path: root/block/blk-core.c
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2013-07-18block: queue work on power efficient wqViresh Kumar
Block layer uses workqueues for multiple purposes. There is no real dependency of scheduling these on the cpu which scheduled them. On a idle system, it is observed that and idle cpu wakes up many times just to service this work. It would be better if we can schedule it on a cpu which the scheduler believes to be the most appropriate one. This patch replaces normal workqueues with power efficient versions. Cc: Jens Axboe <axboe@kernel.dk> Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org> Signed-off-by: Tejun Heo <tj@kernel.org> (cherry picked from commit 695588f9454bdbc7c1a2fbb8a6bfdcfba6183348) Signed-off-by: Mark Brown <broonie@linaro.org>
2013-05-17blkpm: avoid sleep when holding queue lockAaron Lu
In blk_post_runtime_resume, an autosuspend request will be initiated for the device. Since we are holding the queue lock, we can't sleep and thus we should use the async version to initiate an autosuspend, i.e. pm_request_suspend instead of pm_runtime_suspend, which might sleep. Signed-off-by: Aaron Lu <aaron.lu@intel.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2013-05-08Merge branch 'for-3.10/core' of git://git.kernel.dk/linux-blockLinus Torvalds
Pull block core updates from Jens Axboe: - Major bit is Kents prep work for immutable bio vecs. - Stable candidate fix for a scheduling-while-atomic in the queue bypass operation. - Fix for the hang on exceeded rq->datalen 32-bit unsigned when merging discard bios. - Tejuns changes to convert the writeback thread pool to the generic workqueue mechanism. - Runtime PM framework, SCSI patches exists on top of these in James' tree. - A few random fixes. * 'for-3.10/core' of git://git.kernel.dk/linux-block: (40 commits) relay: move remove_buf_file inside relay_close_buf partitions/efi.c: replace useless kzalloc's by kmalloc's fs/block_dev.c: fix iov_shorten() criteria in blkdev_aio_read() block: fix max discard sectors limit blkcg: fix "scheduling while atomic" in blk_queue_bypass_start Documentation: cfq-iosched: update documentation help for cfq tunables writeback: expose the bdi_wq workqueue writeback: replace custom worker pool implementation with unbound workqueue writeback: remove unused bdi_pending_list aoe: Fix unitialized var usage bio-integrity: Add explicit field for owner of bip_buf block: Add an explicit bio flag for bios that own their bvec block: Add bio_alloc_pages() block: Convert some code to bio_for_each_segment_all() block: Add bio_for_each_segment_all() bounce: Refactor __blk_queue_bounce to not use bi_io_vec raid1: use bio_copy_data() pktcdvd: Use bio_reset() in disabled code to kill bi_idx usage pktcdvd: use bio_copy_data() block: Add bio_copy_data() ...
2013-04-18Revert "block: add missing block_bio_complete() tracepoint"Linus Torvalds
This reverts commit 3a366e614d0837d9fc23f78cdb1a1186ebc3387f. Wanlong Gao reports that it causes a kernel panic on his machine several minutes after boot. Reverting it removes the panic. Jens says: "It's not quite clear why that is yet, so I think we should just revert the commit for 3.9 final (which I'm assuming is pretty close). The wifi is crap at the LSF hotel, so sending this email instead of queueing up a revert and pull request." Reported-by: Wanlong Gao <gaowanlong@cn.fujitsu.com> Requested-by: Jens Axboe <axboe@kernel.dk> Cc: Tejun Heo <tj@kernel.org> Cc: Steven Rostedt <rostedt@goodmis.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2013-03-24Merge branch 'for-jens' of http://evilpiepirate.org/git/linux-bcache into ↵Jens Axboe
for-3.10/core This contains Kents prep work for the immutable bio_vecs.
