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2009-11-13nohz: Prevent clocksource wrapping during idleJon Hunter
The dynamic tick allows the kernel to sleep for periods longer than a single tick, but it does not limit the sleep time currently. In the worst case the kernel could sleep longer than the wrap around time of the time keeping clock source which would result in losing track of time. Prevent this by limiting it to the safe maximum sleep time of the current time keeping clock source. The value is calculated when the clock source is registered. [ tglx: simplified the code a bit and massaged the commit msg ] Signed-off-by: Jon Hunter <jon-hunter@ti.com> Cc: John Stultz <johnstul@us.ibm.com> LKML-Reference: <1250617512-23567-2-git-send-email-jon-hunter@ti.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2009-09-24time: add function to convert between calendar time and broken-down time for ↵Zhaolei
universal use There are many similar code in kernel for one object: convert time between calendar time and broken-down time. Here is some source I found: fs/ncpfs/dir.c fs/smbfs/proc.c fs/fat/misc.c fs/udf/udftime.c fs/cifs/netmisc.c net/netfilter/xt_time.c drivers/scsi/ips.c drivers/input/misc/hp_sdc_rtc.c drivers/rtc/rtc-lib.c arch/ia64/hp/sim/boot/fw-emu.c arch/m68k/mac/misc.c arch/powerpc/kernel/time.c arch/parisc/include/asm/rtc.h ... We can make a common function for this type of conversion, At least we can get following benefit: 1: Make kernel simple and unify 2: Easy to fix bug in converting code 3: Reduce clone of code in future For example, I'm trying to make ftrace display walltime, this patch will make me easy. This code is based on code from glibc-2.6 Signed-off-by: Zhao Lei <zhaolei@cn.fujitsu.com> Cc: OGAWA Hirofumi <hirofumi@mail.parknet.co.jp> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Ingo Molnar <mingo@elte.hu> Cc: Pavel Machek <pavel@ucw.cz> Cc: Andi Kleen <andi@firstfloor.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-09-15time: Prevent 32 bit overflow with set_normalized_timespec()Thomas Gleixner
set_normalized_timespec() nsec argument is of type long. The recent timekeeping changes of ktime_get_ts() feed ts->tv_nsec + tomono.tv_nsec + nsecs to set_normalized_timespec(). On 32 bit machines that sum can be larger than (1 << 31) and therefor result in a negative value which screws up the result completely. Make the nsec argument of set_normalized_timespec() s64 to fix the problem at hand. This also prevents similar problems for future users of set_normalized_timespec(). Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Tested-by: Carsten Emde <carsten.emde@osadl.org> LKML-Reference: <new-submission> Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: John Stultz <johnstul@us.ibm.com>
2009-08-21time: Introduce CLOCK_REALTIME_COARSEjohn stultz
After talking with some application writers who want very fast, but not fine-grained timestamps, I decided to try to implement new clock_ids to clock_gettime(): CLOCK_REALTIME_COARSE and CLOCK_MONOTONIC_COARSE which returns the time at the last tick. This is very fast as we don't have to access any hardware (which can be very painful if you're using something like the acpi_pm clocksource), and we can even use the vdso clock_gettime() method to avoid the syscall. The only trade off is you only get low-res tick grained time resolution. This isn't a new idea, I know Ingo has a patch in the -rt tree that made the vsyscall gettimeofday() return coarse grained time when the vsyscall64 sysctrl was set to 2. However this affects all applications on a system. With this method, applications can choose the proper speed/granularity trade-off for themselves. Signed-off-by: John Stultz <johnstul@us.ibm.com> Cc: Andi Kleen <andi@firstfloor.org> Cc: nikolag@ca.ibm.com Cc: Darren Hart <dvhltc@us.ibm.com> Cc: arjan@infradead.org Cc: jonathan@jonmasters.org LKML-Reference: <1250734414.6897.5.camel@localhost.localdomain> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2009-08-15timekeeping: Introduce read_boot_clockMartin Schwidefsky
Add the new function read_boot_clock to get the exact time the system has been started. For architectures without support for exact boot time a new weak function is added that returns 0. Use the exact boot time to initialize wall_to_monotonic, or xtime if the read_boot_clock returned 0. Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: Ingo Molnar <mingo@elte.hu> Acked-by: John Stultz <johnstul@us.ibm.com> Cc: Daniel Walker <dwalker@fifo99.com> LKML-Reference: <20090814134811.296703241@de.ibm.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2009-08-15timekeeping: Increase granularity of read_persistent_clock()Martin Schwidefsky
The persistent clock of some architectures (e.g. s390) have a better granularity than seconds. To reduce the delta between the host clock and the guest clock in a virtualized system change the read_persistent_clock function to return a struct timespec. Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: Ingo Molnar <mingo@elte.hu> Acked-by: John Stultz <johnstul@us.ibm.com> Cc: Daniel Walker <dwalker@fifo99.com> LKML-Reference: <20090814134811.013873340@de.ibm.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2009-08-15timekeeping: Introduce timekeeping_leap_insertJohn Stultz
