, as they may be artificially +constrained to some subset of the CPUs allowed to them, for lack of +load balancing to the other CPUs. + +1.7.1 sched_load_balance implementation details. +------------------------------------------------ + +The per-cpuset flag 'sched_load_balance' defaults to enabled (contrary +to most cpuset flags.) When enabled for a cpuset, the kernel will +ensure that it can load balance across all the CPUs in that cpuset +(makes sure that all the CPUs in the cpus_allowed of that cpuset are +in the same sched domain.) + +If two overlapping cpusets both have 'sched_load_balance' enabled, +then they will be (must be) both in the same sched domain. + +If, as is the default, the top cpuset has 'sched_load_balance' enabled, +then by the above that means there is a single sched domain covering +the whole system, regardless of any other cpuset settings. + +The kernel commits to user space that it will avoid load balancing +where it can. It will pick as fine a granularity partition of sched +domains as it can while still providing load balancing for any set +of CPUs allowed to a cpuset having 'sched_load_balance' enabled. + +The internal kernel cpuset to scheduler interface passes from the +cpuset code to the scheduler code a partition of the load balanced +CPUs in the system. This partition is a set of subsets (represented +as an array of cpumask_t) of CPUs, pairwise disjoint, that cover all +the CPUs that must be load balanced. + +Whenever the 'sched_load_balance' flag changes, or CPUs come or go +from a cpuset with this flag enabled, or a cpuset with this flag +enabled is removed, the cpuset code builds a new such partition and +passes it to the scheduler sched domain setup code, to have the sched +domains rebuilt as necessary. + +This partition exactly defines what sched domains the scheduler should +setup - one sched domain for each element (cpumask_t) in the partition. + +The scheduler remembers the currently active sched domain partitions. +When the scheduler routine partition_sched_domains() is invoked from +the cpuset code to update these sched domains, it compares the new +partition requested with the current, and updates its sched domains, +removing the old and adding the new, for each change. + + +1.8 What is sched_relax_domain_level ? +-------------------------------------- + +In sched domain, the scheduler migrates tasks in 2 ways; periodic load +balance on tick, and at time of some schedule events. + +When a task is woken up, scheduler try to move the task on idle CPU. +For example, if a task A running on CPU X activates another task B +on the same CPU X, and if CPU Y is X's sibling and performing idle, +then scheduler migrate task B to CPU Y so that task B can start on +CPU Y without waiting task A on CPU X. + +And if a CPU run out of tasks in its runqueue, the CPU try to pull +extra tasks from other busy CPUs to help them before it is going to +be idle. + +Of course it takes some searching cost to find movable tasks and/or +idle CPUs, the scheduler might not search all CPUs in the domain +everytime. In fact, in some architectures, the searching ranges on +events are limited in the same socket or node where the CPU locates, +while the load balance on tick searchs all. + +For example, assume CPU Z is relatively far from CPU X. Even if CPU Z +is idle while CPU X and the siblings are busy, scheduler can't migrate +woken task B from X to Z since it is out of its searching range. +As the result, task B on CPU X need to wait task A or wait load balance +on the next tick. For some applications in special situation, waiting +1 tick may be too long. + +The 'sched_relax_domain_level' file allows you to request changing +this searching range as you like. This file takes int value which +indicates size of searching range in levels ideally as follows, +otherwise initial value -1 that indicates the cpuset has no request. + + -1 : no request. use system default or follow request of others. + 0 : no search. + 1 : search siblings (hyperthreads in a core). + 2 : search cores in a package. + 3 : search cpus in a node [= system wide on non-NUMA system] + ( 4 : search nodes in a chunk of node [on NUMA system] ) + ( 5 : search system wide [on NUMA system] ) + +The system default is architecture dependent. The system default +can be changed using the relax_domain_level= boot parameter. + +This file is per-cpuset and affect the sched domain where the cpuset +belongs to. Therefore if the flag 'sched_load_balance' of a cpuset +is disabled, then 'sched_relax_domain_level' have no effect since +there is no sched domain belonging the cpuset. + +If multiple cpusets are overlapping and hence they form a single sched +domain, the largest value among those is used. Be careful, if one +requests 0 and others are -1 then 0 is used. + +Note that modifying this file will have both good and bad effects, +and whether it is acceptable or not will be depend on your situation. +Don't modify this file if you are not sure. + +If your situation is: + - The migration costs between each cpu can be assumed considerably + small(for you) due to your special application's behavior or + special hardware support for CPU cache etc. + - The searching cost doesn't have impact(for you) or you can make + the searching cost enough small by managing cpuset to compact etc. + - The latency is required even it sacrifices cache hit rate etc. +then increasing 'sched_relax_domain_level' would benefit you. + + +1.9 How do I use cpusets ? +-------------------------- + +In order to minimize the impact of cpusets on critical kernel +code, such as the scheduler, and due to the fact that the kernel +does not support one task updating the memory placement of another +task directly, the impact on a task of changing its cpuset CPU +or Memory Node placement, or of changing to which cpuset a task +is attached, is subtle. + +If a cpuset has its Memory Nodes modified, then for each task attached +to that cpuset, the next time that the kernel attempts to allocate +a page of memory for that task, the kernel will notice the change +in the tasks cpuset, and update its per-task memory placement to +remain within the new cpusets memory placement. If the task was using +mempolicy MPOL_BIND, and the nodes to which it was bound overlap with +its new cpuset, then the task will continue to use whatever subset +of MPOL_BIND nodes are still allowed in the new cpuset. If the task +was using MPOL_BIND and now none of its MPOL_BIND nodes are allowed +in the new cpuset, then the task will be essentially treated as if it +was MPOL_BIND bound to the new cpuset (even though its numa placement, +as queried by get_mempolicy(), doesn't change). If a task is moved +from one cpuset to another, then the kernel will adjust the tasks +memory placement, as above, the next time that the kernel attempts +to allocate a page of memory for that task. + +If a cpuset has its 'cpus' modified, then each task in that cpuset +will have its allowed CPU placement changed immediately. Similarly, +if a tasks pid is written to a cpusets 'tasks' file, in either its +current cpuset or another cpuset, then its allowed CPU placement is +changed immediately. If such a task had been bound to some subset +of its cpuset using the sched_setaffinity() call, the task will be +allowed to run on any CPU allowed in its new cpuset, negating the +affect of the prior sched_setaffinity() call. + +In summary, the memory placement of a task whose cpuset is changed is +updated by the kernel, on the next allocation of a page for that task, +but the processor placement is not updated, until that tasks pid is +rewritten to the 'tasks' file of its cpuset. This is done to avoid +impacting the scheduler code in the kernel with a check for changes +in a tasks processor placement. + +Normally, once a page is allocated (given a physical page +of main memory) then that page stays on whatever node it +was allocated, so long as it remains allocated, even if the +cpusets memory placement policy 'mems' subsequently changes. +If the cpuset flag file 'memory_migrate' is set true, then when +tasks are attached to that cpuset, any pages that task had +allocated to it on nodes in its previous cpuset are migrated +to the tasks new cpuset. The relative placement of the page within +the cpuset is preserved during these migration operations if possible. +For example if the page was on the second valid node of the prior cpuset +then the page will be placed on the second valid node of the new cpuset. + +Also if 'memory_migrate' is set true, then if that cpusets +'mems' file is modified, pages allocated to tasks in that +cpuset, that were on nodes in the previous setting of 'mems', +will be moved to nodes in the new setting of 'mems.' +Pages that were not in the tasks prior cpuset, or in the cpusets +prior 'mems' setting, will not be moved. + +There is an exception to the above. If hotplug functionality is used +to remove all the CPUs that are currently assigned to a cpuset, +then all the tasks in that cpuset will be moved to the nearest ancestor +with non-empty cpus. But the moving of some (or all) tasks might fail if +cpuset is bound with another cgroup subsystem which has some restrictions +on task attaching. In this failing case, those tasks will stay +in the original cpuset, and the kernel will automatically update +their cpus_allowed to allow all online CPUs. When memory hotplug +functionality for removing Memory Nodes is available, a similar exception +is expected to apply there as well. In general, the kernel prefers to +violate cpuset placement, over starving a task that has had all +its allowed CPUs or Memory Nodes taken offline. + +There is a second exception to the above. GFP_ATOMIC requests are +kernel internal allocations that must be satisfied, immediately. +The kernel may drop some request, in rare cases even panic, if a +GFP_ATOMIC alloc fails. If the request cannot be satisfied within +the current tasks cpuset, then we relax the cpuset, and look for +memory anywhere we can find it. It's better to violate the cpuset +than stress the kernel. + +To start a new job that is to be contained within a cpuset, the steps are: + + 1) mkdir /dev/cpuset + 2) mount -t cgroup -ocpuset cpuset /dev/cpuset + 3) Create the new cpuset by doing mkdir's and write's (or echo's) in + the /dev/cpuset virtual file system. + 4) Start a task that will be the "founding father" of the new job. + 5) Attach that task to the new cpuset by writing its pid to the + /dev/cpuset tasks file for that cpuset. + 6) fork, exec or clone the job tasks from this founding father task. + +For example, the following sequence of commands will setup a cpuset +named "Charlie", containing just CPUs 2 and 3, and Memory Node 1, +and then start a subshell 'sh' in that cpuset: + + mount -t cgroup -ocpuset cpuset /dev/cpuset + cd /dev/cpuset + mkdir Charlie + cd Charlie + /bin/echo 2-3 > cpus + /bin/echo 1 > mems + /bin/echo $$ > tasks + sh + # The subshell 'sh' is now running in cpuset Charlie + # The next line should display '/Charlie' + cat /proc/self/cpuset + +In the future, a C library interface to cpusets will likely be +available. For now, the only way to query or modify cpusets is +via the cpuset file system, using the various cd, mkdir, echo, cat, +rmdir commands from the shell, or their equivalent from C. + +The sched_setaffinity calls can also be done at the shell prompt using +SGI's runon or Robert Love's taskset. The mbind and set_mempolicy +calls can be done at the shell prompt using the numactl command +(part of Andi Kleen's numa package). + +2. Usage Examples and Syntax +============================ + +2.1 Basic Usage +--------------- + +Creating, modifying, using the cpusets can be done through the cpuset +virtual filesystem. + +To mount it, type: +# mount -t cgroup -o cpuset cpuset /dev/cpuset + +Then under /dev/cpuset you can find a tree that corresponds to the +tree of the cpusets in the system. For instance, /dev/cpuset +is the cpuset that holds the whole system. + +If you want to create a new cpuset under /dev/cpuset: +# cd /dev/cpuset +# mkdir my_cpuset + +Now you want to do something with this cpuset. +# cd my_cpuset + +In this directory you can find several files: +# ls +cpu_exclusive memory_migrate mems tasks +cpus memory_pressure notify_on_release +mem_exclusive memory_spread_page sched_load_balance +mem_hardwall memory_spread_slab sched_relax_domain_level + +Reading them will give you information about the state of this cpuset: +the CPUs and Memory Nodes it can use, the processes that are using +it, its properties. By writing to these files you can manipulate +the cpuset. + +Set some flags: +# /bin/echo 1 > cpu_exclusive + +Add some cpus: +# /bin/echo 0-7 > cpus + +Add some mems: +# /bin/echo 0-7 > mems + +Now attach your shell to this cpuset: +# /bin/echo $$ > tasks + +You can also create cpusets inside your cpuset by using mkdir in this +directory. +# mkdir my_sub_cs + +To remove a cpuset, just use rmdir: +# rmdir my_sub_cs +This will fail if the cpuset is in use (has cpusets inside, or has +processes attached). + +Note that for legacy reasons, the "cpuset" filesystem exists as a +wrapper around the cgroup filesystem. + +The command + +mount -t cpuset X /dev/cpuset + +is equivalent to + +mount -t cgroup -ocpuset X /dev/cpuset +echo "/sbin/cpuset_release_agent" > /dev/cpuset/release_agent + +2.2 Adding/removing cpus +------------------------ + +This is the syntax to use when writing in the cpus or mems files +in cpuset directories: + +# /bin/echo 1-4 > cpus -> set cpus list to cpus 1,2,3,4 +# /bin/echo 1,2,3,4 > cpus -> set cpus list to cpus 1,2,3,4 + +2.3 Setting flags +----------------- + +The syntax is very simple: + +# /bin/echo 1 > cpu_exclusive -> set flag 'cpu_exclusive' +# /bin/echo 0 > cpu_exclusive -> unset flag 'cpu_exclusive' + +2.4 Attaching processes +----------------------- + +# /bin/echo PID > tasks + +Note that it is PID, not PIDs. You can only attach ONE task at a time. +If you have several tasks to attach, you have to do it one after another: + +# /bin/echo PID1 > tasks +# /bin/echo PID2 > tasks + ... +# /bin/echo PIDn > tasks + + +3. Questions +============ + +Q: what's up with this '/bin/echo' ? +A: bash's builtin 'echo' command does not check calls to write() against + errors. If you use it in the cpuset file system, you won't be + able to tell whether a command succeeded or failed. + +Q: When I attach processes, only the first of the line gets really attached ! +A: We can only return one error code per call to write(). So you should also + put only ONE pid. + +4. Contact +========== + +Web: http://www.bullopensource.org/cpuset diff --git a/Documentation/cgroups/devices.txt b/Documentation/cgroups/devices.txt new file mode 100644 index 00000000000..7cc6e6a6067 --- /dev/null +++ b/Documentation/cgroups/devices.txt @@ -0,0 +1,52 @@ +Device Whitelist Controller + +1. Description: + +Implement a cgroup to track and enforce open and mknod restrictions +on device files. A device cgroup associates a device access +whitelist with each cgroup. A whitelist entry has 4 fields. +'type' is a (all), c (char), or b (block). 'all' means it applies +to all types and all major and minor numbers. Major and minor are +either an integer or * for all. Access is a composition of r +(read), w (write), and m (mknod). + +The root device cgroup starts with rwm to 'all'. A child device +cgroup gets a copy of the parent. Administrators can then remove +devices from the whitelist or add new entries. A child cgroup can +never receive a device access which is denied by its parent. However +when a device access is removed from a parent it will not also be +removed from the child(ren). + +2. User Interface + +An entry is added using devices.allow, and removed using +devices.deny. For instance + + echo 'c 1:3 mr' > /cgroups/1/devices.allow + +allows cgroup 1 to read and mknod the device usually known as +/dev/null. Doing + + echo a > /cgroups/1/devices.deny + +will remove the default 'a *:* rwm' entry. Doing + + echo a > /cgroups/1/devices.allow + +will add the 'a *:* rwm' entry to the whitelist. + +3. Security + +Any task can move itself between cgroups. This clearly won't +suffice, but we can decide the best way to adequately restrict +movement as people get some experience with this. We may just want +to require CAP_SYS_ADMIN, which at least is a separate bit from +CAP_MKNOD. We may want to just refuse moving to a cgroup which +isn't a descendent of the current one. Or we may want to use +CAP_MAC_ADMIN, since we really are trying to lock down root. + +CAP_SYS_ADMIN is needed to modify the whitelist or move another +task to a new cgroup. (Again we'll probably want to change that). + +A cgroup may not be granted more permissions than the cgroup's +parent has. diff --git a/Documentation/cgroups/memcg_test.txt b/Documentation/cgroups/memcg_test.txt new file mode 100644 index 00000000000..19533f93b7a --- /dev/null +++ b/Documentation/cgroups/memcg_test.txt @@ -0,0 +1,342 @@ +Memory Resource Controller(Memcg) Implementation Memo. +Last Updated: 2008/12/15 +Base Kernel Version: based on 2.6.28-rc8-mm. + +Because VM is getting complex (one of reasons is memcg...), memcg's behavior +is complex. This is a document for memcg's internal behavior. +Please note that implementation details can be changed. + +(*) Topics on API should be in Documentation/cgroups/memory.txt) + +0. How to record usage ? + 2 objects are used. + + page_cgroup ....an object per page. + Allocated at boot or memory hotplug. Freed at memory hot removal. + + swap_cgroup ... an entry per swp_entry. + Allocated at swapon(). Freed at swapoff(). + + The page_cgroup has USED bit and double count against a page_cgroup never + occurs. swap_cgroup is used only when a charged page is swapped-out. + +1. Charge + + a page/swp_entry may be charged (usage += PAGE_SIZE) at + + mem_cgroup_newpage_charge() + Called at new page fault and Copy-On-Write. + + mem_cgroup_try_charge_swapin() + Called at do_swap_page() (page fault on swap entry) and swapoff. + Followed by charge-commit-cancel protocol. (With swap accounting) + At commit, a charge recorded in swap_cgroup is removed. + + mem_cgroup_cache_charge() + Called at add_to_page_cache() + + mem_cgroup_cache_charge_swapin() + Called at shmem's swapin. + + mem_cgroup_prepare_migration() + Called before migration. "extra" charge is done and followed by + charge-commit-cancel protocol. + At commit, charge against oldpage or newpage will be committed. + +2. Uncharge + a page/swp_entry may be uncharged (usage -= PAGE_SIZE) by + + mem_cgroup_uncharge_page() + Called when an anonymous page is fully unmapped. I.e., mapcount goes + to 0. If the page is SwapCache, uncharge is delayed until + mem_cgroup_uncharge_swapcache(). + + mem_cgroup_uncharge_cache_page() + Called when a page-cache is deleted from radix-tree. If the page is + SwapCache, uncharge is delayed until mem_cgroup_uncharge_swapcache(). + + mem_cgroup_uncharge_swapcache() + Called when SwapCache is removed from radix-tree. The charge itself + is moved to swap_cgroup. (If mem+swap controller is disabled, no + charge to swap occurs.) + + mem_cgroup_uncharge_swap() + Called when swp_entry's refcnt goes down to 0. A charge against swap + disappears. + + mem_cgroup_end_migration(old, new) + At success of migration old is uncharged (if necessary), a charge + to new page is committed. At failure, charge to old page is committed. + +3. charge-commit-cancel + In some case, we can't know this "charge" is valid or not at charging + (because of races). + To handle such case, there are charge-commit-cancel functions. + mem_cgroup_try_charge_XXX + mem_cgroup_commit_charge_XXX + mem_cgroup_cancel_charge_XXX + these are used in swap-in and migration. + + At try_charge(), there are no flags to say "this page is charged". + at this point, usage += PAGE_SIZE. + + At commit(), the function checks the page should be charged or not + and set flags or avoid charging.(usage -= PAGE_SIZE) + + At cancel(), simply usage -= PAGE_SIZE. + +Under below explanation, we assume CONFIG_MEM_RES_CTRL_SWAP=y. + +4. Anonymous + Anonymous page is newly allocated at + - page fault into MAP_ANONYMOUS mapping. + - Copy-On-Write. + It is charged right after it's allocated before doing any page table + related operations. Of course, it's uncharged when another page is used + for the fault address. + + At freeing anonymous page (by exit() or munmap()), zap_pte() is called + and pages for ptes are freed one by one.(see mm/memory.c). Uncharges + are done at page_remove_rmap() when page_mapcount() goes down to 0. + + Another page freeing is by page-reclaim (vmscan.c) and anonymous + pages are swapped out. In this case, the page is marked as + PageSwapCache(). uncharge() routine doesn't uncharge the page marked + as SwapCache(). It's delayed until __delete_from_swap_cache(). + + 4.1 Swap-in. + At swap-in, the page is taken from swap-cache. There are 2 cases. + + (a) If the SwapCache is newly allocated and read, it has no charges. + (b) If the SwapCache has been mapped by processes, it has been + charged already. + + This swap-in is one of the most complicated work. In do_swap_page(), + following events occur when pte is unchanged. + + (1) the page (SwapCache) is looked up. + (2) lock_page() + (3) try_charge_swapin() + (4) reuse_swap_page() (may call delete_swap_cache()) + (5) commit_charge_swapin() + (6) swap_free(). + + Considering following situation for example. + + (A) The page has not been charged before (2) and reuse_swap_page() + doesn't call delete_from_swap_cache(). + (B) The page has not been charged before (2) and reuse_swap_page() + calls delete_from_swap_cache(). + (C) The page has been charged before (2) and reuse_swap_page() doesn't + call delete_from_swap_cache(). + (D) The page has been charged before (2) and reuse_swap_page() calls + delete_from_swap_cache(). + + memory.usage/memsw.usage changes to this page/swp_entry will be + Case (A) (B) (C) (D) + Event + Before (2) 0/ 1 0/ 1 1/ 1 1/ 1 + =========================================== + (3) +1/+1 +1/+1 +1/+1 +1/+1 + (4) - 0/ 0 - -1/ 0 + (5) 0/-1 0/ 0 -1/-1 0/ 0 + (6) - 0/-1 - 0/-1 + =========================================== + Result 1/ 1 1/ 1 1/ 1 1/ 1 + + In any cases, charges to this page should be 1/ 1. + + 4.2 Swap-out. + At swap-out, typical state transition is below. + + (a) add to swap cache. (marked as SwapCache) + swp_entry's refcnt += 1. + (b) fully unmapped. + swp_entry's refcnt += # of ptes. + (c) write back to swap. + (d) delete from swap cache. (remove from SwapCache) + swp_entry's refcnt -= 1. + + + At (b), the page is marked as SwapCache and not uncharged. + At (d), the page is removed from SwapCache and a charge in page_cgroup + is moved to swap_cgroup. + + Finally, at task exit, + (e) zap_pte() is called and swp_entry's refcnt -=1 -> 0. + Here, a charge in swap_cgroup disappears. + +5. Page Cache + Page Cache is charged at + - add_to_page_cache_locked(). + + uncharged at + - __remove_from_page_cache(). + + The logic is very clear. (About migration, see below) + Note: __remove_from_page_cache() is called by remove_from_page_cache() + and __remove_mapping(). + +6. Shmem(tmpfs) Page Cache + Memcg's charge/uncharge have special handlers of shmem. The best way + to understand shmem's page state transition is to read mm/shmem.c. + But brief explanation of the behavior of memcg around shmem will be + helpful to understand the logic. + + Shmem's page (just leaf page, not direct/indirect block) can be on + - radix-tree of shmem's inode. + - SwapCache. + - Both on radix-tree and SwapCache. This happens at swap-in + and swap-out, + + It's charged when... + - A new page is added to shmem's radix-tree. + - A swp page is read. (move a charge from swap_cgroup to page_cgroup) + It's uncharged when + - A page is removed from radix-tree and not SwapCache. + - When SwapCache is removed, a charge is moved to swap_cgroup. + - When swp_entry's refcnt goes down to 0, a charge in swap_cgroup + disappears. + +7. Page Migration + One of the most complicated functions is page-migration-handler. + Memcg has 2 routines. Assume that we are migrating a page's contents + from OLDPAGE to NEWPAGE. + + Usual migration logic is.. + (a) remove the page from LRU. + (b) allocate NEWPAGE (migration target) + (c) lock by lock_page(). + (d) unmap all mappings. + (e-1) If necessary, replace entry in radix-tree. + (e-2) move contents of a page. + (f) map all mappings again. + (g) pushback the page to LRU. + (-) OLDPAGE will be freed. + + Before (g), memcg should complete all necessary charge/uncharge to + NEWPAGE/OLDPAGE. + + The point is.... + - If OLDPAGE is anonymous, all charges will be dropped at (d) because + try_to_unmap() drops all mapcount and the page will not be + SwapCache. + + - If OLDPAGE is SwapCache, charges will be kept at (g) because + __delete_from_swap_cache() isn't called at (e-1) + + - If OLDPAGE is page-cache, charges will be kept at (g) because + remove_from_swap_cache() isn't called at (e-1) + + memcg provides following hooks. + + - mem_cgroup_prepare_migration(OLDPAGE) + Called after (b) to account a charge (usage += PAGE_SIZE) against + memcg which OLDPAGE belongs to. + + - mem_cgroup_end_migration(OLDPAGE, NEWPAGE) + Called after (f) before (g). + If OLDPAGE is used, commit OLDPAGE again. If OLDPAGE is already + charged, a charge by prepare_migration() is automatically canceled. + If NEWPAGE is used, commit NEWPAGE and uncharge OLDPAGE. + + But zap_pte() (by exit or munmap) can be called while migration, + we have to check if OLDPAGE/NEWPAGE is a valid page after commit(). + +8. LRU + Each memcg has its own private LRU. Now, it's handling is under global + VM's control (means that it's handled under global zone->lru_lock). + Almost all routines around memcg's LRU is called by global LRU's + list management functions under zone->lru_lock(). + + A special function is mem_cgroup_isolate_pages(). This scans + memcg's private LRU and call __isolate_lru_page() to extract a page + from LRU. + (By __isolate_lru_page(), the page is removed from both of global and + private LRU.) + + +9. Typical Tests. + + Tests for racy cases. + + 9.1 Small limit to memcg. + When you do test to do racy case, it's good test to set memcg's limit + to be very small rather than GB. Many races found in the test under + xKB or xxMB limits. + (Memory behavior under GB and Memory behavior under MB shows very + different situation.) + + 9.2 Shmem + Historically, memcg's shmem handling was poor and we saw some amount + of troubles here. This is because shmem is page-cache but can be + SwapCache. Test with shmem/tmpfs is always good test. + + 9.3 Migration + For NUMA, migration is an another special case. To do easy test, cpuset + is useful. Following is a sample script to do migration. + + mount -t cgroup -o cpuset none /opt/cpuset + + mkdir /opt/cpuset/01 + echo 1 > /opt/cpuset/01/cpuset.cpus + echo 0 > /opt/cpuset/01/cpuset.mems + echo 1 > /opt/cpuset/01/cpuset.memory_migrate + mkdir /opt/cpuset/02 + echo 1 > /opt/cpuset/02/cpuset.cpus + echo 1 > /opt/cpuset/02/cpuset.mems + echo 1 > /opt/cpuset/02/cpuset.memory_migrate + + In above set, when you moves a task from 01 to 02, page migration to + node 0 to node 1 will occur. Following is a script to migrate all + under cpuset. + -- + move_task() + { + for pid in $1 + do + /bin/echo $pid >$2/tasks 2>/dev/null + echo -n $pid + echo -n " " + done + echo END + } + + G1_TASK=`cat ${G1}/tasks` + G2_TASK=`cat ${G2}/tasks` + move_task "${G1_TASK}" ${G2} & + -- + 9.4 Memory hotplug. + memory hotplug test is one of good test. + to offline memory, do following. + # echo offline > /sys/devices/system/memory/memoryXXX/state + (XXX is the place of memory) + This is an easy way to test page migration, too. + + 9.5 mkdir/rmdir + When using hierarchy, mkdir/rmdir test should be done. + Use tests like the following. + + echo 1 >/opt/cgroup/01/memory/use_hierarchy + mkdir /opt/cgroup/01/child_a + mkdir /opt/cgroup/01/child_b + + set limit to 01. + add limit to 01/child_b + run jobs under child_a and child_b + + create/delete following groups at random while jobs are running. + /opt/cgroup/01/child_a/child_aa + /opt/cgroup/01/child_b/child_bb + /opt/cgroup/01/child_c + + running new jobs in new group is also good. + + 9.6 Mount with other subsystems. + Mounting with other subsystems is a good test because there is a + race and lock dependency with other cgroup subsystems. + + example) + # mount -t cgroup none /cgroup -t cpuset,memory,cpu,devices + + and do task move, mkdir, rmdir etc...under this. diff --git a/Documentation/cgroups/memory.txt b/Documentation/cgroups/memory.txt new file mode 100644 index 00000000000..e1501964df1 --- /dev/null +++ b/Documentation/cgroups/memory.txt @@ -0,0 +1,399 @@ +Memory Resource Controller + +NOTE: The Memory Resource Controller has been generically been referred +to as the memory controller in this document. Do not confuse memory controller +used here with the memory controller that is used in hardware. + +Salient features + +a. Enable control of both RSS (mapped) and Page Cache (unmapped) pages +b. The infrastructure allows easy addition of other types of memory to control +c. Provides *zero overhead* for non memory controller users +d. Provides a double LRU: global memory pressure causes reclaim from the + global LRU; a cgroup on hitting a limit, reclaims from the per + cgroup LRU + +NOTE: Swap Cache (unmapped) is not accounted now. + +Benefits and Purpose of the memory controller + +The memory controller isolates the memory behaviour of a group of tasks +from the rest of the system. The article on LWN [12] mentions some probable +uses of the memory controller. The memory controller can be used to + +a. Isolate an application or a group of applications + Memory hungry applications can be isolated and limited to a smaller + amount of memory. +b. Create a cgroup with limited amount of memory, this can be used + as a good alternative to booting with mem=XXXX. +c. Virtualization solutions can control the amount of memory they want + to assign to a virtual machine instance. +d. A CD/DVD burner could control the amount of memory used by the + rest of the system to ensure that burning does not fail due to lack + of available memory. +e. There are several other use cases, find one or use the controller just + for fun (to learn and hack on the VM subsystem). + +1. History + +The memory controller has a long history. A request for comments for the memory +controller was posted by Balbir Singh [1]. At the time the RFC was posted +there were several implementations for memory control. The goal of the +RFC was to build consensus and agreement for the minimal features required +for memory control. The first RSS controller was posted by Balbir Singh[2] +in Feb 2007. Pavel Emelianov [3][4][5] has since posted three versions of the +RSS controller. At OLS, at the resource management BoF, everyone suggested +that we handle both page cache and RSS together. Another request was raised +to allow user space handling of OOM. The current memory controller is +at version 6; it combines both mapped (RSS) and unmapped Page +Cache Control [11]. + +2. Memory Control + +Memory is a unique resource in the sense that it is present in a limited +amount. If a task requires a lot of CPU processing, the task can spread +its processing over a period of hours, days, months or years, but with +memory, the same physical memory needs to be reused to accomplish the task. + +The memory controller implementation has been divided into phases. These +are: + +1. Memory controller +2. mlock(2) controller +3. Kernel user memory accounting and slab control +4. user mappings length controller + +The memory controller is the first controller developed. + +2.1. Design + +The core of the design is a counter called the res_counter. The res_counter +tracks the current memory usage and limit of the group of processes associated +with the controller. Each cgroup has a memory controller specific data +structure (mem_cgroup) associated with it. + +2.2. Accounting + + +--------------------+ + | mem_cgroup | + | (res_counter) | + +--------------------+ + / ^ \ + / | \ + +---------------+ | +---------------+ + | mm_struct | |.... | mm_struct | + | | | | | + +---------------+ | +---------------+ + | + + --------------+ + | + +---------------+ +------+--------+ + | page +----------> page_cgroup| + | | | | + +---------------+ +---------------+ + + (Figure 1: Hierarchy of Accounting) + + +Figure 1 shows the important aspects of the controller + +1. Accounting happens per cgroup +2. Each mm_struct knows about which cgroup it belongs to +3. Each page has a pointer to the page_cgroup, which in turn knows the + cgroup it belongs to + +The accounting is done as follows: mem_cgroup_charge() is invoked to setup +the necessary data structures and check if the cgroup that is being charged +is over its limit. If it is then reclaim is invoked on the cgroup. +More details can be found in the reclaim section of this document. +If everything goes well, a page meta-data-structure called page_cgroup is +allocated and associated with the page. This routine also adds the page to +the per cgroup LRU. + +2.2.1 Accounting details + +All mapped anon pages (RSS) and cache pages (Page Cache) are accounted. +(some pages which never be reclaimable and will not be on global LRU + are not accounted. we just accounts pages under usual vm management.) + +RSS pages are accounted at page_fault unless they've already been accounted +for earlier. A file page will be accounted for as Page Cache when it's +inserted into inode (radix-tree). While it's mapped into the page tables of +processes, duplicate accounting is carefully avoided. + +A RSS page is unaccounted when it's fully unmapped. A PageCache page is +unaccounted when it's removed from radix-tree. + +At page migration, accounting information is kept. + +Note: we just account pages-on-lru because our purpose is to control amount +of used pages. not-on-lru pages are tend to be out-of-control from vm view. + +2.3 Shared Page Accounting + +Shared pages are accounted on the basis of the first touch approach. The +cgroup that first touches a page is accounted for the page. The principle +behind this approach is that a cgroup that aggressively uses a shared +page will eventually get charged for it (once it is uncharged from +the cgroup that brought it in -- this will happen on memory pressure). + +Exception: If CONFIG_CGROUP_CGROUP_MEM_RES_CTLR_SWAP is not used.. +When you do swapoff and make swapped-out pages of shmem(tmpfs) to +be backed into memory in force, charges for pages are accounted against the +caller of swapoff rather than the users of shmem. + + +2.4 Swap Extension (CONFIG_CGROUP_MEM_RES_CTLR_SWAP) +Swap Extension allows you to record charge for swap. A swapped-in page is +charged back to original page allocator if possible. + +When swap is accounted, following files are added. + - memory.memsw.usage_in_bytes. + - memory.memsw.limit_in_bytes. + +usage of mem+swap is limited by memsw.limit_in_bytes. + +Note: why 'mem+swap' rather than swap. +The global LRU(kswapd) can swap out arbitrary pages. Swap-out means +to move account from memory to swap...there is no change in usage of +mem+swap. + +In other words, when we want to limit the usage of swap without affecting +global LRU, mem+swap limit is better than just limiting swap from OS point +of view. + +2.5 Reclaim + +Each cgroup maintains a per cgroup LRU that consists of an active +and inactive list. When a cgroup goes over its limit, we first try +to reclaim memory from the cgroup so as to make space for the new +pages that the cgroup has touched. If the reclaim is unsuccessful, +an OOM routine is invoked to select and kill the bulkiest task in the +cgroup. + +The reclaim algorithm has not been modified for cgroups, except that +pages that are selected for reclaiming come from the per cgroup LRU +list. + +2. Locking + +The memory controller uses the following hierarchy + +1. zone->lru_lock is used for selecting pages to be isolated +2. mem->per_zone->lru_lock protects the per cgroup LRU (per zone) +3. lock_page_cgroup() is used to protect page->page_cgroup + +3. User Interface + +0. Configuration + +a. Enable CONFIG_CGROUPS +b. Enable CONFIG_RESOURCE_COUNTERS +c. Enable CONFIG_CGROUP_MEM_RES_CTLR + +1. Prepare the cgroups +# mkdir -p /cgroups +# mount -t cgroup none /cgroups -o memory + +2. Make the new group and move bash into it +# mkdir /cgroups/0 +# echo $$ > /cgroups/0/tasks + +Since now we're in the 0 cgroup, +We can alter the memory limit: +# echo 4M > /cgroups/0/memory.limit_in_bytes + +NOTE: We can use a suffix (k, K, m, M, g or G) to indicate values in kilo, +mega or gigabytes. + +# cat /cgroups/0/memory.limit_in_bytes +4194304 + +NOTE: The interface has now changed to display the usage in bytes +instead of pages + +We can check the usage: +# cat /cgroups/0/memory.usage_in_bytes +1216512 + +A successful write to this file does not guarantee a successful set of +this limit to the value written into the file. This can be due to a +number of factors, such as rounding up to page boundaries or the total +availability of memory on the system. The user is required to re-read +this file after a write to guarantee the value committed by the kernel. + +# echo 1 > memory.limit_in_bytes +# cat memory.limit_in_bytes +4096 + +The memory.failcnt field gives the number of times that the cgroup limit was +exceeded. + +The memory.stat file gives accounting information. Now, the number of +caches, RSS and Active pages/Inactive pages are shown. + +4. Testing + +Balbir posted lmbench, AIM9, LTP and vmmstress results [10] and [11]. +Apart from that v6 has been tested with several applications and regular +daily use. The controller has also been tested on the PPC64, x86_64 and +UML platforms. + +4.1 Troubleshooting + +Sometimes a user might find that the application under a cgroup is +terminated. There are several causes for this: + +1. The cgroup limit is too low (just too low to do anything useful) +2. The user is using anonymous memory and swap is turned off or too low + +A sync followed by echo 1 > /proc/sys/vm/drop_caches will help get rid of +some of the pages cached in the cgroup (page cache pages). + +4.2 Task migration + +When a task migrates from one cgroup to another, it's charge is not +carried forward. The pages allocated from the original cgroup still +remain charged to it, the charge is dropped when the page is freed or +reclaimed. + +4.3 Removing a cgroup + +A cgroup can be removed by rmdir, but as discussed in sections 4.1 and 4.2, a +cgroup might have some charge associated with it, even though all +tasks have migrated away from it. +Such charges are freed(at default) or moved to its parent. When moved, +both of RSS and CACHES are moved to parent. +If both of them are busy, rmdir() returns -EBUSY. See 5.1 Also. + +Charges recorded in swap information is not updated at removal of cgroup. +Recorded information is discarded and a cgroup which uses swap (swapcache) +will be charged as a new owner of it. + + +5. Misc. interfaces. + +5.1 force_empty + memory.force_empty interface is provided to make cgroup's memory usage empty. + You can use this interface only when the cgroup has no tasks. + When writing anything to this + + # echo 0 > memory.force_empty + + Almost all pages tracked by this memcg will be unmapped and freed. Some of + pages cannot be freed because it's locked or in-use. Such pages are moved + to parent and this cgroup will be empty. But this may return -EBUSY in + some too busy case. + + Typical use case of this interface is that calling this before rmdir(). + Because rmdir() moves all pages to parent, some out-of-use page caches can be + moved to the parent. If you want to avoid that, force_empty will be useful. + +5.2 stat file + memory.stat file includes following statistics (now) + cache - # of pages from page-cache and shmem. + rss - # of pages from anonymous memory. + pgpgin - # of event of charging + pgpgout - # of event of uncharging + active_anon - # of pages on active lru of anon, shmem. + inactive_anon - # of pages on active lru of anon, shmem + active_file - # of pages on active lru of file-cache + inactive_file - # of pages on inactive lru of file cache + unevictable - # of pages cannot be reclaimed.(mlocked etc) + + Below is depend on CONFIG_DEBUG_VM. + inactive_ratio - VM inernal parameter. (see mm/page_alloc.c) + recent_rotated_anon - VM internal parameter. (see mm/vmscan.c) + recent_rotated_file - VM internal parameter. (see mm/vmscan.c) + recent_scanned_anon - VM internal parameter. (see mm/vmscan.c) + recent_scanned_file - VM internal parameter. (see mm/vmscan.c) + + Memo: + recent_rotated means recent frequency of lru rotation. + recent_scanned means recent # of scans to lru. + showing for better debug please see the code for meanings. + + +5.3 swappiness + Similar to /proc/sys/vm/swappiness, but affecting a hierarchy of groups only. + + Following cgroup's swapiness can't be changed. + - root cgroup (uses /proc/sys/vm/swappiness). + - a cgroup which uses hierarchy and it has child cgroup. + - a cgroup which uses hierarchy and not the root of hierarchy. + + +6. Hierarchy support + +The memory controller supports a deep hierarchy and hierarchical accounting. +The hierarchy is created by creating the appropriate cgroups in the +cgroup filesystem. Consider for example, the following cgroup filesystem +hierarchy + + root + / | \ + / | \ + a b c + | \ + | \ + d e + +In the diagram above, with hierarchical accounting enabled, all memory +usage of e, is accounted to its ancestors up until the root (i.e, c and root), +that has memory.use_hierarchy enabled. If one of the ancestors goes over its +limit, the reclaim algorithm reclaims from the tasks in the ancestor and the +children of the ancestor. + +6.1 Enabling hierarchical accounting and reclaim + +The memory controller by default disables the hierarchy feature. Support +can be enabled by writing 1 to memory.use_hierarchy file of the root cgroup + +# echo 1 > memory.use_hierarchy + +The feature can be disabled by + +# echo 0 > memory.use_hierarchy + +NOTE1: Enabling/disabling will fail if the cgroup already has other +cgroups created below it. + +NOTE2: This feature can be enabled/disabled per subtree. + +7. TODO + +1. Add support for accounting huge pages (as a separate controller) +2. Make per-cgroup scanner reclaim not-shared pages first +3. Teach controller to account for shared-pages +4. Start reclamation in the background when the limit is + not yet hit but the usage is getting closer + +Summary + +Overall, the memory controller has been a stable controller and has been +commented and discussed quite extensively in the community. + +References + +1. Singh, Balbir. RFC: Memory Controller, http://lwn.net/Articles/206697/ +2. Singh, Balbir. Memory Controller (RSS Control), + http://lwn.net/Articles/222762/ +3. Emelianov, Pavel. Resource controllers based on process cgroups + http://lkml.org/lkml/2007/3/6/198 +4. Emelianov, Pavel. RSS controller based on process cgroups (v2) + http://lkml.org/lkml/2007/4/9/78 +5. Emelianov, Pavel. RSS controller based on process cgroups (v3) + http://lkml.org/lkml/2007/5/30/244 +6. Menage, Paul. Control Groups v10, http://lwn.net/Articles/236032/ +7. Vaidyanathan, Srinivasan, Control Groups: Pagecache accounting and control + subsystem (v3), http://lwn.net/Articles/235534/ +8. Singh, Balbir. RSS controller v2 test results (lmbench), + http://lkml.org/lkml/2007/5/17/232 +9. Singh, Balbir. RSS controller v2 AIM9 results + http://lkml.org/lkml/2007/5/18/1 +10. Singh, Balbir. Memory controller v6 test results, + http://lkml.org/lkml/2007/8/19/36 +11. Singh, Balbir. Memory controller introduction (v6), + http://lkml.org/lkml/2007/8/17/69 +12. Corbet, Jonathan, Controlling memory use in cgroups, + http://lwn.net/Articles/243795/ diff --git a/Documentation/cgroups/resource_counter.txt b/Documentation/cgroups/resource_counter.txt new file mode 100644 index 00000000000..f196ac1d7d2 --- /dev/null +++ b/Documentation/cgroups/resource_counter.txt @@ -0,0 +1,181 @@ + + The Resource Counter + +The resource counter, declared at include/linux/res_counter.h, +is supposed to facilitate the resource management by controllers +by providing common stuff for accounting. + +This "stuff" includes the res_counter structure and routines +to work with it. + + + +1. Crucial parts of the res_counter structure + + a. unsigned long long usage + + The usage value shows the amount of a resource that is consumed + by a group at a given time. The units of measurement should be + determined by the controller that uses this counter. E.g. it can + be bytes, items or any other unit the controller operates on. + + b. unsigned long long max_usage + + The maximal value of the usage over time. + + This value is useful when gathering statistical information about + the particular group, as it shows the actual resource requirements + for a particular group, not just some usage snapshot. + + c. unsigned long long limit + + The maximal allowed amount of resource to consume by the group. In + case the group requests for more resources, so that the usage value + would exceed the limit, the resource allocation is rejected (see + the next section). + + d. unsigned long long failcnt + + The failcnt stands for "failures counter". This is the number of + resource allocation attempts that failed. + + c. spinlock_t lock + + Protects changes of the above values. + + + +2. Basic accounting routines + + a. void res_counter_init(struct res_counter *rc) + + Initializes the resource counter. As usual, should be the first + routine called for a new counter. + + b. int res_counter_charge[_locked] + (struct res_counter *rc, unsigned long val) + + When a resource is about to be allocated it has to be accounted + with the appropriate resource counter (controller should determine + which one to use on its own). This operation is called "charging". + + This is not very important which operation - resource allocation + or charging - is performed first, but + * if the allocation is performed first, this may create a + temporary resource over-usage by the time resource counter is + charged; + * if the charging is performed first, then it should be uncharged + on error path (if the one is called). + + c. void res_counter_uncharge[_locked] + (struct res_counter *rc, unsigned long val) + + When a resource is released (freed) it should be de-accounted + from the resource counter it was accounted to. This is called + "uncharging". + + The _locked routines imply that the res_counter->lock is taken. + + + 2.1 Other accounting routines + + There are more routines that may help you with common needs, like + checking whether the limit is reached or resetting the max_usage + value. They are all declared in include/linux/res_counter.h. + + + +3. Analyzing the resource counter registrations + + a. If the failcnt value constantly grows, this means that the counter's + limit is too tight. Either the group is misbehaving and consumes too + many resources, or the configuration is not suitable for the group + and the limit should be increased. + + b. The max_usage value can be used to quickly tune the group. One may + set the limits to maximal values and either load the container with + a common pattern or leave one for a while. After this the max_usage + value shows the amount of memory the container would require during + its common activity. + + Setting the limit a bit above this value gives a pretty good + configuration that works in most of the cases. + + c. If the max_usage is much less than the limit, but the failcnt value + is growing, then the group tries to allocate a big chunk of resource + at once. + + d. If the max_usage is much less than the limit, but the failcnt value + is 0, then this group is given too high limit, that it does not + require. It is better to lower the limit a bit leaving more resource + for other groups. + + + +4. Communication with the control groups subsystem (cgroups) + +All the resource controllers that are using cgroups and resource counters +should provide files (in the cgroup filesystem) to work with the resource +counter fields. They are recommended to adhere to the following rules: + + a. File names + + Field name File name + --------------------------------------------------- + usage usage_in_ + max_usage max_usage_in_ + limit limit_in_ + failcnt failcnt + lock no file :) + + b. Reading from file should show the corresponding field value in the + appropriate format. + + c. Writing to file + + Field Expected behavior + ---------------------------------- + usage prohibited + max_usage reset to usage + limit set the limit + failcnt reset to zero + + + +5. Usage example + + a. Declare a task group (take a look at cgroups subsystem for this) and + fold a res_counter into it + + struct my_group { + struct res_counter res; + + + } + + b. Put hooks in resource allocation/release paths + + int alloc_something(...) + { + if (res_counter_charge(res_counter_ptr, amount) < 0) + return -ENOMEM; + + + } + + void release_something(...) + { + res_counter_uncharge(res_counter_ptr, amount); + + + } + + In order to keep the usage value self-consistent, both the + "res_counter_ptr" and the "amount" in release_something() should be + the same as they were in the alloc_something() when the releasing + resource was allocated. + + c. Provide the way to read res_counter values and set them (the cgroups + still can help with it). + + c. Compile and run :) diff --git a/Documentation/controllers/cpuacct.txt b/Documentation/controllers/cpuacct.txt deleted file mode 100644 index bb775fbe43d..00000000000 --- a/Documentation/controllers/cpuacct.txt +++ /dev/null @@ -1,32 +0,0 @@ -CPU Accounting Controller -------------------------- - -The CPU accounting controller is used to group tasks using cgroups and -account the CPU usage of these groups of tasks. - -The CPU accounting controller supports multi-hierarchy groups. An accounting -group accumulates the CPU usage of all of its child groups and the tasks -directly present in its group. - -Accounting groups can be created by first mounting the cgroup filesystem. - -# mkdir /cgroups -# mount -t cgroup -ocpuacct none /cgroups - -With the above step, the initial or the parent accounting group -becomes visible at /cgroups. At bootup, this group includes all the -tasks in the system. /cgroups/tasks lists the tasks in this cgroup. -/cgroups/cpuacct.usage gives the CPU time (in nanoseconds) obtained by -this group which is essentially the CPU time obtained by all the tasks -in the system. - -New accounting groups can be created under the parent group /cgroups. - -# cd /cgroups -# mkdir g1 -# echo $$ > g1 - -The above steps create a new group g1 and move the current shell -process (bash) into it. CPU time consumed by this bash and its children -can be obtained from g1/cpuacct.usage and the same is accumulated in -/cgroups/cpuacct.usage also. diff --git a/Documentation/controllers/devices.txt b/Documentation/controllers/devices.txt deleted file mode 100644 index 7cc6e6a6067..00000000000 --- a/Documentation/controllers/devices.txt +++ /dev/null @@ -1,52 +0,0 @@ -Device Whitelist Controller - -1. Description: - -Implement a cgroup to track and enforce open and mknod restrictions -on device files. A device cgroup associates a device access -whitelist with each cgroup. A whitelist entry has 4 fields. -'type' is a (all), c (char), or b (block). 'all' means it applies -to all types and all major and minor numbers. Major and minor are -either an integer or * for all. Access is a composition of r -(read), w (write), and m (mknod). - -The root device cgroup starts with rwm to 'all'. A child device -cgroup gets a copy of the parent. Administrators can then remove -devices from the whitelist or add new entries. A child cgroup can -never receive a device access which is denied by its parent. However -when a device access is removed from a parent it will not also be -removed from the child(ren). - -2. User Interface - -An entry is added using devices.allow, and removed using -devices.deny. For instance - - echo 'c 1:3 mr' > /cgroups/1/devices.allow - -allows cgroup 1 to read and mknod the device usually known as -/dev/null. Doing - - echo a > /cgroups/1/devices.deny - -will remove the default 'a *:* rwm' entry. Doing - - echo a > /cgroups/1/devices.allow - -will add the 'a *:* rwm' entry to the whitelist. - -3. Security - -Any task can move itself between cgroups. This clearly won't -suffice, but we can decide the best way to adequately restrict -movement as people get some experience with this. We may just want -to require CAP_SYS_ADMIN, which at least is a separate bit from -CAP_MKNOD. We may want to just refuse moving to a cgroup which -isn't a descendent of the current one. Or we may want to use -CAP_MAC_ADMIN, since we really are trying to lock down root. - -CAP_SYS_ADMIN is needed to modify the whitelist or move another -task to a new cgroup. (Again we'll probably want to change that). - -A cgroup may not be granted more permissions than the cgroup's -parent has. diff --git a/Documentation/controllers/memcg_test.txt b/Documentation/controllers/memcg_test.txt deleted file mode 100644 index 08d4d3ea0d7..00000000000 --- a/Documentation/controllers/memcg_test.txt +++ /dev/null @@ -1,342 +0,0 @@ -Memory Resource Controller(Memcg) Implementation Memo. -Last Updated: 2008/12/15 -Base Kernel Version: based on 2.6.28-rc8-mm. - -Because VM is getting complex (one of reasons is memcg...), memcg's behavior -is complex. This is a document for memcg's internal behavior. -Please note that implementation details can be changed. - -(*) Topics on API should be in Documentation/controllers/memory.txt) - -0. How to record usage ? - 2 objects are used. - - page_cgroup ....an object per page. - Allocated at boot or memory hotplug. Freed at memory hot removal. - - swap_cgroup ... an entry per swp_entry. - Allocated at swapon(). Freed at swapoff(). - - The page_cgroup has USED bit and double count against a page_cgroup never - occurs. swap_cgroup is used only when a charged page is swapped-out. - -1. Charge - - a page/swp_entry may be charged (usage += PAGE_SIZE) at - - mem_cgroup_newpage_charge() - Called at new page fault and Copy-On-Write. - - mem_cgroup_try_charge_swapin() - Called at do_swap_page() (page fault on swap entry) and swapoff. - Followed by charge-commit-cancel protocol. (With swap accounting) - At commit, a charge recorded in swap_cgroup is removed. - - mem_cgroup_cache_charge() - Called at add_to_page_cache() - - mem_cgroup_cache_charge_swapin() - Called at shmem's swapin. - - mem_cgroup_prepare_migration() - Called before migration. "extra" charge is done and followed by - charge-commit-cancel protocol. - At commit, charge against oldpage or newpage will be committed. - -2. Uncharge - a page/swp_entry may be uncharged (usage -= PAGE_SIZE) by - - mem_cgroup_uncharge_page() - Called when an anonymous page is fully unmapped. I.e., mapcount goes - to 0. If the page is SwapCache, uncharge is delayed until - mem_cgroup_uncharge_swapcache(). - - mem_cgroup_uncharge_cache_page() - Called when a page-cache is deleted from radix-tree. If the page is - SwapCache, uncharge is delayed until mem_cgroup_uncharge_swapcache(). - - mem_cgroup_uncharge_swapcache() - Called when SwapCache is removed from radix-tree. The charge itself - is moved to swap_cgroup. (If mem+swap controller is disabled, no - charge to swap occurs.) - - mem_cgroup_uncharge_swap() - Called when swp_entry's refcnt goes down to 0. A charge against swap - disappears. - - mem_cgroup_end_migration(old, new) - At success of migration old is uncharged (if necessary), a charge - to new page is committed. At failure, charge to old page is committed. - -3. charge-commit-cancel - In some case, we can't know this "charge" is valid or not at charging - (because of races). - To handle such case, there are charge-commit-cancel functions. - mem_cgroup_try_charge_XXX - mem_cgroup_commit_charge_XXX - mem_cgroup_cancel_charge_XXX - these are used in swap-in and migration. - - At try_charge(), there are no flags to say "this page is charged". - at this point, usage += PAGE_SIZE. - - At commit(), the function checks the page should be charged or not - and set flags or avoid charging.(usage -= PAGE_SIZE) - - At cancel(), simply usage -= PAGE_SIZE. - -Under below explanation, we assume CONFIG_MEM_RES_CTRL_SWAP=y. - -4. Anonymous - Anonymous page is newly allocated at - - page fault into MAP_ANONYMOUS mapping. - - Copy-On-Write. - It is charged right after it's allocated before doing any page table - related operations. Of course, it's uncharged when another page is used - for the fault address. - - At freeing anonymous page (by exit() or munmap()), zap_pte() is called - and pages for ptes are freed one by one.(see mm/memory.c). Uncharges - are done at page_remove_rmap() when page_mapcount() goes down to 0. - - Another page freeing is by page-reclaim (vmscan.c) and anonymous - pages are swapped out. In this case, the page is marked as - PageSwapCache(). uncharge() routine doesn't uncharge the page marked - as SwapCache(). It's delayed until __delete_from_swap_cache(). - - 4.1 Swap-in. - At swap-in, the page is taken from swap-cache. There are 2 cases. - - (a) If the SwapCache is newly allocated and read, it has no charges. - (b) If the SwapCache has been mapped by processes, it has been - charged already. - - This swap-in is one of the most complicated work. In do_swap_page(), - following events occur when pte is unchanged. - - (1) the page (SwapCache) is looked up. - (2) lock_page() - (3) try_charge_swapin() - (4) reuse_swap_page() (may call delete_swap_cache()) - (5) commit_charge_swapin() - (6) swap_free(). - - Considering following situation for example. - - (A) The page has not been charged before (2) and reuse_swap_page() - doesn't call delete_from_swap_cache(). - (B) The page has not been charged before (2) and reuse_swap_page() - calls delete_from_swap_cache(). - (C) The page has been charged before (2) and reuse_swap_page() doesn't - call delete_from_swap_cache(). - (D) The page has been charged before (2) and reuse_swap_page() calls - delete_from_swap_cache(). - - memory.usage/memsw.usage changes to this page/swp_entry will be - Case (A) (B) (C) (D) - Event - Before (2) 0/ 1 0/ 1 1/ 1 1/ 1 - =========================================== - (3) +1/+1 +1/+1 +1/+1 +1/+1 - (4) - 0/ 0 - -1/ 0 - (5) 0/-1 0/ 0 -1/-1 0/ 0 - (6) - 0/-1 - 0/-1 - =========================================== - Result 1/ 1 1/ 1 1/ 1 1/ 1 - - In any cases, charges to this page should be 1/ 1. - - 4.2 Swap-out. - At swap-out, typical state transition is below. - - (a) add to swap cache. (marked as SwapCache) - swp_entry's refcnt += 1. - (b) fully unmapped. - swp_entry's refcnt += # of ptes. - (c) write back to swap. - (d) delete from swap cache. (remove from SwapCache) - swp_entry's refcnt -= 1. - - - At (b), the page is marked as SwapCache and not uncharged. - At (d), the page is removed from SwapCache and a charge in page_cgroup - is moved to swap_cgroup. - - Finally, at task exit, - (e) zap_pte() is called and swp_entry's refcnt -=1 -> 0. - Here, a charge in swap_cgroup disappears. - -5. Page Cache - Page Cache is charged at - - add_to_page_cache_locked(). - - uncharged at - - __remove_from_page_cache(). - - The logic is very clear. (About migration, see below) - Note: __remove_from_page_cache() is called by remove_from_page_cache() - and __remove_mapping(). - -6. Shmem(tmpfs) Page Cache - Memcg's charge/uncharge have special handlers of shmem. The best way - to understand shmem's page state transition is to read mm/shmem.c. - But brief explanation of the behavior of memcg around shmem will be - helpful to understand the logic. - - Shmem's page (just leaf page, not direct/indirect block) can be on - - radix-tree of shmem's inode. - - SwapCache. - - Both on radix-tree and SwapCache. This happens at swap-in - and swap-out, - - It's charged when... - - A new page is added to shmem's radix-tree. - - A swp page is read. (move a charge from swap_cgroup to page_cgroup) - It's uncharged when - - A page is removed from radix-tree and not SwapCache. - - When SwapCache is removed, a charge is moved to swap_cgroup. - - When swp_entry's refcnt goes down to 0, a charge in swap_cgroup - disappears. - -7. Page Migration - One of the most complicated functions is page-migration-handler. - Memcg has 2 routines. Assume that we are migrating a page's contents - from OLDPAGE to NEWPAGE. - - Usual migration logic is.. - (a) remove the page from LRU. - (b) allocate NEWPAGE (migration target) - (c) lock by lock_page(). - (d) unmap all mappings. - (e-1) If necessary, replace entry in radix-tree. - (e-2) move contents of a page. - (f) map all mappings again. - (g) pushback the page to LRU. - (-) OLDPAGE will be freed. - - Before (g), memcg should complete all necessary charge/uncharge to - NEWPAGE/OLDPAGE. - - The point is.... - - If OLDPAGE is anonymous, all charges will be dropped at (d) because - try_to_unmap() drops all mapcount and the page will not be - SwapCache. - - - If OLDPAGE is SwapCache, charges will be kept at (g) because - __delete_from_swap_cache() isn't called at (e-1) - - - If OLDPAGE is page-cache, charges will be kept at (g) because - remove_from_swap_cache() isn't called at (e-1) - - memcg provides following hooks. - - - mem_cgroup_prepare_migration(OLDPAGE) - Called after (b) to account a charge (usage += PAGE_SIZE) against - memcg which OLDPAGE belongs to. - - - mem_cgroup_end_migration(OLDPAGE, NEWPAGE) - Called after (f) before (g). - If OLDPAGE is used, commit OLDPAGE again. If OLDPAGE is already - charged, a charge by prepare_migration() is automatically canceled. - If NEWPAGE is used, commit NEWPAGE and uncharge OLDPAGE. - - But zap_pte() (by exit or munmap) can be called while migration, - we have to check if OLDPAGE/NEWPAGE is a valid page after commit(). - -8. LRU - Each memcg has its own private LRU. Now, it's handling is under global - VM's control (means that it's handled under global zone->lru_lock). - Almost all routines around memcg's LRU is called by global LRU's - list management functions under zone->lru_lock(). - - A special function is mem_cgroup_isolate_pages(). This scans - memcg's private LRU and call __isolate_lru_page() to extract a page - from LRU. - (By __isolate_lru_page(), the page is removed from both of global and - private LRU.) - - -9. Typical Tests. - - Tests for racy cases. - - 9.1 Small limit to memcg. - When you do test to do racy case, it's good test to set memcg's limit - to be very small rather than GB. Many races found in the test under - xKB or xxMB limits. - (Memory behavior under GB and Memory behavior under MB shows very - different situation.) - - 9.2 Shmem - Historically, memcg's shmem handling was poor and we saw some amount - of troubles here. This is because shmem is page-cache but can be - SwapCache. Test with shmem/tmpfs is always good test. - - 9.3 Migration - For NUMA, migration is an another special case. To do easy test, cpuset - is useful. Following is a sample script to do migration. - - mount -t cgroup -o cpuset none /opt/cpuset - - mkdir /opt/cpuset/01 - echo 1 > /opt/cpuset/01/cpuset.cpus - echo 0 > /opt/cpuset/01/cpuset.mems - echo 1 > /opt/cpuset/01/cpuset.memory_migrate - mkdir /opt/cpuset/02 - echo 1 > /opt/cpuset/02/cpuset.cpus - echo 1 > /opt/cpuset/02/cpuset.mems - echo 1 > /opt/cpuset/02/cpuset.memory_migrate - - In above set, when you moves a task from 01 to 02, page migration to - node 0 to node 1 will occur. Following is a script to migrate all - under cpuset. - -- - move_task() - { - for pid in $1 - do - /bin/echo $pid >$2/tasks 2>/dev/null - echo -n $pid - echo -n " " - done - echo END - } - - G1_TASK=`cat ${G1}/tasks` - G2_TASK=`cat ${G2}/tasks` - move_task "${G1_TASK}" ${G2} & - -- - 9.4 Memory hotplug. - memory hotplug test is one of good test. - to offline memory, do following. - # echo offline > /sys/devices/system/memory/memoryXXX/state - (XXX is the place of memory) - This is an easy way to test page migration, too. - - 9.5 mkdir/rmdir - When using hierarchy, mkdir/rmdir test should be done. - Use tests like the following. - - echo 1 >/opt/cgroup/01/memory/use_hierarchy - mkdir /opt/cgroup/01/child_a - mkdir /opt/cgroup/01/child_b - - set limit to 01. - add limit to 01/child_b - run jobs under child_a and child_b - - create/delete following groups at random while jobs are running. - /opt/cgroup/01/child_a/child_aa - /opt/cgroup/01/child_b/child_bb - /opt/cgroup/01/child_c - - running new jobs in new group is also good. - - 9.6 Mount with other subsystems. - Mounting with other subsystems is a good test because there is a - race and lock dependency with