2013-03-23block: Add bio_end_sector()Kent Overstreet
Just a little convenience macro - main reason to add it now is preparing for immutable bio vecs, it'll reduce the size of the patch that puts bi_sector/bi_size/bi_idx into a struct bvec_iter. Signed-off-by: Kent Overstreet <koverstreet@google.com> CC: Jens Axboe <axboe@kernel.dk> CC: Lars Ellenberg <drbd-dev@lists.linbit.com> CC: Jiri Kosina <jkosina@suse.cz> CC: Alasdair Kergon <agk@redhat.com> CC: dm-devel@redhat.com CC: Neil Brown <neilb@suse.de> CC: Martin Schwidefsky <schwidefsky@de.ibm.com> CC: Heiko Carstens <heiko.carstens@de.ibm.com> CC: linux-s390@vger.kernel.org CC: Chris Mason <chris.mason@fusionio.com> CC: Steven Whitehouse <swhiteho@redhat.com> Acked-by: Steven Whitehouse <swhiteho@redhat.com>
2013-03-23block: Refactor blk_update_request()Kent Overstreet
Converts it to use bio_advance(), simplifying it quite a bit in the process. Note that req_bio_endio() now always calls bio_advance() - which means it always loops over the biovec, not just on partial completions. Don't expect it to affect performance, but worth noting. Tested it by forcing partial updates, and dumping before and after on various bio/bvec fields when doing a partial update. Signed-off-by: Kent Overstreet <koverstreet@google.com> CC: Jens Axboe <axboe@kernel.dk>
2013-03-22block: implement runtime pm strategyLin Ming
When a request is added: If device is suspended or is suspending and the request is not a PM request, resume the device. When the last request finishes: Call pm_runtime_mark_last_busy(). When pick a request: If device is resuming/suspending, then only PM request is allowed to go. The idea and API is designed by Alan Stern and described here: http://marc.info/?l=linux-scsi&m=133727953625963&w=2 Signed-off-by: Lin Ming <ming.m.lin@intel.com> Signed-off-by: Aaron Lu <aaron.lu@intel.com> Acked-by: Alan Stern <stern@rowland.harvard.edu> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2013-03-22block: add runtime pm helpersLin Ming
Add runtime pm helper functions: void blk_pm_runtime_init(struct request_queue *q, struct device *dev) - Initialization function for drivers to call. int blk_pre_runtime_suspend(struct request_queue *q) - If any requests are in the queue, mark last busy and return -EBUSY. Otherwise set q->rpm_status to RPM_SUSPENDING and return 0. void blk_post_runtime_suspend(struct request_queue *q, int err) - If the suspend succeeded then set q->rpm_status to RPM_SUSPENDED. Otherwise set it to RPM_ACTIVE and mark last busy. void blk_pre_runtime_resume(struct request_queue *q) - Set q->rpm_status to RPM_RESUMING. void blk_post_runtime_resume(struct request_queue *q, int err) - If the resume succeeded then set q->rpm_status to RPM_ACTIVE and call __blk_run_queue, then mark last busy and autosuspend. Otherwise set q->rpm_status to RPM_SUSPENDED. The idea and API is designed by Alan Stern and described here: http://marc.info/?l=linux-scsi&m=133727953625963&w=2 Signed-off-by: Lin Ming <ming.m.lin@intel.com> Signed-off-by: Aaron Lu <aaron.lu@intel.com> Acked-by: Alan Stern <stern@rowland.harvard.edu> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2013-02-28Merge branch 'for-3.9/core' of git://git.kernel.dk/linux-blockLinus Torvalds
Pull block IO core bits from Jens Axboe: "Below are the core block IO bits for 3.9. It was delayed a few days since my workstation kept crashing every 2-8h after pulling it into current -git, but turns out it is a bug in the new pstate code (divide by zero, will report separately). In any case, it contains: - The big cfq/blkcg update from Tejun and and Vivek. - Additional block and writeback tracepoints from Tejun. - Improvement of the should sort (based on queues) logic in the plug flushing. - _io() variants of the wait_for_completion() interface, using io_schedule() instead of schedule() to contribute to io wait properly. - Various little fixes. You'll get two trivial merge conflicts, which should be easy enough to fix up" Fix up the trivial conflicts due to hlist traversal cleanups (commit b67bfe0d42ca: "hlist: drop the node parameter from iterators"). * 'for-3.9/core' of git://git.kernel.dk/linux-block: (39 commits) block: remove redundant check to bd_openers() block: use i_size_write() in bd_set_size() cfq: fix lock imbalance with failed allocations drivers/block/swim3.c: fix null pointer dereference block: don't select PERCPU_RWSEM block: account iowait time when waiting for completion of IO request sched: add wait_for_completion_io[_timeout] writeback: add more tracepoints block: add block_{touch|dirty}_buffer tracepoint buffer: make touch_buffer() an exported function block: add @req to bio_{front|back}_merge tracepoints block: add missing block_bio_complete() tracepoint block: Remove should_sort judgement when flush blk_plug block,elevator: use new hashtable implementation cfq-iosched: add hierarchical cfq_group statistics cfq-iosched: collect stats from dead cfqgs cfq-iosched: separate out cfqg_stats_reset() from cfq_pd_reset_stats() blkcg: make blkcg_print_blkgs() grab q locks instead of blkcg lock block: RCU free request_queue blkcg: implement blkg_[rw]stat_recursive_sum() and blkg_[rw]stat_merge() ...