Move the adjustment of xtime, wall_to_monotonic and the update of the vsyscall variables to the timekeeping code. Signed-off-by: John Stultz <johnstul@us.ibm.com> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com> LKML-Reference: <20090814134807.609730216@de.ibm.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2009-05-02timekeeping: create arch_gettimeoffset infrastructurejohn stultz
Some arches don't supply their own clocksource. This is mainly the case in architectures that get their inter-tick times by reading the counter on their interval timer. Since these timers wrap every tick, they're not really useful as clocksources. Wrapping them to act like one is possible but not very efficient. So we provide a callout these arches can implement for use with the jiffies clocksource to provide finer then tick granular time. [ Impact: ease the migration to generic time keeping ] Signed-off-by: John Stultz <johnstul@us.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2009-03-26make exported headers use strict posix typesArnd Bergmann
A number of standard posix types are used in exported headers, which is not allowed if __STRICT_KERNEL_NAMES is defined. In order to get rid of the non-__STRICT_KERNEL_NAMES part and to make sane headers the default, we have to change them all to safe types. There are also still some leftovers in reiserfs_fs.h, elfcore.h and coda.h, but these files have not compiled in user space for a long time. This leaves out the various integer types ({u_,u,}int{8,16,32,64}_t), which we take care of separately. Signed-off-by: Arnd Bergmann <arnd@arndb.de> Acked-by: Mauro Carvalho Chehab <mchehab@redhat.com> Cc: David Airlie <airlied@linux.ie> Cc: Arnaldo Carvalho de Melo <acme@ghostprotocols.net> Cc: YOSHIFUJI Hideaki <yoshfuji@linux-ipv6.org> Cc: netdev@vger.kernel.org Cc: linux-ppp@vger.kernel.org Cc: Jaroslav Kysela <perex@perex.cz> Cc: Takashi Iwai <tiwai@suse.de> Cc: David Woodhouse <dwmw2@infradead.org> Signed-off-by: H. Peter Anvin <hpa@linux.intel.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-12-31sched_clock: prevent scd->clock from moving backwards, take #2Thomas Gleixner
Redo: 5b7dba4: sched_clock: prevent scd->clock from moving backwards which had to be reverted due to s2ram hangs: ca7e716: Revert "sched_clock: prevent scd->clock from moving backwards" ... this time with resume restoring GTOD later in the sequence taken into account as well. The "timekeeping_suspended" flag is not very nice but we cannot call into GTOD before it has been properly resumed and the scheduler will run very early in the resume sequence. Cc: <stable@kernel.org> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-10-22Merge branch 'timers/range-hrtimers' into v28-range-hrtimers-for-linus-v2Thomas Gleixner
Conflicts: kernel/time/tick-sched.c Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-10-20Merge branches 'timers/clocksource', 'timers/hrtimers', 'timers/nohz', ↵Thomas Gleixner
'timers/ntp', 'timers/posixtimers' and 'timers/debug' into v28-timers-for-linus
2008-10-17Merge commit 'linus/master' into merge-linusArjan van de Ven
Conflicts: arch/x86/kvm/i8254.c
2008-10-16compat: generic compat get/settimeofdayChristoph Hellwig
Nothing arch specific in get/settimeofday. The details of the timeval conversion varied a little from arch to arch, but all with the same results. Also add an extern declaration for sys_tz to linux/time.h because externs in .c files are fowned upon. I'll kill the externs in various other files in a sparate patch. [akpm@linux-foundation.org: coding-style fixes] Signed-off-by: Christoph Hellwig <hch@lst.de> Acked-by: David S. Miller <davem@davemloft.net> [ sparc bits ] Cc: "Luck, Tony" <tony.luck@intel.com> Cc: Ralf Baechle <ralf@linux-mips.org> Acked-by: Kyle McMartin <kyle@mcmartin.ca> Cc: Matthew Wilcox <matthew@wil.cx> Cc: Grant Grundler <grundler@parisc-linux.org> Cc: Paul Mackerras <paulus@samba.org> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: Heiko Carstens <heiko.carstens@de.ibm.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: "H. Peter Anvin" <hpa@zytor.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-09-14timers: fix itimer/many thread hangFrank Mayhar
Overview This patch reworks the handling of POSIX CPU timers, including the ITIMER_PROF, ITIMER_VIRT timers and rlimit handling. It was put together with the help of Roland McGrath, the owner and original writer of this code. The problem we ran into, and the reason for this rework, has to do with using a profiling timer in a process with a large number of threads. It appears that the performance of the old implementation of run_posix_cpu_timers() was at least O(n*3) (where "n" is the number of threads in a process) or worse. Everything is fine with an increasing number of threads until the time taken for that routine to run becomes the same as or greater than the tick time, at which point things degrade rather quickly. This patch fixes bug 9906, "Weird hang with NPTL and SIGPROF." Code Changes This rework corrects the implementation of run_posix_cpu_timers() to make it run in constant time for a particular machine. (Performance may vary between one machine and another depending upon whether the kernel is built as single- or multiprocessor and, in the latter case, depending upon the number of running processors.) To do this, at each tick we now update fields in signal_struct as well as task_struct. The run_posix_cpu_timers() function