other cgroup subsystems. - - example) - # mount -t cgroup none /cgroup -t cpuset,memory,cpu,devices - - and do task move, mkdir, rmdir etc...under this. diff --git a/Documentation/controllers/memory.txt b/Documentation/controllers/memory.txt deleted file mode 100644 index e1501964df1..00000000000 --- a/Documentation/controllers/memory.txt +++ /dev/null @@ -1,399 +0,0 @@ -Memory Resource Controller - -NOTE: The Memory Resource Controller has been generically been referred -to as the memory controller in this document. Do not confuse memory controller -used here with the memory controller that is used in hardware. - -Salient features - -a. Enable control of both RSS (mapped) and Page Cache (unmapped) pages -b. The infrastructure allows easy addition of other types of memory to control -c. Provides *zero overhead* for non memory controller users -d. Provides a double LRU: global memory pressure causes reclaim from the - global LRU; a cgroup on hitting a limit, reclaims from the per - cgroup LRU - -NOTE: Swap Cache (unmapped) is not accounted now. - -Benefits and Purpose of the memory controller - -The memory controller isolates the memory behaviour of a group of tasks -from the rest of the system. The article on LWN [12] mentions some probable -uses of the memory controller. The memory controller can be used to - -a. Isolate an application or a group of applications - Memory hungry applications can be isolated and limited to a smaller - amount of memory. -b. Create a cgroup with limited amount of memory, this can be used - as a good alternative to booting with mem=XXXX. -c. Virtualization solutions can control the amount of memory they want - to assign to a virtual machine instance. -d. A CD/DVD burner could control the amount of memory used by the - rest of the system to ensure that burning does not fail due to lack - of available memory. -e. There are several other use cases, find one or use the controller just - for fun (to learn and hack on the VM subsystem). - -1. History - -The memory controller has a long history. A request for comments for the memory -controller was posted by Balbir Singh [1]. At the time the RFC was posted -there were several implementations for memory control. The goal of the -RFC was to build consensus and agreement for the minimal features required -for memory control. The first RSS controller was posted by Balbir Singh[2] -in Feb 2007. Pavel Emelianov [3][4][5] has since posted three versions of the -RSS controller. At OLS, at the resource management BoF, everyone suggested -that we handle both page cache and RSS together. Another request was raised -to allow user space handling of OOM. The current memory controller is -at version 6; it combines both mapped (RSS) and unmapped Page -Cache Control [11]. - -2. Memory Control - -Memory is a unique resource in the sense that it is present in a limited -amount. If a task requires a lot of CPU processing, the task can spread -its processing over a period of hours, days, months or years, but with -memory, the same physical memory needs to be reused to accomplish the task. - -The memory controller implementation has been divided into phases. These -are: - -1. Memory controller -2. mlock(2) controller -3. Kernel user memory accounting and slab control -4. user mappings length controller - -The memory controller is the first controller developed. - -2.1. Design - -The core of the design is a counter called the res_counter. The res_counter -tracks the current memory usage and limit of the group of processes associated -with the controller. Each cgroup has a memory controller specific data -structure (mem_cgroup) associated with it. - -2.2. Accounting - - +--------------------+ - | mem_cgroup | - | (res_counter) | - +--------------------+ - / ^ \ - / | \ - +---------------+ | +---------------+ - | mm_struct | |.... | mm_struct | - | | | | | - +---------------+ | +---------------+ - | - + --------------+ - | - +---------------+ +------+--------+ - | page +----------> page_cgroup| - | | | | - +---------------+ +---------------+ - - (Figure 1: Hierarchy of Accounting) - - -Figure 1 shows the important aspects of the controller - -1. Accounting happens per cgroup -2. Each mm_struct knows about which cgroup it belongs to -3. Each page has a pointer to the page_cgroup, which in turn knows the - cgroup it belongs to - -The accounting is done as follows: mem_cgroup_charge() is invoked to setup -the necessary data structures and check if the cgroup that is being charged -is over its limit. If it is then reclaim is invoked on the cgroup. -More details can be found in the reclaim section of this document. -If everything goes well, a page meta-data-structure called page_cgroup is -allocated and associated with the page. This routine also adds the page to -the per cgroup LRU. - -2.2.1 Accounting details - -All mapped anon pages (RSS) and cache pages (Page Cache) are accounted. -(some pages which never be reclaimable and will not be on global LRU - are not accounted. we just accounts pages under usual vm management.) - -RSS pages are accounted at page_fault unless they've already been accounted -for earlier. A file page will be accounted for as Page Cache when it's -inserted into inode (radix-tree). While it's mapped into the page tables of -processes, duplicate accounting is carefully avoided. - -A RSS page is unaccounted when it's fully unmapped. A PageCache page is -unaccounted when it's removed from radix-tree. - -At page migration, accounting information is kept. - -Note: we just account pages-on-lru because our purpose is to control amount -of used pages. not-on-lru pages are tend to be out-of-control from vm view. - -2.3 Shared Page Accounting - -Shared pages are accounted on the basis of the first touch approach. The -cgroup that first touches a page is accounted for the page. The principle -behind this approach is that a cgroup that aggressively uses a shared -page will eventually get charged for it (once it is uncharged from -the cgroup that brought it in -- this will happen on memory pressure). - -Exception: If CONFIG_CGROUP_CGROUP_MEM_RES_CTLR_SWAP is not used.. -When you do swapoff and make swapped-out pages of shmem(tmpfs) to -be backed into memory in force, charges for pages are accounted against the -caller of swapoff rather than the users of shmem. - - -2.4 Swap Extension (CONFIG_CGROUP_MEM_RES_CTLR_SWAP) -Swap Extension allows you to record charge for swap. A swapped-in page is -charged back to original page allocator if possible. - -When swap is accounted, following files are added. - - memory.memsw.usage_in_bytes. - - memory.memsw.limit_in_bytes. - -usage of mem+swap is limited by memsw.limit_in_bytes. - -Note: why 'mem+swap' rather than swap. -The global LRU(kswapd) can swap out arbitrary pages. Swap-out means -to move account from memory to swap...there is no change in usage of -mem+swap. - -In other words, when we want to limit the usage of swap without affecting -global LRU, mem+swap limit is better than just limiting swap from OS point -of view. - -2.5 Reclaim - -Each cgroup maintains a per cgroup LRU that consists of an active -and inactive list. When a cgroup goes over its limit, we first try -to reclaim memory from the cgroup so as to make space for the new -pages that the cgroup has touched. If the reclaim is unsuccessful, -an OOM routine is invoked to select and kill the bulkiest task in the -cgroup. - -The reclaim algorithm has not been modified for cgroups, except that -pages that are selected for reclaiming come from the per cgroup LRU -list. - -2. Locking - -The memory controller uses the following hierarchy - -1. zone->lru_lock is used for selecting pages to be isolated -2. mem->per_zone->lru_lock protects the per cgroup LRU (per zone) -3. lock_page_cgroup() is used to protect page->page_cgroup - -3. User Interface - -0. Configuration - -a. Enable CONFIG_CGROUPS -b. Enable CONFIG_RESOURCE_COUNTERS -c. Enable CONFIG_CGROUP_MEM_RES_CTLR - -1. Prepare the cgroups -# mkdir -p /cgroups -# mount -t cgroup none /cgroups -o memory - -2. Make the new group and move bash into it -# mkdir /cgroups/0 -# echo $$ > /cgroups/0/tasks - -Since now we're in the 0 cgroup, -We can alter the memory limit: -# echo 4M > /cgroups/0/memory.limit_in_bytes - -NOTE: We can use a suffix (k, K, m, M, g or G) to indicate values in kilo, -mega or gigabytes. - -# cat /cgroups/0/memory.limit_in_bytes -4194304 - -NOTE: The interface has now changed to display the usage in bytes -instead of pages - -We can check the usage: -# cat /cgroups/0/memory.usage_in_bytes -1216512 - -A successful write to this file does not guarantee a successful set of -this limit to the value written into the file. This can be due to a -number of factors, such as rounding up to page boundaries or the total -availability of memory on the system. The user is required to re-read -this file after a write to guarantee the value committed by the kernel. - -# echo 1 > memory.limit_in_bytes -# cat memory.limit_in_bytes -4096 - -The memory.failcnt field gives the number of times that the cgroup limit was -exceeded. - -The memory.stat file gives accounting information. Now, the number of -caches, RSS and Active pages/Inactive pages are shown. - -4. Testing - -Balbir posted lmbench, AIM9, LTP and vmmstress results [10] and [11]. -Apart from that v6 has been tested with several applications and regular -daily use. The controller has also been tested on the PPC64, x86_64 and -UML platforms. - -4.1 Troubleshooting - -Sometimes a user might find that the application under a cgroup is -terminated. There are several causes for this: - -1. The cgroup limit is too low (just too low to do anything useful) -2. The user is using anonymous memory and swap is turned off or too low - -A sync followed by echo 1 > /proc/sys/vm/drop_caches will help get rid of -some of the pages cached in the cgroup (page cache pages). - -4.2 Task migration - -When a task migrates from one cgroup to another, it's charge is not -carried forward. The pages allocated from the original cgroup still -remain charged to it, the charge is dropped when the page is freed or -reclaimed. - -4.3 Removing a cgroup - -A cgroup can be removed by rmdir, but as discussed in sections 4.1 and 4.2, a -cgroup might have some charge associated with it, even though all -tasks have migrated away from it. -Such charges are freed(at default) or moved to its parent. When moved, -both of RSS and CACHES are moved to parent. -If both of them are busy, rmdir() returns -EBUSY. See 5.1 Also. - -Charges recorded in swap information is not updated at removal of cgroup. -Recorded information is discarded and a cgroup which uses swap (swapcache) -will be charged as a new owner of it. - - -5. Misc. interfaces. - -5.1 force_empty - memory.force_empty interface is provided to make cgroup's memory usage empty. - You can use this interface only when the cgroup has no tasks. - When writing anything to this - - # echo 0 > memory.force_empty - - Almost all pages tracked by this memcg will be unmapped and freed. Some of - pages cannot be freed because it's locked or in-use. Such pages are moved - to parent and this cgroup will be empty. But this may return -EBUSY in - some too busy case. - - Typical use case of this interface is that calling this before rmdir(). - Because rmdir() moves all pages to parent, some out-of-use page caches can be - moved to the parent. If you want to avoid that, force_empty will be useful. - -5.2 stat file - memory.stat file includes following statistics (now) - cache - # of pages from page-cache and shmem. - rss - # of pages from anonymous memory. - pgpgin - # of event of charging - pgpgout - # of event of uncharging - active_anon - # of pages on active lru of anon, shmem. - inactive_anon - # of pages on active lru of anon, shmem - active_file - # of pages on active lru of file-cache - inactive_file - # of pages on inactive lru of file cache - unevictable - # of pages cannot be reclaimed.(mlocked etc) - - Below is depend on CONFIG_DEBUG_VM. - inactive_ratio - VM inernal parameter. (see mm/page_alloc.c) - recent_rotated_anon - VM internal parameter. (see mm/vmscan.c) - recent_rotated_file - VM internal parameter. (see mm/vmscan.c) - recent_scanned_anon - VM internal parameter. (see mm/vmscan.c) - recent_scanned_file - VM internal parameter. (see mm/vmscan.c) - - Memo: - recent_rotated means recent frequency of lru rotation. - recent_scanned means recent # of scans to lru. - showing for better debug please see the code for meanings. - - -5.3 swappiness - Similar to /proc/sys/vm/swappiness, but affecting a hierarchy of groups only. - - Following cgroup's swapiness can't be changed. - - root cgroup (uses /proc/sys/vm/swappiness). - - a cgroup which uses hierarchy and it has child cgroup. - - a cgroup which uses hierarchy and not the root of hierarchy. - - -6. Hierarchy support - -The memory controller supports a deep hierarchy and hierarchical accounting. -The hierarchy is created by creating the appropriate cgroups in the -cgroup filesystem. Consider for example, the following cgroup filesystem -hierarchy - - root - / | \ - / | \ - a b c - | \ - | \ - d e - -In the diagram above, with hierarchical accounting enabled, all memory -usage of e, is accounted to its ancestors up until the root (i.e, c and root), -that has memory.use_hierarchy enabled. If one of the ancestors goes over its -limit, the reclaim algorithm reclaims from the tasks in the ancestor and the -children of the ancestor. - -6.1 Enabling hierarchical accounting and reclaim - -The memory controller by default disables the hierarchy feature. Support -can be enabled by writing 1 to memory.use_hierarchy file of the root cgroup - -# echo 1 > memory.use_hierarchy - -The feature can be disabled by - -# echo 0 > memory.use_hierarchy - -NOTE1: Enabling/disabling will fail if the cgroup already has other -cgroups created below it. - -NOTE2: This feature can be enabled/disabled per subtree. - -7. TODO - -1. Add support for accounting huge pages (as a separate controller) -2. Make per-cgroup scanner reclaim not-shared pages first -3. Teach controller to account for shared-pages -4. Start reclamation in the background when the limit is - not yet hit but the usage is getting closer - -Summary - -Overall, the memory controller has been a stable controller and has been -commented and discussed quite extensively in the community. - -References - -1. Singh, Balbir. RFC: Memory Controller, http://lwn.net/Articles/206697/ -2. Singh, Balbir. Memory Controller (RSS Control), - http://lwn.net/Articles/222762/ -3. Emelianov, Pavel. Resource controllers based on process cgroups - http://lkml.org/lkml/2007/3/6/198 -4. Emelianov, Pavel. RSS controller based on process cgroups (v2) - http://lkml.org/lkml/2007/4/9/78 -5. Emelianov, Pavel. RSS controller based on process cgroups (v3) - http://lkml.org/lkml/2007/5/30/244 -6. Menage, Paul. Control Groups v10, http://lwn.net/Articles/236032/ -7. Vaidyanathan, Srinivasan, Control Groups: Pagecache accounting and control - subsystem (v3), http://lwn.net/Articles/235534/ -8. Singh, Balbir. RSS controller v2 test results (lmbench), - http://lkml.org/lkml/2007/5/17/232 -9. Singh, Balbir. RSS controller v2 AIM9 results - http://lkml.org/lkml/2007/5/18/1 -10. Singh, Balbir. Memory controller v6 test results, - http://lkml.org/lkml/2007/8/19/36 -11. Singh, Balbir. Memory controller introduction (v6), - http://lkml.org/lkml/2007/8/17/69 -12. Corbet, Jonathan, Controlling memory use in cgroups, - http://lwn.net/Articles/243795/ diff --git a/Documentation/controllers/resource_counter.txt b/Documentation/controllers/resource_counter.txt deleted file mode 100644 index f196ac1d7d2..00000000000 --- a/Documentation/controllers/resource_counter.txt +++ /dev/null @@ -1,181 +0,0 @@ - - The Resource Counter - -The resource counter, declared at include/linux/res_counter.h, -is supposed to facilitate the resource management by controllers -by providing common stuff for accounting. - -This "stuff" includes the res_counter structure and routines -to work with it. - - - -1. Crucial parts of the res_counter structure - - a. unsigned long long usage - - The usage value shows the amount of a resource that is consumed - by a group at a given time. The units of measurement should be - determined by the controller that uses this counter. E.g. it can - be bytes, items or any other unit the controller operates on. - - b. unsigned long long max_usage - - The maximal value of the usage over time. - - This value is useful when gathering statistical information about - the particular group, as it shows the actual resource requirements - for a particular group, not just some usage snapshot. - - c. unsigned long long limit - - The maximal allowed amount of resource to consume by the group. In - case the group requests for more resources, so that the usage value - would exceed the limit, the resource allocation is rejected (see - the next section). - - d. unsigned long long failcnt - - The failcnt stands for "failures counter". This is the number of - resource allocation attempts that failed. - - c. spinlock_t lock - - Protects changes of the above values. - - - -2. Basic accounting routines - - a. void res_counter_init(struct res_counter *rc) - - Initializes the resource counter. As usual, should be the first - routine called for a new counter. - - b. int res_counter_charge[_locked] - (struct res_counter *rc, unsigned long val) - - When a resource is about to be allocated it has to be accounted - with the appropriate resource counter (controller should determine - which one to use on its own). This operation is called "charging". - - This is not very important which operation - resource allocation - or charging - is performed first, but - * if the allocation is performed first, this may create a - temporary resource over-usage by the time resource counter is - charged; - * if the charging is performed first, then it should be uncharged - on error path (if the one is called). - - c. void res_counter_uncharge[_locked] - (struct res_counter *rc, unsigned long val) - - When a resource is released (freed) it should be de-accounted - from the resource counter it was accounted to. This is called - "uncharging". - - The _locked routines imply that the res_counter->lock is taken. - - - 2.1 Other accounting routines - - There are more routines that may help you with common needs, like - checking whether the limit is reached or resetting the max_usage - value. They are all declared in include/linux/res_counter.h. - - - -3. Analyzing the resource counter registrations - - a. If the failcnt value constantly grows, this means that the counter's - limit is too tight. Either the group is misbehaving and consumes too - many resources, or the configuration is not suitable for the group - and the limit should be increased. - - b. The max_usage value can be used to quickly tune the group. One may - set the limits to maximal values and either load the container with - a common pattern or leave one for a while. After this the max_usage - value shows the amount of memory the container would require during - its common activity. - - Setting the limit a bit above this value gives a pretty good - configuration that works in most of the cases. - - c. If the max_usage is much less than the limit, but the failcnt value - is growing, then the group tries to allocate a big chunk of resource - at once. - - d. If the max_usage is much less than the limit, but the failcnt value - is 0, then this group is given too high limit, that it does not - require. It is better to lower the limit a bit leaving more resource - for other groups. - - - -4. Communication with the control groups subsystem (cgroups) - -All the resource controllers that are using cgroups and resource counters -should provide files (in the cgroup filesystem) to work with the resource -counter fields. They are recommended to adhere to the following rules: - - a. File names - - Field name File name - --------------------------------------------------- - usage usage_in_ - max_usage max_usage_in_ - limit limit_in_ - failcnt failcnt - lock no file :) - - b. Reading from file should show the corresponding field value in the - appropriate format. - - c. Writing to file - - Field Expected behavior - ---------------------------------- - usage prohibited - max_usage reset to usage - limit set the limit - failcnt reset to zero - - - -5. Usage example - - a. Declare a task group (take a look at cgroups subsystem for this) and - fold a res_counter into it - - struct my_group { - struct res_counter res; - - - } - - b. Put hooks in resource allocation/release paths - - int alloc_something(...) - { - if (res_counter_charge(res_counter_ptr, amount) < 0) - return -ENOMEM; - - - } - - void release_something(...) - { - res_counter_uncharge(res_counter_ptr, amount); - - - } - - In order to keep the usage value self-consistent, both the - "res_counter_ptr" and the "amount" in release_something() should be - the same as they were in the alloc_something() when the releasing - resource was allocated. - - c. Provide the way to read res_counter values and set them (the cgroups - still can help with it). - - c. Compile and run :) diff --git a/Documentation/cpusets.txt b/Documentation/cpusets.txt deleted file mode 100644 index 5c86c258c79..00000000000 --- a/Documentation/cpusets.txt +++ /dev/null @@ -1,808 +0,0 @@ - CPUSETS - ------- - -Copyright (C) 2004 BULL SA. -Written by Simon.Derr@bull.net - -Portions Copyright (c) 2004-2006 Silicon Graphics, Inc. -Modified by Paul Jackson -Modified by Christoph Lameter -Modified by Paul Menage -Modified by Hidetoshi Seto - -CONTENTS: -========= - -1. Cpusets - 1.1 What are cpusets ? - 1.2 Why are cpusets needed ? - 1.3 How are cpusets implemented ? - 1.4 What are exclusive cpusets ? - 1.5 What is memory_pressure ? - 1.6 What is memory spread ? - 1.7 What is sched_load_balance ? - 1.8 What is sched_relax_domain_level ? - 1.9 How do I use cpusets ? -2. Usage Examples and Syntax - 2.1 Basic Usage - 2.2 Adding/removing cpus - 2.3 Setting flags - 2.4 Attaching processes -3. Questions -4. Contact - -1. Cpusets -========== - -1.1 What are cpusets ? ----------------------- - -Cpusets provide a mechanism for assigning a set of CPUs and Memory -Nodes to a set of tasks. In this document "Memory Node" refers to -an on-line node that contains memory. - -Cpusets constrain the CPU and Memory placement of tasks to only -the resources within a tasks current cpuset. They form a nested -hierarchy visible in a virtual file system. These are the essential -hooks, beyond what is already present, required to manage dynamic -job placement on large systems. - -Cpusets use the generic cgroup subsystem described in -Documentation/cgroups/cgroups.txt. - -Requests by a task, using the sched_setaffinity(2) system call to -include CPUs in its CPU affinity mask, and using the mbind(2) and -set_mempolicy(2) system calls to include Memory Nodes in its memory -policy, are both filtered through that tasks cpuset, filtering out any -CPUs or Memory Nodes not in that cpuset. The scheduler will not -schedule a task on a CPU that is not allowed in its cpus_allowed -vector, and the kernel page allocator will not allocate a page on a -node that is not allowed in the requesting tasks mems_allowed vector. - -User level code may create and destroy cpusets by name in the cgroup -virtual file system, manage the attributes and permissions of these -cpusets and which CPUs and Memory Nodes are assigned to each cpuset, -specify and query to which cpuset a task is assigned, and list the -task pids assigned to a cpuset. - - -1.2 Why are cpusets needed ? ----------------------------- - -The management of large computer systems, with many processors (CPUs), -complex memory cache hierarchies and multiple Memory Nodes having -non-uniform access times (NUMA) presents additional challenges for -the efficient scheduling and memory placement of processes. - -Frequently more modest sized systems can be operated with adequate -efficiency just by letting the operating system automatically share -the available CPU and Memory resources amongst the requesting tasks. - -But larger systems, which benefit more from careful processor and -memory placement to reduce memory access times and contention, -and which typically represent a larger investment for the customer, -can benefit from explicitly placing jobs on properly sized subsets of -the system. - -This can be especially valuable on: - - * Web Servers running multiple instances of the same web application, - * Servers running different applications (for instance, a web server - and a database), or - * NUMA systems running large HPC applications with demanding - performance characteristics. - -These subsets, or "soft partitions" must be able to be dynamically -adjusted, as the job mix changes, without impacting other concurrently -executing jobs. The location of the running jobs pages may also be moved -when the memory locations are changed. - -The kernel cpuset patch provides the minimum essential kernel -mechanisms required to efficiently implement such subsets. It -leverages existing CPU and Memory Placement facilities in the Linux -kernel to avoid any additional impact on the critical scheduler or -memory allocator code. - - -1.3 How are cpusets implemented ? ---------------------------------- - -Cpusets provide a Linux kernel mechanism to constrain which CPUs and -Memory Nodes are used by a process or set of processes. - -The Linux kernel already has a pair of mechanisms to specify on which -CPUs a task may be scheduled (sched_setaffinity) and on which Memory -Nodes it may obtain memory (mbind, set_mempolicy). - -Cpusets extends these two mechanisms as follows: - - - Cpusets are sets of allowed CPUs and Memory Nodes, known to the - kernel. - - Each task in the system is attached to a cpuset, via a pointer - in the task structure to a reference counted cgroup structure. - - Calls to sched_setaffinity are filtered to just those CPUs - allowed in that tasks cpuset. - - Calls to mbind and set_mempolicy are filtered to just - those Memory Nodes allowed in that tasks cpuset. - - The root cpuset contains all the systems CPUs and Memory - Nodes. - - For any cpuset, one can define child cpusets containing a subset - of the parents CPU and Memory Node resources. - - The hierarchy of cpusets can be mounted at /dev/cpuset, for - browsing and manipulation from user space. - - A cpuset may be marked exclusive, which ensures that no other - cpuset (except direct ancestors and descendents) may contain - any overlapping CPUs or Memory Nodes. - - You can list all the tasks (by pid) attached to any cpuset. - -The implementation of cpusets requires a few, simple hooks -into the rest of the kernel, none in performance critical paths: - - - in init/main.c, to initialize the root cpuset at system boot. - - in fork and exit, to attach and detach a task from its cpuset. - - in sched_setaffinity, to mask the requested CPUs by what's - allowed in that tasks cpuset. - - in sched.c migrate_all_tasks(), to keep migrating tasks within - the CPUs allowed by their cpuset, if possible. - - in the mbind and set_mempolicy system calls, to mask the requested - Memory Nodes by what's allowed in that tasks cpuset. - - in page_alloc.c, to restrict memory to allowed nodes. - - in vmscan.c, to restrict page recovery to the current cpuset. - -You should mount the "cgroup" filesystem type in order to enable -browsing and modifying the cpusets presently known to the kernel. No -new system calls are added for cpusets - all support for querying and -modifying cpusets is via this cpuset file system. - -The /proc//status file for each task has four added lines, -displaying the tasks cpus_allowed (on which CPUs it may be scheduled) -and mems_allowed (on which Memory Nodes it may obtain memory), -in the two formats seen in the following example: - - Cpus_allowed: ffffffff,ffffffff,ffffffff,ffffffff - Cpus_allowed_list: 0-127 - Mems_allowed: ffffffff,ffffffff - Mems_allowed_list: 0-63 - -Each cpuset is represented by a directory in the cgroup file system -containing (on top of the standard cgroup files) the following -files describing that cpuset: - - - cpus: list of CPUs in that cpuset - - mems: list of Memory Nodes in that cpuset - - memory_migrate flag: if set, move pages to cpusets nodes - - cpu_exclusive flag: is cpu placement exclusive? - - mem_exclusive flag: is memory placement exclusive? - - mem_hardwall flag: is memory allocation hardwalled - - memory_pressure: measure of how much paging pressure in cpuset - -In addition, the root cpuset only has the following file: - - memory_pressure_enabled flag: compute memory_pressure? - -New cpusets are created using the mkdir system call or shell -command. The properties of a cpuset, such as its flags, allowed -CPUs and Memory Nodes, and attached tasks, are modified by writing -to the appropriate file in that cpusets directory, as listed above. - -The named hierarchical structure of nested cpusets allows partitioning -a large system into nested, dynamically changeable, "soft-partitions". - -The attachment of each task, automatically inherited at fork by any -children of that task, to a cpuset allows organizing the work load -on a system into related sets of tasks such that each set is constrained -to using the CPUs and Memory Nodes of a particular cpuset. A task -may be re-attached to any other cpuset, if allowed by the permissions -on the necessary cpuset file system directories. - -Such management of a system "in the large" integrates smoothly with -the detailed placement done on individual tasks and memory regions -using the sched_setaffinity, mbind and set_mempolicy system calls. - -The following rules apply to each cpuset: - - - Its CPUs and Memory Nodes must be a subset of its parents. - - It can't be marked exclusive unless its parent is. - - If its cpu or memory is exclusive, they may not overlap any sibling. - -These rules, and the natural hierarchy of cpusets, enable efficient -enforcement of the exclusive guarantee, without having to scan all -cpusets every time any of them change to ensure nothing overlaps a -exclusive cpuset. Also, the use of a Linux virtual file system (vfs) -to represent the cpuset hierarchy provides for a familiar permission -and name space for cpusets, with a minimum of additional kernel code. - -The cpus and mems files in the root (top_cpuset) cpuset are -read-only. The cpus file automatically tracks the value of -cpu_online_map using a CPU hotplug notifier, and the mems file -automatically tracks the value of node_states[N_HIGH_MEMORY]--i.e., -nodes with memory--using the cpuset_track_online_nodes() hook. - - -1.4 What are exclusive cpusets ? --------------------------------- - -If a cpuset is cpu or mem exclusive, no other cpuset, other than -a direct ancestor or descendent, may share any of the same CPUs or -Memory Nodes. - -A cpuset that is mem_exclusive *or* mem_hardwall is "hardwalled", -i.e. it restricts kernel allocations for page, buffer and other data -commonly shared by the kernel across multiple users. All cpusets, -whether hardwalled or not, restrict allocations of memory for user -space. This enables configuring a system so that several independent -jobs can share common kernel data, such as file system pages, while -isolating each job's user allocation in its own cpuset. To do this, -construct a large mem_exclusive cpuset to hold all the jobs, and -construct child, non-mem_exclusive cpusets for each individual job. -Only a small amount of typical kernel memory, such as requests from -interrupt handlers, is allowed to be taken outside even a -mem_exclusive cpuset. - - -1.5 What is memory_pressure ? ------------------------------ -The memory_pressure of a cpuset provides a simple per-cpuset metric -of the rate that the tasks in a cpuset are attempting to free up in -use memory on the nodes of the cpuset to satisfy additional memory -requests. - -This enables batch managers monitoring jobs running in dedicated -cpusets to efficiently detect what level of memory pressure that job -is causing. - -This is useful both on tightly managed systems running a wide mix of -submitted jobs, which may choose to terminate or re-prioritize jobs that -are trying to use more memory than allowed on the nodes assigned them, -and with tightly coupled, long running, massively parallel scientific -computing jobs that will