2013-02-21block: optionally snapshot page contents to provide stable pages during writeDarrick J. Wong
This provides a band-aid to provide stable page writes on jbd without needing to backport the fixed locking and page writeback bit handling schemes of jbd2. The band-aid works by using bounce buffers to snapshot page contents instead of waiting. For those wondering about the ext3 bandage -- fixing the jbd locking (which was done as part of ext4dev years ago) is a lot of surgery, and setting PG_writeback on data pages when we actually hold the page lock dropped ext3 performance by nearly an order of magnitude. If we're going to migrate iscsi and raid to use stable page writes, the complaints about high latency will likely return. We might as well centralize their page snapshotting thing to one place. Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com> Tested-by: Andy Lutomirski <luto@amacapital.net> Cc: Adrian Hunter <adrian.hunter@intel.com> Cc: Artem Bityutskiy <dedekind1@gmail.com> Reviewed-by: Jan Kara <jack@suse.cz> Cc: Joel Becker <jlbec@evilplan.org> Cc: Mark Fasheh <mfasheh@suse.com> Cc: Steven Whitehouse <swhiteho@redhat.com> Cc: Jens Axboe <axboe@kernel.dk> Cc: Eric Van Hensbergen <ericvh@gmail.com> Cc: Ron Minnich <rminnich@sandia.gov> Cc: Latchesar Ionkov <lucho@ionkov.net> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2013-01-14block: add @req to bio_{front|back}_merge tracepointsTejun Heo
bio_{front|back}_merge tracepoints report a bio merging into an existing request but didn't specify which request the bio is being merged into. Add @req to it. This makes it impossible to share the event template with block_bio_queue - split it out. @req isn't used or exported to userland at this point and there is no userland visible behavior change. Later changes will make use of the extra parameter. Signed-off-by: Tejun Heo <tj@kernel.org> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2013-01-14block: add missing block_bio_complete() tracepointTejun Heo
bio completion didn't kick block_bio_complete TP. Only dm was explicitly triggering the TP on IO completion. This makes block_bio_complete TP useless for tracers which want to know about bios, and all other bio based drivers skip generating blktrace completion events. This patch makes all bio completions via bio_endio() generate block_bio_complete TP. * Explicit trace_block_bio_complete() invocation removed from dm and the trace point is unexported. * @rq dropped from trace_block_bio_complete(). bios may fly around w/o queue associated. Verifying and accessing the assocaited queue belongs to TP probes. * blktrace now gets both request and bio completions. Make it ignore bio completions if request completion path is happening. This makes all bio based drivers generate blktrace completion events properly and makes the block_bio_complete TP actually useful. v2: With this change, block_bio_complete TP could be invoked on sg commands which have bio's with %NULL bi_bdev. Update TP assignment code to check whether bio->bi_bdev is %NULL before dereferencing. Signed-off-by: Tejun Heo <tj@kernel.org> Original-patch-by: Namhyung Kim <namhyung@gmail.com> Cc: Tejun Heo <tj@kernel.org> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Alasdair Kergon <agk@redhat.com> Cc: dm-devel@redhat.com Cc: Neil Brown <neilb@suse.de> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2013-01-11block: Remove should_sort judgement when flush blk_plugJianpeng Ma
