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2007-07-16bsg: add SG_IO to SG v4FUJITA Tomonori
This adds SG_IO support to SG v4. Signed-off-by: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp> Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2007-07-16bsg: replace SG v3 with SG v4FUJITA Tomonori
This patch replaces SG v3 in bsg with SG v4 (except for SG_IO). Signed-off-by: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp> Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2007-07-16block: export blk_verify_command for SG v4FUJITA Tomonori
blk_fill_sghdr_rq doesn't work for SG v4 so verify_command needed to be exported. Signed-off-by: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp> Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2007-07-16bsg: minor cleanupsFUJITA Tomonori
This just kills linux/config.h and dprintk warnings. Signed-off-by: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp> Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2007-07-16block: changes for blk_rq_unmap_user new APIFUJITA Tomonori
This converts block/scsi_ioctl.c use blk_rq_unmap_user new API. blk_unmap_sghdr_rq is too simple and it might be better to remove it. Signed-off-by: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp> Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2007-07-16bsg: support for full generic block layer SG v3Jens Axboe
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2007-07-10Use list_for_each_entry() instead of list_for_each() in the block deviceMatthias Kaehlcke
elevator Signed-off-by: Matthias Kaehlcke <matthias.kaehlcke@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2007-07-10Use menuconfigs instead of menus, so the whole menu can be disabled at onceJan Engelhardt
instead of going through all options. Signed-off-by: Jan Engelhardt <jengelh@gmx.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2007-07-10cfq-iosched: fix async queue behaviourJens Axboe
With the cfq_queue hash removal, we inadvertently got rid of the async queue sharing. This was not intentional, in fact CFQ purposely shares the async queue per priority level to get good merging for async writes. So put some logic in cfq_get_queue() to track the shared queues. Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2007-07-10[BLOCK] drop unnecessary bvec rewinding from flush_dry_bio_endioTejun Heo
Barrier bios are completed twice - once after the barrier write itself is done and again after the whole sequence is complete. flush_dry_bio_endio() is for the first completion. It doesn't really complete the bio. It rewinds bvec and resets bio so that it can be completed again when the whole barrier sequence is complete. The bvec rewinding code has the following problems. 1. The rewinding code is wrong because filesystems may pass bvec with non zero bv_offset. 2. The block layer doesn't guarantee anything about the state of bvec array on request completion. bv_offset and len are updated iff __end_that_request_first() completes the bvec partially. Because of #2, #1 doesn't really matter (nobody cares whether bvec is re-wound correctly or not) but then again by not doing unwinding at all, we'll always give back the same bvec to the caller as full bvec completion doesn't alter bvecs and the final completion is always full completion. Drop unnecessary rewinding code. This is spotted by Neil Brown. Signed-off-by: Tejun Heo <htejun@gmail.com> Cc: Neil Brown <neilb@suse.de> Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2007-07-10blk_hw_contig_segment(): bad segment size checksJens Axboe
Two bugs in there: - The virt oversize check should use the current bio hardware back size and the next bio front size, not the same bio. Spotted by Neil Brown. - The segment size check should add hw front sizes, not total bio sizes. Spotted by James Bottomley Acked-by: James Bottomley <James.Bottomley@SteelEye.com> Acked-by: NeilBrown <neilb@suse.de> Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2007-06-15block: always requeue !fs requests at the frontTejun Heo