dramatically fail to meet required performance -goals if they start to use more memory than allowed to them. - -This mechanism provides a very economical way for the batch manager -to monitor a cpuset for signs of memory pressure. It's up to the -batch manager or other user code to decide what to do about it and -take action. - -==> Unless this feature is enabled by writing "1" to the special file - /dev/cpuset/memory_pressure_enabled, the hook in the rebalance - code of __alloc_pages() for this metric reduces to simply noticing - that the cpuset_memory_pressure_enabled flag is zero. So only - systems that enable this feature will compute the metric. - -Why a per-cpuset, running average: - - Because this meter is per-cpuset, rather than per-task or mm, - the system load imposed by a batch scheduler monitoring this - metric is sharply reduced on large systems, because a scan of - the tasklist can be avoided on each set of queries. - - Because this meter is a running average, instead of an accumulating - counter, a batch scheduler can detect memory pressure with a - single read, instead of having to read and accumulate results - for a period of time. - - Because this meter is per-cpuset rather than per-task or mm, - the batch scheduler can obtain the key information, memory - pressure in a cpuset, with a single read, rather than having to - query and accumulate results over all the (dynamically changing) - set of tasks in the cpuset. - -A per-cpuset simple digital filter (requires a spinlock and 3 words -of data per-cpuset) is kept, and updated by any task attached to that -cpuset, if it enters the synchronous (direct) page reclaim code. - -A per-cpuset file provides an integer number representing the recent -(half-life of 10 seconds) rate of direct page reclaims caused by -the tasks in the cpuset, in units of reclaims attempted per second, -times 1000. - - -1.6 What is memory spread ? ---------------------------- -There are two boolean flag files per cpuset that control where the -kernel allocates pages for the file system buffers and related in -kernel data structures. They are called 'memory_spread_page' and -'memory_spread_slab'. - -If the per-cpuset boolean flag file 'memory_spread_page' is set, then -the kernel will spread the file system buffers (page cache) evenly -over all the nodes that the faulting task is allowed to use, instead -of preferring to put those pages on the node where the task is running. - -If the per-cpuset boolean flag file 'memory_spread_slab' is set, -then the kernel will spread some file system related slab caches, -such as for inodes and dentries evenly over all the nodes that the -faulting task is allowed to use, instead of preferring to put those -pages on the node where the task is running. - -The setting of these flags does not affect anonymous data segment or -stack segment pages of a task. - -By default, both kinds of memory spreading are off, and memory -pages are allocated on the node local to where the task is running, -except perhaps as modified by the tasks NUMA mempolicy or cpuset -configuration, so long as sufficient free memory pages are available. - -When new cpusets are created, they inherit the memory spread settings -of their parent. - -Setting memory spreading causes allocations for the affected page -or slab caches to ignore the tasks NUMA mempolicy and be spread -instead. Tasks using mbind() or set_mempolicy() calls to set NUMA -mempolicies will not notice any change in these calls as a result of -their containing tasks memory spread settings. If memory spreading -is turned off, then the currently specified NUMA mempolicy once again -applies to memory page allocations. - -Both 'memory_spread_page' and 'memory_spread_slab' are boolean flag -files. By default they contain "0", meaning that the feature is off -for that cpuset. If a "1" is written to that file, then that turns -the named feature on. - -The implementation is simple. - -Setting the flag 'memory_spread_page' turns on a per-process flag -PF_SPREAD_PAGE for each task that is in that cpuset or subsequently -joins that cpuset. The page allocation calls for the page cache -is modified to perform an inline check for this PF_SPREAD_PAGE task -flag, and if set, a call to a new routine cpuset_mem_spread_node() -returns the node to prefer for the allocation. - -Similarly, setting 'memory_spread_slab' turns on the flag -PF_SPREAD_SLAB, and appropriately marked slab caches will allocate -pages from the node returned by cpuset_mem_spread_node(). - -The cpuset_mem_spread_node() routine is also simple. It uses the -value of a per-task rotor cpuset_mem_spread_rotor to select the next -node in the current tasks mems_allowed to prefer for the allocation. - -This memory placement policy is also known (in other contexts) as -round-robin or interleave. - -This policy can provide substantial improvements for jobs that need -to place thread local data on the corresponding node, but that need -to access large file system data sets that need to be spread across -the several nodes in the jobs cpuset in order to fit. Without this -policy, especially for jobs that might have one thread reading in the -data set, the memory allocation across the nodes in the jobs cpuset -can become very uneven. - -1.7 What is sched_load_balance ? --------------------------------- - -The kernel scheduler (kernel/sched.c) automatically load balances -tasks. If one CPU is underutilized, kernel code running on that -CPU will look for tasks on other more overloaded CPUs and move those -tasks to itself, within the constraints of such placement mechanisms -as cpusets and sched_setaffinity. - -The algorithmic cost of load balancing and its impact on key shared -kernel data structures such as the task list increases more than -linearly with the number of CPUs being balanced. So the scheduler -has support to partition the systems CPUs into a number of sched -domains such that it only load balances within each sched domain. -Each sched domain covers some subset of the CPUs in the system; -no two sched domains overlap; some CPUs might not be in any sched -domain and hence won't be load balanced. - -Put simply, it costs less to balance between two smaller sched domains -than one big one, but doing so means that overloads in one of the -two domains won't be load balanced to the other one. - -By default, there is one sched domain covering all CPUs, except those -marked isolated using the kernel boot time "isolcpus=" argument. - -This default load balancing across all CPUs is not well suited for -the following two situations: - 1) On large systems, load balancing across many CPUs is expensive. - If the system is managed using cpusets to place independent jobs - on separate sets of CPUs, full load balancing is unnecessary. - 2) Systems supporting realtime on some CPUs need to minimize - system overhead on those CPUs, including avoiding task load - balancing if that is not needed. - -When the per-cpuset flag "sched_load_balance" is enabled (the default -setting), it requests that all the CPUs in that cpusets allowed 'cpus' -be contained in a single sched domain, ensuring that load balancing -can move a task (not otherwised pinned, as by sched_setaffinity) -from any CPU in that cpuset to any other. - -When the per-cpuset flag "sched_load_balance" is disabled, then the -scheduler will avoid load balancing across the CPUs in that cpuset, ---except-- in so far as is necessary because some overlapping cpuset -has "sched_load_balance" enabled. - -So, for example, if the top cpuset has the flag "sched_load_balance" -enabled, then the scheduler will have one sched domain covering all -CPUs, and the setting of the "sched_load_balance" flag in any other -cpusets won't matter, as we're already fully load balancing. - -Therefore in the above two situations, the top cpuset flag -"sched_load_balance" should be disabled, and only some of the smaller, -child cpusets have this flag enabled. - -When doing this, you don't usually want to leave any unpinned tasks in -the top cpuset that might use non-trivial amounts of CPU, as such tasks -may be artificially constrained to some subset of CPUs, depending on -the particulars of this flag setting in descendent cpusets. Even if -such a task could use spare CPU cycles in some other CPUs, the kernel -scheduler might not consider the possibility of load balancing that -task to that underused CPU. - -Of course, tasks pinned to a particular CPU can be left in a cpuset -that disables "sched_load_balance" as those tasks aren't going anywhere -else anyway. - -There is an impedance mismatch here, between cpusets and sched domains. -Cpusets are hierarchical and nest. Sched domains are flat; they don't -overlap and each CPU is in at most one sched domain. - -It is necessary for sched domains to be flat because load balancing -across partially overlapping sets of CPUs would risk unstable dynamics -that would be beyond our understanding. So if each of two partially -overlapping cpusets enables the flag 'sched_load_balance', then we -form a single sched domain that is a superset of both. We won't move -a task to a CPU outside it cpuset, but the scheduler load balancing -code might waste some compute cycles considering that possibility. - -This mismatch is why there is not a simple one-to-one relation -between which cpusets have the flag "sched_load_balance" enabled, -and the sched domain configuration. If a cpuset enables the flag, it -will get balancing across all its CPUs, but if it disables the flag, -it will only be assured of no load balancing if no other overlapping -cpuset enables the flag. - -If two cpusets have partially overlapping 'cpus' allowed, and only -one of them has this flag enabled, then the other may find its -tasks only partially load balanced, just on the overlapping CPUs. -This is just the general case of the top_cpuset example given a few -paragraphs above. In the general case, as in the top cpuset case, -don't leave tasks that might use non-trivial amounts of CPU in -such partially load balanced cpusets, as they may be artificially -constrained to some subset of the CPUs allowed to them, for lack of -load balancing to the other CPUs. - -1.7.1 sched_load_balance implementation details. ------------------------------------------------- - -The per-cpuset flag 'sched_load_balance' defaults to enabled (contrary -to most cpuset flags.) When enabled for a cpuset, the kernel will -ensure that it can load balance across all the CPUs in that cpuset -(makes sure that all the CPUs in the cpus_allowed of that cpuset are -in the same sched domain.) - -If two overlapping cpusets both have 'sched_load_balance' enabled, -then they will be (must be) both in the same sched domain. - -If, as is the default, the top cpuset has 'sched_load_balance' enabled, -then by the above that means there is a single sched domain covering -the whole system, regardless of any other cpuset settings. - -The kernel commits to user space that it will avoid load balancing -where it can. It will pick as fine a granularity partition of sched -domains as it can while still providing load balancing for any set -of CPUs allowed to a cpuset having 'sched_load_balance' enabled. - -The internal kernel cpuset to scheduler interface passes from the -cpuset code to the scheduler code a partition of the load balanced -CPUs in the system. This partition is a set of subsets (represented -as an array of cpumask_t) of CPUs, pairwise disjoint, that cover all -the CPUs that must be load balanced. - -Whenever the 'sched_load_balance' flag changes, or CPUs come or go -from a cpuset with this flag enabled, or a cpuset with this flag -enabled is removed, the cpuset code builds a new such partition and -passes it to the scheduler sched domain setup code, to have the sched -domains rebuilt as necessary. - -This partition exactly defines what sched domains the scheduler should -setup - one sched domain for each element (cpumask_t) in the partition. - -The scheduler remembers the currently active sched domain partitions. -When the scheduler routine partition_sched_domains() is invoked from -the cpuset code to update these sched domains, it compares the new -partition requested with the current, and updates its sched domains, -removing the old and adding the new, for each change. - - -1.8 What is sched_relax_domain_level ? --------------------------------------- - -In sched domain, the scheduler migrates tasks in 2 ways; periodic load -balance on tick, and at time of some schedule events. - -When a task is woken up, scheduler try to move the task on idle CPU. -For example, if a task A running on CPU X activates another task B -on the same CPU X, and if CPU Y is X's sibling and performing idle, -then scheduler migrate task B to CPU Y so that task B can start on -CPU Y without waiting task A on CPU X. - -And if a CPU run out of tasks in its runqueue, the CPU try to pull -extra tasks from other busy CPUs to help them before it is going to -be idle. - -Of course it takes some searching cost to find movable tasks and/or -idle CPUs, the scheduler might not search all CPUs in the domain -everytime. In fact, in some architectures, the searching ranges on -events are limited in the same socket or node where the CPU locates, -while the load balance on tick searchs all. - -For example, assume CPU Z is relatively far from CPU X. Even if CPU Z -is idle while CPU X and the siblings are busy, scheduler can't migrate -woken task B from X to Z since it is out of its searching range. -As the result, task B on CPU X need to wait task A or wait load balance -on the next tick. For some applications in special situation, waiting -1 tick may be too long. - -The 'sched_relax_domain_level' file allows you to request changing -this searching range as you like. This file takes int value which -indicates size of searching range in levels ideally as follows, -otherwise initial value -1 that indicates the cpuset has no request. - - -1 : no request. use system default or follow request of others. - 0 : no search. - 1 : search siblings (hyperthreads in a core). - 2 : search cores in a package. - 3 : search cpus in a node [= system wide on non-NUMA system] - ( 4 : search nodes in a chunk of node [on NUMA system] ) - ( 5 : search system wide [on NUMA system] ) - -The system default is architecture dependent. The system default -can be changed using the relax_domain_level= boot parameter. - -This file is per-cpuset and affect the sched domain where the cpuset -belongs to. Therefore if the flag 'sched_load_balance' of a cpuset -is disabled, then 'sched_relax_domain_level' have no effect since -there is no sched domain belonging the cpuset. - -If multiple cpusets are overlapping and hence they form a single sched -domain, the largest value among those is used. Be careful, if one -requests 0 and others are -1 then 0 is used. - -Note that modifying this file will have both good and bad effects, -and whether it is acceptable or not will be depend on your situation. -Don't modify this file if you are not sure. - -If your situation is: - - The migration costs between each cpu can be assumed considerably - small(for you) due to your special application's behavior or - special hardware support for CPU cache etc. - - The searching cost doesn't have impact(for you) or you can make - the searching cost enough small by managing cpuset to compact etc. - - The latency is required even it sacrifices cache hit rate etc. -then increasing 'sched_relax_domain_level' would benefit you. - - -1.9 How do I use cpusets ? --------------------------- - -In order to minimize the impact of cpusets on critical kernel -code, such as the scheduler, and due to the fact that the kernel -does not support one task updating the memory placement of another -task directly, the impact on a task of changing its cpuset CPU -or Memory Node placement, or of changing to which cpuset a task -is attached, is subtle. - -If a cpuset has its Memory Nodes modified, then for each task attached -to that cpuset, the next time that the kernel attempts to allocate -a page of memory for that task, the kernel will notice the change -in the tasks cpuset, and update its per-task memory placement to -remain within the new cpusets memory placement. If the task was using -mempolicy MPOL_BIND, and the nodes to which it was bound overlap with -its new cpuset, then the task will continue to use whatever subset -of MPOL_BIND nodes are still allowed in the new cpuset. If the task -was using MPOL_BIND and now none of its MPOL_BIND nodes are allowed -in the new cpuset, then the task will be essentially treated as if it -was MPOL_BIND bound to the new cpuset (even though its numa placement, -as queried by get_mempolicy(), doesn't change). If a task is moved -from one cpuset to another, then the kernel will adjust the tasks -memory placement, as above, the next time that the kernel attempts -to allocate a page of memory for that task. - -If a cpuset has its 'cpus' modified, then each task in that cpuset -will have its allowed CPU placement changed immediately. Similarly, -if a tasks pid is written to a cpusets 'tasks' file, in either its -current cpuset or another cpuset, then its allowed CPU placement is -changed immediately. If such a task had been bound to some subset -of its cpuset using the sched_setaffinity() call, the task will be -allowed to run on any CPU allowed in its new cpuset, negating the -affect of the prior sched_setaffinity() call. - -In summary, the memory placement of a task whose cpuset is changed is -updated by the kernel, on the next allocation of a page for that task, -but the processor placement is not updated, until that tasks pid is -rewritten to the 'tasks' file of its cpuset. This is done to avoid -impacting the scheduler code in the kernel with a check for changes -in a tasks processor placement. - -Normally, once a page is allocated (given a physical page -of main memory) then that page stays on whatever node it -was allocated, so long as it remains allocated, even if the -cpusets memory placement policy 'mems' subsequently changes. -If the cpuset flag file 'memory_migrate' is set true, then when -tasks are attached to that cpuset, any pages that task had -allocated to it on nodes in its previous cpuset are migrated -to the tasks new cpuset. The relative placement of the page within -the cpuset is preserved during these migration operations if possible. -For example if the page was on the second valid node of the prior cpuset -then the page will be placed on the second valid node of the new cpuset. - -Also if 'memory_migrate' is set true, then if that cpusets -'mems' file is modified, pages allocated to tasks in that -cpuset, that were on nodes in the previous setting of 'mems', -will be moved to nodes in the new setting of 'mems.' -Pages that were not in the tasks prior cpuset, or in the cpusets -prior 'mems' setting, will not be moved. - -There is an exception to the above. If hotplug functionality is used -to remove all the CPUs that are currently assigned to a cpuset, -then all the tasks in that cpuset will be moved to the nearest ancestor -with non-empty cpus. But the moving of some (or all) tasks might fail if -cpuset is bound with another cgroup subsystem which has some restrictions -on task attaching. In this failing case, those tasks will stay -in the original cpuset, and the kernel will automatically update -their cpus_allowed to allow all online CPUs. When memory hotplug -functionality for removing Memory Nodes is available, a similar exception -is expected to apply there as well. In general, the kernel prefers to -violate cpuset placement, over starving a task that has had all -its allowed CPUs or Memory Nodes taken offline. - -There is a second exception to the above. GFP_ATOMIC requests are -kernel internal allocations that must be satisfied, immediately. -The kernel may drop some request, in rare cases even panic, if a -GFP_ATOMIC alloc fails. If the request cannot be satisfied within -the current tasks cpuset, then we relax the cpuset, and look for -memory anywhere we can find it. It's better to violate the cpuset -than stress the kernel. - -To start a new job that is to be contained within a cpuset, the steps are: - - 1) mkdir /dev/cpuset - 2) mount -t cgroup -ocpuset cpuset /dev/cpuset - 3) Create the new cpuset by doing mkdir's and write's (or echo's) in - the /dev/cpuset virtual file system. - 4) Start a task that will be the "founding father" of the new job. - 5) Attach that task to the new cpuset by writing its pid to the - /dev/cpuset tasks file for that cpuset. - 6) fork, exec or clone the job tasks from this founding father task. - -For example, the following sequence of commands will setup a cpuset -named "Charlie", containing just CPUs 2 and 3, and Memory Node 1, -and then start a subshell 'sh' in that cpuset: - - mount -t cgroup -ocpuset cpuset /dev/cpuset - cd /dev/cpuset - mkdir Charlie - cd Charlie - /bin/echo 2-3 > cpus - /bin/echo 1 > mems - /bin/echo $$ > tasks - sh - # The subshell 'sh' is now running in cpuset Charlie - # The next line should display '/Charlie' - cat /proc/self/cpuset - -In the future, a C library interface to cpusets will likely be -available. For now, the only way to query or modify cpusets is -via the cpuset file system, using the various cd, mkdir, echo, cat, -rmdir commands from the shell, or their equivalent from C. - -The sched_setaffinity calls can also be done at the shell prompt using -SGI's runon or Robert Love's taskset. The mbind and set_mempolicy -calls can be done at the shell prompt using the numactl command -(part of Andi Kleen's numa package). - -2. Usage Examples and Syntax -============================ - -2.1 Basic Usage ---------------- - -Creating, modifying, using the cpusets can be done through the cpuset -virtual filesystem. - -To mount it, type: -# mount -t cgroup -o cpuset cpuset /dev/cpuset - -Then under /dev/cpuset you can find a tree that corresponds to the -tree of the cpusets in the system. For instance, /dev/cpuset -is the cpuset that holds the whole system. - -If you want to create a new cpuset under /dev/cpuset: -# cd /dev/cpuset -# mkdir my_cpuset - -Now you want to do something with this cpuset. -# cd my_cpuset - -In this directory you can find several files: -# ls -cpu_exclusive memory_migrate mems tasks -cpus memory_pressure notify_on_release -mem_exclusive memory_spread_page sched_load_balance -mem_hardwall memory_spread_slab sched_relax_domain_level - -Reading them will give you information about the state of this cpuset: -the CPUs and Memory Nodes it can use, the processes that are using -it, its properties. By writing to these files you can manipulate -the cpuset. - -Set some flags: -# /bin/echo 1 > cpu_exclusive - -Add some cpus: -# /bin/echo 0-7 > cpus - -Add some mems: -# /bin/echo 0-7 > mems - -Now attach your shell to this cpuset: -# /bin/echo $$ > tasks - -You can also create cpusets inside your cpuset by using mkdir in this -directory. -# mkdir my_sub_cs - -To remove a cpuset, just use rmdir: -# rmdir my_sub_cs -This will fail if the cpuset is in use (has cpusets inside, or has -processes attached). - -Note that for legacy reasons, the "cpuset" filesystem exists as a -wrapper around the cgroup filesystem. - -The command - -mount -t cpuset X /dev/cpuset - -is equivalent to - -mount -t cgroup -ocpuset X /dev/cpuset -echo "/sbin/cpuset_release_agent" > /dev/cpuset/release_agent - -2.2 Adding/removing cpus ------------------------- - -This is the syntax to use when writing in the cpus or mems files -in cpuset directories: - -# /bin/echo 1-4 > cpus -> set cpus list to cpus 1,2,3,4 -# /bin/echo 1,2,3,4 > cpus -> set cpus list to cpus 1,2,3,4 - -2.3 Setting flags ------------------ - -The syntax is very simple: - -# /bin/echo 1 > cpu_exclusive -> set flag 'cpu_exclusive' -# /bin/echo 0 > cpu_exclusive -> unset flag 'cpu_exclusive' - -2.4 Attaching processes ------------------------ - -# /bin/echo PID > tasks - -Note that it is PID, not PIDs. You can only attach ONE task at a time. -If you have several tasks to attach, you have to do it one after another: - -# /bin/echo PID1 > tasks -# /bin/echo PID2 > tasks - ... -# /bin/echo PIDn > tasks - - -3. Questions -============ - -Q: what's up with this '/bin/echo' ? -A: bash's builtin 'echo' command does not check calls to write() against - errors. If you use it in the cpuset file system, you won't be - able to tell whether a command succeeded or failed. - -Q: When I attach processes, only the first of the line gets really attached ! -A: We can only return one error code per call to write(). So you should also - put only ONE pid. - -4. Contact -========== - -Web: http://www.bullopensource.org/cpuset diff --git a/Documentation/scheduler/sched-design-CFS.txt b/Documentation/scheduler/sched-design-CFS.txt index 8398ca4ff4e..6f33593e59e 100644 --- a/Documentation/scheduler/sched-design-CFS.txt +++ b/Documentation/scheduler/sched-design-CFS.txt @@ -231,7 +231,7 @@ CPU bandwidth control purposes: This options needs CONFIG_CGROUPS to be defined, and lets the administrator create arbitrary groups of tasks, using the "cgroup" pseudo filesystem. See - Documentation/cgroups.txt for more information about this filesystem. + Documentation/cgroups/cgroups.txt for more information about this filesystem. Only one of these options to group tasks can be chosen and not both. -- cgit v1.2.3 From 65a67bd2644bef225ee318dde76016a4697218fa Mon Sep 17 00:00:00 2001 From: Marcus Meissner Date: Thu, 15 Jan 2009 13:51:00 -0800 Subject: Documentation/accounting/getdelays.c: fix endless loop When no option is passed to getdelays it just hangs, waiting for a reply which will never come. This patch prints usage() when no output marker is specified. Signed-off-by: Marcus Meissner Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- Documentation/accounting/getdelays.c | 4 ++++ 1 file changed, 4 insertions(+) (limited to 'Documentation') diff --git a/Documentation/accounting/getdelays.c b/Documentation/accounting/getdelays.c index cc49400b4af..7ea231172c8 100644 --- a/Documentation/accounting/getdelays.c +++ b/Documentation/accounting/getdelays.c @@ -392,6 +392,10 @@ int main(int argc, char *argv[]) goto err; } } + if (!maskset && !tid && !containerset) { + usage(); + goto err; + } do { int i; -- cgit v1.2.3 From 219beb291ba9275dd676578724103abed4cfbfe3 Mon Sep 17 00:00:00 2001 From: Pavel Machek Date: Thu, 15 Jan 2009 13:51:24 -0800 Subject: lis3: fix documentation to fit into 80 columns MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Fix lis3 documentation to fit into 80 columns. Signed-off-by: Pavel Machek Cc: Éric Piel Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- Documentation/hwmon/lis3lv02d | 30 +++++++++++++++++------------- 1 file changed, 17 insertions(+), 13 deletions(-) (limited to 'Documentation') diff --git a/Documentation/hwmon/lis3lv02d b/Documentation/hwmon/lis3lv02d index 65dfb0c0fd6..0fcfc4a7ccd 100644 --- a/Documentation/hwmon/lis3lv02d +++ b/Documentation/hwmon/lis3lv02d @@ -13,18 +13,21 @@ Author: Description ----------- -This driver provides support for the accelerometer found in various HP laptops -sporting the feature officially called "HP Mobile Data Protection System 3D" or -"HP 3D DriveGuard". It detect automatically laptops with this sensor. Known models -(for now the HP 2133, nc6420, nc2510, nc8510, nc84x0, nw9440 and nx9420) will -have their axis automatically oriented on standard way (eg: you can directly -play neverball). The accelerometer data is readable via +This driver provides support for the accelerometer found in various HP +laptops sporting the feature officially called "HP Mobile Data +Protection System 3D" or "HP 3D DriveGuard". It detect automatically +laptops with this sensor. Known models (for now the HP 2133, nc6420, +nc2510, nc8510, nc84x0, nw9440 and nx9420) will have their axis +automatically oriented on standard way (eg: you can directly play +neverball). The accelerometer data is readable via /sys/devices/platform/lis3lv02d. Sysfs attributes under /sys/devices/platform/lis3lv02d/: position - 3D position that the accelerometer reports. Format: "(x,y,z)" -calibrate - read: values (x, y, z) that are used as the base for input class device operation. - write: forces the base to be recalibrated with the current position. +calibrate - read: values (x, y, z) that are used as the base for input + class device operation. + write: forces the base to be recalibrated with the current + position. rate - reports the sampling rate of the accelerometer device in HZ This driver also provides an absolute input class device, allowing @@ -39,11 +42,12 @@ the accelerometer are converted into a "standard" organisation of the axes * When the laptop is horizontal the position reported is about 0 for X and Y and a positive value for Z * If the left side is elevated, X increases (becomes positive) - * If the front side (where the touchpad is) is elevated, Y decreases (becomes negative) + * If the front side (where the touchpad is) is elevated, Y decreases + (becomes negative) * If the laptop is put upside-down, Z becomes negative -If your laptop model is not recognized (cf "dmesg"), you can send an email to the -authors to add it to the database. When reporting a new laptop, please include -the output of "dmidecode" plus the value of /sys/devices/platform/lis3lv02d/position -in these four cases. +If your laptop model is not recognized (cf "dmesg"), you can send an +email to the authors to add it to the database. When reporting a new +laptop, please include the output of "dmidecode" plus the value of +/sys/devices/platform/lis3lv02d/position in these four cases. -- cgit v1.2.3 From cd9f8e64c232eeb1247950007ee95de00b89ba7a Mon Sep 17 00:00:00 2001 From: Henrik Kretzschmar Date: Sun, 18 Jan 2009 10:40:24 +0100 Subject: sound: Remove removed OSS kernel parameters from doc Remove removed OSS kernel parameters from kernel-parameters.txt Remove the kernel parameters from the OSS drivers of the chips es1371 (removed 10-2007/2.6.24) and cs4232 (removed 02-2008/2.6.25) from the kernel parameters documentation. Signed-off-by: Henrik Kretzschmar Signed-off-by: Takashi Iwai --- Documentation/kernel-parameters.txt | 7 ------- 1 file changed, 7 deletions(-) (limited to 'Documentation') diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt index 8511d3532c2..d8362cf9909 100644 --- a/Documentation/kernel-parameters.txt +++ b/Documentation/kernel-parameters.txt @@ -577,9 +577,6 @@ and is between 256 and 4096 characters. It is defined in the file a memory unit (amount[KMG]). See also Documentation/kdump/kdump.txt for a example. - cs4232= [HW,OSS] - Format: ,,,,, - cs89x0_dma= [HW,NET] Format: @@ -732,10 +729,6 @@ and is between 256 and 4096 characters. It is defined in the file Default value is 0. Value can be changed at runtime via /selinux/enforce. - es1371= [HW,OSS] - Format: ,[,[]] - See also header of sound/oss/es1371.c. - ether= [HW,NET] Ethernet cards parameters This option is obsoleted by the "netdev=" option, which has equivalent usage. See its documentation for details. -- cgit v1.2.3 From 32ed3f4640631ab7a4c0bc0f1463cf019d510341 Mon Sep 17 00:00:00 2001 From: Matthew Ranostay Date: Thu, 22 Jan 2009 20:53:29 -0500 Subject: ALSA: hda: Add STAC92HD83XXX_PWR_REF quirk Some revisions of the 92hd8xxx codec's not supporting port power downs in which the using of it causes capture and also randomly playback streams to not function at all. Thus by disabling it by default and adding a option to enable it manually will fix all issue on current and future revisions. Signed-off-by: Matthew Ranostay Signed-off-by: Takashi Iwai --- Documentation/sound/alsa/HD-Audio-Models.txt | 1 + 1 file changed, 1 insertion(+) (limited to 'Documentation') diff --git a/Documentation/sound/alsa/HD-Audio-Models.txt b/Documentation/sound/alsa/HD-Audio-Models.txt index 64eb1100eec..0f5d26bea80 100644 --- a/Documentation/sound/alsa/HD-Audio-Models.txt +++ b/Documentation/sound/alsa/HD-Audio-Models.txt @@ -349,6 +349,7 @@ STAC92HD73* STAC92HD83* =========== ref Reference board + mic-ref Reference board with power managment for ports STAC9872 ======== -- cgit v1.2.3 From e955281cd6afef7ad7ea11cae0ca71d78a7b2b2b Mon Sep 17 00:00:00 2001 From: Jesse Barnes Date: Mon, 26 Jan 2009 12:19:23 -0800 Subject: networking: document "nc" in addition to "netcat" in netconsole.txt It always annoyed me that the netconsole documentation didn't give me the correct command for my distro. Update it with a command line that actually works on my Fedora install. Signed-off-by: Jesse Barnes Signed-off-by: Randy Dunlap Signed-off-by: Matt Mackall Signed-off-by: David S. Miller --- Documentation/networking/netconsole.txt | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) (limited to 'Documentation') diff --git a/Documentation/networking/netconsole.txt b/Documentation/networking/netconsole.txt index 3c2f2b32863..8d022073e3e 100644 --- a/Documentation/networking/netconsole.txt +++ b/Documentation/networking/netconsole.txt @@ -51,7 +51,8 @@ Built-in netconsole starts immediately after the TCP stack is initialized and attempts to bring up the supplied dev at the supplied address. -The remote host can run either 'netcat -u -l -p ' or syslogd. +The remote host can run either 'netcat -u -l -p ', +'nc -l -u ' or syslogd. Dynamic reconfiguration: ======================== -- cgit v1.2.3 From 096abd77038a2ff74efd194d074eadcde80fb97d Mon Sep 17 00:00:00 2001 From: James Lentini Date: Thu, 8 Jan 2009 13:13:26 -0500 Subject: update port number in NFS/RDMA documentation Update the NFS/RDMA documentation to use the new port number assigned by IANA. Signed-off-by: James Lentini Signed-off-by: J. Bruce Fields --- Documentation/filesystems/nfs-rdma.txt | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) (limited to 'Documentation') diff --git a/Documentation/filesystems/nfs-rdma.txt b/Documentation/filesystems/nfs-rdma.txt index 44bd766f2e5..85eaeaddd27 100644 --- a/Documentation/filesystems/nfs-rdma.txt +++ b/Documentation/filesystems/nfs-rdma.txt @@ -251,7 +251,7 @@ NFS/RDMA Setup Instruct the server to listen on the RDMA transport: - $ echo rdma 2050 > /proc/fs/nfsd/portlist + $ echo rdma 20049 > /proc/fs/nfsd/portlist - On the client system @@ -263,7 +263,7 @@ NFS/RDMA Setup Regardless of how the client was built (module or built-in), use this command to mount the NFS/RDMA server: - $ mount -o rdma,port=2050 :/ /mnt + $ mount -o rdma,port=20049 :/ /mnt To verify that the mount is using RDMA, run "cat /proc/mounts" and check the "proto" field for the given mount. -- cgit v1.2.3 From 720893fd5fb6de1f752f816a89e630f08ae8b20a Mon Sep 17 00:00:00 2001 From: Tsugikazu Shibata Date: Fri, 23 Jan 2009 09:59:50 +0900 Subject: Sync patch for jp_JP/stable_kernel_rules.txt Updated jp_JP/stable_kernel_rules.txt due to changes in the main version of the file. Also, this patch is already reviewed by Japanese translation community called JF. Signed-off-by: Tsugikazu Shibata Signed-off-by: Greg Kroah-Hartman --- Documentation/ja_JP/stable_kernel_rules.txt | 15 ++++++++++----- 1 file changed, 10 insertions(+), 5 deletions(-) (limited to 'Documentation') diff --git a/Documentation/ja_JP/stable_kernel_rules.txt b/Documentation/ja_JP/stable_kernel_rules.txt index b3ffe870de3..14265837c4c 100644 --- a/Documentation/ja_JP/stable_kernel_rules.txt +++ b/Documentation/ja_JP/stable_kernel_rules.txt @@ -12,11 +12,11 @@ file at first. ================================== これは、 -linux-2.6.24/Documentation/stable_kernel_rules.txt +linux-2.6.29/Documentation/stable_kernel_rules.txt の和訳です。 