uses those fields to make its decisions. We define a new structure, "task_cputime," to contain user, system and scheduler times and use these in appropriate places: struct task_cputime { cputime_t utime; cputime_t stime; unsigned long long sum_exec_runtime; }; This is included in the structure "thread_group_cputime," which is a new substructure of signal_struct and which varies for uniprocessor versus multiprocessor kernels. For uniprocessor kernels, it uses "task_cputime" as a simple substructure, while for multiprocessor kernels it is a pointer: struct thread_group_cputime { struct task_cputime totals; }; struct thread_group_cputime { struct task_cputime *totals; }; We also add a new task_cputime substructure directly to signal_struct, to cache the earliest expiration of process-wide timers, and task_cputime also replaces the it_*_expires fields of task_struct (used for earliest expiration of thread timers). The "thread_group_cputime" structure contains process-wide timers that are updated via account_user_time() and friends. In the non-SMP case the structure is a simple aggregator; unfortunately in the SMP case that simplicity was not achievable due to cache-line contention between CPUs (in one measured case performance was actually _worse_ on a 16-cpu system than the same test on a 4-cpu system, due to this contention). For SMP, the thread_group_cputime counters are maintained as a per-cpu structure allocated using alloc_percpu(). The timer functions update only the timer field in the structure corresponding to the running CPU, obtained using per_cpu_ptr(). We define a set of inline functions in sched.h that we use to maintain the thread_group_cputime structure and hide the differences between UP and SMP implementations from the rest of the kernel. The thread_group_cputime_init() function initializes the thread_group_cputime structure for the given task. The thread_group_cputime_alloc() is a no-op for UP; for SMP it calls the out-of-line function thread_group_cputime_alloc_smp() to allocate and fill in the per-cpu structures and fields. The thread_group_cputime_free() function, also a no-op for UP, in SMP frees the per-cpu structures. The thread_group_cputime_clone_thread() function (also a UP no-op) for SMP calls thread_group_cputime_alloc() if the per-cpu structures haven't yet been allocated. The thread_group_cputime() function fills the task_cputime structure it is passed with the contents of the thread_group_cputime fields; in UP it's that simple but in SMP it must also safely check that tsk->signal is non-NULL (if it is it just uses the appropriate fields of task_struct) and, if so, sums the per-cpu values for each online CPU. Finally, the three functions account_group_user_time(), account_group_system_time() and account_group_exec_runtime() are used by timer functions to update the respective fields of the thread_group_cputime structure. Non-SMP operation is trivial and will not be mentioned further. The per-cpu structure is always allocated when a task creates its first new thread, via a call to thread_group_cputime_clone_thread() from copy_signal(). It is freed at process exit via a call to thread_group_cputime_free() from cleanup_signal(). All functions that formerly summed utime/stime/sum_sched_runtime values from from all threads in the thread group now use thread_group_cputime() to snapshot the values in the thread_group_cputime structure or the values in the task structure itself if the per-cpu structure hasn't been allocated. Finally, the code in kernel/posix-cpu-timers.c has changed quite a bit. The run_posix_cpu_timers() function has been split into a fast path and a slow path; the former safely checks whether there are any expired thread timers and, if not, just returns, while the slow path does the heavy lifting. With the dedicated thread group fields, timers are no longer "rebalanced" and the process_timer_rebalance() function and related code has gone away. All summing loops are gone and all code that used them now uses the thread_group_cputime() inline. When process-wide timers are set, the new task_cputime structure in signal_struct is used to cache the earliest expiration; this is checked in the fast path. Performance The fix appears not to add significant overhead to existing operations. It generally performs the same as the current code except in two cases, one in which it performs slightly worse (Case 5 below) and one in which it performs very significantly better (Case 2 below). Overall it's a wash except in those two cases. I've since done somewhat more involved testing on a dual-core Opteron system. Case 1: With no itimer running, for a test with 100,000 threads, the fixed kernel took 1428.5 seconds, 513 seconds more than the unfixed system, all of which was spent in the system. There were twice as many voluntary context switches with the fix as without it. Case 2: With an itimer running at .01 second ticks and 4000 threads (the most an unmodified kernel can handle), the fixed kernel ran the test in eight percent of the time (5.8 seconds as opposed to 70 seconds) and had better tick accuracy (.012 seconds per tick as opposed to .023 seconds per tick). Case 3: A 4000-thread test with an initial timer tick of .01 second and an interval of 10,000 seconds (i.e. a timer that ticks only once) had very nearly the same performance in both