In commit 975927b942c932,it add blk_rq_pos to sort rq when flushing. Although this commit was used for the situation which blk_plug handled multi devices on the same time like md device. I think there must be some situations like this but only single device. So remove the should_sort judgement. Because the parameter should_sort is only for this purpose,it can delete should_sort from blk_plug. CC: Shaohua Li <shli@kernel.org> Signed-off-by: Jianpeng Ma <majianpeng@gmail.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2012-12-14block: export block_unplug tracepointNeilBrown
This allows stacked devices (like md/raid5) to provide blktrace tracing, including unplug events. Reported-by: Fengguang Wu <fengguang.wu@intel.com> Signed-off-by: NeilBrown <neilb@suse.de> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2012-12-06block: Make blk_cleanup_queue() wait until request_fn finishedBart Van Assche
Some request_fn implementations, e.g. scsi_request_fn(), unlock the queue lock internally. This may result in multiple threads executing request_fn for the same queue simultaneously. Keep track of the number of active request_fn calls and make sure that blk_cleanup_queue() waits until all active request_fn invocations have finished. A block driver may start cleaning up resources needed by its request_fn as soon as blk_cleanup_queue() finished, so blk_cleanup_queue() must wait for all outstanding request_fn invocations to finish. Signed-off-by: Bart Van Assche <bvanassche@acm.org> Reported-by: Chanho Min <chanho.min@lge.com> Cc: James Bottomley <JBottomley@Parallels.com> Cc: Mike Christie <michaelc@cs.wisc.edu> Acked-by: Tejun Heo <tj@kernel.org> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2012-12-06block: Avoid scheduling delayed work on a dead queueBart Van Assche
Running a queue must continue after it has been marked dying until it has been marked dead. So the function blk_run_queue_async() must not schedule delayed work after blk_cleanup_queue() has marked a queue dead. Hence add a test for that queue state in blk_run_queue_async() and make sure that queue_unplugged() invokes that function with the queue lock held. This avoids that the queue state can change after it has been tested and before mod_delayed_work() is invoked. Drop the queue dying test in queue_unplugged() since it is now superfluous: __blk_run_queue() already tests whether or not the queue is dead. Signed-off-by: Bart Van Assche <bvanassche@acm.org> Cc: Mike Christie <michaelc@cs.wisc.edu> Acked-by: Tejun Heo <tj@kernel.org> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2012-12-06block: Avoid that request_fn is invoked on a dead queueBart Van Assche
A block driver may start cleaning up resources needed by its request_fn as soon as blk_cleanup_queue() finished, so request_fn must not be invoked after draining finished. This is important when blk_run_queue() is invoked without any requests in progress. As an example, if blk_drain_queue() and scsi_run_queue() run in parallel, blk_drain_queue() may have finished all requests after scsi_run_queue() has taken a SCSI device off the starved list but before that last function has had a chance to run the queue. Signed-off-by: Bart Van Assche <bvanassche@acm.org> Cc: James Bottomley <JBottomley@Parallels.com> Cc: Mike Christie <michaelc@cs.wisc.edu> Cc: Chanho Min <chanho.min@lge.com> Acked-by: Tejun Heo <tj@kernel.org> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2012-12-06block: Let blk_drain_queue() caller obtain the queue lockBart Van Assche