SCSI marks internal commands with REQ_PREEMPT and push it at the front of the request queue using blk_execute_rq(). When entering suspended or frozen state, SCSI devices are quiesced using scsi_device_quiesce(). In quiesced state, only REQ_PREEMPT requests are processed. This is how SCSI blocks other requests out while suspending and resuming. As all internal commands are pushed at the front of the queue, this usually works. Unfortunately, this interacts badly with ordered requeueing. To preserve request order on requeueing (due to busy device, active EH or other failures), requests are sorted according to ordered sequence on requeue if IO barrier is in progress. The following sequence deadlocks. 1. IO barrier sequence issues. 2. Suspend requested. Queue is quiesced with part or all of IO barrier sequence at the front. 3. During suspending or resuming, SCSI issues internal command which gets deferred and requeued for some reason. As the command is issued after the IO barrier in #1, ordered requeueing code puts the request after IO barrier sequence. 4. The device is ready to process requests again but still is in quiesced state and the first request of the queue isn't REQ_PREEMPT, so command processing is deadlocked - suspending/resuming waits for the issued request to complete while the request can't be processed till device is put back into running state by resuming. This can be fixed by always putting !fs requests at the front when requeueing. The following thread reports this deadlock. http://thread.gmane.org/gmane.linux.kernel/537473 Signed-off-by: Tejun Heo <htejun@gmail.com> Acked-by: David Greaves <david@dgreaves.com> Acked-by: Jeff Garzik <jeff@garzik.org> Signed-off-by: Jens Axboe <jens.axboe@oracle.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-05-23genhd: send async notification on media changeKristen Carlson Accardi
Send an uevent to user space to indicate that a media change event has occurred. Signed-off-by: Kristen Carlson Accardi <kristen.c.accardi@intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-05-23genhd: expose AN to user spaceKristen Carlson Accardi
Allow user space to determine if a disk supports Asynchronous Notification of media changes. This is done by adding a new sysfs file "capability_flags", which is documented in (insert file name). This sysfs file will export all disk capabilities flags to user space. We also define a new flag to define the media change notification capability. Signed-off-by: Kristen Carlson Accardi <kristen.c.accardi@intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-05-15ll_rw_blk: fix gcc 4.2 warning on current_io_context()Jens Axboe
current_io_context() is both static and exported with EXPORT_SYMBOL(). As there are no users outside of ll_rw_blk.c itself, just kill the export. Problem reported by Martin Michlmayr <tbm@cyrius.com> Signed-off-by: Jens Axboe <jens.axboe@oracle.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-05-11When stacked block devices are in-use (e.g. md or dm), the recursive callsNeil Brown
to generic_make_request can use up a lot of space, and we would rather they didn't. As generic_make_request is a void function, and as it is generally not expected that it will have any effect immediately, it is safe to delay any call to generic_make_request until there is sufficient stack space available. As ->bi_next is reserved for the driver to use, it can have no valid value when generic_make_request is called, and as __make_request implicitly assumes it will be NULL (ELEVATOR_BACK_MERGE fork of switch) we can be certain that all callers set it to NULL. We can therefore safely use bi_next to link pending requests together, providing we clear it before making the real call. So, we choose to allow each thread to only be active in one generic_make_request at a time. If a subsequent (recursive) call is made, the bio is linked into a per-thread list, and is handled when the active call completes. As the list of pending bios is per-thread, there are no locking issues to worry about. I say above that it is "safe to delay any call...". There are, however, some behaviours of a make_request_fn which would make it unsafe. These include any behaviour that assumes anything will have changed after a recursive call to generic_make_request. These could include: - waiting for that call to finish and call it's bi_end_io function. md use to sometimes do this (marking the superblock dirty before completing a write) but doesn't any more - inspecting the bio for fields that generic_make_request might change, such as bi_sector or bi_bdev. It is hard to see a good reason for this, and I don't think anyone actually does it. - inspecing the queue to see if, e.g. it is 'full' yet. Again, I think this