cases: 6.3 seconds elapsed for the fixed kernel versus 5.5 seconds for the unfixed kernel. With fewer threads (eight in these tests), the Case 1 test ran in essentially the same time on both the modified and unmodified kernels (5.2 seconds versus 5.8 seconds). The Case 2 test ran in about the same time as well, 5.9 seconds versus 5.4 seconds but again with much better tick accuracy, .013 seconds per tick versus .025 seconds per tick for the unmodified kernel. Since the fix affected the rlimit code, I also tested soft and hard CPU limits. Case 4: With a hard CPU limit of 20 seconds and eight threads (and an itimer running), the modified kernel was very slightly favored in that while it killed the process in 19.997 seconds of CPU time (5.002 seconds of wall time), only .003 seconds of that was system time, the rest was user time. The unmodified kernel killed the process in 20.001 seconds of CPU (5.014 seconds of wall time) of which .016 seconds was system time. Really, though, the results were too close to call. The results were essentially the same with no itimer running. Case 5: With a soft limit of 20 seconds and a hard limit of 2000 seconds (where the hard limit would never be reached) and an itimer running, the modified kernel exhibited worse tick accuracy than the unmodified kernel: .050 seconds/tick versus .028 seconds/tick. Otherwise, performance was almost indistinguishable. With no itimer running this test exhibited virtually identical behavior and times in both cases. In times past I did some limited performance testing. those results are below. On a four-cpu Opteron system without this fix, a sixteen-thread test executed in 3569.991 seconds, of which user was 3568.435s and system was 1.556s. On the same system with the fix, user and elapsed time were about the same, but system time dropped to 0.007 seconds. Performance with eight, four and one thread were comparable. Interestingly, the timer ticks with the fix seemed more accurate: The sixteen-thread test with the fix received 149543 ticks for 0.024 seconds per tick, while the same test without the fix received 58720 for 0.061 seconds per tick. Both cases were configured for an interval of 0.01 seconds. Again, the other tests were comparable. Each thread in this test computed the primes up to 25,000,000. I also did a test with a large number of threads, 100,000 threads, which is impossible without the fix. In this case each thread computed the primes only up to 10,000 (to make the runtime manageable). System time dominated, at 1546.968 seconds out of a total 2176.906 seconds (giving a user time of 629.938s). It received 147651 ticks for 0.015 seconds per tick, still quite accurate. There is obviously no comparable test without the fix. Signed-off-by: Frank Mayhar <fmayhar@google.com> Cc: Roland McGrath <roland@redhat.com> Cc: Alexey Dobriyan <adobriyan@gmail.com> Cc: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-09-05select: add a timespec_add_safe() functionThomas Gleixner
For the select() rework, it's important to be able to add timespec structures in an overflow-safe manner. This patch adds a timespec_add_safe() function for this which is similar in operation to ktime_add_safe(), but works on a struct timespec. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Arjan van de Ven <arjan@linux.intel.com>
2008-08-21clocksource: introduce CLOCK_MONOTONIC_RAWJohn Stultz
In talking with Josip Loncaric, and his work on clock synchronization (see btime.sf.net), he mentioned that for really close synchronization, it is useful to have access to "hardware time", that is a notion of time that is not in any way adjusted by the clock slewing done to keep close time sync. Part of the issue is if we are using the kernel's ntp adjusted representation of time in order to measure how we should correct time, we can run into what Paul McKenney aptly described as "Painting a road using the lines we're painting as the guide". I had been thinking of a similar problem, and was trying to come up with a way to give users access to a purely hardware based time representation that avoided users having to know the underlying frequency and mask values needed to deal with the wide variety of possible underlying hardware counters. My solution is to introduce CLOCK_MONOTONIC_RAW. This exposes a nanosecond based time value, that increments starting at bootup and has no frequency adjustments made to it what so ever. The time is accessed from userspace via the posix_clock_gettime() syscall, passing CLOCK_MONOTONIC_RAW as the clock_id. Signed-off-by: John Stultz <johnstul@us.ibm.com> Signed-off-by: Roman Zippel <zippel@linux-m68k.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-06-12always_inline timespec_add_nsJeremy Fitzhardinge
timespec_add_ns is used from the x86-64 vdso, which cannot call out to other kernel code. Make sure that timespec_add_ns is always inlined (and only uses always_inlined functions) to make sure there are no unexpected calls. Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-06-12common implementation of iterative div/modJeremy Fitzhardinge