翻訳団体： JF プロジェクト < http://www.linux.or.jp/JF/ > -翻訳日： 2007/12/30 +翻訳日： 2009/1/14 翻訳者： Tsugikazu Shibata 校正者： 武井伸光さん、 かねこさん (Seiji Kaneko) @@ -38,12 +38,15 @@ linux-2.6.24/Documentation/stable_kernel_rules.txt - ビルドエラー(CONFIG_BROKENになっているものを除く), oops, ハング、デー タ破壊、現実のセキュリティ問題、その他 "ああ、これはダメだね"という ようなものを修正しなければならない。短く言えば、重大な問題。 + - 新しい device ID とクオークも受け入れられる。 - どのように競合状態が発生するかの説明も一緒に書かれていない限り、 "理論的には競合状態になる"ようなものは不可。 - いかなる些細な修正も含めることはできない。(スペルの修正、空白のクリー ンアップなど) - - 対応するサブシステムメンテナが受け入れたものでなければならない。 - Documentation/SubmittingPatches の規則に従ったものでなければならない。 + - パッチ自体か同等の修正が Linus のツリーに既に存在しなければならない。 +　 Linus のツリーでのコミットID を -stable へのパッチ投稿の際に引用す + ること。 -stable ツリーにパッチを送付する手続き- @@ -52,8 +55,10 @@ linux-2.6.24/Documentation/stable_kernel_rules.txt - 送信者はパッチがキューに受け付けられた際には ACK を、却下された場合 には NAK を受け取る。この反応は開発者たちのスケジュールによって、数 日かかる場合がある。 - - もし受け取られたら、パッチは他の開発者たちのレビューのために - -stable キューに追加される。 + - もし受け取られたら、パッチは他の開発者たちと関連するサブシステムの + メンテナーによるレビューのために -stable キューに追加される。 + - パッチに stable@kernel.org のアドレスが付加されているときには、それ + が Linus のツリーに入る時に自動的に stable チームに email される。 - セキュリティパッチはこのエイリアス (stable@kernel.org) に送られるべ きではなく、代わりに security@kernel.org のアドレスに送られる。 -- cgit v1.2.3 From 6a1b699678c8c0d45f88a37b32358a9e82bef6bb Mon Sep 17 00:00:00 2001 From: "Hans J. Koch" Date: Wed, 7 Jan 2009 00:12:37 +0100 Subject: UIO: Add missing documentation of features added recently MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit The following features were added to the UIO framework in the near past: * Generic drivers for platform devices (uio_pdrv, uio_pdrv_genirq) * an "offset" sysfs attribute for memory mappings Unfortunately, all this went in without documentation (won't happen again...) This patch updates UIO documentation. Signed-off-by: Hans J. Koch Acked-by: Uwe Kleine-König Signed-off-by: Greg Kroah-Hartman --- Documentation/DocBook/uio-howto.tmpl | 88 ++++++++++++++++++++++++++++++++++++ 1 file changed, 88 insertions(+) (limited to 'Documentation') diff --git a/Documentation/DocBook/uio-howto.tmpl b/Documentation/DocBook/uio-howto.tmpl index b787e4721c9..52e1b79ce0e 100644 --- a/Documentation/DocBook/uio-howto.tmpl +++ b/Documentation/DocBook/uio-howto.tmpl @@ -41,6 +41,12 @@ GPL version 2. + + 0.7 + 2008-12-23 + hjk + Added generic platform drivers and offset attribute. + 0.6 2008-12-05 @@ -312,6 +318,16 @@ interested in translating it, please email me pointed to by addr. + + + offset: The offset, in bytes, that has to be + added to the pointer returned by mmap() to get + to the actual device memory. This is important if the device's memory + is not page aligned. Remember that pointers returned by + mmap() are always page aligned, so it is good + style to always add this offset. + + @@ -594,6 +610,78 @@ framework to set up sysfs files for this region. Simply leave it alone. + +Using uio_pdrv for platform devices + + In many cases, UIO drivers for platform devices can be handled in a + generic way. In the same place where you define your + struct platform_device, you simply also implement + your interrupt handler and fill your + struct uio_info. A pointer to this + struct uio_info is then used as + platform_data for your platform device. + + + You also need to set up an array of struct resource + containing addresses and sizes of your memory mappings. This + information is passed to the driver using the + .resource and .num_resources + elements of struct platform_device. + + + You now have to set the .name element of + struct platform_device to + "uio_pdrv" to use the generic UIO platform device + driver. This driver will fill the mem[] array + according to the resources given, and register the device. + + + The advantage of this approach is that you only have to edit a file + you need to edit anyway. You do not have to create an extra driver. + + + + +Using uio_pdrv_genirq for platform devices + + Especially in embedded devices, you frequently find chips where the + irq pin is tied to its own dedicated interrupt line. In such cases, + where you can be really sure the interrupt is not shared, we can take + the concept of uio_pdrv one step further and use a + generic interrupt handler. That's what + uio_pdrv_genirq does. + + + The setup for this driver is the same as described above for + uio_pdrv, except that you do not implement an + interrupt handler. The .handler element of + struct uio_info must remain + NULL. The .irq_flags element + must not contain IRQF_SHARED. + + + You will set the .name element of + struct platform_device to + "uio_pdrv_genirq" to use this driver. + + + The generic interrupt handler of uio_pdrv_genirq + will simply disable the interrupt line using + disable_irq_nosync(). After doing its work, + userspace can reenable the interrupt by writing 0x00000001 to the UIO + device file. The driver already implements an + irq_control() to make this possible, you must not + implement your own. + + + Using uio_pdrv_genirq not only saves a few lines of + interrupt handler code. You also do not need to know anything about + the chip's internal registers to create the kernel part of the driver. + All you need to know is the irq number of the pin the chip is + connected to. + + + -- cgit v1.2.3 From f90c3c0bdd7a3f16eecf1b077f5e031c44ddb605 Mon Sep 17 00:00:00 2001 From: Simon Harrison Date: Fri, 9 Jan 2009 09:07:07 -0300 Subject: V4L/DVB (10210): Fix a bug on v4lgrab.c v4lgrab breaks the fputc macro on some systems, because of #defined FILE. Also, I also added comments because it was not at all clear that to get gspca cameras to work with this application you need v4l1compat. Signed-off-by: Simon Harrison Signed-off-by: Mauro Carvalho Chehab --- Documentation/video4linux/v4lgrab.c | 25 +++++++++++++++++-------- 1 file changed, 17 insertions(+), 8 deletions(-) (limited to 'Documentation') diff --git a/Documentation/video4linux/v4lgrab.c b/Documentation/video4linux/v4lgrab.c index 079b628481c..d6e70bef8ad 100644 --- a/Documentation/video4linux/v4lgrab.c +++ b/Documentation/video4linux/v4lgrab.c @@ -4,12 +4,21 @@ * * Compile with: * gcc -s -Wall -Wstrict-prototypes v4lgrab.c -o v4lgrab - * Use as: - * v4lgrab >image.ppm + * Use as: + * v4lgrab >image.ppm * * Copyright (C) 1998-05-03, Phil Blundell - * Copied from http://www.tazenda.demon.co.uk/phil/vgrabber.c - * with minor modifications (Dave Forrest, drf5n@virginia.edu). + * Copied from http://www.tazenda.demon.co.uk/phil/vgrabber.c + * with minor modifications (Dave Forrest, drf5n@virginia.edu). + * + * + * For some cameras you may need to pre-load libv4l to perform + * the necessary decompression, e.g.: + * + * export LD_PRELOAD=/usr/lib/libv4l/v4l1compat.so + * ./v4lgrab >image.ppm + * + * see http://hansdegoede.livejournal.com/3636.html for details. * */ @@ -24,7 +33,7 @@ #include #include -#define FILE "/dev/video0" +#define VIDEO_DEV "/dev/video0" /* Stole this from tvset.c */ @@ -90,7 +99,7 @@ int get_brightness_adj(unsigned char *image, long size, int *brightness) { int main(int argc, char ** argv) { - int fd = open(FILE, O_RDONLY), f; + int fd = open(VIDEO_DEV, O_RDONLY), f; struct video_capability cap; struct video_window win; struct video_picture vpic; @@ -100,13 +109,13 @@ int main(int argc, char ** argv) unsigned int i, src_depth; if (fd < 0) { - perror(FILE); + perror(VIDEO_DEV); exit(1); } if (ioctl(fd, VIDIOCGCAP, &cap) < 0) { perror("VIDIOGCAP"); - fprintf(stderr, "(" FILE " not a video4linux device?)\n"); + fprintf(stderr, "(" VIDEO_DEV " not a video4linux device?)\n"); close(fd); exit(1); } -- cgit v1.2.3 From 27ad27993313312a4ad0047d0a944c425cd511a5 Mon Sep 17 00:00:00 2001 From: Artem Bityutskiy Date: Thu, 29 Jan 2009 16:34:30 +0200 Subject: UBIFS: remove fast unmounting This UBIFS feature has never worked properly, and it was a mistake to add it because we simply have no use-cases. So, lets still accept the fast_unmount mount option, but ignore it. This does not change much, because UBIFS commit in sync_fs anyway, and sync_fs is called while unmounting. Signed-off-by: Artem Bityutskiy --- Documentation/filesystems/ubifs.txt | 7 ------- 1 file changed, 7 deletions(-) (limited to 'Documentation') diff --git a/Documentation/filesystems/ubifs.txt b/Documentation/filesystems/ubifs.txt index 84da2a4ba25..12fedb7834c 100644 --- a/Documentation/filesystems/ubifs.txt +++ b/Documentation/filesystems/ubifs.txt @@ -79,13 +79,6 @@ Mount options (*) == default. -norm_unmount (*) commit on unmount; the journal is committed - when the file-system is unmounted so that the - next mount does not have to replay the journal - and it becomes very fast; -fast_unmount do not commit on unmount; this option makes - unmount faster, but the next mount slower - because of the need to replay the journal. bulk_read read more in one go to take advantage of flash media that read faster sequentially no_bulk_read (*) do not bulk-read -- cgit v1.2.3 From 58092d1e0a896eb1d9163d58f93df7ed704fa8e1 Mon Sep 17 00:00:00 2001 From: Stephen Hemminger Date: Thu, 29 Jan 2009 16:16:31 -0800 Subject: net: update documentation ip aliases This documentation is old. Add a short note to describe why aliases are no long necessary, and remove the old contact/edit info. Signed-off-by: Stephen Hemminger Signed-off-by: David S. Miller --- Documentation/networking/alias.txt | 25 ++++++------------------- 1 file changed, 6 insertions(+), 19 deletions(-) (limited to 'Documentation') diff --git a/Documentation/networking/alias.txt b/Documentation/networking/alias.txt index cd12c2ff518..85046f53fcf 100644 --- a/Documentation/networking/alias.txt +++ b/Documentation/networking/alias.txt @@ -2,13 +2,13 @@ IP-Aliasing: ============ -IP-aliases are additional IP-addresses/masks hooked up to a base -interface by adding a colon and a string when running ifconfig. -This string is usually numeric, but this is not a must. - -IP-Aliases are avail if CONFIG_INET (`standard' IPv4 networking) -is configured in the kernel. +IP-aliases are an obsolete way to manage multiple IP-addresses/masks +per interface. Newer tools such as iproute2 support multiple +address/prefixes per interface, but aliases are still supported +for backwards compatibility. +An alias is formed by adding a colon and a string when running ifconfig. +This string is usually numeric, but this is not a must. o Alias creation. Alias creation is done by 'magic' interface naming: eg. to create a @@ -38,16 +38,3 @@ o Relationship with main device If the base device is shut down the added aliases will be deleted too. - - -Contact -------- -Please finger or e-mail me: - Juan Jose Ciarlante - -Updated by Erik Schoenfelder - -; local variables: -; mode: indented-text -; mode: auto-fill -; end: -- cgit v1.2.3 From b44d49ab0954accefba4c71274ab58abe1c25c52 Mon Sep 17 00:00:00 2001 From: Tim 'mithro' Ansell Date: Thu, 22 Jan 2009 15:06:41 +1100 Subject: lguest: disable the FORTIFY for lguest. Makes all the warnings go away when compiling lguest on Ubuntu on Intrepid or greater. Signed-off-by: Timothy R Ansell Signed-off-by: Rusty Russell --- Documentation/lguest/Makefile | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'Documentation') diff --git a/Documentation/lguest/Makefile b/Documentation/lguest/Makefile index 725eef81cd4..1f4f9e888bd 100644 --- a/Documentation/lguest/Makefile +++ b/Documentation/lguest/Makefile @@ -1,5 +1,5 @@ # This creates the demonstration utility "lguest" which runs a Linux guest. -CFLAGS:=-Wall -Wmissing-declarations -Wmissing-prototypes -O3 -I../../include -I../../arch/x86/include +CFLAGS:=-Wall -Wmissing-declarations -Wmissing-prototypes -O3 -I../../include -I../../arch/x86/include -U_FORTIFY_SOURCE LDLIBS:=-lz all: lguest -- cgit v1.2.3 From 9e9e3cbc62da43c66e894d5a61fa08b427e25202 Mon Sep 17 00:00:00 2001 From: Evgeniy Polyakov Date: Thu, 29 Jan 2009 14:25:09 -0800 Subject: mm: OOM documentation update Signed-off-by: Evgeniy Polyakov Acked-by: David Rientjes Cc: Randy Dunlap Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- Documentation/filesystems/proc.txt | 28 ++++++++++++++++++++++++++++ 1 file changed, 28 insertions(+) (limited to 'Documentation') diff --git a/Documentation/filesystems/proc.txt b/Documentation/filesystems/proc.txt index bbebc3a43ac..a87be42f821 100644 --- a/Documentation/filesystems/proc.txt +++ b/Documentation/filesystems/proc.txt @@ -2027,6 +2027,34 @@ increase the likelihood of this process being killed by the oom-killer. Valid values are in the range -16 to +15, plus the special value -17, which disables oom-killing altogether for this process. +The process to be killed in an out-of-memory situation is selected among all others +based on its badness score. This value equals the original memory size of the process +and is then updated according to its CPU time (utime + stime) and the +run time (uptime - start time). The longer it runs the smaller is the score. +Badness score is divided by the square root of the CPU time and then by +the double square root of the run time. + +Swapped out tasks are killed first. Half of each child's memory size is added to +the parent's score if they do not share the same memory. Thus forking servers +are the prime candidates to be killed. Having only one 'hungry' child will make +parent less preferable than the child. + +/proc//oom_score shows process' current badness score. + +The following heuristics are then applied: + * if the task was reniced, its score doubles + * superuser or direct hardware access tasks (CAP_SYS_ADMIN, CAP_SYS_RESOURCE + or CAP_SYS_RAWIO) have their score divided by 4 + * if oom condition happened in one cpuset and checked task does not belong + to it, its score is divided by 8 + * the resulting score is multiplied by two to the power of oom_adj, i.e. + points <<= oom_adj when it is positive and + points >>= -(oom_adj) otherwise + +The task with the highest badness score is then selected and its children +are killed, process itself will be killed in an OOM situation when it does +not have children or some of them disabled oom like described above. + 2.13 /proc//oom_score - Display current oom-killer score ------------------------------------------------------------- -- cgit v1.2.3 From 8d50d369d1b3ccc4d96ce01f62146173ee7064ca Mon Sep 17 00:00:00 2001 From: KAMEZAWA Hiroyuki Date: Thu, 29 Jan 2009 14:25:14 -0800 Subject: memcg: update document to mention that swapoff should be tested Considering the recently found problem "memcg: fix refcnt handling at swapoff", it's better to mention swapoff behavior in the memcg_test document. Signed-off-by: KAMEZAWA Hiroyuki Acked-by: Balbir Singh Cc: Li Zefan Cc: Daisuke Nishimura Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- Documentation/cgroups/memcg_test.txt | 24 ++++++++++++++++++++++-- 1 file changed, 22 insertions(+), 2 deletions(-) (limited to 'Documentation') diff --git a/Documentation/cgroups/memcg_test.txt b/Documentation/cgroups/memcg_test.txt index 19533f93b7a..523a9c16c40 100644 --- a/Documentation/cgroups/memcg_test.txt +++ b/Documentation/cgroups/memcg_test.txt @@ -1,6 +1,6 @@ Memory Resource Controller(Memcg) Implementation Memo. -Last Updated: 2008/12/15 -Base Kernel Version: based on 2.6.28-rc8-mm. +Last Updated: 2009/1/19 +Base Kernel Version: based on 2.6.29-rc2. Because VM is getting complex (one of reasons is memcg...), memcg's behavior is complex. This is a document for memcg's internal behavior. @@ -340,3 +340,23 @@ Under below explanation, we assume CONFIG_MEM_RES_CTRL_SWAP=y. # mount -t cgroup none /cgroup -t cpuset,memory,cpu,devices and do task move, mkdir, rmdir etc...under this. + + 9.7 swapoff. + Besides management of swap is one of complicated parts of memcg, + call path of swap-in at swapoff is not same as usual swap-in path.. + It's worth to be tested explicitly. + + For example, test like following is good. + (Shell-A) + # mount -t cgroup none /cgroup -t memory + # mkdir /cgroup/test + # echo 40M > /cgroup/test/memory.limit_in_bytes + # echo 0 > /cgroup/test/tasks + Run malloc(100M) program under this. You'll see 60M of swaps. + (Shell-B) + # move all tasks in /cgroup/test to /cgroup + # /sbin/swapoff -a + # rmdir /test/cgroup + # kill malloc task. + + Of course, tmpfs v.s. swapoff test should be tested, too. -- cgit v1.2.3 From 5872fb94f85d2e4fdef94657bd14e1a492df9825 Mon Sep 17 00:00:00 2001 From: Randy Dunlap Date: Thu, 29 Jan 2009 16:28:02 -0800 Subject: Documentation: move DMA-mapping.txt to Doc/PCI/ Move DMA-mapping.txt to Documentation/PCI/. DMA-mapping.txt was supposed to be moved from Documentation/ to Documentation/PCI/. The 00-INDEX files in those two directories were updated, along with a few other text files, but the file itself somehow escaped being moved, so move it and update more text files and source files with its new location. Signed-off-by: Randy Dunlap Acked-by: Greg Kroah-Hartman cc: Jesse Barnes Signed-off-by: Linus Torvalds --- Documentation/DMA-API.txt | 2 +- Documentation/IO-mapping.txt | 4 ++-- Documentation/block/biodoc.txt | 5 +++-- Documentation/usb/dma.txt | 11 ++++++----- 4 files changed, 12 insertions(+), 10 deletions(-) (limited to 'Documentation') diff --git a/Documentation/DMA-API.txt b/Documentation/DMA-API.txt index 52441694fe0..2a3fcc55e98 100644 --- a/Documentation/DMA-API.txt +++ b/Documentation/DMA-API.txt @@ -5,7 +5,7 @@ This document describes the DMA API. For a more gentle introduction phrased in terms of the pci_ equivalents (and actual examples) see -DMA-mapping.txt +Documentation/PCI/PCI-DMA-mapping.txt. This API is split into two pieces. Part I describes the API and the corresponding pci_ API. Part II describes the extensions to the API diff --git a/Documentation/IO-mapping.txt b/Documentation/IO-mapping.txt index 86edb61bdee..78a440695e1 100644 --- a/Documentation/IO-mapping.txt +++ b/Documentation/IO-mapping.txt @@ -1,6 +1,6 @@ [ NOTE: The virt_to_bus() and bus_to_virt() functions have been - superseded by the functionality provided by the PCI DMA - interface (see Documentation/DMA-mapping.txt). They continue + superseded by the functionality provided by the PCI DMA interface + (see Documentation/PCI/PCI-DMA-mapping.txt). They continue to be documented below for historical purposes, but new code must not use them. --davidm 00/12/12 ] diff --git a/Documentation/block/biodoc.txt b/Documentation/block/biodoc.txt index 3c5434c83da..5d2480d33b4 100644 --- a/Documentation/block/biodoc.txt +++ b/Documentation/block/biodoc.txt @@ -186,8 +186,9 @@ a virtual address mapping (unlike the earlier scheme of virtual address do not have a corresponding kernel virtual address space mapping) and low-memory pages. -Note: Please refer to DMA-mapping.txt for a discussion on PCI high mem DMA -aspects and mapping of scatter gather lists, and support for 64 bit PCI. +Note: Please refer to Documentation/PCI/PCI-DMA-mapping.txt for a discussion +on PCI high mem DMA aspects and mapping of scatter gather lists, and support +for 64 bit PCI. Special handling is required only for cases where i/o needs to happen on pages at physical memory addresses beyond what the device can support. In these diff --git a/Documentation/usb/dma.txt b/Documentation/usb/dma.txt index e8b50b7de9d..cfdcd16e3ab 100644 --- a/Documentation/usb/dma.txt +++ b/Documentation/usb/dma.txt @@ -6,8 +6,9 @@ in the kernel usb programming guide (kerneldoc, from the source code). API OVERVIEW The big picture is that USB drivers can continue to ignore most DMA issues, -though they still must provide DMA-ready buffers (see DMA-mapping.txt). -That's how they've worked through the 2.4 (and earlier) kernels. +though they still must provide DMA-ready buffers (see +Documentation/PCI/PCI-DMA-mapping.txt). That's how they've worked through +the 2.4 (and earlier) kernels. OR: they can now be DMA-aware. @@ -62,8 +63,8 @@ and effects like cache-trashing can impose subtle penalties. force a consistent memory access ordering by using memory barriers. It's not using a streaming DMA mapping, so it's good for small transfers on systems where the I/O would otherwise thrash an IOMMU mapping. (See - Documentation/DMA-mapping.txt for definitions of "coherent" and "streaming" - DMA mappings.) + Documentation/PCI/PCI-DMA-mapping.txt for definitions of "coherent" and + "streaming" DMA mappings.) Asking for 1/Nth of a page (as well as asking for N pages) is reasonably space-efficient. @@ -93,7 +94,7 @@ WORKING WITH EXISTING BUFFERS Existing buffers aren't usable for DMA without first being mapped into the DMA address space of the device. However, most buffers passed to your driver can safely be used with such DMA mapping. (See the first section -of DMA-mapping.txt, titled "What memory is DMA-able?") +of Documentation/PCI/PCI-DMA-mapping.txt, titled "What memory is DMA-able?") - When you're using scatterlists, you can map everything at once. On some systems, this kicks in an IOMMU and turns the scatterlists into single -- cgit v1.2.3 From 0acbc6c651911dc9ffb4f59b34306bc1ccb751e5 Mon Sep 17 00:00:00 2001 From: Teemu Likonen Date: Thu, 29 Jan 2009 16:28:16 -0800 Subject: Documentation: update CodingStyle tips for Emacs users With the previous Emacs tips example the kernel style was made available for files in the kernel-tree only. This patch updates the tip to add a separate cc-mode indent style ("linux-tabs-only"). This makes it easy to switch between different indent styles and also makes the kernel style easily available for any filetype mode (c++, awk, ...) that is managed by the Emacs cc-mode. Signed-off-by: Teemu Likonen Signed-off-by: Randy Dunlap Signed-off-by: Linus Torvalds --- Documentation/CodingStyle | 15 +++++++++++---- 1 file changed, 11 insertions(+), 4 deletions(-) (limited to 'Documentation') diff --git a/Documentation/CodingStyle b/Documentation/CodingStyle index 1875e502f87..7b5762eded2 100644 --- a/Documentation/CodingStyle +++ b/Documentation/CodingStyle @@ -483,6 +483,16 @@ values. To do the latter, you can stick the following in your .emacs file: (* (max steps 1) c-basic-offset))) +(add-hook 'c-mode-common-hook + (lambda () + ;; Add kernel style + (c-add-style + "linux-tabs-only" + '("linux" (c-offsets-alist + (arglist-cont-nonempty + c-lineup-gcc-asm-reg + c-lineup-arglist-tabs-only)))))) + (add-hook 'c-mode-hook (lambda () (let ((filename (buffer-file-name))) @@ -490,10 +500,7 @@ values. To do the latter, you can stick the following in your .emacs file: (when (and filename (string-match "~/src/linux-trees" filename)) (setq indent-tabs-mode t) - (c-set-style "linux") - (c-set-offset 'arglist-cont-nonempty - '(c-lineup-gcc-asm-reg - c-lineup-arglist-tabs-only)))))) + (c-set-style "linux-tabs-only"))))) This will make emacs go better with the kernel coding style for C files below ~/src/linux-trees. -- cgit v1.2.3 From 70221395ba980392ba98c1d78f6c9f77be03df9e Mon Sep 17 00:00:00 2001 From: Dan Carpenter Date: Thu, 29 Jan 2009 16:28:28 -0800 Subject: fix emacs indenting howto filename expansion I don't think emacs understands tilde expansion, so use "expand-file-name" to do that. Signed-off-by: Dan Carpenter Signed-off-by: Randy Dunlap Signed-off-by: Linus Torvalds --- Documentation/CodingStyle | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) (limited to 'Documentation') diff --git a/Documentation/CodingStyle b/Documentation/CodingStyle index 7b5762eded2..72968cd5eaf 100644 --- a/Documentation/CodingStyle +++ b/Documentation/CodingStyle @@ -498,7 +498,8 @@ values. To do the latter, you can stick the following in your .emacs file: (let ((filename (buffer-file-name))) ;; Enable kernel mode for the appropriate files (when (and filename - (string-match "~/src/linux-trees" filename)) + (string-match (expand-file-name "~/src/linux-trees") + filename)) (setq indent-tabs-mode t) (c-set-style "linux-tabs-only"))))) -- cgit v1.2.3 From 242f45da5b7bf63c50f1f18301750712e7885dd6 Mon Sep 17 00:00:00 2001 From: Bill Nottingham Date: Thu, 29 Jan 2009 16:28:40 -0800 Subject: Documentation/Changes: add required versions for new filesystems btrfs requires version 0.18 of its tools, and squashfs requires 4.0. ext3 should use and ext4 requires v1.41.4 of e2fsprogs. Signed-off-by: Bill Nottingham Signed-off-by: Randy Dunlap cc: Ted Tso Signed-off-by: Linus Torvalds --- Documentation/Changes | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) (limited to 'Documentation') diff --git a/Documentation/Changes b/Documentation/Changes index cb2b141b1c3..b95082be4d5 100644 --- a/Documentation/Changes +++ b/Documentation/Changes @@ -33,10 +33,12 @@ o Gnu make 3.79.1 # make --version o binutils 2.12 # ld -v o util-linux 2.10o # fdformat --version o module-init-tools 0.9.10 # depmod -V -o e2fsprogs 1.29 # tune2fs +o e2fsprogs 1.41.4 # e2fsck -V o jfsutils 1.1.3 # fsck.jfs -V o reiserfsprogs 3.6.3 # reiserfsck -V 2>&1|grep reiserfsprogs o xfsprogs 2.6.0 # xfs_db -V +o squashfs-tools 4.0 # mksquashfs -version +o btrfs-progs 0.18 # btrfsck o pcmciautils 004 # pccardctl -V o quota-tools 3.09 # quota -V o PPP 2.4.0 # pppd --version -- cgit v1.2.3 From 7598909e3ee2a08726276d6415b69dadb52d0d76 Mon Sep 17 00:00:00 2001 From: Nikanth Karthikesan Date: Tue, 27 Jan 2009 09:29:24 +0100 Subject: Mark mandatory elevator functions in the biodoc.txt biodoc.txt mentions that elevator functions marked with * are mandatory, but no function is marked with *. Mark the 3 functions which should be implemented by any io scheduler. Signed-off-by: Nikanth Karthikesan Signed-off-by: Jens Axboe --- Documentation/block/biodoc.txt | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) (limited to 'Documentation') diff --git a/Documentation/block/biodoc.txt b/Documentation/block/biodoc.txt index 5d2480d33b4..ecad6ee7570 100644 --- a/Documentation/block/biodoc.txt +++ b/Documentation/block/biodoc.txt @@ -954,14 +954,14 @@ elevator_allow_merge_fn called whenever the block layer determines results in some sort of conflict internally, this hook allows it to do that. -elevator_dispatch_fn fills the dispatch queue with ready requests. +elevator_dispatch_fn* fills the dispatch queue with ready requests. I/O schedulers are free to postpone requests by not filling the dispatch queue unless @force is non-zero. Once dispatched, I/O schedulers are not allowed to manipulate the requests - they belong to generic dispatch queue. -elevator_add_req_fn called to add a new request into the scheduler +elevator_add_req_fn* called to add a new request into the scheduler elevator_queue_empty_fn returns true if the merge queue is empty. Drivers shouldn't use this, but rather check @@ -991,7 +991,7 @@ elevator_activate_req_fn Called when device driver first sees a request. elevator_deactivate_req_fn Called when device driver decides to delay a request by requeueing it. -elevator_init_fn +elevator_init_fn* elevator_exit_fn Allocate and free any elevator specific storage for a queue. -- cgit v1.2.3 From 34df9f69a4e298e2e8b939d8a7cc0d55846ba544 Mon Sep 17 00:00:00 2001 From: Grant Likely Date: Fri, 30 Jan 2009 08:23:33 -0700 Subject: powerpc/5200: update device tree binding documentation This patch updates the mpc5200 binding documentation to match actual usage conventions, to remove incorrect information, and to remove topics which are more thoroughly described elsewhere. Signed-off-by: Grant Likely Reviewed-by: Wolfram Sang --- Documentation/powerpc/dts-bindings/fsl/mpc5200.txt | 180 +++++++++++++ .../powerpc/mpc52xx-device-tree-bindings.txt | 277 --------------------- 2 files changed, 180 insertions(+), 277 deletions(-) create mode 100644 Documentation/powerpc/dts-bindings/fsl/mpc5200.txt delete mode 100644 Documentation/powerpc/mpc52xx-device-tree-bindings.txt (limited to 'Documentation') diff --git a/Documentation/powerpc/dts-bindings/fsl/mpc5200.txt b/Documentation/powerpc/dts-bindings/fsl/mpc5200.txt new file mode 100644 index 00000000000..8447fd7090d --- /dev/null +++ b/Documentation/powerpc/dts-bindings/fsl/mpc5200.txt @@ -0,0 +1,180 @@ +MPC5200 Device Tree Bindings +---------------------------- + +(c) 2006-2009 Secret Lab Technologies Ltd +Grant Likely + +Naming conventions +------------------ +For mpc5200 on-chip devices, the format for each compatible value is +-[-]. The OS should be able to match a device driver +to the device based solely on the compatible value. If two drivers +match on the compatible list; the 'most compatible' driver should be +selected. + +The split between the MPC5200 and the MPC5200B leaves a bit of a +conundrum. How should the compatible property be set up to provide +maximum compatibility information; but still accurately describe the +chip? For the MPC5200; the answer is easy. Most of the SoC devices +originally appeared on the MPC5200. Since they didn't exist anywhere +else; the 5200 compatible properties will contain only one item; +"fsl,mpc5200-". + +The 5200B is almost the same as the 5200, but not quite. It fixes +silicon bugs and it adds a small number of enhancements. Most of the +devices either provide exactly the same interface as on the 5200. A few +devices have extra functions but still have a backwards compatible mode. +To express this information as completely as possible, 5200B device trees +should have two items in the compatible list: + compatible = "fsl,mpc5200b-","fsl,mpc5200-"; + +It is *strongly* recommended that 5200B device trees follow this convention +(instead of only listing the base mpc5200 item). + +ie. ethernet on mpc5200: compatible = "fsl,mpc5200-fec"; + ethernet on mpc5200b: compatible = "fsl,mpc5200b-fec", "fsl,mpc5200-fec"; + +Modal devices, like PSCs, also append the configured function to the +end of the compatible field. ie. A PSC in i2s mode would specify +"fsl,mpc5200-psc-i2s", not "fsl,mpc5200-i2s". This convention is chosen to +avoid naming conflicts with non-psc devices providing the same +function. For example, "fsl,mpc5200-spi" and "fsl,mpc5200-psc-spi" describe +the mpc5200 simple spi device and a PSC spi mode respectively. + +At the time of writing, exact chip may be either 'fsl,mpc5200' or +'fsl,mpc5200b'. + +The soc node +------------ +This node describes the on chip SOC peripherals. Every mpc5200 based +board will have this node, and as such there is a common naming +convention for SOC devices. + +Required properties: +name description +---- ----------- +ranges Memory range of the internal memory mapped registers. + Should be <0 [baseaddr] 0xc000> +reg Should be <[baseaddr] 0x100> +compatible mpc5200: "fsl,mpc5200-immr" + mpc5200b: "fsl,mpc5200b-immr" +system-frequency 'fsystem' frequency in Hz; XLB, IPB, USB and PCI + clocks are derived from the fsystem clock. +bus-frequency IPB bus frequency in Hz. Clock rate + used by most of the soc devices. + +soc child nodes +--------------- +Any on chip SOC devices available to Linux must appear as soc5200 child nodes. + +Note: The tables below show the value for the mpc5200. A mpc5200b device +tree should use the "fsl,mpc5200b-","fsl,mpc5200-" form. + +Required soc5200 child nodes: +name compatible Description +---- ---------- ----------- +cdm@ fsl,mpc5200-cdm Clock Distribution +interrupt-controller@ fsl,mpc5200-pic need an interrupt + controller to boot +bestcomm@ fsl,mpc5200-bestcomm Bestcomm DMA controller + +Recommended soc5200 child nodes; populate as needed for your board +name compatible Description +---- ---------- ----------- +timer@ fsl,mpc5200-gpt General purpose timers +gpio@ fsl,mpc5200-gpio MPC5200 simple gpio controller +gpio@ fsl,mpc5200-gpio-wkup MPC5200 wakeup gpio controller +rtc@ fsl,mpc5200-rtc Real time clock +mscan@ fsl,mpc5200-mscan CAN bus controller +pci@ fsl,mpc5200-pci PCI bridge +serial@ fsl,mpc5200-psc-uart PSC in serial mode +i2s@ fsl,mpc5200-psc-i2s PSC in i2s mode +ac97@ fsl,mpc5200-psc-ac97 PSC in ac97 mode +spi@ fsl,mpc5200-psc-spi PSC in spi mode +irda@ fsl,mpc5200-psc-irda PSC in IrDA mode +spi@ fsl,mpc5200-spi MPC5200 spi device +ethernet@ fsl,mpc5200-fec MPC5200 ethernet device +ata@ fsl,mpc5200-ata IDE ATA interface +i2c@ fsl,mpc5200-i2c I2C controller +usb@ fsl,mpc5200-ohci,ohci-be USB controller +xlb@ fsl,mpc5200-xlb XLB arbitrator + +fsl,mpc5200-gpt nodes +--------------------- +On the mpc5200 and 5200b, GPT0 has a watchdog timer function. If the board +design supports the internal wdt, then the device node for GPT0 should +include the empty property 'fsl,has-wdt'. + +An mpc5200-gpt can be used as a single line GPIO controller. To do so, +add the following properties to the gpt node: + gpio-controller; + #gpio-cells = <2>; +When referencing the GPIO line from another node, the first cell must always +be zero and the second cell represents the gpio flags and described in the +gpio device tree binding. + +An mpc5200-gpt can be used as a single line edge sensitive interrupt +controller. To do so, add the following properties to the gpt node: + interrupt-controller; + #interrupt-cells = <1>; +When referencing the IRQ line from another node, the cell represents the +sense mode; 1 for edge rising, 2 for edge falling. + +fsl,mpc5200-psc nodes +--------------------- +The PSCs should include a cell-index which is the index of the PSC in +hardware. cell-index is used to determine which shared SoC registers to +use when setting up PSC clocking. cell-index number starts at '0'. ie: + PSC1 has 'cell-index = <0>' + PSC4 has 'cell-index = <3>' + +PSC in i2s mode: The mpc5200 and mpc5200b PSCs are not compatible when in +i2s mode. An 'mpc5200b-psc-i2s' node cannot include 'mpc5200-psc-i2s' in the +compatible field. + + +fsl,mpc5200-gpio and fsl,mpc5200-gpio-wkup nodes +------------------------------------------------ +Each GPIO controller node should have the empty property gpio-controller and +#gpio-cells set to 2. First cell is the GPIO number which is interpreted +according to the bit numbers in the GPIO control registers. The second cell +is for flags which is currently unused. + +fsl,mpc5200-fec nodes +--------------------- +The FEC node can specify one of the following properties to configure +the MII link: +- fsl,7-wire-mode - An empty property that specifies the link uses 7-wire + mode instead of MII +- current-speed - Specifies that the MII should be configured for a fixed + speed. This property should contain two cells. The + first cell specifies the speed in Mbps and the second + should be '0' for half duplex and '1' for full duplex +- phy-handle - Contains a phandle to an Ethernet PHY. + +Interrupt controller (fsl,mpc5200-pic) node +------------------------------------------- +The mpc5200 pic binding splits hardware IRQ numbers into two levels. The +split reflects the layout of the PIC hardware itself, which groups +interrupts into one of three groups; CRIT, MAIN or PERP. Also, the +Bestcomm dma engine has it's own set of interrupt sources which are +cascaded off of peripheral interrupt 0, which the driver interprets as a +fourth group, SDMA. + +The interrupts property for device nodes using the mpc5200 pic consists +of three cells; + + L1 := [CRIT=0, MAIN=1, PERP=2, SDMA=3] + L2 := interrupt number; directly mapped from the value in the + "ICTL PerStat, MainStat, CritStat Encoded Register" + level := [LEVEL_HIGH=0, EDGE_RISING=1, EDGE_FALLING=2, LEVEL_LOW=3] + +For external IRQs, use the following interrupt property values (how to +specify external interrupts is a frequently asked question): +External interrupts: + external irq0: interrupts = <0 0 n>; + external irq1: interrupts = <1 1 n>; + external irq2: interrupts = <1 2 n>; + external irq3: interrupts = <1 3 n>; +'n' is sense (0: level high, 1: edge rising, 2: edge falling 3: level low) + diff --git a/Documentation/powerpc/mpc52xx-device-tree-bindings.txt b/Documentation/powerpc/mpc52xx-device-tree-bindings.txt deleted file mode 100644 index 6f12f1c79c0..00000000000 --- a/Documentation/powerpc/mpc52xx-device-tree-bindings.txt +++ /dev/null @@ -1,277 +0,0 @@ -MPC5200 Device Tree Bindings ----------------------------- - -(c) 2006-2007 Secret Lab Technologies Ltd -Grant Likely - -********** DRAFT *********** -* WARNING: Do not depend on the stability of these bindings just yet. -* The MPC5200 device tree conventions are still in flux -* Keep an eye on the linuxppc-dev mailing list for more details -********** DRAFT *********** - -I - Introduction -================ -Boards supported by the arch/powerpc architecture require device tree be -passed by the boot loader to the kernel at boot time. The device tree -describes what devices are present on the board and how they are -connected. The device tree can either be passed as a binary blob (as -described in Documentation/powerpc/booting-without-of.txt), or passed -by Open Firmware (IEEE 1275) compatible firmware using an OF compatible -client interface API. - -This document specifies the requirements on the device-tree for mpc5200 -based boards. These requirements are above and beyond the details -specified in either the Open Firmware spec or booting-without-of.txt - -All new mpc5200-based boards are expected to match this document. In -cases where this document is not sufficient to support a new board port, -this document should be updated as part of adding the new board support. - -II - Philosophy -=============== -The core of this document is naming convention. The whole point of -defining this convention is to reduce or eliminate the number of -special cases required to support a 5200 board. If all 5200 boards -follow the same convention, then generic 5200 support code will work -rather than coding special cases for each new board. - -This section tries to capture the thought process behind why the naming -convention is what it is. - -1. names ---------- -There is strong convention/requirements already established for children -of the root node. 'cpus' describes the processor cores, 'memory' -describes memory, and 'chosen' provides boot configuration. Other nodes -are added to describe devices attached to the processor local bus. - -Following convention already established with other system-on-chip -processors, 5200 device trees should use the name 'soc5200' for the -parent node of on chip devices, and the root node should be its parent. - -Child nodes are typically named after the configured function. ie. -the FEC node is named 'ethernet', and a PSC in uart mode is named 'serial'. - -2. device_type property ------------------------ -similar to the node name convention above; the device_type reflects the -configured function of a device. ie. 'serial' for a uart and 'spi' for -an spi controller. However, while node names *should* reflect the -configured function, device_type *must* match the configured function -exactly. - -3. compatible property ----------------------- -Since device_type isn't enough to match devices to drivers, there also -needs to be a naming convention for the compatible property. Compatible -is an list of device descriptions sorted from specific to generic. For -the mpc5200, the required format for each compatible value is --[-]. The OS should be able to match a device driver -to the device based solely on the compatible value. If two drivers -match on the compatible list; the 'most compatible' driver should be -selected. - -The split between the MPC5200 and the MPC5200B leaves a bit of a -conundrum. How should the compatible property be set up to provide -maximum compatibility information; but still accurately describe the -chip? For the MPC5200; the answer is easy. Most of the SoC devices -originally appeared on the MPC5200. Since they didn't exist anywhere -else; the 5200 compatible properties will contain only one item; -"mpc5200-". - -The 5200B is almost the same as the 5200, but not quite. It fixes -silicon bugs and it adds a small number of enhancements. Most of the -devices either provide exactly the same interface as on the 5200. A few -devices have extra functions but still have a backwards compatible mode. -To express this information as completely as possible, 5200B device trees -should have two items in the compatible list; -"mpc5200b-\0mpc5200-". It is *strongly* recommended -that 5200B device trees follow this convention (instead of only listing -the base mpc5200 item). - -If another chip appear on the market with one of the mpc5200 SoC -devices, then the compatible list should include mpc5200-. - -ie. ethernet on mpc5200: compatible = "mpc5200-ethernet" - ethernet on mpc5200b: compatible = "mpc5200b-ethernet\0mpc5200-ethernet" - -Modal devices, like PSCs, also append the configured function to the -end of the compatible field. ie. A PSC in i2s mode would specify -"mpc5200-psc-i2s", not "mpc5200-i2s". This convention is chosen to -avoid naming conflicts with non-psc devices providing the same -function. For example, "mpc5200-spi" and "mpc5200-psc-spi" describe -the mpc5200 simple spi device and a PSC spi mode respectively. - -If the soc device is more generic and present on other SOCs, the -compatible property can specify the more generic device type also. - -ie. mscan: compatible = "mpc5200-mscan\0fsl,mscan"; - -At the time of writing, exact chip may be either 'mpc5200' or -'mpc5200b'. - -Device drivers should always try to match as generically as possible. - -III - Structure -=============== -The device tree for an mpc5200 board follows the structure defined in -booting-without-of.txt with the following additional notes: - -0) the root node ----------------- -Typical root description node; see booting-without-of - -1) The cpus node ----------------- -The cpus node follows the basic layout described in booting-without-of. -The bus-frequency property holds the XLB bus frequency -The clock-frequency property holds the core frequency - -2) The memory node ------------------- -Typical memory description node; see booting-without-of. - -3) The soc5200 node -------------------- -This node describes the on chip SOC peripherals. Every mpc5200 based -board will have this node, and as such there is a common naming -convention for SOC devices. - -Required properties: -name type description ----- ---- ----------- -device_type string must be "soc" -ranges int should be <0 baseaddr baseaddr+10000> -reg int must be -compatible string mpc5200: "mpc5200-soc" - mpc5200b: "mpc5200b-soc\0mpc5200-soc" -system-frequency int Fsystem frequency; source of all - other clocks. -bus-frequency int IPB bus frequency in HZ. Clock rate - used by most of the soc devices. -#interrupt-cells int must be <3>. - -Recommended properties: -name type description ----- ---- ----------- -model string Exact model of the chip; - ie: model="fsl,mpc5200" -revision string Silicon revision of chip - ie: revision="M08A" - -The 'model' and 'revision' properties are *strongly* recommended. Having -them presence acts as a bit of a safety net for working around as yet -undiscovered bugs on one version of silicon. For example, device drivers -can use the model and revision properties to decide if a bug fix should -be turned on. - -4) soc5200 child nodes ----------------------- -Any on chip SOC devices available to Linux must appear as soc5200 child nodes. - -Note: The tables below show the value for the mpc5200. A mpc5200b device -tree should use the "mpc5200b-\0mpc5200- form. - -Required soc5200 child nodes: -name device_type compatible Description ----- ----------- ---------- ----------- -cdm@ cdm mpc5200-cmd Clock Distribution -pic@ interrupt-controller mpc5200-pic need an interrupt - controller to boot -bestcomm@ dma-controller mpc5200-bestcomm 5200 pic also requires - the bestcomm device - -Recommended soc5200 child nodes; populate as needed for your board -name device_type compatible Description ----- ----------- ---------- ----------- -gpt@ gpt fsl,mpc5200-gpt General purpose timers -gpt@ gpt fsl,mpc5200-gpt-gpio General purpose - timers in GPIO mode -gpio@ fsl,mpc5200-gpio MPC5200 simple gpio - controller -gpio@ fsl,mpc5200-gpio-wkup MPC5200 wakeup gpio - controller -rtc@ rtc mpc5200-rtc Real time clock -mscan@ mscan mpc5200-mscan CAN bus controller -pci@ pci mpc5200-pci PCI bridge -serial@ serial mpc5200-psc-uart PSC in serial mode -i2s@ sound mpc5200-psc-i2s PSC in i2s mode -ac97@ sound mpc5200-psc-ac97 PSC in ac97 mode -spi@ spi mpc5200-psc-spi PSC in spi mode -irda@ irda mpc5200-psc-irda PSC in IrDA mode -spi@ spi mpc5200-spi MPC5200 spi device -ethernet@ network mpc5200-fec MPC5200 ethernet device -ata@ ata mpc5200-ata IDE ATA interface -i2c@ i2c mpc5200-i2c I2C controller -usb@ usb-ohci-be mpc5200-ohci,ohci-be USB controller -xlb@ xlb mpc5200-xlb XLB arbitrator - -Important child node properties -name type description ----- ---- ----------- -cell-index int When multiple devices are present, is the - index of the device in the hardware (ie. There - are 6 PSC on the 5200 numbered PSC1 to PSC6) - PSC1 has 'cell-index = <0>' - PSC4 has 'cell-index = <3>' - -5) General Purpose Timer nodes (child of soc5200 node) -On the mpc5200 and 5200b, GPT0 has a watchdog timer function. If the board -design supports the internal wdt, then the device node for GPT0 should -include the empty property 'fsl,has-wdt'. - -6) PSC nodes (child of soc5200 node) -PSC nodes can define the optional 'port-number' property to force assignment -order of serial ports. For example, PSC5 might be physically connected to -the port labeled 'COM1' and PSC1 wired to 'COM1'. In this case, PSC5 would -have a "port-number = <0>" property, and PSC1 would have "port-number = <1>". - -PSC in i2s mode: The mpc5200 and mpc5200b PSCs are not compatible when in -i2s mode. An 'mpc5200b-psc-i2s' node cannot include 'mpc5200-psc-i2s' in the -compatible field. - -7) GPIO controller nodes -Each GPIO controller node should have the empty property gpio-controller and -#gpio-cells set to 2. First cell is the GPIO number which is interpreted -according to the bit numbers in the GPIO control registers. The second cell -is for flags which is currently unsused. - -8) FEC nodes -The FEC node can specify one of the following properties to configure -the MII link: -"fsl,7-wire-mode" - An empty property that specifies the link uses 7-wire - mode instead of MII -"current-speed" - Specifies that the MII should be configured for a fixed - speed. This property should contain two cells. The - first cell specifies the speed in Mbps and the second - should be '0' for half duplex and '1' for full duplex -"phy-handle" - Contains a phandle to an Ethernet PHY. - -IV - Extra Notes -================ - -1. Interrupt mapping --------------------- -The mpc5200 pic driver splits hardware IRQ numbers into two levels. The -split reflects the layout of the PIC hardware itself, which groups -interrupts into one of three groups; CRIT, MAIN or PERP. Also, the -Bestcomm dma engine has it's own set of interrupt sources which are -cascaded off of peripheral interrupt 0, which the driver interprets as a -fourth group, SDMA. - -The interrupts property for device nodes using the mpc5200 pic consists -of three cells; - - L1 := [CRIT=0, MAIN=1, PERP=2, SDMA=3] - L2 := interrupt number; directly mapped from the value in the - "ICTL PerStat, MainStat, CritStat Encoded Register" - level := [LEVEL_HIGH=0, EDGE_RISING=1, EDGE_FALLING=2, LEVEL_LOW=3] - -2. Shared registers -------------------- -Some SoC devices share registers between them. ie. the i2c devices use -a single clock control register, and almost all device are affected by -the port_config register. Devices which need to manipulate shared regs -should look to the parent SoC node. The soc node is responsible -for arbitrating all shared register access. -- cgit v1.2.3 From cbb5901b904e122139e97c6f4caed9b1f13c3455 Mon Sep 17 00:00:00 2001 From: Jens Axboe Date: Mon, 2 Feb 2009 13:02:31 +0100 Subject: block: add text file detailing queue/ sysfs files Signed-off-by: Jens Axboe --- Documentation/block/queue-sysfs.txt | 63 +++++++++++++++++++++++++++++++++++++ 1 file changed, 63 insertions(+) create mode 100644 Documentation/block/queue-sysfs.txt (limited to 'Documentation') diff --git a/Documentation/block/queue-sysfs.txt b/Documentation/block/queue-sysfs.txt new file mode 100644 index 00000000000..e164403f60e --- /dev/null +++ b/Documentation/block/queue-sysfs.txt @@ -0,0 +1,63 @@ +Queue sysfs files +================= + +This text file will detail the queue files that are located in the sysfs tree +for each block device. Note that stacked devices typically do not export +any settings, since their queue merely functions are a remapping target. +These files are the ones found in the /sys/block/xxx/queue/ directory. + +Files denoted with a RO postfix are readonly and the RW postfix means +read-write. + +hw_sector_size (RO) +------------------- +This is the hardware sector size of the device, in bytes. + +max_hw_sectors_kb (RO) +---------------------- +This is the maximum number of kilobytes supported in a single data transfer. + +max_sectors_kb (RW) +------------------- +This is the maximum number of kilobytes that the block layer will allow +for a filesystem request. Must be smaller than or equal to the maximum +size allowed by the hardware. + +nomerges (RW) +------------- +This enables the user to disable the lookup logic involved with IO merging +requests in the block layer. Merging may still occur through a direct +1-hit cache, since that comes for (almost) free. The IO scheduler will not +waste cycles doing tree/hash lookups for merges if nomerges is 1. Defaults +to 0, enabling all merges. + +nr_requests (RW) +---------------- +This controls how many requests may be allocated in the block layer for +read or write requests. Note that the total allocated number may be twice +this amount, since it applies only to reads or writes (not the accumulated +sum). + +read_ahead_kb (RW) +------------------ +Maximum number of kilobytes to read-ahead for filesystems on this block +device. + +rq_affinity (RW) +---------------- +If this option is enabled, the block layer will migrate request completions +to the CPU that originally submitted the request. For some workloads +this provides a significant reduction in CPU cycles due to caching effects. + +scheduler (RW) +-------------- +When read, this file will display the current and available IO schedulers +for this block device. The currently active IO scheduler will be enclosed +in [] brackets. Writing an IO scheduler name to this file will switch +control of this block device to that new IO scheduler. Note that writing +an IO scheduler name to this file will attempt to load that IO scheduler +module, if it isn't already present in the system. + + + +Jens Axboe , February 2009 -- cgit v1.2.3 From 62663ea8220366472fe20462831f2d69d7987439 Mon Sep 17 00:00:00 2001 From: Thomas Renninger Date: Tue, 3 Feb 2009 17:46:46 +0100 Subject: ACPI: cpufreq: Remove deprecated /proc/acpi/processor/../performance proc entries They were long enough set deprecated... Update Documentation/cpu-freq/users-guide.txt: The deprecated files listed there seen not to exist for some time anymore already. Signed-off-by: Thomas Renninger Signed-off-by: Len Brown --- Documentation/cpu-freq/user-guide.txt | 16 ---------------- 1 file changed, 16 deletions(-) (limited to 'Documentation') diff --git a/Documentation/cpu-freq/user-guide.txt b/Documentation/cpu-freq/user-guide.txt index e3443ddcfb8..917918f84fc 100644 --- a/Documentation/cpu-freq/user-guide.txt +++ b/Documentation/cpu-freq/user-guide.txt @@ -195,19 +195,3 @@ scaling_setspeed. By "echoing" a new frequency into this you can change the speed of the CPU, but only within the limits of scaling_min_freq and scaling_max_freq. - - -3.2 Deprecated Interfaces -------------------------- - -Depending on your kernel configuration, you might find the following -cpufreq-related files: -/proc/cpufreq -/proc/sys/cpu/*/speed -/proc/sys/cpu/*/speed-min -/proc/sys/cpu/*/speed-max - -These are files for deprecated interfaces to cpufreq, which offer far -less functionality. Because of this, these interfaces aren't described -here. - -- cgit v1.2.3 From 97c44836cdec1ea713a15d84098a1a908157e68f Mon Sep 17 00:00:00 2001 From: "Timothy S. Nelson" Date: Fri, 30 Jan 2009 06:12:47 +1100 Subject: PCI: return error on failure to read PCI ROMs This patch makes the ROM reading code return an error to user space if the size of the ROM read is equal to 0. The patch also emits a warnings if the contents of the ROM are invalid, and documents the effects of the "enable" file on ROM reading. Signed-off-by: Timothy S. Nelson Acked-by: Alex Villacis-Lasso Signed-off-by: Jesse Barnes --- Documentation/filesystems/sysfs-pci.txt | 13 ++++++++++++- 1 file changed, 12 insertions(+), 1 deletion(-) (limited to 'Documentation') diff --git a/Documentation/filesystems/sysfs-pci.txt b/Documentation/filesystems/sysfs-pci.txt index 68ef48839c0..9f8740ca3f3 100644 --- a/Documentation/filesystems/sysfs-pci.txt +++ b/Documentation/filesystems/sysfs-pci.txt @@ -9,6 +9,7 @@ that support it. For example, a given bus might look like this: | |-- class | |-- config | |-- device + | |-- enable | |-- irq | |-- local_cpus | |-- resource @@ -32,6 +33,7 @@ files, each with their own function. class PCI class (ascii, ro) config PCI config space (binary, rw) device PCI device (ascii, ro) + enable Whether the device is enabled (ascii, rw) irq IRQ number (ascii, ro) local_cpus nearby CPU mask (cpumask, ro) resource PCI resource host addresses (ascii, ro) @@ -57,10 +59,19 @@ used to do actual device programming from userspace. Note that some platforms don't support mmapping of certain resources, so be sure to check the return value from any attempted mmap. +The 'enable' file provides a counter that indicates how many times the device +has been enabled. If the 'enable' file currently returns '4', and a '1' is +echoed into it, it will then return '5'. Echoing a '0' into it will decrease +the count. Even when it returns to 0, though, some of the initialisation +may not be reversed. + The 'rom' file is special in that it provides read-only access to the device's ROM file, if available. It's disabled by default, however, so applications should write the string "1" to the file to enable it before attempting a read -call, and disable it following the access by writing "0" to the file. +call, and disable it following the access by writing "0" to the file. Note +that the device must be enabled for a rom read to return data succesfully. +In the event a driver is not bound to the device, it can be enabled using the +'enable' file, documented above. Accessing legacy resources through sysfs ---------------------------------------- -- cgit v1.2.3 From 0cd5c3c80a0ebd68c08312fa7d8c13149cc61c4c Mon Sep 17 00:00:00 2001 From: Kyle McMartin Date: Wed, 4 Feb 2009 14:29:19 -0800 Subject: x86: disable intel_iommu support by default Due to recurring issues with DMAR support on certain platforms. There's a number of filesystem corruption incidents reported: https://bugzilla.redhat.com/show_bug.cgi?id=479996 http://bugzilla.kernel.org/show_bug.cgi?id=12578 Provide a Kconfig option to change whether it is enabled by default. If disabled, it can still be reenabled by passing intel_iommu=on to the kernel. Keep the .config option off by default. Signed-off-by: Kyle McMartin Signed-off-by: Andrew Morton Acked-By: David Woodhouse Signed-off-by: Ingo Molnar --- Documentation/kernel-parameters.txt | 2 ++ 1 file changed, 2 insertions(+) (limited to 'Documentation') diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt index d8362cf9909..b182626739e 100644 --- a/Documentation/kernel-parameters.txt +++ b/Documentation/kernel-parameters.txt @@ -937,6 +937,8 @@ and is between 256 and 4096 characters. It is defined in the file intel_iommu= [DMAR] Intel IOMMU driver (DMAR) option + on + Enable intel iommu driver. off Disable intel iommu driver. igfx_off [Default Off] -- cgit v1.2.3 From f40b45a2e45b0f02aeedfcfbb28d8e2d4b8b86b1 Mon Sep 17 00:00:00 2001 From: Randy Dunlap Date: Wed, 11 Feb 2009 13:04:31 -0800 Subject: kernel-doc: preferred ending marker and examples Fix kernel-doc-nano-HOWTO.txt to use */ as the ending marker in kernel-doc examples and state that */ is the preferred ending marker. Signed-off-by: Randy Dunlap Reported-by: Robert Love Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- Documentation/kernel-doc-nano-HOWTO.txt | 7 ++++--- 1 file changed, 4 insertions(+), 3 deletions(-) (limited to 'Documentation') diff --git a/Documentation/kernel-doc-nano-HOWTO.txt b/Documentation/kernel-doc-nano-HOWTO.txt index d73fbd2b2b4..026ec7d5738 100644 --- a/Documentation/kernel-doc-nano-HOWTO.txt +++ b/Documentation/kernel-doc-nano-HOWTO.txt @@ -43,7 +43,8 @@ Only comments so marked will be considered by the kernel-doc scripts, and any comment so marked must be in kernel-doc format. Do not use "/**" to be begin a comment block unless the comment block contains kernel-doc formatted comments. The closing comment marker for -kernel-doc comments can be either "*/" or "**/". +kernel-doc comments can be either "*/" or "**/", but "*/" is +preferred in the Linux kernel tree. Kernel-doc comments should be placed just before the function or data structure being described. @@ -63,7 +64,7 @@ Example kernel-doc function comment: * comment lines. * * The longer description can have multiple paragraphs. - **/ + */ The first line, with the short description, must be on a single line. @@ -85,7 +86,7 @@ Example kernel-doc data structure comment. * perhaps with more lines and words. * * Longer description of this structure. - **/ + */ The kernel-doc function comments describe each parameter to the function, in order, with the @name lines. -- cgit v1.2.3 From f82da723398ff18d49275a5f03de6cae5f592e8e Mon Sep 17 00:00:00 2001 From: Andrew Morton Date: Thu, 12 Feb 2009 16:47:01 -0800 Subject: Documentation/connector/cn_test.c: don't use gfp_any() cn_test_timer_func() is a timer handler and can never use GFP_KERNEL - there's no point in using gfp_any() here. Also, use setup_timer(). Signed-off-by: Andrew Morton Signed-off-by: David S. Miller --- Documentation/connector/cn_test.c | 6 ++---- 1 file changed, 2 insertions(+), 4 deletions(-) (limited to 'Documentation') diff --git a/Documentation/connector/cn_test.c b/Documentation/connector/cn_test.c index be7af146dd3..6977c178729 100644 --- a/Documentation/connector/cn_test.c +++ b/Documentation/connector/cn_test.c @@ -137,7 +137,7 @@ static void cn_test_timer_func(unsigned long __data) memcpy(m + 1, data, m->len); - cn_netlink_send(m, 0, gfp_any()); + cn_netlink_send(m, 0, GFP_ATOMIC); kfree(m); } @@ -160,10 +160,8 @@ static int cn_test_init(void) goto err_out; } - init_timer(&cn_test_timer); - cn_test_timer.function = cn_test_timer_func; + setup_timer(&cn_test_timer, cn_test_timer_func, 0); cn_test_timer.expires = jiffies + HZ; - cn_test_timer.data = 0; add_timer(&cn_test_timer); return 0; -- cgit v1.2.3 From a08f6e04d74478d91f34a0484e69e89870adb33d Mon Sep 17 00:00:00 2001 From: Alex Chiang Date: Fri, 13 Feb 2009 12:03:17 -0700 Subject: PCI: Documentation: fix minor PCIe HOWTO thinko Update doc to correctly refer to replacing the pci_register_driver API, and not the non-existent "pci_module_init" API. Signed-off-by: Alex Chiang Signed-off-by: Jesse Barnes --- Documentation/PCI/PCIEBUS-HOWTO.txt | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'Documentation') diff --git a/Documentation/PCI/PCIEBUS-HOWTO.txt b/Documentation/PCI/PCIEBUS-HOWTO.txt index 9a07e38631b..6bd5f372ade 100644 --- a/Documentation/PCI/PCIEBUS-HOWTO.txt +++ b/Documentation/PCI/PCIEBUS-HOWTO.txt @@ -93,7 +93,7 @@ the PCI Express Port Bus driver from loading a service driver. int pcie_port_service_register(struct pcie_port_service_driver *new) -This API replaces the Linux Driver Model's pci_module_init API. A +This API replaces the Linux Driver Model's pci_register_driver API. A service driver should always calls pcie_port_service_register at module init. Note that after service driver being loaded, calls such as pci_enable_device(dev) and pci_set_master(dev) are no longer -- cgit v1.2.3 From f9aa28adfc6a4b01268ebb6d88566cca8627905f Mon Sep 17 00:00:00 2001 From: Pekka Paalanen Date: Sat, 3 Jan 2009 21:09:27 +0200 Subject: doc: mmiotrace.txt, buffer size control change Impact: prevents confusing the user when buffer size is inadequate The tracing framework offers a resizeable buffer, which mmiotrace uses to record events. If the buffer is full, the following events will be lost. Events should not be lost, so the documentation instructs the user to increase the buffer size. The buffer size is set via a debugfs file. Mmiotrace documentation was not updated the same time the debugfs file was changed. The old file was tracing/trace_entries and first contained the number of entries the buffer had space for, per cpu. Nowadays this file is replaced with the file tracing/buffer_size_kb, which tells the amount of memory reserved for the buffer, per cpu, in kilobytes. Previously, a flag had to be toggled via the debugfs file tracing/tracing_enabled when the buffer size was changed. This is no longer necessary. The mmiotrace documentation is updated to reflect the current state of the tracing framework. Signed-off-by: Pekka Paalanen Signed-off-by: Steven Rostedt Signed-off-by: Ingo Molnar --- Documentation/tracers/mmiotrace.txt | 6 ++---- 1 file changed, 2 insertions(+), 4 deletions(-) (limited to 'Documentation') diff --git a/Documentation/tracers/mmiotrace.txt b/Documentation/tracers/mmiotrace.txt index cde23b4a12a..5731c67abc5 100644 --- a/Documentation/tracers/mmiotrace.txt +++ b/Documentation/tracers/mmiotrace.txt @@ -78,12 +78,10 @@ to view your kernel log and look for "mmiotrace has lost events" warning. If events were lost, the trace is incomplete. You should enlarge the buffers and try again. Buffers are enlarged by first seeing how large the current buffers are: -$ cat /debug/tracing/trace_entries +$ cat /debug/tracing/buffer_size_kb gives you a number. Approximately double this number and write it back, for instance: -$ echo 0 > /debug/tracing/tracing_enabled -$ echo 128000 > /debug/tracing/trace_entries -$ echo 1 > /debug/tracing/tracing_enabled +$ echo 128000 > /debug/tracing/buffer_size_kb Then start again from the top. If you are doing a trace for a driver project, e.g. Nouveau, you should also -- cgit v1.2.3 From b851ee7921fabdd7dfc96ffc4e9609f5062bd12b Mon Sep 17 00:00:00 2001 From: Li Zefan Date: Wed, 18 Feb 2009 14:48:14 -0800 Subject: cgroups: update documentation about css_set hash table The css_set hash table was introduced in 2.6.26, so update the documentation accordingly. Signed-off-by: Li Zefan Acked-by: Paul Menage Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- Documentation/cgroups/cgroups.txt | 6 ++---- 1 file changed, 2 insertions(+), 4 deletions(-) (limited to 'Documentation') diff --git a/Documentation/cgroups/cgroups.txt b/Documentation/cgroups/cgroups.txt index d9e5d6f41b9..93feb844448 100644 --- a/Documentation/cgroups/cgroups.txt +++ b/Documentation/cgroups/cgroups.txt @@ -252,10 +252,8 @@ cgroup file system directories. When a task is moved from one cgroup to another, it gets a new css_set pointer - if there's an already existing css_set with the desired collection of cgroups then that group is reused, else a new -css_set is allocated. Note that the current implementation uses a -linear search to locate an appropriate existing css_set, so isn't -very efficient. A future version will use a hash table for better -performance. +css_set is allocated. The appropriate existing css_set is located by +looking into a hash table. To allow access from a cgroup to the css_sets (and hence tasks) that comprise it, a set of cg_cgroup_link objects form a lattice; -- cgit v1.2.3 From ef2cfc790bf5f0ff189b01eabc0f4feb5e8524df Mon Sep 17 00:00:00 2001 From: Pavel Machek Date: Wed, 18 Feb 2009 14:48:23 -0800 Subject: hp accelerometer: add freefall detection MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit This adds freefall handling to hp_accel driver. According to HP, it should just work, without us having to set the chip up by hand. hpfall.c is example .c program that parks the disk when accelerometer detects free fall. It should work; for now, it uses fixed 20seconds protection period. Signed-off-by: Pavel Machek Cc: Thomas Renninger Cc: Éric Piel Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- Documentation/hwmon/hpfall.c | 101 ++++++++++++++++++++++++++++++++++++++++++ Documentation/hwmon/lis3lv02d | 8 ++++ 2 files changed, 109 insertions(+) create mode 100644 Documentation/hwmon/hpfall.c (limited to 'Documentation') diff --git a/Documentation/hwmon/hpfall.c b/Documentation/hwmon/hpfall.c new file mode 100644 index 00000000000..bbea1ccfd46 --- /dev/null +++ b/Documentation/hwmon/hpfall.c @@ -0,0 +1,101 @@ +/* Disk protection for HP machines. + * + * Copyright 2008 Eric Piel + * Copyright 2009 Pavel Machek + * + * GPLv2. + */ + +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include + +void write_int(char *path, int i) +{ + char buf[1024]; + int fd = open(path, O_RDWR); + if (fd < 0) { + perror("open"); + exit(1); + } + sprintf(buf, "%d", i); + if (write(fd, buf, strlen(buf)) != strlen(buf)) { + perror("write"); + exit(1); + } + close(fd); +} + +void set_led(int on) +{ + write_int("/sys/class/leds/hp::hddprotect/brightness", on); +} + +void protect(int seconds) +{ + write_int("/sys/block/sda/device/unload_heads", seconds*1000); +} + +int on_ac(void) +{ +// /sys/class/power_supply/AC0/online +} + +int lid_open(void) +{ +// /proc/acpi/button/lid/LID/state +} + +void ignore_me(void) +{ + protect(0); + set_led(0); + +} + +int main(int argc, char* argv[]) +{ + int fd, ret; + + fd = open("/dev/freefall", O_RDONLY); + if (fd < 0) { + perror("open"); + return EXIT_FAILURE; + } + + signal(SIGALRM, ignore_me); + + for (;;) { + unsigned char count; + + ret = read(fd, &count, sizeof(count)); + alarm(0); + if ((ret == -1) && (errno == EINTR)) { + /* Alarm expired, time to unpark the heads */ + continue; + } + + if (ret != sizeof(count)) { + perror("read"); + break; + } + + protect(21); + set_led(1); + if (1 || on_ac() || lid_open()) { + alarm(2); + } else { + alarm(20); + } + } + + close(fd); + return EXIT_SUCCESS; +} diff --git a/Documentation/hwmon/lis3lv02d b/Documentation/hwmon/lis3lv02d index 0fcfc4a7ccd..287f8c90265 100644 --- a/Documentation/hwmon/lis3lv02d +++ b/Documentation/hwmon/lis3lv02d @@ -33,6 +33,14 @@ rate - reports the sampling rate of the accelerometer device in HZ This driver also provides an absolute input class device, allowing the laptop to act as a pinball machine-esque joystick. +Another feature of the driver is misc device called "freefall" that +acts similar to /dev/rtc and reacts on free-fall interrupts received +from the device. It supports blocking operations, poll/select and +fasync operation modes. You must read 1 bytes from the device. The +result is number of free-fall interrupts since the last successful +read (or 255 if number of interrupts would not fit). + + Axes orientation ---------------- -- cgit v1.2.3 From 97bef7dd05563807539122c488a5dd93ed327722 Mon Sep 17 00:00:00 2001 From: Bernhard Walle Date: Wed, 18 Feb 2009 14:48:40 -0800 Subject: Bernhard has moved Since I don't work for SUSE any more and the bwalle@suse.de address is invalid, correct it in the copyright headers and documentation. Signed-off-by: Bernhard Walle Cc: Greg KH Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- Documentation/ABI/testing/sysfs-firmware-memmap | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'Documentation') diff --git a/Documentation/ABI/testing/sysfs-firmware-memmap b/Documentation/ABI/testing/sysfs-firmware-memmap index 0d99ee6ae02..eca0d65087d 100644 --- a/Documentation/ABI/testing/sysfs-firmware-memmap +++ b/Documentation/ABI/testing/sysfs-firmware-memmap @@ -1,6 +1,6 @@ What: /sys/firmware/memmap/ Date: June 2008 -Contact: Bernhard Walle +Contact: Bernhard Walle Description: On all platforms, the firmware provides a memory map which the kernel reads. The resources from that memory map are registered -- cgit v1.2.3 From 3fd076dd955a34c35dc456f4ef676e03cdced044 Mon Sep 17 00:00:00 2001 From: Li Zefan Date: Fri, 20 Feb 2009 15:38:48 -0800 Subject: cpuset: various documentation fixes and updates I noticed the old commit 8f5aa26c75b7722e80c0c5c5bb833d41865d7019 ("cpusets: update_cpumask documentation fix") is not a complete fix, resulting in inconsistent paragraphs. This patch fixes it and does other fixes and updates: - s/migrate_all_tasks()/migrate_live_tasks()/ - describe more cpuset control files - s/cpumask_t/struct cpumask/ - document cpu hotplug and change of 'sched_relax_domain_level' may cause domain rebuild - document various ways to query and modify cpusets - the equivalent of "mount -t cpuset" is "mount -t cgroup -o cpuset,noprefix" Signed-off-by: Li Zefan Acked-by: Randy Dunlap Cc: Paul Menage Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- Documentation/cgroups/cpusets.txt | 65 ++++++++++++++++++++++----------------- 1 file changed, 37 insertions(+), 28 deletions(-) (limited to 'Documentation') diff --git a/Documentation/cgroups/cpusets.txt b/Documentation/cgroups/cpusets.txt index 5c86c258c79..0611e9528c7 100644 --- a/Documentation/cgroups/cpusets.txt +++ b/Documentation/cgroups/cpusets.txt @@ -142,7 +142,7 @@ into the rest of the kernel, none in performance critical paths: - in fork and exit, to attach and detach a task from its cpuset. - in sched_setaffinity, to mask the requested CPUs by what's allowed in that tasks cpuset. - - in sched.c migrate_all_tasks(), to keep migrating tasks within + - in sched.c migrate_live_tasks(), to keep migrating tasks within the CPUs allowed by their cpuset, if possible. - in the mbind and set_mempolicy system calls, to mask the requested Memory Nodes by what's allowed in that tasks cpuset. @@ -175,6 +175,10 @@ files describing that cpuset: - mem_exclusive flag: is memory placement exclusive? - mem_hardwall flag: is memory allocation hardwalled - memory_pressure: measure of how much paging pressure in cpuset + - memory_spread_page flag: if set, spread page cache evenly on allowed nodes + - memory_spread_slab flag: if set, spread slab cache evenly on allowed nodes + - sched_load_balance flag: if set, load balance within CPUs on that cpuset + - sched_relax_domain_level: the searching range when migrating tasks In addition, the root cpuset only has the following file: - memory_pressure_enabled flag: compute memory_pressure? @@ -252,7 +256,7 @@ is causing. This is useful both on tightly managed systems running a wide mix of submitted jobs, which may choose to terminate or re-prioritize jobs that -are trying to use more memory than allowed on the nodes assigned them, +are trying to use more memory than allowed on the nodes assigned to them, and with tightly coupled, long running, massively parallel scientific computing jobs that will dramatically fail to meet required performance goals if they start to use more memory than allowed to them. @@ -378,7 +382,7 @@ as cpusets and sched_setaffinity. The algorithmic cost of load balancing and its impact on key shared kernel data structures such as the task list increases more than linearly with the number of CPUs being balanced. So the scheduler -has support to partition the systems CPUs into a number of sched +has support to partition the systems CPUs into a number of sched domains such that it only load balances within each sched domain. Each sched domain covers some subset of the CPUs in the system; no two sched domains overlap; some CPUs might not be in any sched @@ -485,17 +489,22 @@ of CPUs allowed to a cpuset having 'sched_load_balance' enabled. The internal kernel cpuset to scheduler interface passes from the cpuset code to the scheduler code a partition of the load balanced CPUs in the system. This partition is a set of subsets (represented -as an array of cpumask_t) of CPUs, pairwise disjoint, that cover all -the CPUs that must be load balanced. - -Whenever the 'sched_load_balance' flag changes, or CPUs come or go -from a cpuset with this flag enabled, or a cpuset with this flag -enabled is removed, the cpuset code builds a new such partition and -passes it to the scheduler sched domain setup code, to have the sched -domains rebuilt as necessary. +as an array of struct cpumask) of CPUs, pairwise disjoint, that cover +all the CPUs that must be load balanced. + +The cpuset code builds a new such partition and passes it to the +scheduler sched domain setup code, to have the sched domains rebuilt +as necessary, whenever: + - the 'sched_load_balance' flag of a cpuset with non-empty CPUs changes, + - or CPUs come or go from a cpuset with this flag enabled, + - or 'sched_relax_domain_level' value of a cpuset with non-empty CPUs + and with this flag enabled changes, + - or a cpuset with non-empty CPUs and with this flag enabled is removed, + - or a cpu is offlined/onlined. This partition exactly defines what sched domains the scheduler should -setup - one sched domain for each element (cpumask_t) in the partition. +setup - one sched domain for each element (struct cpumask) in the +partition. The scheduler remembers the currently active sched domain partitions. When the scheduler routine partition_sched_domains() is invoked from @@ -559,7 +568,7 @@ domain, the largest value among those is used. Be careful, if one requests 0 and others are -1 then 0 is used. Note that modifying this file will have both good and bad effects, -and whether it is acceptable or not will be depend on your situation. +and whether it is acceptable or not depends on your situation. Don't modify this file if you are not sure. If your situation is: @@ -600,19 +609,15 @@ to allocate a page of memory for that task. If a cpuset has its 'cpus' modified, then each task in that cpuset will have its allowed CPU placement changed immediately. Similarly, -if a tasks pid is written to a cpusets 'tasks' file, in either its -current cpuset or another cpuset, then its allowed CPU placement is -changed immediately. If such a task had been bound to some subset -of its cpuset using the sched_setaffinity() call, the task will be -allowed to run on any CPU allowed in its new cpuset, negating the -affect of the prior sched_setaffinity() call. +if a tasks pid is written to another cpusets 'tasks' file, then its +allowed CPU placement is changed immediately. If such a task had been +bound to some subset of its cpuset using the sched_setaffinity() call, +the task will be allowed to run on any CPU allowed in its new cpuset, +negating the effect of the prior sched_setaffinity() call. In summary, the memory placement of a task whose cpuset is changed is updated by the kernel, on the next allocation of a page for that task, -but the processor placement is not updated, until that tasks pid is -rewritten to the 'tasks' file of its cpuset. This is done to avoid -impacting the scheduler code in the kernel with a check for changes -in a tasks processor placement. +and the processor placement is updated immediately. Normally, once a page is allocated (given a physical page of main memory) then that page stays on whatever node it @@ -681,10 +686,14 @@ and then start a subshell 'sh' in that cpuset: # The next line should display '/Charlie' cat /proc/self/cpuset -In the future, a C library interface to cpusets will likely be -available. For now, the only way to query or modify cpusets is -via the cpuset file system, using the various cd, mkdir, echo, cat, -rmdir commands from the shell, or their equivalent from C. +There are ways to query or modify cpusets: + - via the cpuset file system directly, using the various cd, mkdir, echo, + cat, rmdir commands from the shell, or their equivalent from C. + - via the C library libcpuset. + - via the C library libcgroup. + (http://sourceforge.net/proects/libcg/) + - via the python application cset. + (http://developer.novell.com/wiki/index.php/Cpuset) The sched_setaffinity calls can also be done at the shell prompt using SGI's runon or Robert Love's taskset. The mbind and set_mempolicy @@ -756,7 +765,7 @@ mount -t cpuset X /dev/cpuset is equivalent to -mount -t cgroup -ocpuset X /dev/cpuset +mount -t cgroup -ocpuset,noprefix X /dev/cpuset echo "/sbin/cpuset_release_agent" > /dev/cpuset/release_agent 2.2 Adding/removing cpus -- cgit v1.2.3 From 802d52734adf0f288c49c05ed433872d7559c932 Mon Sep 17 00:00:00 2001 From: Karen Xie Date: Fri, 13 Feb 2009 21:39:04 -0800 Subject: [SCSI] cxgb3i: Fix spelling errors in documentation Signed-off-by: Karen Xie Signed-off-by: James Bottomley --- Documentation/scsi/cxgb3i.txt | 11 +++++------ 1 file changed, 5 insertions(+), 6 deletions(-) (limited to 'Documentation') diff --git a/Documentation/scsi/cxgb3i.txt b/Documentation/scsi/cxgb3i.txt index 8141fa01978..7ac8032ee9b 100644 --- a/Documentation/scsi/cxgb3i.txt +++ b/Documentation/scsi/cxgb3i.txt @@ -4,7 +4,7 @@ Introduction ============ The Chelsio T3 ASIC based Adapters (S310, S320, S302, S304, Mezz cards, etc. -series of products) supports iSCSI acceleration and iSCSI Direct Data Placement +series of products) support iSCSI acceleration and iSCSI Direct Data Placement (DDP) where the hardware handles the expensive byte touching operations, such as CRC computation and verification, and direct DMA to the final host memory destination: @@ -31,9 +31,9 @@ destination: the TCP segments onto the wire. It handles TCP retransmission if needed. - On receving, S3 h/w recovers the iSCSI PDU by reassembling TCP + On receiving, S3 h/w recovers the iSCSI PDU by reassembling TCP segments, separating the header and data, calculating and verifying - the digests, then forwards the header to the host. The payload data, + the digests, then forwarding the header to the host. The payload data, if possible, will be directly placed into the pre-posted host DDP buffer. Otherwise, the payload data will be sent to the host too. @@ -68,9 +68,8 @@ The following steps need to be taken to accelerates the open-iscsi initiator: sure the ip address is unique in the network. 3. edit /etc/iscsi/iscsid.conf - The default setting for MaxRecvDataSegmentLength (131072) is too big, - replace "node.conn[0].iscsi.MaxRecvDataSegmentLength" to be a value no - bigger than 15360 (for example 8192): + The default setting for MaxRecvDataSegmentLength (131072) is too big; + replace with a value no bigger than 15360 (for example 8192): node.conn[0].iscsi.MaxRecvDataSegmentLength = 8192 -- cgit v1.2.3 From 245127dbe9ea1e5a93aae0d3ede09992f1e99f53 Mon Sep 17 00:00:00 2001 From: Mike Murphy Date: Sun, 22 Feb 2009 01:17:14 -0500 Subject: PATCH [1/2] Documentation/driver-model/device.txt: fix struct device_attribute Fix the presented definition of struct device_attribute to match the actual definition in include/linux/device.h Signed-off-by: Mike Murphy Signed-off-by: Linus Torvalds --- Documentation/driver-model/device.txt | 8 +++++--- 1 file changed, 5 insertions(+), 3 deletions(-) (limited to 'Documentation') diff --git a/Documentation/driver-model/device.txt b/Documentation/driver-model/device.txt index a05ec50f800..a7cbfff40d0 100644 --- a/Documentation/driver-model/device.txt +++ b/Documentation/driver-model/device.txt @@ -127,9 +127,11 @@ void unlock_device(struct device * dev); Attributes ~~~~~~~~~~ struct device_attribute { - struct attribute attr; - ssize_t (*show)(struct device * dev, char * buf, size_t count, loff_t off); - ssize_t (*store)(struct device * dev, const char * buf, size_t count, loff_t off); + struct attribute attr; + ssize_t (*show)(struct device *dev, struct device_attribute *attr, + char *buf); + ssize_t (*store)(struct device *dev, struct device_attribute *attr, + const char *buf, size_t count); }; Attributes of devices can be exported via drivers using a simple -- cgit v1.2.3 From f8a1af6bbc63218cabce742a7a291ac7c08bbd00 Mon Sep 17 00:00:00 2001 From: Mike Murphy Date: Sun, 22 Feb 2009 01:19:23 -0500 Subject: PATCH [2/2] Documentation/filesystems/sysfs.txt: fix descriptions of device attributes Fix descriptions of device attributes to be consistent with the actual implementations in include/linux/device.h Signed-off-by: Mike Murphy Signed-off-by: Linus Torvalds --- Documentation/filesystems/sysfs.txt | 50 +++++++++++++++++++++---------------- 1 file changed, 28 insertions(+), 22 deletions(-) (limited to 'Documentation') diff --git a/Documentation/filesystems/sysfs.txt b/Documentation/filesystems/sysfs.txt index 9e9c348275a..7e81e37c0b1 100644 --- a/Documentation/filesystems/sysfs.txt +++ b/Documentation/filesystems/sysfs.txt @@ -2,8 +2,10 @@ sysfs - _The_ filesystem for exporting kernel objects. Patrick Mochel +Mike Murphy -10 January 2003 +Revised: 22 February 2009 +Original: 10 January 2003 What it is: @@ -64,12 +66,13 @@ An attribute definition is simply: struct attribute { char * name; + struct module *owner; mode_t mode; }; -int sysfs_create_file(struct kobject * kobj, struct attribute * attr); -void sysfs_remove_file(struct kobject * kobj, struct attribute * attr); +int sysfs_create_file(struct kobject * kobj, const struct attribute * attr); +void sysfs_remove_file(struct kobject * kobj, const struct attribute * attr); A bare attribute contains no means to read or write the value of the @@ -80,9 +83,11 @@ a specific object type. For example, the driver model defines struct device_attribute like: struct device_attribute { - struct attribute attr; - ssize_t (*show)(struct device * dev, char * buf); - ssize_t (*store)(struct device * dev, const char * buf); + struct attribute attr; + ssize_t (*show)(struct device *dev, struct device_attribute *attr, + char *buf); + ssize_t (*store)(struct device *dev, struct device_attribute *attr, + const char *buf, size_t count); }; int device_create_file(struct device *, struct device_attribute *); @@ -90,12 +95,8 @@ void device_remove_file(struct device *, struct device_attribute *); It also defines this helper for defining device attributes: -#define DEVICE_ATTR(_name, _mode, _show, _store) \ -struct device_attribute dev_attr_##_name = { \ - .attr = {.name = __stringify(_name) , .mode = _mode }, \ - .show = _show, \ - .store = _store, \ -}; +#define DEVICE_ATTR(_name, _mode, _show, _store) \ +struct device_attribute dev_attr_##_name = __ATTR(_name, _mode, _show, _store) For example, declaring @@ -107,9 +108,9 @@ static struct device_attribute dev_attr_foo = { .attr = { .name = "foo", .mode = S_IWUSR | S_IRUGO, + .show = show_foo, + .store = store_foo, }, - .show = show_foo, - .store = store_foo, }; @@ -161,10 +162,12 @@ To read or write attributes, show() or store() methods must be specified when declaring the attribute. The method types should be as simple as those defined for device attributes: - ssize_t (*show)(struct device * dev, char * buf); - ssize_t (*store)(struct device * dev, const char * buf); +ssize_t (*show)(struct device * dev, struct device_attribute * attr, + char * buf); +ssize_t (*store)(struct device * dev, struct device_attribute * attr, + const char * buf); -IOW, they should take only an object and a buffer as parameters. +IOW, they should take only an object, an attribute, and a buffer as parameters. sysfs allocates a buffer of size (PAGE_SIZE) and passes it to the @@ -299,14 +302,16 @@ The following interface layers currently exist in sysfs: Structure: struct device_attribute { - struct attribute attr; - ssize_t (*show)(struct device * dev, char * buf); - ssize_t (*store)(struct device * dev, const char * buf); + struct attribute attr; + ssize_t (*show)(struct device *dev, struct device_attribute *attr, + char *buf); + ssize_t (*store)(struct device *dev, struct device_attribute *attr, + const char *buf, size_t count); }; Declaring: -DEVICE_ATTR(_name, _str, _mode, _show, _store); +DEVICE_ATTR(_name, _mode, _show, _store); Creation/Removal: @@ -342,7 +347,8 @@ Structure: struct driver_attribute { struct attribute attr; ssize_t (*show)(struct device_driver *, char * buf); - ssize_t (*store)(struct device_driver *, const char * buf); + ssize_t (*store)(struct device_driver *, const char * buf, + size_t count); }; Declaring: -- cgit v1.2.3 From f7f84f38cd916552c175f1f3d09cb6e85c1b29fc Mon Sep 17 00:00:00 2001 From: Randy Dunlap Date: Sun, 22 Feb 2009 12:15:45 -0800 Subject: docbook: split kernel-api for device-drivers The kernel-api docbook was much larger than any of the others, so processing it took longer and needed some docbook extras in some cases, so split it into kernel-api (infrastructure etc.) and device drivers/device subsystems. This allows these docbooks to be generated in parallel. (This reduced the docbook processing time on my 4-proc system with make -j4 from about 5min:16sec to about 2min:01sec.) The chapters that were moved from kernel-api to device-drivers are: Driver Basics Device drivers infrastructure Parallel Port Devices Message-based devices Sound Devices 16x50 UART Driver Frame Buffer Library Input Subsystem Serial Peripheral Interface (SPI) I2C and SMBus Subsystem Signed-off-by: Randy Dunlap Acked-by: Sam Ravnborg Signed-off-by: Linus Torvalds --- Documentation/DocBook/Makefile | 2 +- Documentation/DocBook/device-drivers.tmpl | 418 ++++++++++++++++++++++++++++++ Documentation/DocBook/kernel-api.tmpl | 377 --------------------------- 3 files changed, 419 insertions(+), 378 deletions(-) create mode 100644 Documentation/DocBook/device-drivers.tmpl (limited to 'Documentation') diff --git a/Documentation/DocBook/Makefile b/Documentation/DocBook/Makefile index dc3154e4927..1462ed86d40 100644 --- a/Documentation/DocBook/Makefile +++ b/Documentation/DocBook/Makefile @@ -6,7 +6,7 @@ # To add a new book the only step required is to add the book to the # list of DOCBOOKS. -DOCBOOKS := z8530book.xml mcabook.xml \ +DOCBOOKS := z8530book.xml mcabook.xml device-drivers.xml \ kernel-hacking.xml kernel-locking.xml deviceiobook.xml \ procfs-guide.xml writing_usb_driver.xml networking.xml \ kernel-api.xml filesystems.xml lsm.xml usb.xml kgdb.xml \ diff --git a/Documentation/DocBook/device-drivers.tmpl b/Documentation/DocBook/device-drivers.tmpl new file mode 100644 index 00000000000..94a20fe8fed --- /dev/null +++ b/Documentation/DocBook/device-drivers.tmpl @@ -0,0 +1,418 @@ + + + + + + Linux Device Drivers + + + + This documentation is free software; you can redistribute + it and/or modify it under the terms of the GNU General Public + License as published by the Free Software Foundation; either + version 2 of the License, or (at your option) any later + version. + + + + This program is distributed in the hope that it will be + useful, but WITHOUT ANY WARRANTY; without even the implied + warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. + See the GNU General Public License for more details. + + + + You should have received a copy of the GNU General Public + License along with this program; if not, write to the Free + Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, + MA 02111-1307 USA + + + + For more details see the file COPYING in the source + distribution of Linux. + + + + + + + + Driver Basics + Driver Entry and Exit points +!Iinclude/linux/init.h + + + Atomic and pointer manipulation +!Iarch/x86/include/asm/atomic_32.h +!Iarch/x86/include/asm/unaligned.h + + + Delaying, scheduling, and timer routines +!Iinclude/linux/sched.h +!Ekernel/sched.c +!Ekernel/timer.c + + High-resolution timers +!Iinclude/linux/ktime.h +!Iinclude/linux/hrtimer.h +!Ekernel/hrtimer.c + + Workqueues and Kevents +!Ekernel/workqueue.c + + Internal Functions +!Ikernel/exit.c +!Ikernel/signal.c +!Iinclude/linux/kthread.h +!Ekernel/kthread.c + + + Kernel objects manipulation + +!Elib/kobject.c + + + Kernel utility functions +!Iinclude/linux/kernel.h +!Ekernel/printk.c +!Ekernel/panic.c +!Ekernel/sys.c +!Ekernel/rcupdate.c + + + Device Resource Management +!Edrivers/base/devres.c + + + + + + Device drivers infrastructure + Device Drivers Base + +!Edrivers/base/driver.c +!Edrivers/base/core.c +!Edrivers/base/class.c +!Edrivers/base/firmware_class.c +!Edrivers/base/transport_class.c + +!Edrivers/base/sys.c + +!Edrivers/base/platform.c +!Edrivers/base/bus.c + + Device Drivers Power Management +!Edrivers/base/power/main.c + + Device Drivers ACPI Support + +!Edrivers/acpi/scan.c +!Idrivers/acpi/scan.c + + + Device drivers PnP support +!Idrivers/pnp/core.c + +!Edrivers/pnp/card.c +!Idrivers/pnp/driver.c +!Edrivers/pnp/manager.c +!Edrivers/pnp/support.c + + Userspace IO devices +!Edrivers/uio/uio.c +!Iinclude/linux/uio_driver.h + + + + + Parallel Port Devices +!Iinclude/linux/parport.h +!Edrivers/parport/ieee1284.c +!Edrivers/parport/share.c +!Idrivers/parport/daisy.c + + + + Message-based devices + Fusion message devices +!Edrivers/message/fusion/mptbase.c +!Idrivers/message/fusion/mptbase.c +!Edrivers/message/fusion/mptscsih.c +!Idrivers/message/fusion/mptscsih.c +!Idrivers/message/fusion/mptctl.c +!Idrivers/message/fusion/mptspi.c +!Idrivers/message/fusion/mptfc.c +!Idrivers/message/fusion/mptlan.c + + I2O message devices +!Iinclude/linux/i2o.h +!Idrivers/message/i2o/core.h +!Edrivers/message/i2o/iop.c +!Idrivers/message/i2o/iop.c +!Idrivers/message/i2o/config-osm.c +!Edrivers/message/i2o/exec-osm.c +!Idrivers/message/i2o/exec-osm.c +!Idrivers/message/i2o/bus-osm.c +!Edrivers/message/i2o/device.c +!Idrivers/message/i2o/device.c +!Idrivers/message/i2o/driver.c +!Idrivers/message/i2o/pci.c +!Idrivers/message/i2o/i2o_block.c +!Idrivers/message/i2o/i2o_scsi.c +!Idrivers/message/i2o/i2o_proc.c + + + + + Sound Devices +!Iinclude/sound/core.h +!Esound/sound_core.c +!Iinclude/sound/pcm.h +!Esound/core/pcm.c +!Esound/core/device.c +!Esound/core/info.c +!Esound/core/rawmidi.c +!Esound/core/sound.c +!Esound/core/memory.c +!Esound/core/pcm_memory.c +!Esound/core/init.c +!Esound/core/isadma.c +!Esound/core/control.c +!Esound/core/pcm_lib.c +!Esound/core/hwdep.c +!Esound/core/pcm_native.c +!Esound/core/memalloc.c + + + + + 16x50 UART Driver +!Iinclude/linux/serial_core.h +!Edrivers/serial/serial_core.c +!Edrivers/serial/8250.c + + + + Frame Buffer Library + + + The frame buffer drivers depend heavily on four data structures. + These structures are declared in include/linux/fb.h. They are + fb_info, fb_var_screeninfo, fb_fix_screeninfo and fb_monospecs. + The last three can be made available to and from userland. + + + + fb_info defines the current state of a particular video card. + Inside fb_info, there exists a fb_ops structure which is a + collection of needed functions to make fbdev and fbcon work. + fb_info is only visible to the kernel. + + + + fb_var_screeninfo is used to describe the features of a video card + that are user defined. With fb_var_screeninfo, things such as + depth and the resolution may be defined. + + + + The next structure is fb_fix_screeninfo. This defines the + properties of a card that are created when a mode is set and can't + be changed otherwise. A good example of this is the start of the + frame buffer memory. This "locks" the address of the frame buffer + memory, so that it cannot be changed or moved. + + + + The last structure is fb_monospecs. In the old API, there was + little importance for fb_monospecs. This allowed for forbidden things + such as setting a mode of 800x600 on a fix frequency monitor. With + the new API, fb_monospecs prevents such things, and if used + correctly, can prevent a monitor from being cooked. fb_monospecs + will not be useful until kernels 2.5.x. + + + Frame Buffer Memory +!Edrivers/video/fbmem.c + + + Frame Buffer Colormap +!Edrivers/video/fbcmap.c + + + Frame Buffer Video Mode Database +!Idrivers/video/modedb.c +!Edrivers/video/modedb.c + + Frame Buffer Macintosh Video Mode Database +!Edrivers/video/macmodes.c + + Frame Buffer Fonts + + Refer to the file drivers/video/console/fonts.c for more information. + + + + + + + Input Subsystem +!Iinclude/linux/input.h +!Edrivers/input/input.c +!Edrivers/input/ff-core.c +!Edrivers/input/ff-memless.c + + + + Serial Peripheral Interface (SPI) + + SPI is the "Serial Peripheral Interface", widely used with + embedded systems because it is a simple and efficient + interface: basically a multiplexed shift register. + Its three signal wires hold a clock (SCK, often in the range + of 1-20 MHz), a "Master Out, Slave In" (MOSI) data line, and + a "Master In, Slave Out" (MISO) data line. + SPI is a full duplex protocol; for each bit shifted out the + MOSI line (one per clock) another is shifted in on the MISO line. + Those bits are assembled into words of various sizes on the + way to and from system memory. + An additional chipselect line is usually active-low (nCS); + four signals are normally used for each peripheral, plus + sometimes an interrupt. + + + The SPI bus facilities listed here provide a generalized + interface to declare SPI busses and devices, manage them + according to the standard Linux driver model, and perform + input/output operations. + At this time, only "master" side interfaces are supported, + where Linux talks to SPI peripherals and does not implement + such a peripheral itself. + (Interfaces to support implementing SPI slaves would + necessarily look different.) + + + The programming interface is structured around two kinds of driver, + and two kinds of device. + A "Controller Driver" abstracts the controller hardware, which may + be as simple as a set of GPIO pins or as complex as a pair of FIFOs + connected to dual DMA engines on the other side of the SPI shift + register (maximizing throughput). Such drivers bridge between + whatever bus they sit on (often the platform bus) and SPI, and + expose the SPI side of their device as a + struct spi_master. + SPI devices are children of that master, represented as a + struct spi_device and manufactured from + struct spi_board_info descriptors which + are usually provided by board-specific initialization code. + A struct spi_driver is called a + "Protocol Driver", and is bound to a spi_device using normal + driver model calls. + + + The I/O model is a set of queued messages. Protocol drivers + submit one or more struct spi_message + objects, which are processed and completed asynchronously. + (There are synchronous wrappers, however.) Messages are + built from one or more struct spi_transfer + objects, each of which wraps a full duplex SPI transfer. + A variety of protocol tweaking options are needed, because + different chips adopt very different policies for how they + use the bits transferred with SPI. + +!Iinclude/linux/spi/spi.h +!Fdrivers/spi/spi.c spi_register_board_info +!Edrivers/spi/spi.c + + + + I<superscript>2</superscript>C and SMBus Subsystem + + + I2C (or without fancy typography, "I2C") + is an acronym for the "Inter-IC" bus, a simple bus protocol which is + widely used where low data rate communications suffice. + Since it's also a licensed trademark, some vendors use another + name (such as "Two-Wire Interface", TWI) for the same bus. + I2C only needs two signals (SCL for clock, SDA for data), conserving + board real estate and minimizing signal quality issues. + Most I2C devices use seven bit addresses, and bus speeds of up + to 400 kHz; there's a high speed extension (3.4 MHz) that's not yet + found wide use. + I2C is a multi-master bus; open drain signaling is used to + arbitrate between masters, as well as to handshake and to + synchronize clocks from slower clients. + + + + The Linux I2C programming interfaces support only the master + side of bus interactions, not the slave side. + The programming interface is structured around two kinds of driver, + and two kinds of device. + An I2C "Adapter Driver" abstracts the controller hardware; it binds + to a physical device (perhaps a PCI device or platform_device) and + exposes a struct i2c_adapter representing + each I2C bus segment it manages. + On each I2C bus segment will be I2C devices represented by a + struct i2c_client. Those devices will + be bound to a struct i2c_driver, + which should follow the standard Linux driver model. + (At this writing, a legacy model is more widely used.) + There are functions to perform various I2C protocol operations; at + this writing all such functions are usable only from task context. + + + + The System Management Bus (SMBus) is a sibling protocol. Most SMBus + systems are also I2C conformant. The electrical constraints are + tighter for SMBus, and it standardizes particular protocol messages + and idioms. Controllers that support I2C can also support most + SMBus operations, but SMBus controllers don't support all the protocol + options that an I2C controller will. + There are functions to perform various SMBus protocol operations, + either using I2C primitives or by issuing SMBus commands to + i2c_adapter devices which don't support those I2C operations. + + +!Iinclude/linux/i2c.h +!Fdrivers/i2c/i2c-boardinfo.c i2c_register_board_info +!Edrivers/i2c/i2c-core.c + + + diff --git a/Documentation/DocBook/kernel-api.tmpl b/Documentation/DocBook/kernel-api.tmpl index 5818ff75786..bc962cda650 100644 --- a/Documentation/DocBook/kernel-api.tmpl +++ b/Documentation/DocBook/kernel-api.tmpl @@ -38,58 +38,6 @@ - - Driver Basics - Driver Entry and Exit points -!Iinclude/linux/init.h - - - Atomic and pointer manipulation -!Iarch/x86/include/asm/atomic_32.h -!Iarch/x86/include/asm/unaligned.h - - - Delaying, scheduling, and timer routines -!Iinclude/linux/sched.h -!Ekernel/sched.c -!Ekernel/timer.c - - High-resolution timers -!Iinclude/linux/ktime.h -!Iinclude/linux/hrtimer.h -!Ekernel/hrtimer.c - - Workqueues and Kevents -!Ekernel/workqueue.c - - Internal Functions -!Ikernel/exit.c -!Ikernel/signal.c -!Iinclude/linux/kthread.h -!Ekernel/kthread.c - - - Kernel objects manipulation - -!Elib/kobject.c - - - Kernel utility functions -!Iinclude/linux/kernel.h -!Ekernel/printk.c -!Ekernel/panic.c -!Ekernel/sys.c -!Ekernel/rcupdate.c - - - Device Resource Management -!Edrivers/base/devres.c - - - - Data Types Doubly Linked Lists @@ -298,62 +246,6 @@ X!Earch/x86/kernel/mca_32.c !Ikernel/acct.c - - Device drivers infrastructure - Device Drivers Base - -!Edrivers/base/driver.c -!Edrivers/base/core.c -!Edrivers/base/class.c -!Edrivers/base/firmware_class.c -!Edrivers/base/transport_class.c - -!Edrivers/base/sys.c - -!Edrivers/base/platform.c -!Edrivers/base/bus.c - - Device Drivers Power Management -!Edrivers/base/power/main.c - - Device Drivers ACPI Support - -!Edrivers/acpi/scan.c -!Idrivers/acpi/scan.c - - - Device drivers PnP support -!Idrivers/pnp/core.c - -!Edrivers/pnp/card.c -!Idrivers/pnp/driver.c -!Edrivers/pnp/manager.c -!Edrivers/pnp/support.c - - Userspace IO devices -!Edrivers/uio/uio.c -!Iinclude/linux/uio_driver.h - - - Block Devices !Eblock/blk-core.c @@ -381,275 +273,6 @@ X!Edrivers/pnp/system.c !Edrivers/char/misc.c - - Parallel Port Devices -!Iinclude/linux/parport.h -!Edrivers/parport/ieee1284.c -!Edrivers/parport/share.c -!Idrivers/parport/daisy.c - - - - Message-based devices - Fusion message devices -!Edrivers/message/fusion/mptbase.c -!Idrivers/message/fusion/mptbase.c -!Edrivers/message/fusion/mptscsih.c -!Idrivers/message/fusion/mptscsih.c -!Idrivers/message/fusion/mptctl.c -!Idrivers/message/fusion/mptspi.c -!Idrivers/message/fusion/mptfc.c -!Idrivers/message/fusion/mptlan.c - - I2O message devices -!Iinclude/linux/i2o.h -!Idrivers/message/i2o/core.h -!Edrivers/message/i2o/iop.c -!Idrivers/message/i2o/iop.c -!Idrivers/message/i2o/config-osm.c -!Edrivers/message/i2o/exec-osm.c -!Idrivers/message/i2o/exec-osm.c -!Idrivers/message/i2o/bus-osm.c -!Edrivers/message/i2o/device.c -!Idrivers/message/i2o/device.c -!Idrivers/message/i2o/driver.c -!Idrivers/message/i2o/pci.c -!Idrivers/message/i2o/i2o_block.c -!Idrivers/message/i2o/i2o_scsi.c -!Idrivers/message/i2o/i2o_proc.c - - - - - Sound Devices -!Iinclude/sound/core.h -!Esound/sound_core.c -!Iinclude/sound/pcm.h -!Esound/core/pcm.c -!Esound/core/device.c -!Esound/core/info.c -!Esound/core/rawmidi.c -!Esound/core/sound.c -!Esound/core/memory.c -!Esound/core/pcm_memory.c -!Esound/core/init.c -!Esound/core/isadma.c -!Esound/core/control.c -!Esound/core/pcm_lib.c -!Esound/core/hwdep.c -!Esound/core/pcm_native.c -!Esound/core/memalloc.c - - - - - 16x50 UART Driver -!Iinclude/linux/serial_core.h -!Edrivers/serial/serial_core.c -!Edrivers/serial/8250.c - - - - Frame Buffer Library - - - The frame buffer drivers depend heavily on four data structures. - These structures are declared in include/linux/fb.h. They are - fb_info, fb_var_screeninfo, fb_fix_screeninfo and fb_monospecs. - The last three can be made available to and from userland. - - - - fb_info defines the current state of a particular video card. - Inside fb_info, there exists a fb_ops structure which is a - collection of needed functions to make fbdev and fbcon work. - fb_info is only visible to the kernel. - - - - fb_var_screeninfo is used to describe the features of a video card - that are user defined. With fb_var_screeninfo, things such as - depth and the resolution may be defined. - - - - The next structure is fb_fix_screeninfo. This defines the - properties of a card that are created when a mode is set and can't - be changed otherwise. A good example of this is the start of the - frame buffer memory. This "locks" the address of the frame buffer - memory, so that it cannot be changed or moved. - - - - The last structure is fb_monospecs. In the old API, there was - little importance for fb_monospecs. This allowed for forbidden things - such as setting a mode of 800x600 on a fix frequency monitor. With - the new API, fb_monospecs prevents such things, and if used - correctly, can prevent a monitor from being cooked. fb_monospecs - will not be useful until kernels 2.5.x. - - - Frame Buffer Memory -!Edrivers/video/fbmem.c - - - Frame Buffer Colormap -!Edrivers/video/fbcmap.c - - - Frame Buffer Video Mode Database -!Idrivers/video/modedb.c -!Edrivers/video/modedb.c - - Frame Buffer Macintosh Video Mode Database -!Edrivers/video/macmodes.c - - Frame Buffer Fonts - - Refer to the file drivers/video/console/fonts.c for more information. - - - - - - - Input Subsystem -!Iinclude/linux/input.h -!Edrivers/input/input.c -!Edrivers/input/ff-core.c -!Edrivers/input/ff-memless.c - - - - Serial Peripheral Interface (SPI) - - SPI is the "Serial Peripheral Interface", widely used with - embedded systems because it is a simple and efficient - interface: basically a multiplexed shift register. - Its three signal wires hold a clock (SCK, often in the range - of 1-20 MHz), a "Master Out, Slave In" (MOSI) data line, and - a "Master In, Slave Out" (MISO) data line. - SPI is a full duplex protocol; for each bit shifted out the - MOSI line (one per clock) another is shifted in on the MISO line. - Those bits are assembled into words of various sizes on the - way to and from system memory. - An additional chipselect line is usually active-low (nCS); - four signals are normally used for each peripheral, plus - sometimes an interrupt. - - - The SPI bus facilities listed here provide a generalized - interface to declare SPI busses and devices, manage them - according to the standard Linux driver model, and perform - input/output operations. - At this time, only "master" side interfaces are supported, - where Linux talks to SPI peripherals and does not implement - such a peripheral itself. - (Interfaces to support implementing SPI slaves would - necessarily look different.) - - - The programming interface is structured around two kinds of driver, - and two kinds of device. - A "Controller Driver" abstracts the controller hardware, which may - be as simple as a set of GPIO pins or as complex as a pair of FIFOs - connected to dual DMA engines on the other side of the SPI shift - register (maximizing throughput). Such drivers bridge between - whatever bus they sit on (often the platform bus) and SPI, and - expose the SPI side of their device as a - struct spi_master. - SPI devices are children of that master, represented as a - struct spi_device and manufactured from - struct spi_board_info descriptors which - are usually provided by board-specific initialization code. - A struct spi_driver is called a - "Protocol Driver", and is bound to a spi_device using normal - driver model calls. - - - The I/O model is a set of queued messages. Protocol drivers - submit one or more struct spi_message - objects, which are processed and completed asynchronously. - (There are synchronous wrappers, however.) Messages are - built from one or more struct spi_transfer - objects, each of which wraps a full duplex SPI transfer. - A variety of protocol tweaking options are needed, because - different chips adopt very different policies for how they - use the bits transferred with SPI. - -!Iinclude/linux/spi/spi.h -!Fdrivers/spi/spi.c spi_register_board_info -!Edrivers/spi/spi.c - - - - I<superscript>2</superscript>C and SMBus Subsystem - - - I2C (or without fancy typography, "I2C") - is an acronym for the "Inter-IC" bus, a simple bus protocol which is - widely used where low data rate communications suffice. - Since it's also a licensed trademark, some vendors use another - name (such as "Two-Wire Interface", TWI) for the same bus. - I2C only needs two signals (SCL for clock, SDA for data), conserving - board real estate and minimizing signal quality issues. - Most I2C devices use seven bit addresses, and bus speeds of up - to 400 kHz; there's a high speed extension (3.4 MHz) that's not yet - found wide use. - I2C is a multi-master bus; open drain signaling is used to - arbitrate between masters, as well as to handshake and to - synchronize clocks from slower clients. - - - - The Linux I2C programming interfaces support only the master - side of bus interactions, not the slave side. - The programming interface is structured around two kinds of driver, - and two kinds of device. - An I2C "Adapter Driver" abstracts the controller hardware; it binds - to a physical device (perhaps a PCI device or platform_device) and - exposes a struct i2c_adapter representing - each I2C bus segment it manages. - On each I2C bus segment will be I2C devices represented by a - struct i2c_client. Those devices will - be bound to a struct i2c_driver, - which should follow the standard Linux driver model. - (At this writing, a legacy model is more widely used.) - There are functions to perform various I2C protocol operations; at - this writing all such functions are usable only from task context. - - - - The System Management Bus (SMBus) is a sibling protocol. Most SMBus - systems are also I2C conformant. The electrical constraints are - tighter for SMBus, and it standardizes particular protocol messages - and idioms. Controllers that support I2C can also support most - SMBus operations, but SMBus controllers don't support all the protocol - options that an I2C controller will. - There are functions to perform various SMBus protocol operations, - either using I2C primitives or by issuing SMBus commands to - i2c_adapter devices which don't support those I2C operations. - - -!Iinclude/linux/i2c.h -!Fdrivers/i2c/i2c-boardinfo.c i2c_register_board_info -!Edrivers/i2c/i2c-core.c - - Clock Framework -- cgit v1.2.3 From af23f573e817642479fdd05e2b5da5b268eacfaf Mon Sep 17 00:00:00 2001 From: Randy Dunlap Date: Sun, 22 Feb 2009 17:05:22 -0800 Subject: acpi/doc: add missing param value Add missing parameter value to list of available values for acpi=. Signed-off-by: Randy Dunlap Signed-off-by: Linus Torvalds --- Documentation/kernel-parameters.txt | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'Documentation') diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt index b182626739e..319785b6dcb 100644 --- a/Documentation/kernel-parameters.txt +++ b/Documentation/kernel-parameters.txt @@ -134,7 +134,7 @@ and is between 256 and 4096 characters. It is defined in the file acpi= [HW,ACPI,X86-64,i386] Advanced Configuration and Power Interface - Format: { force | off | ht | strict | noirq } + Format: { force | off | ht | strict | noirq | rsdt } force -- enable ACPI if default was off off -- disable ACPI if default was on noirq -- do not use ACPI for IRQ routing -- cgit v1.2.3 From 954a8b8162ecab1d5ddf6c5b993b2d4da3fcaef7 Mon Sep 17 00:00:00 2001 From: Kyle McMartin Date: Thu, 19 Feb 2009 16:48:14 -0500 Subject: x86, doc: fix references to Documentation/x86/i386/boot.txt Impact: Documentation fix The amazing dancing boot.txt file has jumped places again. It should never have been in Documentation/x86/i386, since it never was 32-bit-specific, but it unfortunately ended up there for a while. Signed-off-by: Kyle McMartin Signed-off-by: H. Peter Anvin --- Documentation/kernel-parameters.txt | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) (limited to 'Documentation') diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt index 319785b6dcb..f6d5d5b9b2b 100644 --- a/Documentation/kernel-parameters.txt +++ b/Documentation/kernel-parameters.txt @@ -114,7 +114,7 @@ In addition, the following text indicates that the option: Parameters denoted with BOOT are actually interpreted by the boot loader, and have no meaning to the kernel directly. Do not modify the syntax of boot loader parameters without extreme -need or coordination with . +need or coordination with . There are also arch-specific kernel-parameters not documented here. See for example . @@ -2449,7 +2449,7 @@ and is between 256 and 4096 characters. It is defined in the file See Documentation/fb/modedb.txt. vga= [BOOT,X86-32] Select a particular video mode - See Documentation/x86/i386/boot.txt and + See Documentation/x86/boot.txt and Documentation/svga.txt. Use vga=ask for menu. This is actually a boot loader parameter; the value is -- cgit v1.2.3 From d22157b3d7a24d953ef5cce4515436be65b2e121 Mon Sep 17 00:00:00 2001 From: Chris Wright Date: Mon, 23 Feb 2009 21:50:35 -0800 Subject: PCI: add some sysfs ABI docs Add sysfs ABI docs for driver entries bind, unbind and new_id. These entries are pretty old, from 2.6.0 onwards AFAIK, so this documents current behaviour. Signed-off-by: Chris Wright Acked-by: Greg Kroah-Hartman Signed-off-by: Jesse Barnes --- Documentation/ABI/testing/sysfs-bus-pci | 43 +++++++++++++++++++++++++++++++++ 1 file changed, 43 insertions(+) (limited to 'Documentation') diff --git a/Documentation/ABI/testing/sysfs-bus-pci b/Documentation/ABI/testing/sysfs-bus-pci index ceddcff4082..e638e15a889 100644 --- a/Documentation/ABI/testing/sysfs-bus-pci +++ b/Documentation/ABI/testing/sysfs-bus-pci @@ -1,3 +1,46 @@ +What: /sys/bus/pci/drivers/.../bind +Date: December 2003 +Contact: linux-pci@vger.kernel.org +Description: + Writing a device location to this file will cause + the driver to attempt to bind to the device found at + this location. This is useful for overriding default + bindings. The format for the location is: DDDD:BB:DD.F. + That is Domain:Bus:Device.Function and is the same as + found in /sys/bus/pci/devices/. For example: + # echo 0000:00:19.0 > /sys/bus/pci/drivers/foo/bind + (Note: kernels before 2.6.28 may require echo -n). + +What: /sys/bus/pci/drivers/.../unbind +Date: December 2003 +Contact: linux-pci@vger.kernel.org +Description: + Writing a device location to this file will cause the + driver to attempt to unbind from the device found at + this location. This may be useful when overriding default + bindings. The format for the location is: DDDD:BB:DD.F. + That is Domain:Bus:Device.Function and is the same as + found in /sys/bus/pci/devices/. For example: + # echo 0000:00:19.0 > /sys/bus/pci/drivers/foo/unbind + (Note: kernels before 2.6.28 may require echo -n). + +What: /sys/bus/pci/drivers/.../new_id +Date: December 2003 +Contact: linux-pci@vger.kernel.org +Description: + Writing a device ID to this file will attempt to + dynamically add a new device ID to a PCI device driver. + This may allow the driver to support more hardware than + was included in the driver's static device ID support + table at compile time. The format for the device ID is: + VVVV DDDD SVVV SDDD CCCC MMMM PPPP. That is Vendor ID, + Device ID, Subsystem Vendor ID, Subsystem Device ID, + Class, Class Mask, and Private Driver Data. The Vendor ID + and Device ID fields are required, the rest are optional. + Upon successfully adding an ID, the driver will probe + for the device and attempt to bind to it. For example: + # echo "8086 10f5" > /sys/bus/pci/drivers/foo/new_id + What: /sys/bus/pci/devices/.../vpd Date: February 2008 Contact: Ben Hutchings -- cgit v1.2.3 From 0af80c04e2f2e45ae09fceb17df8050f828a5c40 Mon Sep 17 00:00:00 2001 From: David Fries Date: Wed, 25 Feb 2009 20:28:21 +0100 Subject: ide: ide.c 'clear' fix, update "ide=nodma" documentation Documentation/kernel-parameters.txt - ide=nodma is no longer valid. drivers/ide/Kconfig - The module is ide-core.ko not ide. drivers/ide/ide.c - It took me a while to figure out what the arguments %d.%d:%d to nodma module parameter ment, so I added a comment to each. - Added a comment to each of the sscanf lines. - There is a bug, if j is 0 it would previously clear all the other bits except the current device, changed in three different places. mask &= (1 << i) should be mask &= ~(1 << i). Signed-off-by: David Fries [bart: s/disk/device/ in ide.c, beautify patch description] Signed-off-by: Bartlomiej Zolnierkiewicz --- Documentation/kernel-parameters.txt | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) (limited to 'Documentation') diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt index 319785b6dcb..0ed3234125e 100644 --- a/Documentation/kernel-parameters.txt +++ b/Documentation/kernel-parameters.txt @@ -868,8 +868,10 @@ and is between 256 and 4096 characters. It is defined in the file icn= [HW,ISDN] Format: [,[,[,]]] - ide= [HW] (E)IDE subsystem - Format: ide=nodma or ide=doubler + ide-core.nodma= [HW] (E)IDE subsystem + Format: =0.0 to prevent dma on hda, =0.1 hdb =1.0 hdc + .vlb_clock .pci_clock .noflush .noprobe .nowerr .cdrom + .chs .ignore_cable are additional options See Documentation/ide/ide.txt. idebus= [HW] (E)IDE subsystem - VLB/PCI bus speed -- cgit v1.2.3 From f5a3258335eef2baf534243da00bcd0e760dd2b5 Mon Sep 17 00:00:00 2001 From: Uwe Bugla Date: Mon, 23 Feb 2009 10:54:20 -0300 Subject: V4L/DVB (10695): Update Technisat card documentation Fixes for documentation of Technisat-based cards Signed-off-by: Uwe Bugla Signed-off-by: Patrick Boettcher Signed-off-by: Mauro Carvalho Chehab --- Documentation/dvb/technisat.txt | 34 ++++++++++++++++++++-------------- 1 file changed, 20 insertions(+), 14 deletions(-) (limited to 'Documentation') diff --git a/Documentation/dvb/technisat.txt b/Documentation/dvb/technisat.txt index cdf6ee4b2da..3f435ffb289 100644 --- a/Documentation/dvb/technisat.txt +++ b/Documentation/dvb/technisat.txt @@ -1,5 +1,5 @@ -How to set up the Technisat devices -=================================== +How to set up the Technisat/B2C2 Flexcop devices +================================================ 1) Find out what device you have ================================ @@ -16,54 +16,60 @@ DVB: registering frontend 0 (Conexant CX24123/CX24109)... If the Technisat is the only TV device in your box get rid of unnecessary modules and check this one: "Multimedia devices" => "Customise analog and hybrid tuner modules to build" -In this directory uncheck every driver which is activated there. +In this directory uncheck every driver which is activated there (except "Simple tuner support" for case 9 only). Then please activate: 2a) Main module part: a.)"Multimedia devices" => "DVB/ATSC adapters" => "Technisat/B2C2 FlexcopII(b) and FlexCopIII adapters" -b.)"Multimedia devices" => "DVB/ATSC adapters" => "Technisat/B2C2 FlexcopII(b) and FlexCopIII adapters" => "Technisat/B2C2 Air/Sky/Cable2PC PCI" in case of a PCI card OR +b.)"Multimedia devices" => "DVB/ATSC adapters" => "Technisat/B2C2 FlexcopII(b) and FlexCopIII adapters" => "Technisat/B2C2 Air/Sky/Cable2PC PCI" in case of a PCI card +OR c.)"Multimedia devices" => "DVB/ATSC adapters" => "Technisat/B2C2 FlexcopII(b) and FlexCopIII adapters" => "Technisat/B2C2 Air/Sky/Cable2PC USB" in case of an USB 1.1 adapter d.)"Multimedia devices" => "DVB/ATSC adapters" => "Technisat/B2C2 FlexcopII(b) and FlexCopIII adapters" => "Enable debug for the B2C2 FlexCop drivers" Notice: d.) is helpful for troubleshooting 2b) Frontend module part: -1.) Revision 2.3: +1.) SkyStar DVB-S Revision 2.3: a.)"Multimedia devices" => "Customise DVB frontends" => "Customise the frontend modules to build" b.)"Multimedia devices" => "Customise DVB frontends" => "Zarlink VP310/MT312/ZL10313 based" -2.) Revision 2.6: +2.) SkyStar DVB-S Revision 2.6: a.)"Multimedia devices" => "Customise DVB frontends" => "Customise the frontend modules to build" b.)"Multimedia devices" => "Customise DVB frontends" => "ST STV0299 based" -3.) Revision 2.7: +3.) SkyStar DVB-S Revision 2.7: a.)"Multimedia devices" => "Customise DVB frontends" => "Customise the frontend modules to build" b.)"Multimedia devices" => "Customise DVB frontends" => "Samsung S5H1420 based" c.)"Multimedia devices" => "Customise DVB frontends" => "Integrant ITD1000 Zero IF tuner for DVB-S/DSS" d.)"Multimedia devices" => "Customise DVB frontends" => "ISL6421 SEC controller" -4.) Revision 2.8: +4.) SkyStar DVB-S Revision 2.8: a.)"Multimedia devices" => "Customise DVB frontends" => "Customise the frontend modules to build" b.)"Multimedia devices" => "Customise DVB frontends" => "Conexant CX24113/CX24128 tuner for DVB-S/DSS" c.)"Multimedia devices" => "Customise DVB frontends" => "Conexant CX24123 based" d.)"Multimedia devices" => "Customise DVB frontends" => "ISL6421 SEC controller" -5.) DVB-T card: +5.) AirStar DVB-T card: a.)"Multimedia devices" => "Customise DVB frontends" => "Customise the frontend modules to build" b.)"Multimedia devices" => "Customise DVB frontends" => "Zarlink MT352 based" -6.) DVB-C card: +6.) CableStar DVB-C card: a.)"Multimedia devices" => "Customise DVB frontends" => "Customise the frontend modules to build" b.)"Multimedia devices" => "Customise DVB frontends" => "ST STV0297 based" -7.) ATSC card 1st generation: +7.) AirStar ATSC card 1st generation: a.)"Multimedia devices" => "Customise DVB frontends" => "Customise the frontend modules to build" b.)"Multimedia devices" => "Customise DVB frontends" => "Broadcom BCM3510" -8.) ATSC card 2nd generation: +8.) AirStar ATSC card 2nd generation: a.)"Multimedia devices" => "Customise DVB frontends" => "Customise the frontend modules to build" b.)"Multimedia devices" => "Customise DVB frontends" => "NxtWave Communications NXT2002/NXT2004 based" -c.)"Multimedia devices" => "Customise DVB frontends" => "LG Electronics LGDT3302/LGDT3303 based" +c.)"Multimedia devices" => "Customise DVB frontends" => "Generic I2C PLL based tuners" -Author: Uwe Bugla December 2008 +9.) AirStar ATSC card 3rd generation: +a.)"Multimedia devices" => "Customise DVB frontends" => "Customise the frontend modules to build" +b.)"Multimedia devices" => "Customise DVB frontends" => "LG Electronics LGDT3302/LGDT3303 based" +c.)"Multimedia devices" => "Customise analog and hybrid tuner modules to build" => "Simple tuner support" + +Author: Uwe Bugla February 2009 -- cgit v1.2.3 From b391d0f08fb0858f7d2cc034ddcca6cd0545bd7d Mon Sep 17 00:00:00 2001 From: Uwe Bugla Date: Mon, 23 Feb 2009 10:56:11 -0300 Subject: V4L/DVB (10696): Remove outdated README for the flexcop-driver This patch removes an outdated README for the flexcop-driver. Signed-off-by: Uwe Bugla Signed-off-by: Patrick Boettcher Signed-off-by: Mauro Carvalho Chehab --- Documentation/dvb/README.flexcop | 205 --------------------------------------- 1 file changed, 205 deletions(-) delete mode 100644 Documentation/dvb/README.flexcop (limited to 'Documentation') diff --git a/Documentation/dvb/README.flexcop b/Documentation/dvb/README.flexcop deleted file mode 100644 index 5515469de7c..00000000000 --- a/Documentation/dvb/README.flexcop +++ /dev/null @@ -1,205 +0,0 @@ -This README escorted the skystar2-driver rewriting procedure. It describes the -state of the new flexcop-driver set and some internals are written down here -too. - -This document hopefully describes things about the flexcop and its -device-offsprings. Goal was to write an easy-to-write and easy-to-read set of -drivers based on the skystar2.c and other information. - -Remark: flexcop-pci.c was a copy of skystar2.c, but every line has been -touched and rewritten. - -History & News -============== - 2005-04-01 - correct USB ISOC transfers (thanks to Vadim Catana) - - - - -General coding processing -========================= - -We should proceed as follows (as long as no one complains): - -0) Think before start writing code! - -1) rewriting the skystar2.c with the help of the flexcop register descriptions -and splitting up the files to a pci-bus-part and a flexcop-part. -The new driver will be called b2c2-flexcop-pci.ko/b2c2-flexcop-usb.ko for the -device-specific part and b2c2-flexcop.ko for the common flexcop-functions. - -2) Search for errors in the leftover of flexcop-pci.c (compare with pluto2.c -and other pci drivers) - -3) make some beautification (see 'Improvements when rewriting (refactoring) is -done') - -4) Testing the new driver and maybe substitute the skystar2.c with it, to reach -a wider tester audience. - -5) creating an usb-bus-part using the already written flexcop code for the pci -card. - -Idea: create a kernel-object for the flexcop and export all important -functions. This option saves kernel-memory, but maybe a lot of functions have -to be exported to kernel namespace. - - -Current situation -================= - -0) Done :) -1) Done (some minor issues left) -2) Done -3) Not ready yet, more information is necessary -4) next to be done (see the table below) -5) USB driver is working (yes, there are some minor issues) - -What seems to be ready? ------------------------ - -1) Rewriting -1a) i2c is cut off from the flexcop-pci.c and seems to work -1b) moved tuner and demod stuff from flexcop-pci.c to flexcop-tuner-fe.c -1c) moved lnb and diseqc stuff from flexcop-pci.c to flexcop-tuner-fe.c -1e) eeprom (reading MAC address) -1d) sram (no dynamic sll size detection (commented out) (using default as JJ told me)) -1f) misc. register accesses for reading parameters (e.g. resetting, revision) -1g) pid/mac filter (flexcop-hw-filter.c) -1i) dvb-stuff initialization in flexcop.c (done) -1h) dma stuff (now just using the size-irq, instead of all-together, to be done) -1j) remove flexcop initialization from flexcop-pci.c completely (done) -1l) use a well working dma IRQ method (done, see 'Known bugs and problems and TODO') -1k) cleanup flexcop-files (remove unused EXPORT_SYMBOLs, make static from -non-static where possible, moved code to proper places) - -2) Search for errors in the leftover of flexcop-pci.c (partially done) -5a) add MAC address reading -5c) feeding of ISOC data to the software demux (format of the isochronous data -and speed optimization, no real error) (thanks to Vadim Catana) - -What to do in the near future? --------------------------------------- -(no special order here) - -5) USB driver -5b) optimize isoc-transfer (submitting/killing isoc URBs when transfer is starting) - -Testing changes ---------------- - -O = item is working -P = item is partially working -X = item is not working -N = item does not apply here - = item need to be examined - - | PCI | USB -item | mt352 | nxt2002 | stv0299 | mt312 | mt352 | nxt2002 | stv0299 | mt312 --------+-------+---------+---------+-------+-------+---------+---------+------- -1a) | O | | | | N | N | N | N -1b) | O | | | | | | O | -1c) | N | N | | | N | N | O | -1d) | O | O -1e) | O | O -1f) | P -1g) | O -1h) | P | -1i) | O | N -1j) | O | N -1l) | O | N -2) | O | N -5a) | N | O -5b)* | N | -5c) | N | O - -* - not done yet - -Known bugs and problems and TODO --------------------------------- - -1g/h/l) when pid filtering is enabled on the pci card - -DMA usage currently: - The DMA is splitted in 2 equal-sized subbuffers. The Flexcop writes to first - address and triggers an IRQ when it's full and starts writing to the second - address. When the second address is full, the IRQ is triggered again, and - the flexcop writes to first address again, and so on. - The buffersize of each address is currently 640*188 bytes. - - Problem is, when using hw-pid-filtering and doing some low-bandwidth - operation (like scanning) the buffers won't be filled enough to trigger - the IRQ. That's why: - - When PID filtering is activated, the timer IRQ is used. Every 1.97 ms the IRQ - is triggered. Is the current write address of DMA1 different to the one - during the last IRQ, then the data is passed to the demuxer. - - There is an additional DMA-IRQ-method: packet count IRQ. This isn't - implemented correctly yet. - - The solution is to disable HW PID filtering, but I don't know how the DVB - API software demux behaves on slow systems with 45MBit/s TS. - -Solved bugs :) --------------- -1g) pid-filtering (somehow pid index 4 and 5 (EMM_PID and ECM_PID) aren't -working) -SOLUTION: also index 0 was affected, because net_translation is done for -these indexes by default - -5b) isochronous transfer does only work in the first attempt (for the Sky2PC -USB, Air2PC is working) SOLUTION: the flexcop was going asleep and never really -woke up again (don't know if this need fixes, see -flexcop-fe-tuner.c:flexcop_sleep) - -NEWS: when the driver is loaded and unloaded and loaded again (w/o doing -anything in the while the driver is loaded the first time), no transfers take -place anymore. - -Improvements when rewriting (refactoring) is done -================================================= - -- split sleeping of the flexcop (misc_204.ACPI3_sig = 1;) from lnb_control - (enable sleeping for other demods than dvb-s) -- add support for CableStar (stv0297 Microtune 203x/ALPS) (almost done, incompatibilities with the Nexus-CA) - -Debugging ---------- -- add verbose debugging to skystar2.c (dump the reg_dw_data) and compare it - with this flexcop, this is important, because i2c is now using the - flexcop_ibi_value union from flexcop-reg.h (do you have a better idea for - that, please tell us so). - -Everything which is identical in the following table, can be put into a common -flexcop-module. - - PCI USB -------------------------------------------------------------------------------- -Different: -Register access: accessing IO memory USB control message -I2C bus: I2C bus of the FC USB control message -Data transfer: DMA isochronous transfer -EEPROM transfer: through i2c bus not clear yet - -Identical: -Streaming: accessing registers -PID Filtering: accessing registers -Sram destinations: accessing registers -Tuner/Demod: I2C bus -DVB-stuff: can be written for common use - -Acknowledgements (just for the rewriting part) -================ - -Bjarne Steinsbo thought a lot in the first place of the pci part for this code -sharing idea. - -Andreas Oberritter for providing a recent PCI initialization template -(pluto2.c). - -Boleslaw Ciesielski for pointing out a problem with firmware loader. - -Vadim Catana for correcting the USB transfer. - -comments, critics and ideas to linux-dvb@linuxtv.org. -- cgit v1.2.3