is very unlikely to be useful, or to be done. Signed-off-by: Neil Brown <neilb@suse.de> Cc: Jens Axboe <axboe@kernel.dk> Cc: <dm-devel@redhat.com> Alasdair G Kergon <agk@redhat.com> said: I can see nothing wrong with this in principle. For device-mapper at the moment though it's essential that, while the bio mappings may now get delayed, they still get processed in exactly the same order as they were passed to generic_make_request(). My main concern is whether the timing changes implicit in this patch will make the rare data-corrupting races in the existing snapshot code more likely. (I'm working on a fix for these races, but the unfinished patch is already several hundred lines long.) It would be helpful if some people on this mailing list would test this patch in various scenarios and report back. Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2007-05-09Merge git://git.kernel.org/pub/scm/linux/kernel/git/bunk/trivialLinus Torvalds
* git://git.kernel.org/pub/scm/linux/kernel/git/bunk/trivial: (25 commits) sound: convert "sound" subdirectory to UTF-8 MAINTAINERS: Add cxacru website/mailing list include files: convert "include" subdirectory to UTF-8 general: convert "kernel" subdirectory to UTF-8 documentation: convert the Documentation directory to UTF-8 Convert the toplevel files CREDITS and MAINTAINERS to UTF-8. remove broken URLs from net drivers' output Magic number prefix consistency change to Documentation/magic-number.txt trivial: s/i_sem /i_mutex/ fix file specification in comments drivers/base/platform.c: fix small typo in doc misc doc and kconfig typos Remove obsolete fat_cvf help text Fix occurrences of "the the " Fix minor typoes in kernel/module.c Kconfig: Remove reference to external mqueue library Kconfig: A couple of grammatical fixes in arch/i386/Kconfig Correct comments in genrtc.c to refer to correct /proc file. Fix more "deprecated" spellos. Fix "deprecated" typoes. ... Fix trivial comment conflict in kernel/relay.c.
2007-05-09Add suspend-related notifications for CPU hotplugRafael J. Wysocki
Since nonboot CPUs are now disabled after tasks and devices have been frozen and the CPU hotplug infrastructure is used for this purpose, we need special CPU hotplug notifications that will help the CPU-hotplug-aware subsystems distinguish normal CPU hotplug events from CPU hotplug events related to a system-wide suspend or resume operation in progress. This patch introduces such notifications and causes them to be used during suspend and resume transitions. It also changes all of the CPU-hotplug-aware subsystems to take these notifications into consideration (for now they are handled in the same way as the corresponding "normal" ones). [oleg@tv-sign.ru: cleanups] Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl> Cc: Gautham R Shenoy <ego@in.ibm.com> Cc: Pavel Machek <pavel@ucw.cz> Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-05-09unify flush_work/flush_work_keventd and rename it to cancel_work_syncOleg Nesterov
flush_work(wq, work) doesn't need the first parameter, we can use cwq->wq (this was possible from the very beginnig, I missed this). So we can unify flush_work_keventd and flush_work. Also, rename flush_work() to cancel_work_sync() and fix all callers. Perhaps this is not the best name, but "flush_work" is really bad. (akpm: this is why the earlier patches bypassed maintainers) Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru> Cc: Jeff Garzik <jeff@garzik.org> Cc: "David S. Miller" <davem@davemloft.net> Cc: Jens Axboe <jens.axboe@oracle.com> Cc: Tejun Heo <htejun@gmail.com> Cc: Auke Kok <auke-jan.h.kok@intel.com>, Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-05-09kblockd: use flush_workAndrew Morton
Switch the kblockd flushing from a global flush to a more specific flush_work(). (akpm: bypassed maintainers, sorry. There are other patches which depend on this) Cc: "Maciej W. Rozycki" <macro@linux-mips.org> Cc: David Howells <dhowells@redhat.com> Cc: Jens Axboe <axboe@suse.de> Cc: Nick Piggin <nickpiggin@yahoo.com.au> Cc: Oleg Nesterov <oleg@tv-sign.ru> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-05-09Display all possible partitions when the root filesystem failed to mountDave Gilbert