We have a few instances of the open-coded iterative div/mod loop, used when we don't expcet the dividend to be much bigger than the divisor. Unfortunately modern gcc's have the tendency to strength "reduce" this into a full mod operation, which isn't necessarily any faster, and even if it were, doesn't exist if gcc implements it in libgcc. The workaround is to put a dummy asm statement in the loop to prevent gcc from performing the transformation. This patch creates a single implementation of this loop, and uses it to replace the open-coded versions I know about. Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: john stultz <johnstul@us.ibm.com> Cc: Segher Boessenkool <segher@kernel.crashing.org> Cc: Christian Kujau <lists@nerdbynature.de> Cc: Robert Hancock <hancockr@shaw.ca> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-03-09time: prevent the loop in timespec_add_ns() from being optimised awaySegher Boessenkool
Since some architectures don't support __udivdi3(). Signed-off-by: Segher Boessenkool <segher@kernel.crashing.org> Cc: john stultz <johnstul@us.ibm.com> Cc: Ingo Molnar <mingo@elte.hu> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-02-08timekeeping: rename timekeeping_is_continuous to timekeeping_valid_for_hresLi Zefan
Function timekeeping_is_continuous() no longer checks flag CLOCK_IS_CONTINUOUS, and it checks CLOCK_SOURCE_VALID_FOR_HRES now. So rename the function accordingly. Signed-off-by: Li Zefan <lizf@cn.fujitsu.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Ingo Molnar <mingo@elte.hu> Cc: john stultz <johnstul@us.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-02-01timekeeping: update xtime_cache when time(zone) changesThomas Gleixner
xtime_cache needs to be updated whenever xtime and or wall_to_monotic are changed. Otherwise users of xtime_cache might see a stale (and in the case of timezone changes utterly wrong) value until the next update happens. Fixup the obvious places, which miss this update. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Acked-by: John Stultz <johnstul@us.ibm.com> Tested-by: Dhaval Giani <dhaval@linux.vnet.ibm.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2007-10-17kernel/time/timekeeping.c: cleanupsAdrian Bunk
- remove the no longer required __attribute__((weak)) of xtime_lock - remove the following no longer used EXPORT_SYMBOL's: - xtime - xtime_lock Signed-off-by: Adrian Bunk <bunk@kernel.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: john stultz <johnstul@us.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-07-25Cache xtime every call to update_wall_timejohn stultz
This avoids xtime lag seen with dynticks, because while 'xtime' itself is still not updated often, we keep a 'xtime_cache' variable around that contains the approximate real-time that _is_ updated each time we do a 'update_wall_time()', and is thus never off by more than one tick. IOW, this restores the original semantics for 'xtime' users, as long as you use the proper abstraction functions (ie 'current_kernel_time()' or 'get_seconds()' depending on whether you want a timespec or just the seconds field). [ Updated Patch. As penance for my sins I've also yanked another #ifdef that was added to avoid the xtime lag w/ hrtimers. ] Signed-off-by: John Stultz <johnstul@us.ibm.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-07-25Cleanup non-arch xtime uses, use get_seconds() or current_kernel_time().john stultz
This avoids use of the kernel-internal "xtime" variable directly outside of the actual time-related functions. Instead, use the helper functions that we already have available to us. This doesn't actually change any behaviour, but this will allow us to fix the fact that "xtime" isn't updated very often with CONFIG_NO_HZ (because much of the realtime information is maintained as separate offsets to 'xtime'), which has caused interfaces that use xtime directly to get a time that is out of sync with the real-time clock by up to a third of a second or so. Signed-off-by: John Stultz <johnstul@us.ibm.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-07-21NTP: move the cmos update code into ntp.cThomas Gleixner
i386 and sparc64 have the identical code to update the cmos clock. Move it into kernel/time/ntp.c as there are other architectures coming along with the same requirements. [akpm@linux-foundation.org: build fixes] Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Cc: Chris Wright <chrisw@sous-sol.org> Cc: Ingo Molnar <mingo@elte.hu> Cc: john stultz <johnstul@us.ibm.com> Cc: David Miller <davem@davemloft.net> Cc: Roman Zippel <zippel@linux-m68k.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-07-17make timespec_equal() take const argumentsJan Engelhardt
Make arguments of timespec_equal() const struct timespec. Signed-off-by: Jan Engelhardt <jengelh@gmx.de> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: john stultz <johnstul@us.ibm.com> Cc: Roman Zippel <zippel@linux-m68k.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-07-16Introduce boot based timeTomas Janousek
The commits 411187fb05cd11676b0979d9fbf3291db69dbce2 (GTOD: persistent clock support) c1d370e167d66b10bca3b602d3740405469383de (i386: use GTOD persistent clock support) changed the monotonic time so that it no longer jumps after resume, but it's not possible to use it for boot time and process start time calculations then. Also, the uptime no longer increases during suspend. I add a variable to track the wall_to_monotonic changes, a function to get the real boot time and a function to get the boot based time from the monotonic one. [akpm@linux-foundation.org: remove exports, add comment] Signed-off-by: Tomas Janousek <tjanouse@redhat.com> Cc: Tomas Smetana <tsmetana@redhat.com> Cc: John Stultz <johnstul@us.ibm.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Ingo Molnar <mingo@elte.hu> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-05-08utimensat implementationUlrich Drepper