Let the caller of blk_drain_queue() obtain the queue lock to improve readability of the patch called "Avoid that request_fn is invoked on a dead queue". Signed-off-by: Bart Van Assche <bvanassche@acm.org> Acked-by: Tejun Heo <tj@kernel.org> Cc: James Bottomley <JBottomley@Parallels.com> Cc: Mike Christie <michaelc@cs.wisc.edu> Cc: Jens Axboe <axboe@kernel.dk> Cc: Chanho Min <chanho.min@lge.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2012-12-06block: Rename queue dead flagBart Van Assche
QUEUE_FLAG_DEAD is used to indicate that queuing new requests must stop. After this flag has been set queue draining starts. However, during the queue draining phase it is still safe to invoke the queue's request_fn, so QUEUE_FLAG_DYING is a better name for this flag. This patch has been generated by running the following command over the kernel source tree: git grep -lEw 'blk_queue_dead|QUEUE_FLAG_DEAD' | xargs sed -i.tmp -e 's/blk_queue_dead/blk_queue_dying/g' \ -e 's/QUEUE_FLAG_DEAD/QUEUE_FLAG_DYING/g'; \ sed -i.tmp -e "s/QUEUE_FLAG_DYING$(printf \\t)*5/QUEUE_FLAG_DYING$(printf \\t)5/g" \ include/linux/blkdev.h; \ sed -i.tmp -e 's/ DEAD/ DYING/g' -e 's/dead queue/a dying queue/' \ -e 's/Dead queue/A dying queue/' block/blk-core.c Signed-off-by: Bart Van Assche <bvanassche@acm.org> Acked-by: Tejun Heo <tj@kernel.org> Cc: James Bottomley <JBottomley@Parallels.com> Cc: Mike Christie <michaelc@cs.wisc.edu> Cc: Jens Axboe <axboe@kernel.dk> Cc: Chanho Min <chanho.min@lge.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2012-11-10block: use NUMA_NO_NODE instead of -1Ezequiel Garcia
Signed-off-by: Ezequiel Garcia <elezegarcia@gmail.com> Modified by me to cover blk_init_queue() as well. Signed-off-by: Jens Axboe <axboe@kernel.dk>
2012-10-25block: Add blk_rq_pos(rq) to sort rq when plushingJianpeng Ma
My workload is a raid5 which had 16 disks. And used our filesystem to write using direct-io mode. I used the blktrace to find those message: 8,16 0 6647 2.453665504 2579 M W 7493152 + 8 [md0_raid5] 8,16 0 6648 2.453672411 2579 Q W 7493160 + 8 [md0_raid5] 8,16 0 6649 2.453672606 2579 M W 7493160 + 8 [md0_raid5] 8,16 0 6650 2.453679255 2579 Q W 7493168 + 8 [md0_raid5] 8,16 0 6651 2.453679441 2579 M W 7493168 + 8 [md0_raid5] 8,16 0 6652 2.453685948 2579 Q W 7493176 + 8 [md0_raid5] 8,16 0 6653 2.453686149 2579 M W 7493176 + 8 [md0_raid5] 8,16 0 6654 2.453693074 2579 Q W 7493184 + 8 [md0_raid5] 8,16 0 6655 2.453693254 2579 M W 7493184 + 8 [md0_raid5] 8,16 0 6656 2.453704290 2579 Q W 7493192 + 8 [md0_raid5] 8,16 0 6657 2.453704482 2579 M W 7493192 + 8 [md0_raid5] 8,16 0 6658 2.453715016 2579 Q W 7493200 + 8 [md0_raid5] 8,16 0 6659 2.453715247 2579 M W 7493200 + 8 [md0_raid5] 8,16 0 6660 2.453721730 2579 Q W 7493208 + 8 [md0_raid5] 8,16 0 6661 2.453721974 2579 M W 7493208 + 8 [md0_raid5] 8,16 0 6662 2.453728202 2579 Q W 7493216 + 8 [md0_raid5] 8,16 0 6663 2.453728436 2579 M W 7493216 + 8 [md0_raid5] 8,16 0 6664 2.453734782 2579 Q W 7493224 + 8 [md0_raid5] 8,16 0 6665 2.453735019 2579 M W 7493224 + 8 [md0_raid5] 8,16 0 6666 2.453741401 2579 Q W 7493232 + 8 [md0_raid5] 8,16 0 6667 2.453741632 2579 M W 7493232 + 8 [md0_raid5] 8,16 0 6668 2.453748148 2579 Q W 7493240 + 8 [md0_raid5] 8,16 0 6669 2.453748386 2579 M W 7493240 + 8 [md0_raid5] 8,16 0 6670 2.453851843 2579 I W 7493144 + 104 [md0_raid5] 8,16 0 0 2.453853661 0 m N cfq2579 insert_request 8,16 0 6671 2.453854064 2579 I W 7493120 + 24 [md0_raid5] 8,16 0 0 2.453854439 0 m N cfq2579 insert_request 8,16 0 6672 2.453854793 2579 U N [md0_raid5] 2 8,16 0 0 2.453855513 0 m N cfq2579 Not idling.st->count:1 