Display all possible partitions when the root filesystem is not mounted. This helps to track spell'o's and missing drivers. Updated to work with newer kernels. Example output: VFS: Cannot open root device "foobar" or unknown-block(0,0) Please append a correct "root=" boot option; here are the available partitions: 0800 8388608 sda driver: sd 0801 192748 sda1 0802 8193150 sda2 0810 4194304 sdb driver: sd Kernel panic - not syncing: VFS: Unable to mount root fs on unknown-block(0,0) [akpm@linux-foundation.org: cleanups, fix printk warnings] Signed-off-by: Jan Engelhardt <jengelh@gmx.de> Cc: Dave Gilbert <linux@treblig.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-05-09Fix occurrences of "the the "Michael Opdenacker
Signed-off-by: Michael Opdenacker <michael@free-electrons.com> Signed-off-by: Adrian Bunk <bunk@stusta.de>
2007-05-08Merge branch 'for-2.6.22' of git://git.kernel.dk/data/git/linux-2.6-blockLinus Torvalds
* 'for-2.6.22' of git://git.kernel.dk/data/git/linux-2.6-block: [PATCH] ll_rw_blk: fix missing bounce in blk_rq_map_kern() [PATCH] splice: always call into page_cache_readahead() [PATCH] splice(): fix interaction with readahead
2007-05-08as: fix antic_expire checkNick Piggin
Fix units mismatch (jiffies vs msecs) in as-iosched.c, spotted by Xiaoning Ding <dingxn@cse.ohio-state.edu>. Signed-off-by: Nick Piggin <npiggin@suse.de> Cc: Jens Axboe <jens.axboe@oracle.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-05-08[PATCH] ll_rw_blk: fix missing bounce in blk_rq_map_kern()Mike Christie
I think we might just need the blk_map_kern users now. For the async execute I added the bounce code already and the block SG_IO has it atleady. I think the blk_map_kern bounce code got dropped because we thought the correct gfp_t would be passed in. But I think all we need is the patch below and all the paths are take care of. The patch is not tested. Patch was made against scsi-misc. The last place that is sending non sg commands may just be md/dm-emc.c but that is is just waiting on alasdair to take some patches that fix that and a bunch of junk in there including adding bounce support. If the patch below is ok though and dm-emc finally gets converted then it will have sg and bonce buffer support. Signed-off-by: Mike Christie <michaelc@cs.wisc.edu> Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2007-05-07KMEM_CACHE(): simplify slab cache creationChristoph Lameter
This patch provides a new macro KMEM_CACHE(<struct>, <flags>) to simplify slab creation. KMEM_CACHE creates a slab with the name of the struct, with the size of the struct and with the alignment of the struct. Additional slab flags may be specified if necessary. Example struct test_slab { int a,b,c; struct list_head; } __cacheline_aligned_in_smp; test_slab_cache = KMEM_CACHE(test_slab, SLAB_PANIC) will create a new slab named "test_slab" of the size sizeof(struct test_slab) and aligned to the alignment of test slab. If it fails then we panic. Signed-off-by: Christoph Lameter <clameter@sgi.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-05-07mm: remove destroy_dirty_buffers from invalidate_bdev()Peter Zijlstra
Remove the destroy_dirty_buffers argument from invalidate_bdev(), it hasn't been used in 6 years (so akpm says). find * -name \*.[ch] | xargs grep -l invalidate_bdev | while read file; do quilt add $file; sed -ie 's/invalidate_bdev(\([^,]*\),[^)]*)/invalidate_bdev(\1)/g' $file; done Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-05-05Merge master.kernel.org:/pub/scm/linux/kernel/git/jejb/scsi-misc-2.6Linus Torvalds
* master.kernel.org:/pub/scm/linux/kernel/git/jejb/scsi-misc-2.6: (87 commits) [SCSI] fusion: fix domain validation loops [SCSI] qla2xxx: fix regression on sparc64 [SCSI] modalias for scsi devices [SCSI] sg: cap reserved_size values at max_sectors [SCSI] BusLogic: stop using check_region [SCSI] tgt: fix rdma transfer bugs [SCSI] aacraid: fix aacraid not finding device [SCSI] aacraid: Correct SMC products in aacraid.txt [SCSI] scsi_error.c: Add EH Start Unit retry [SCSI] aacraid: [Fastboot] Panics for AACRAID driver during 'insmod' for kexec test. [SCSI] ipr: Driver version to 2.3.2 [SCSI] ipr: Faster sg list fetch [SCSI] ipr: Return better qc_issue errors [SCSI] ipr: Disrupt device error [SCSI] ipr: Improve async error logging level control [SCSI] ipr: PCI unblock config access fix [SCSI] ipr: Fix for oops following SATA request sense [SCSI] ipr: Log error for SAS dual path switch [SCSI] ipr: Enable logging of debug error data for all devices [SCSI] ipr: Add new PCI-E IDs to device table ...