Implement utimensat(2) which is an extension to futimesat(2) in that it a) supports nano-second resolution for the timestamps b) allows to selectively ignore the atime/mtime value c) allows to selectively use the current time for either atime or mtime d) supports changing the atime/mtime of a symlink itself along the lines of the BSD lutimes(3) functions For this change the internally used do_utimes() functions was changed to accept a timespec time value and an additional flags parameter. Additionally the sys_utime function was changed to match compat_sys_utime which already use do_utimes instead of duplicating the work. Also, the completely missing futimensat() functionality is added. We have such a function in glibc but we have to resort to using /proc/self/fd/* which not everybody likes (chroot etc). Test application (the syscall number will need per-arch editing): #include <errno.h> #include <fcntl.h> #include <time.h> #include <sys/time.h> #include <stddef.h> #include <syscall.h> #define __NR_utimensat 280 #define UTIME_NOW ((1l << 30) - 1l) #define UTIME_OMIT ((1l << 30) - 2l) int main(void) { int status = 0; int fd = open("ttt", O_RDWR|O_CREAT|O_EXCL, 0666); if (fd == -1) error (1, errno, "failed to create test file \"ttt\""); struct stat64 st1; if (fstat64 (fd, &st1) != 0) error (1, errno, "fstat failed"); struct timespec t[2]; t[0].tv_sec = 0; t[0].tv_nsec = 0; t[1].tv_sec = 0; t[1].tv_nsec = 0; if (syscall(__NR_utimensat, AT_FDCWD, "ttt", t, 0) != 0) error (1, errno, "utimensat failed"); struct stat64 st2; if (fstat64 (fd, &st2) != 0) error (1, errno, "fstat failed"); if (st2.st_atim.tv_sec != 0 || st2.st_atim.tv_nsec != 0) { puts ("atim not reset to zero"); status = 1; } if (st2.st_mtim.tv_sec != 0 || st2.st_mtim.tv_nsec != 0) { puts ("mtim not reset to zero"); status = 1; } if (status != 0) goto out; t[0] = st1.st_atim; t[1].tv_sec = 0; t[1].tv_nsec = UTIME_OMIT; if (syscall(__NR_utimensat, AT_FDCWD, "ttt", t, 0) != 0) error (1, errno, "utimensat failed"); if (fstat64 (fd, &st2) != 0) error (1, errno, "fstat failed"); if (st2.st_atim.tv_sec != st1.st_atim.tv_sec || st2.st_atim.tv_nsec != st1.st_atim.tv_nsec) { puts ("atim not set"); status = 1; } if (st2.st_mtim.tv_sec != 0 || st2.st_mtim.tv_nsec != 0) { puts ("mtim changed from zero"); status = 1; } if (status != 0) goto out; t[0].tv_sec = 0; t[0].tv_nsec = UTIME_OMIT; t[1] = st1.st_mtim; if (syscall(__NR_utimensat, AT_FDCWD, "ttt", t, 0) != 0) error (1, errno, "utimensat failed"); if (fstat64 (fd, &st2) != 0) error (1, errno, "fstat failed"); if (st2.st_atim.tv_sec != st1.st_atim.tv_sec || st2.st_atim.tv_nsec != st1.st_atim.tv_nsec) { puts ("mtim changed from original time"); status = 1; } if (st2.st_mtim.tv_sec != st1.st_mtim.tv_sec || st2.st_mtim.tv_nsec != st1.st_mtim.tv_nsec) { puts ("mtim not set"); status = 1; } if (status != 0) goto out; sleep (2); t[0].tv_sec = 0; t[0].tv_nsec = UTIME_NOW; t[1].tv_sec = 0; t[1].tv_nsec = UTIME_NOW; if (syscall(__NR_utimensat, AT_FDCWD, "ttt", t, 0) != 0) error (1, errno, "utimensat failed"); if (fstat64 (fd, &st2) != 0) error (1, errno, "fstat failed"); struct timeval tv; gettimeofday(&tv,NULL); if (st2.st_atim.tv_sec <= st1.st_atim.tv_sec || st2.st_atim.tv_sec > tv.tv_sec) { puts ("atim not set to NOW"); status = 1; } if (st2.st_mtim.tv_sec <= st1.st_mtim.tv_sec || st2.st_mtim.tv_sec > tv.tv_sec) { puts ("mtim not set to NOW"); status = 1; } if (symlink ("ttt", "tttsym") != 0) error (1, errno, "cannot create symlink"); t[0].tv_sec = 0; t[0].tv_nsec = 0; t[1].tv_sec = 0; t[1].tv_nsec = 0; if (syscall(__NR_utimensat, AT_FDCWD, "tttsym", t, AT_SYMLINK_NOFOLLOW) != 0) error (1, errno, "utimensat failed"); if (lstat64 ("tttsym", &st2) != 0) error (1, errno, "lstat failed"); if (st2.st_atim.tv_sec != 0 || st2.st_atim.tv_nsec != 0) { puts ("symlink atim not reset to zero"); status = 1; } if (st2.st_mtim.tv_sec != 0 || st2.st_mtim.tv_nsec != 0) { puts ("symlink mtim not reset to zero"); status = 1; } if (status != 0) goto out; t[0].tv_sec = 1; t[0].tv_nsec = 0; t[1].tv_sec = 1; t[1].tv_nsec = 0; if (syscall(__NR_utimensat, fd, NULL, t, 0) != 0) error (1, errno, "utimensat failed"); if (fstat64 (fd, &st2) != 0) error (1, errno, "fstat failed"); if (st2.st_atim.tv_sec != 1 || st2.st_atim.tv_nsec != 0) { puts ("atim not reset to one"); status = 1; } if (st2.st_mtim.tv_sec != 1 || st2.st_mtim.tv_nsec != 0) { puts ("mtim not reset to one"); status = 1; } if (status == 0) puts ("all OK"); out: close (fd); unlink ("ttt"); unlink ("tttsym"); return status; } [akpm@linux-foundation.org: add missing i386 syscall table entry] Signed-off-by: Ulrich Drepper <drepper@redhat.com> Cc: Alexey Dobriyan <adobriyan@openvz.org> Cc: Michael Kerrisk <mtk-manpages@gmx.net> Cc: <linux-arch@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-05-08Move timekeeping code to timekeeping.cjohn stultz
Move the timekeeping code out of kernel/timer.c and into kernel/time/timekeeping.c. I made no cleanups or other changes in transit. [akpm@linux-foundation.org: build fix] Signed-off-by: John Stultz <johnstul@us.ibm.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-02-16[PATCH] GTOD: persistent clock supportJohn Stultz