8,16 0 0 2.453855927 0 m N cfq2579 dispatch_insert 8,16 0 0 2.453861771 0 m N cfq2579 dispatched a request 8,16 0 0 2.453862248 0 m N cfq2579 activate rq,drv=1 8,16 0 6673 2.453862332 2579 D W 7493120 + 24 [md0_raid5] 8,16 0 0 2.453865957 0 m N cfq2579 Not idling.st->count:1 8,16 0 0 2.453866269 0 m N cfq2579 dispatch_insert 8,16 0 0 2.453866707 0 m N cfq2579 dispatched a request 8,16 0 0 2.453867061 0 m N cfq2579 activate rq,drv=2 8,16 0 6674 2.453867145 2579 D W 7493144 + 104 [md0_raid5] 8,16 0 6675 2.454147608 0 C W 7493120 + 24 [0] 8,16 0 0 2.454149357 0 m N cfq2579 complete rqnoidle 0 8,16 0 6676 2.454791505 0 C W 7493144 + 104 [0] 8,16 0 0 2.454794803 0 m N cfq2579 complete rqnoidle 0 8,16 0 0 2.454795160 0 m N cfq schedule dispatch From above messages,we can find rq[W 7493144 + 104] and rq[W 7493120 + 24] do not merge. Because the bio order is: 8,16 0 6638 2.453619407 2579 Q W 7493144 + 8 [md0_raid5] 8,16 0 6639 2.453620460 2579 G W 7493144 + 8 [md0_raid5] 8,16 0 6640 2.453639311 2579 Q W 7493120 + 8 [md0_raid5] 8,16 0 6641 2.453639842 2579 G W 7493120 + 8 [md0_raid5] The bio(7493144) first and bio(7493120) later.So the subsequent bios will be divided into two parts. When flushing plug-list,because elv_attempt_insert_merge only support backmerge,not supporting frontmerge. So rq[7493120 + 24] can't merge with rq[7493144 + 104]. From my test,i found those situation can count 25% in our system. Using this patch, there is no this situation. Signed-off-by: Jianpeng Ma <majianpeng@gmail.com> CC:Shaohua Li <shli@kernel.org> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2012-10-11Merge branch 'for-3.7/core' of git://git.kernel.dk/linux-blockLinus Torvalds
Pull block IO update from Jens Axboe: "Core block IO bits for 3.7. Not a huge round this time, it contains: - First series from Kent cleaning up and generalizing bio allocation and freeing. - WRITE_SAME support from Martin. - Mikulas patches to prevent O_DIRECT crashes when someone changes the block size of a device. - Make bio_split() work on data-less bio's (like trim/discards). - A few other minor fixups." Fixed up silent semantic mis-merge as per Mikulas Patocka and Andrew Morton. It is due to the VM no longer using a prio-tree (see commit 6b2dbba8b6ac: "mm: replace vma prio_tree with an interval tree"). So make set_blocksize() use mapping_mapped() instead of open-coding the internal VM knowledge that has changed. * 'for-3.7/core' of git://git.kernel.dk/linux-block: (26 commits) block: makes bio_split support bio without data scatterlist: refactor the sg_nents scatterlist: add sg_nents fs: fix include/percpu-rwsem.h export error percpu-rw-semaphore: fix documentation typos fs/block_dev.c:1644:5: sparse: symbol 'blkdev_mmap' was not declared blockdev: turn a rw semaphore into a percpu rw semaphore Fix a crash when block device is read and block size is changed at the same time block: fix request_queue->flags initialization block: lift the initial queue bypass mode on blk_register_queue() instead of blk_init_allocated_queue() block: ioctl to zero block ranges block: Make blkdev_issue_zeroout use WRITE SAME block: Implement support for WRITE SAME block: Consolidate command flag and queue limit checks for merges block: Clean up special command handling logic block/blk-tag.c: Remove useless kfree block: remove the duplicated setting for congestion_threshold block: reject invalid queue attribute values block: Add bio_clone_bioset(), bio_clone_kmalloc() block: Consolidate bio_alloc_bioset(), bio_kmalloc() ...