2007-05-02remove "struct subsystem" as it is no longer neededGreg Kroah-Hartman
We need to work on cleaning up the relationship between kobjects, ksets and ktypes. The removal of 'struct subsystem' is the first step of this, especially as it is not really needed at all. Thanks to Kay for fixing the bugs in this patch. Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2007-04-30Merge branch 'cfq' into for-linusJens Axboe
2007-04-30[PATCH] elevator: elv_list_lock does not need irq disablingJens Axboe
It's never grabbed from irq context, so just make it plain spin_lock(). Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2007-04-30cfq-iosched: speedup cic rb lookupJens Axboe
We often lookup the same queue many times in succession, so cache the last looked up queue to avoid browsing the rbtree. Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2007-04-30ll_rw_blk: add io_context private pointerJens Axboe
To be used by as/cfq as they see fit. Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2007-04-30cfq-iosched: get rid of cfqq hashVasily Tarasov
cfq hash is no more necessary. We always can get cfqq from io context. cfq_get_io_context_noalloc() function is introduced, because we don't want to allocate cic on merging and checking may_queue. In order to identify sync queue we've used hash key = CFQ_KEY_ASYNC. Since hash is eliminated we need to use other criterion: sync flag for queue is added. In all places where we dig in rb_tree we're in current context, so no additional locking is required. Advantages of this patch: no additional memory for hash, no seeking in hash, code is cleaner. But it is necessary now to seek cic in per-ioc rbtree, but it is faster: - most processes work only with few devices - most systems have only few block devices - it is a rb-tree Signed-off-by: Vasily Tarasov <vtaras@openvz.org> Changes by me: - Merge into CFQ devel branch - Get rid of cfq_get_io_context_noalloc() - Fix various bugs with dereferencing cic->cfqq[] with offset other than 0 or 1. - Fix bug in cfqq setup, is_sync condition was reversed. - Fix bug where only bio_sync() is used, we need to check for a READ too Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2007-04-30cfq-iosched: tighten queue request overlap conditionJens Axboe
For tagged devices, allow overlap of requests if the idle window isn't enabled on the current active queue. Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2007-04-30cfq-iosched: improve sync vs async workloadsJens Axboe
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2007-04-30cfq-iosched: never allow an async queue idlingJens Axboe
We don't enable it by default, don't let it get enabled during runtime. Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2007-04-30cfq-iosched: get rid of ->dispatch_sliceJens Axboe
We can track it fairly accurately locally, let the slice handling take care of the rest. Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2007-04-30cfq-iosched: don't pass unused preemption variable aroundJens Axboe
We don't use it anymore in the slice expiry handling. Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2007-04-30cfq-iosched: get rid of ->cur_rr and ->cfq_listJens Axboe
It's only used for preemption now that the IDLE and RT queues also use the rbtree. If we pass an 'add_front' variable to cfq_service_tree_add(), we can set ->rb_key to 0 to force insertion at the front of the tree. Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2007-04-30cfq-iosched: slice offset should take ioprio into accountJens Axboe
Use the max_slice-cur_slice as the multipler for the insertion offset. Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2007-04-30[PATCH] cfq-iosched: style cleanups and commentsJens Axboe
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2007-04-30cfq-iosched: sort IDLE queues into the rbtreeJens Axboe
Same treatment as the RT conversion, just put the sorted idle branch at the end of the tree. Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2007-04-30cfq-iosched: sort RT queues into the rbtreeJens Axboe
Currently CFQ does a linked insert into the current list for RT queues. We can just factor the class into the rb insertion, and then we don't have to treat RT queues in a special way. It's faster, too. Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2007-04-30[PATCH] cfq-iosched: speed up rbtree handlingJens Axboe