Persistent clock support: do proper timekeeping across suspend/resume. [bunk@stusta.de: cleanup] Signed-off-by: John Stultz <johnstul@us.ibm.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Ingo Molnar <mingo@elte.hu> Cc: Roman Zippel <zippel@linux-m68k.org> Cc: Adrian Bunk <bunk@stusta.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-02-13[PATCH] x86-64: get rid of ARCH_HAVE_XTIME_LOCKEric Dumazet
ARCH_HAVE_XTIME_LOCK is used by x86_64 arch . This arch needs to place a read only copy of xtime_lock into vsyscall page. This read only copy is named __xtime_lock, and xtime_lock is defined in arch/x86_64/kernel/vmlinux.lds.S as an alias. So the declaration of xtime_lock in kernel/timer.c was guarded by ARCH_HAVE_XTIME_LOCK define, defined to true on x86_64. We can get same result with _attribute__((weak)) in the declaration. linker should do the job. Signed-off-by: Eric Dumazet <dada1@cosmosbay.com> Signed-off-by: Andi Kleen <ak@suse.de> Cc: Andi Kleen <ak@suse.de> Signed-off-by: Andrew Morton <akpm@osdl.org>
2007-02-11[PATCH] Add const for time{spec,val}_compare argumentsRolf Eike Beer
The arguments are really const. Mark them const to allow these functions being called from places where the arguments are const without getting useless compiler warnings. Signed-off-by: Rolf Eike Beer <eike-kernel@sf-tec.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2006-07-14[PATCH] per-task-delay-accounting: setupShailabh Nagar
Initialization code related to collection of per-task "delay" statistics which measure how long it had to wait for cpu, sync block io, swapping etc. The collection of statistics and the interface are in other patches. This patch sets up the data structures and allows the statistics collection to be disabled through a kernel boot parameter. Signed-off-by: Shailabh Nagar <nagar@watson.ibm.com> Signed-off-by: Balbir Singh <balbir@in.ibm.com> Cc: Jes Sorensen <jes@sgi.com> Cc: Peter Chubb <peterc@gelato.unsw.edu.au> Cc: Erich Focht <efocht@ess.nec.de> Cc: Levent Serinol <lserinol@gmail.com> Cc: Jay Lan <jlan@engr.sgi.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-06-26Merge branch 'x86-64'Linus Torvalds
* x86-64: (83 commits) [PATCH] x86_64: x86_64 stack usage debugging [PATCH] x86_64: (resend) x86_64 stack overflow debugging [PATCH] x86_64: msi_apic.c build fix [PATCH] x86_64: i386/x86-64 Add nmi watchdog support for new Intel CPUs [PATCH] x86_64: Avoid broadcasting NMI IPIs [PATCH] x86_64: fix apic error on bootup [PATCH] x86_64: enlarge window for stack growth [PATCH] x86_64: Minor string functions optimizations [PATCH] x86_64: Move export symbols to their C functions [PATCH] x86_64: Standardize i386/x86_64 handling of NMI_VECTOR [PATCH] x86_64: Fix modular pc speaker [PATCH] x86_64: remove sys32_ni_syscall() [PATCH] x86_64: Do not use -ffunction-sections for modules [PATCH] x86_64: Add cpu_relax to apic_wait_icr_idle [PATCH] x86_64: adjust kstack_depth_to_print default [PATCH] i386/x86-64: adjust /proc/interrupts column headings [PATCH] x86_64: Fix race in cpu_local_* on preemptible kernels [PATCH] x86_64: Fix fast check in safe_smp_processor_id [PATCH] x86_64: x86_64 setup.c - printing cmp related boottime information [PATCH] i386/x86-64/ia64: Move polling flag into thread_info_status ... Manual resolve of trivial conflict in arch/i386/kernel/Makefile
2006-06-26[PATCH] x86_64: Add useful constants to time.hVojtech Pavlik
In timekeeping code, one often does need to use conversion constants. Naming these leads to code that's easier to understand, showing the reader between which units the conversion is made. Signed-off-by: Vojtech Pavlik <vojtech@suse.cz> Signed-off-by: Andi Kleen <ak@suse.de> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-06-26[PATCH] Time: Introduce arch generic time accessorsjohn stultz
Introduces clocksource switching code and the arch generic time accessor functions that use the clocksource infrastructure. Signed-off-by: John Stultz <johnstul@us.ibm.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-06-26[PATCH] Time: Use clocksource infrastructure for update_wall_timejohn stultz
Modify the update_wall_time function so it increments time using the clocksource abstraction instead of jiffies. Since the only clocksource driver currently provided is the jiffies clocksource, this should result in no functional change. Additionally, a timekeeping_init and timekeeping_resume function has been added to initialize and maintain some of the new timekeping state. [hirofumi@mail.parknet.co.jp: fixlet] Signed-off-by: John Stultz <johnstul@us.ibm.com> Signed-off-by: OGAWA Hirofumi <hirofumi@mail.parknet.co.jp> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-03-26[PATCH] hrtimers: remove nsec_t typedefRoman Zippel
nsec_t predates ktime_t and has mostly been superseded by it. In the few places that are left it's better to make it explicit that we're dealing with 64 bit values here. Signed-off-by: Roman Zippel <zippel@linux-m68k.org> Acked-by: Thomas Gleixner <tglx@linutronix.de> Acked-by: John Stultz <johnstul@us.ibm.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-03-25[PATCH] sys_alarm() unsigned signed conversion fixupThomas Gleixner