2012-10-02Merge branch 'for-3.7' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/wqLinus Torvalds
Pull workqueue changes from Tejun Heo: "This is workqueue updates for v3.7-rc1. A lot of activities this round including considerable API and behavior cleanups. * delayed_work combines a timer and a work item. The handling of the timer part has always been a bit clunky leading to confusing cancelation API with weird corner-case behaviors. delayed_work is updated to use new IRQ safe timer and cancelation now works as expected. * Another deficiency of delayed_work was lack of the counterpart of mod_timer() which led to cancel+queue combinations or open-coded timer+work usages. mod_delayed_work[_on]() are added. These two delayed_work changes make delayed_work provide interface and behave like timer which is executed with process context. * A work item could be executed concurrently on multiple CPUs, which is rather unintuitive and made flush_work() behavior confusing and half-broken under certain circumstances. This problem doesn't exist for non-reentrant workqueues. While non-reentrancy check isn't free, the overhead is incurred only when a work item bounces across different CPUs and even in simulated pathological scenario the overhead isn't too high. All workqueues are made non-reentrant. This removes the distinction between flush_[delayed_]work() and flush_[delayed_]_work_sync(). The former is now as strong as the latter and the specified work item is guaranteed to have finished execution of any previous queueing on return. * In addition to the various bug fixes, Lai redid and simplified CPU hotplug handling significantly. * Joonsoo introduced system_highpri_wq and used it during CPU hotplug. There are two merge commits - one to pull in IRQ safe timer from tip/timers/core and the other to pull in CPU hotplug fixes from wq/for-3.6-fixes as Lai's hotplug restructuring depended on them." Fixed a number of trivial conflicts, but the more interesting conflicts were silent ones where the deprecated interfaces had been used by new code in the merge window, and thus didn't cause any real data conflicts. Tejun pointed out a few of them, I fixed a couple more. * 'for-3.7' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/wq: (46 commits) workqueue: remove spurious WARN_ON_ONCE(in_irq()) from try_to_grab_pending() workqueue: use cwq_set_max_active() helper for workqueue_set_max_active() workqueue: introduce cwq_set_max_active() helper for thaw_workqueues() workqueue: remove @delayed from cwq_dec_nr_in_flight() workqueue: fix possible stall on try_to_grab_pending() of a delayed work item workqueue: use hotcpu_notifier() for workqueue_cpu_down_callback() workqueue: use __cpuinit instead of __devinit for cpu callbacks workqueue: rename manager_mutex to assoc_mutex workqueue: WORKER_REBIND is no longer necessary for idle rebinding workqueue: WORKER_REBIND is no longer necessary for busy rebinding workqueue: reimplement idle worker rebinding workqueue: deprecate __cancel_delayed_work() workqueue: reimplement cancel_delayed_work() using try_to_grab_pending() workqueue: use mod_delayed_work() instead of __cancel + queue workqueue: use irqsafe timer for delayed_work workqueue: clean up delayed_work initializers and add missing one workqueue: make deferrable delayed_work initializer names consistent workqueue: cosmetic whitespace updates for macro definitions workqueue: deprecate system_nrt[_freezable]_wq workqueue: deprecate flush[_delayed]_work_sync() ...
