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* block: always requeue !fs requests at the frontTejun Heo2007-06-151-0/+9
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 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>
* genhd: send async notification on media changeKristen Carlson Accardi2007-05-231-0/+23
| | | | | | | | | 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>
* genhd: expose AN to user spaceKristen Carlson Accardi2007-05-231-1/+9
| | | | | | | | | | | | 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>
* ll_rw_blk: fix gcc 4.2 warning on current_io_context()Jens Axboe2007-05-151-1/+0
| | | | | | | | | | | 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>
* When stacked block devices are in-use (e.g. md or dm), the recursive callsNeil Brown2007-05-111-1/+52
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 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>
* Merge git://git.kernel.org/pub/scm/linux/kernel/git/bunk/trivialLinus Torvalds2007-05-091-1/+1
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | * 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.
| * Fix occurrences of "the the "Michael Opdenacker2007-05-091-1/+1
| | | | | | | | | | Signed-off-by: Michael Opdenacker <michael@free-electrons.com> Signed-off-by: Adrian Bunk <bunk@stusta.de>
* | Add suspend-related notifications for CPU hotplugRafael J. Wysocki2007-05-091-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 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>
* | unify flush_work/flush_work_keventd and rename it to cancel_work_syncOleg Nesterov2007-05-091-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 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>
* | kblockd: use flush_workAndrew Morton2007-05-092-5/+4
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 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>
* | Display all possible partitions when the root filesystem failed to mountDave Gilbert2007-05-091-0/+53
|/ | | | | | | | | | | | | | | | | | | | | | | 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>
* Merge branch 'for-2.6.22' of git://git.kernel.dk/data/git/linux-2.6-blockLinus Torvalds2007-05-081-0/+1
|\ | | | | | | | | | | | | * '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
| * [PATCH] ll_rw_blk: fix missing bounce in blk_rq_map_kern()Mike Christie2007-05-081-0/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 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>
* | as: fix antic_expire checkNick Piggin2007-05-081-3/+3
|/ | | | | | | | | | 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>
* KMEM_CACHE(): simplify slab cache creationChristoph Lameter2007-05-071-4/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | 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>
* mm: remove destroy_dirty_buffers from invalidate_bdev()Peter Zijlstra2007-05-071-2/+2
| | | | | | | | | | | | | | | 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>
* Merge master.kernel.org:/pub/scm/linux/kernel/git/jejb/scsi-misc-2.6Linus Torvalds2007-05-052-1/+5
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | * 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 ...
| * [SCSI] sg: cap reserved_size values at max_sectorsAlan Stern2007-04-172-1/+5
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This patch (as857) modifies the SG_GET_RESERVED_SIZE and SG_SET_RESERVED_SIZE ioctls in the sg driver, capping the values at the device's request_queue's max_sectors value. This will permit cdrecord to obtain a legal value for the maximum transfer length, fixing Bugzilla #7026. The patch also caps the initial reserved_size value. There's no reason to have a reserved buffer larger than max_sectors, since it would be impossible to use the extra space. The corresponding ioctls in the block layer are modified similarly, and the initial value for the reserved_size is set as large as possible. This will effectively make it default to max_sectors. Note that the actual value is meaningless anyway, since block devices don't have a reserved buffer. Finally, the BLKSECTGET ioctl is added to sg, so that there will be a uniform way for users to determine the actual max_sectors value for any raw SCSI transport. Signed-off-by: Alan Stern <stern@rowland.harvard.edu> Acked-by: Jens Axboe <jens.axboe@oracle.com> Acked-by: Douglas Gilbert <dougg@torque.net> Signed-off-by: James Bottomley <James.Bottomley@SteelEye.com>
* | remove "struct subsystem" as it is no longer neededGreg Kroah-Hartman2007-05-021-6/+6
| | | | | | | | | | | | | | | | | | | | | | 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>
* | Merge branch 'cfq' into for-linusJens Axboe2007-04-302-416/+438
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| * | cfq-iosched: speedup cic rb lookupJens Axboe2007-04-301-2/+18
| | | | | | | | | | | | | | | | | | | | | 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>
| * | ll_rw_blk: add io_context private pointerJens Axboe2007-04-301-0/+1
| | | | | | | | | | | | | | | | | | To be used by as/cfq as they see fit. Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
| * | cfq-iosched: get rid of cfqq hashVasily Tarasov2007-04-301-100/+67