alarm() calls the kernel with an unsigend int timeout in seconds. The value is stored in the tv_sec field of a struct timeval to setup the itimer. The tv_sec field of struct timeval is of type long, which causes the tv_sec value to be negative on 32 bit machines if seconds > INT_MAX. Before the hrtimer merge (pre 2.6.16) such a negative value was converted to the maximum jiffies timeout by the timeval_to_jiffies conversion. It's not clear whether this was intended or just happened to be done by the timeval_to_jiffies code. hrtimers expect a timeval in canonical form and treat a negative timeout as already expired. This breaks the legitimate usage of alarm() with a timeout value > INT_MAX seconds. For 32 bit machines it is therefor necessary to limit the internal seconds value to avoid API breakage. Instead of doing this in all implementations of sys_alarm the duplicated sys_alarm code is moved into a common function in itimer.c Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-02-11[PATCH] select: fix returned timevalAndrew Morton
With David Woodhouse <dwmw2@infradead.org> select() presently has a habit of increasing the value of the user's `timeout' argument on return. We were writing back a timeout larger than the original. We _deliberately_ round up, since we know we must wait at _least_ as long as the caller asks us to. The patch adds a couple of helper functions for magnitude comparison of timespecs and of timevals, and uses them to prevent the various poll and select functions from returning a timeout which is larger than the one which was passed in. The patch also fixes a bug in compat_sys_pselect7(): it was adding the new timeout value to the old one and was returning that. It should just return the new timeout value. (We have various handy timespec/timeval-to-from-nsec conversion functions in time.h. But this code open-codes it all). Cc: "David S. Miller" <davem@davemloft.net> Cc: Andi Kleen <ak@muc.de> Cc: Ulrich Drepper <drepper@redhat.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: george anzinger <george@mvista.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-01-31[PATCH] Make sure to always check upper bits of tv_nsec in timespec_valid.Chris Wright
Signed-off-by: Chris Wright <chrisw@sous-sol.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-01-18[PATCH] vfs: *at functions: coreUlrich Drepper
Here is a series of patches which introduce in total 13 new system calls which take a file descriptor/filename pair instead of a single file name. These functions, openat etc, have been discussed on numerous occasions. They are needed to implement race-free filesystem traversal, they are necessary to implement a virtual per-thread current working directory (think multi-threaded backup software), etc. We have in glibc today implementations of the interfaces which use the /proc/self/fd magic. But this code is rather expensive. Here are some results (similar to what Jim Meyering posted before). The test creates a deep directory hierarchy on a tmpfs filesystem. Then rm -fr is used to remove all directories. Without syscall support I get this: real 0m31.921s user 0m0.688s sys 0m31.234s With syscall support the results are much better: real 0m20.699s user 0m0.536s sys 0m20.149s The interfaces are for obvious reasons currently not much used. But they'll be used. coreutils (and Jeff's posixutils) are already using them. Furthermore, code like ftw/fts in libc (maybe even glob) will also start using them. I expect a patch to make follow soon. Every program which is walking the filesystem tree will benefit. Signed-off-by: Ulrich Drepper <drepper@redhat.com> Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com> Cc: Christoph Hellwig <hch@lst.de> Cc: Al Viro <viro@ftp.linux.org.uk> Acked-by: Ingo Molnar <mingo@elte.hu> Cc: Michael Kerrisk <mtk-manpages@gmx.net> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-01-10[PATCH] Remove getnstimestamp()Matt Helsley
Remove getnstimestamp() in favor of ktime.h's ktime_get_ts() Signed-off-by: Matt Helsley <matthltc@us.ibm.com> Cc: john stultz <johnstul@us.ibm.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Ingo Molnar <mingo@elte.hu> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-01-10[PATCH] hrtimer: convert posix timers completelyThomas Gleixner
- convert posix-timers.c to use hrtimers - remove the now obsolete abslist code Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Miklos Szeredi <miklos@szeredi.hu> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-01-10[PATCH] hrtimer: introduce nsec_t type and conversion functionsThomas Gleixner
- introduce the nsec_t type - basic nsec conversion routines: timespec_to_ns(), timeval_to_ns(), ns_to_timespec(), ns_to_timeval(). Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-01-10[PATCH] hrtimer: create and use timespec_valid macroThomas Gleixner
add timespec_valid(ts) [returns false if the timespec is denorm] Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-01-10[PATCH] hrtimer: coding style and white space cleanupIngo Molnar
style and whitespace cleanup of the rest of time.h. Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-01-10[PATCH] hrtimer: coding style clean up of clock constantsIngo Molnar
clean up the CLOCK_ portions of time.h Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-01-10[PATCH] hrtimer: remove unused clock constantsThomas Gleixner
remove unused CLOCK_ constants from time.h Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>