For cases where the rbtree is mainly used for sorting and min retrieval, a nice speedup of the rbtree code is to maintain a cache of the leftmost node in the tree. Also spotted in the CFS CPU scheduler code. Improved by Alan D. Brunelle <Alan.Brunelle@hp.com> by updating the leftmost hint in cfq_rb_first() if it isn't set, instead of only updating it on insert. Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2007-04-30cfq-iosched: rework the whole round-robin list conceptJens Axboe
Drawing on some inspiration from the CFS CPU scheduler design, overhaul the pending cfq_queue concept list management. Currently CFQ uses a doubly linked list per priority level for sorting and service uses. Kill those lists and maintain an rbtree of cfq_queue's, sorted by when to service them. This unfortunately means that the ionice levels aren't as strong anymore, will work on improving those later. We only scale the slice time now, not the number of times we service. This means that latency is better (for all priority levels), but that the distinction between the highest and lower levels aren't as big. The diffstat speaks for itself. cfq-iosched.c | 363 +++++++++++++++++--------------------------------- 1 file changed, 125 insertions(+), 238 deletions(-) Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2007-04-30cfq-iosched: minor updatesJens Axboe
- Move the queue_new flag clear to when the queue is selected - Only select the non-first queue in cfq_get_best_queue(), if there's a substantial difference between the best and first. - Get rid of ->busy_rr - Only select a close cooperator, if the current queue is known to take a while to "think". Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2007-04-30cfq-iosched: development updateJens Axboe
- Implement logic for detecting cooperating processes, so we choose the best available queue whenever possible. - Improve residual slice time accounting. - Remove dead code: we no longer see async requests coming in on sync queues. That part was removed a long time ago. That means that we can also remove the difference between cfq_cfqq_sync() and cfq_cfqq_class_sync(), they are now indentical. And we can kill the on_dispatch array, just make it a counter. - Allow a process to go into the current list, if it hasn't been serviced in this scheduler tick yet. Possible future improvements including caching the cfqq lookup in cfq_close_cooperator(), so we don't have to look it up twice. cfq_get_best_queue() should just use that last decision instead of doing it again. Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2007-04-30cfq-iosched: improve preemption for cooperating tasksJens Axboe
When testing the syslet async io approach, I discovered that CFQ sometimes didn't perform as well as expected. cfq_should_preempt() needs to better check for cooperating tasks, so fix that by allowing preemption of an equal priority queue if the recently queued request is as good a candidate for IO as the one we are currently waiting for. Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2007-04-25cfq-iosched: fix alias + front merge bugJens Axboe
There's a really rare and obscure bug in CFQ, that causes a crash in cfq_dispatch_insert() due to rq == NULL. One example of the resulting oops is seen here: http://lkml.org/lkml/2007/4/15/41 Neil correctly diagnosed the situation for how this can happen: if two concurrent requests with the exact same sector number (due to direct IO or aliasing between MD and the raw device access), the alias handling will add the request to the sortlist, but next_rq remains NULL. Read the more complete analysis at: http://lkml.org/lkml/2007/4/25/57 This looks like it requires md to trigger, even though it should potentially be possible to due with O_DIRECT (at least if you edit the kernel and doctor some of the unplug calls). The fix is to move the ->next_rq update to when we add a request to the rbtree. Then we remove the possibility for a request to exist in the rbtree code, but not have ->next_rq correctly updated. Signed-off-by: Jens Axboe <jens.axboe@oracle.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>