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 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>
| * | cfq-iosched: tighten queue request overlap conditionJens Axboe2007-04-301-1/+2
| | | | | | | | | | | | | | | | | | | | | 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>
| * | cfq-iosched: improve sync vs async workloadsJens Axboe2007-04-301-13/+18
| | | | | | | | | | | | Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
| * | cfq-iosched: never allow an async queue idlingJens Axboe2007-04-301-1/+6
| | | | | | | | | | | | | | | | | | | | | We don't enable it by default, don't let it get enabled during runtime. Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
| * | cfq-iosched: get rid of ->dispatch_sliceJens Axboe2007-04-301-5/+1
| | | | | | | | | | | | | | | | | | | | | 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>
| * | cfq-iosched: don't pass unused preemption variable aroundJens Axboe2007-04-301-15/+13
| | | | | | | | | | | | | | | | | | We don't use it anymore in the slice expiry handling. Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
| * | cfq-iosched: get rid of ->cur_rr and ->cfq_listJens Axboe2007-04-301-55/+32
| | | | | | | | | | | | | | | | | | | | | | | | | | | 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>
| * | cfq-iosched: slice offset should take ioprio into accountJens Axboe2007-04-301-1/+2
| | | | | | | | | | | | | | | | | | Use the max_slice-cur_slice as the multipler for the insertion offset. Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
| * | [PATCH] cfq-iosched: style cleanups and commentsJens Axboe2007-04-301-16/+50
| | | | | | | | | | | | Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
| * | cfq-iosched: sort IDLE queues into the rbtreeJens Axboe2007-04-301-36/+31
| | | | | | | | | | | | | | | | | | | | | 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>
| * | cfq-iosched: sort RT queues into the rbtreeJens Axboe2007-04-301-15/+12
| | | | | | | | | | | | | | | | | | | | | | | | | | | 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>
| * | [PATCH] cfq-iosched: speed up rbtree handlingJens Axboe2007-04-301-14/+48
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 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>
| * | cfq-iosched: rework the whole round-robin list conceptJens Axboe2007-04-301-238/+123
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 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>
| * | cfq-iosched: minor updatesJens Axboe2007-04-301-63/+18
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | - 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>
| * | cfq-iosched: development updateJens Axboe2007-04-301-120/+261
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | - 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>
| * | cfq-iosched: improve preemption for cooperating tasksJens Axboe2007-04-301-6/+20
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 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>
* | | [PATCH] elevator: elv_list_lock does not need irq disablingJens Axboe2007-04-301-8/+9
|/ / | | | | | | | | | | It's never grabbed from irq context, so just make it plain spin_lock(). Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
* | cfq-iosched: fix alias + front merge bugJens Axboe2007-04-251-6/+6
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 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>
* | cfq-iosched: fix sequential write regressionJens Axboe2007-04-201-15/+19
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | We have a 10-15% performance regression for sequential writes on TCQ/NCQ enabled drives in 2.6.21-rcX after the CFQ update went in. It has been reported by Valerie Clement <valerie.clement@bull.net> and the Intel testing folks. The regression is because of CFQ's now more aggressive queue control, limiting the depth available to the device. This patches fixes that regression by allowing a greater depth when only one queue is busy. It has been tested to not impact sync-vs-async workloads too much - we still do a lot better than 2.6.20. Signed-off-by: Jens Axboe <jens.axboe@oracle.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* | [PATCH] remove protection of LANANA-reserved majorsAndrew Morton2007-04-041-2/+0
| | | | | | | | | | | | | | | | | | | | | | | | | | Revert all this. It can cause device-mapper to receive a different major from earlier kernels and it turns out that the Amanda backup program (via GNU tar, apparently) checks major numbers on files when performing incremental backups. Which is a bit broken of Amanda (or tar), but this feature isn't important enough to justify the churn. Cc: Ingo Molnar <mingo@elte.hu> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* | make elv_register() output atomicThibaut VARENE2007-03-271-3/+4
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Booting 2.6.21-rc3-g45592145 I noticed the following on one of my machines in the bootlog: io scheduler noop registered<6>Time: jiffies clocksource has been installed. io scheduler deadline registered (default) Looking at block/elevator.c, it appears that elv_register() uses two consecutive printks in a non-atomic way, leading to the above glitch. The attached trivial patch fixes this issue, by using a single printk. Signed-off-by: Thibaut VARENE <varenet@parisc-linux.org> Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
* | block: blk_max_pfn is somtimes wrongVasily Tarasov2007-03-271-3/+3
|/ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | There is a small problem in handling page bounce. At the moment blk_max_pfn equals max_pfn, which is in fact not maximum possible _number_ of a page frame, but the _amount_ of page frames. For example for the 32bit x86 node with 4Gb RAM, max_pfn = 0x100000, but not 0xFFFF. request_queue structure has a member q->bounce_pfn and queue needs bounce pages for the pages _above_ this limit. This routine is handled by blk_queue_bounce(), where the following check is produced: if (q->bounce_pfn >= blk_max_pfn) return; Assume, that a driver has set q->bounce_pfn to 0xFFFF, but blk_max_pfn equals 0x10000. In such situation the check above fails and for each bio we always fall down for iterating over pages tied to the bio. I want to notice, that for quite a big range of device drivers (ide, md, ...) such problem doesn't happen because they use BLK_BOUNCE_ANY for bounce_pfn. BLK_BOUNCE_ANY is defined as blk_max_pfn << PAGE_SHIFT, and then the check above doesn't fail. But for other drivers, which obtain reuired value from drivers, it fails. For example sata_nv uses ATA_DMA_MASK or dev->dma_mask. I propose to use (max_pfn - 1) for blk_max_pfn. And the same for blk_max_low_pfn. The patch also cleanses some checks related with bounce_pfn. Signed-off-by: Vasily Tarasov <vtaras@openvz.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
* [PATCH] lockdep: annotate BLKPG_DEL_PARTITIONPeter Zijlstra2007-02-201-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | >============================================= >[ INFO: possible recursive locking detected ] >2.6.19-1.2909.fc7 #1 >--------------------------------------------- >anaconda/587 is trying to acquire lock: > (&bdev->bd_mutex){--..}, at: [<c05fb380>] mutex_lock+0x21/0x24 > >but task is already holding lock: > (&bdev->bd_mutex){--..}, at: [<c05fb380>] mutex_lock+0x21/0x24 > >other info that might help us debug this: >1 lock held by anaconda/587: > #0: (&bdev->bd_mutex){--..}, at: [<c05fb380>] mutex_lock+0x21/0x24 > >stack backtrace: > [<c0405812>] show_trace_log_lvl+0x1a/0x2f > [<c0405db2>] show_trace+0x12/0x14 > [<c0405e36>] dump_stack+0x16/0x18 > [<c043bd84>] __lock_acquire+0x116/0xa09 > [<c043c960>] lock_acquire+0x56/0x6f > [<c05fb1fa>] __mutex_lock_slowpath+0xe5/0x24a > [<c05fb380>] mutex_lock+0x21/0x24 > [<c04d82fb>] blkdev_ioctl+0x600/0x76d > [<c04946b1>] block_ioctl+0x1b/0x1f > [<c047ed5a>] do_ioctl+0x22/0x68 > [<c047eff2>] vfs_ioctl+0x252/0x265 > [<c047f04e>] sys_ioctl+0x49/0x63 > [<c0404070>] syscall_call+0x7/0xb Annotate BLKPG_DEL_PARTITION's bd_mutex locking and add a little comment clarifying the bd_mutex locking, because I confused myself and initially thought the lock order was wrong too. Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Neil Brown <neilb@suse.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* [PATCH] rework reserved major handlingAndrew Morton2007-02-201-7/+2
| | | | | | | | | | | | | | | Several people have reported failures in dynamic major device number handling due to the recent changes in there to avoid handing out the local/experimental majors. Rolf reports that this is due to a gcc-4.1.0 bug. The patch refactors that code a lot in an attempt to provoke the compiler into behaving. Cc: 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>
* update I/O sched Kconfig help texts - CFQ is now default, not AS.Jesper Juhl2007-02-171-4/+5
| | | | | | | | Change I/O scheduler description to correctly show CFQ as being the default scheduler and not the anticipatory scheduler that previously was default. Signed-off-by: Jesper Juhl <jesper.juhl@gmail.com> Signed-off-by: Adrian Bunk <bunk@stusta.de>
* [PATCH] mark struct file_operations const 3Arjan van de Ven2007-02-121-1/+1
| | | | | | | | | | | Many struct file_operations in the kernel can be "const". Marking them const moves these to the .rodata section, which avoids false sharing with potential dirty data. In addition it'll catch accidental writes at compile time to these shared resources. Signed-off-by: Arjan van de Ven <arjan@linux.intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* [PATCH] register_blkdev(): don't hand out the LOCAL/EXPERIMENTAL majorsAndrew Morton2007-02-121-0/+8
| | | | | | | | | | | | | As pointed out in http://bugzilla.kernel.org/show_bug.cgi?id=7922, dynamic blockdev major allocation can hand out majors which LANANA has defined as being for local/experimental use. Cc: Torben Mathiasen <device@lanana.org> Cc: Greg KH <greg@kroah.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Tomas Klas <tomas.klas@mepatek.cz> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* cfq-iosched: improve continue or break logic in cfq_dispatchJens Axboe2007-02-111-8/+8
| | | | | | | This improves performance considerably for sync requests when you have command queuing enabled. Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
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