2012-09-21block: fix request_queue->flags initializationTejun Heo
A queue newly allocated with blk_alloc_queue_node() has only QUEUE_FLAG_BYPASS set. For request-based drivers, blk_init_allocated_queue() is called and q->queue_flags is overwritten with QUEUE_FLAG_DEFAULT which doesn't include BYPASS even though the initial bypass is still in effect. In blk_init_allocated_queue(), or QUEUE_FLAG_DEFAULT to q->queue_flags instead of overwriting. Signed-off-by: Tejun Heo <tj@kernel.org> Cc: stable@vger.kernel.org Acked-by: Vivek Goyal <vgoyal@redhat.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2012-09-21block: lift the initial queue bypass mode on blk_register_queue() instead of ↵Tejun Heo
blk_init_allocated_queue() b82d4b197c ("blkcg: make request_queue bypassing on allocation") made request_queues bypassed on allocation to avoid switching on and off bypass mode on a queue being initialized. Some drivers allocate and then destroy a lot of queues without fully initializing them and incurring bypass latency overhead on each of them could add upto significant overhead. Unfortunately, blk_init_allocated_queue() is never used by queues of bio-based drivers, which means that all bio-based driver queues are in bypass mode even after initialization and registration complete successfully. Due to the limited way request_queues are used by bio drivers, this problem is hidden pretty well but it shows up when blk-throttle is used in combination with a bio-based driver. Trying to configure (echoing to cgroupfs file) blk-throttle for a bio-based driver hangs indefinitely in blkg_conf_prep() waiting for bypass mode to end. This patch moves the initial blk_queue_bypass_end() call from blk_init_allocated_queue() to blk_register_queue() which is called for any userland-visible queues regardless of its type. I believe this is correct because I don't think there is any block driver which needs or wants working elevator and blk-cgroup on a queue which isn't visible to userland. If there are such users, we need a different solution. Signed-off-by: Tejun Heo <tj@kernel.org> Reported-by: Joseph Glanville <joseph.glanville@orionvm.com.au> Cc: stable@vger.kernel.org Acked-by: Vivek Goyal <vgoyal@redhat.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2012-09-20block: Implement support for WRITE SAMEMartin K. Petersen
The WRITE SAME command supported on some SCSI devices allows the same block to be efficiently replicated throughout a block range. Only a single logical block is transferred from the host and the storage device writes the same data to all blocks described by the I/O. This patch implements support for WRITE SAME in the block layer. The blkdev_issue_write_same() function can be used by filesystems and block drivers to replicate a buffer across a block range. This can be used to efficiently initialize software RAID devices, etc. Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com> Acked-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2012-09-20block: Consolidate command flag and queue limit checks for mergesMartin K. Petersen
- blk_check_merge_flags() verifies that cmd_flags / bi_rw are compatible. This function is called for both req-req and req-bio merging. - blk_rq_get_max_sectors() and blk_queue_get_max_sectors() can be used to query the maximum sector count for a given request or queue. The calls will return the right value from the queue limits given the type of command (RW, discard, write same, etc.) Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com> Acked-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2012-09-20block: Clean up special command handling logicMartin K. Petersen
Remove special-casing of non-rw fs style requests (discard). The nomerge flags are consolidated in blk_types.h, and rq_mergeable() and bio_mergeable() have been modified to use them. bio_is_rw() is used in place of bio_has_data() a few places. This is done to to distinguish true reads and writes from other fs type requests that carry a payload (e.g. write same). Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com> Acked-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2012-09-09block: remove the duplicated setting for congestion_thresholdJaehoon Chung
Before call the blk_queue_congestion_threshold(), the blk_queue_congestion_threshold() is already called at blk_queue_make_rquest(). Because this code is the duplicated, it has removed. Signed-off-by: Jaehoon Chung <jh80.chung@samsung.com> Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2012-09-09block: Add bio_clone_bioset(), bio_clone_kmalloc()Kent Overstreet
Previously, there was bio_clone() but it only allocated from the fs bio set; as a result various users were open coding it and using __bio_clone(). This changes bio_clone() to become bio_clone_bioset(), and then we add bio_clone() and bio_clone_kmalloc() as wrappers around it, making use of the functionality the last patch adedd. This will also help in a later patch changing how bio cloning works. Signed-off-by: Kent Overstreet <koverstreet@google.com> CC: Jens Axboe <axboe@kernel.dk> CC: NeilBrown <neilb@suse.de> CC: Alasdair Kergon <agk@redhat.com> CC: Boaz Harrosh <bharrosh@panasas.com> CC: Jeff Garzik <jeff@garzik.org> Acked-by: Jeff Garzik <jgarzik@redhat.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2012-09-09block: Kill bi_destructorKent Overstreet
Now that we've got generic code for freeing bios allocated from bio pools, this isn't needed anymore. This patch also makes bio_free() static, since without bi_destructor there should be no need for it to be called anywhere else. bio_free() is now only called from bio_put, so we can refactor those a bit - move some code from bio_put() to bio_free() and kill the redundant bio->bi_next = NULL. v5: Switch to BIO_KMALLOC_POOL ((void *)~0), per Boaz v6: BIO_KMALLOC_POOL now NULL, drop bio_free's EXPORT_SYMBOL v7: No #define BIO_KMALLOC_POOL anymore Signed-off-by: Kent Overstreet <koverstreet@google.com> CC: Jens Axboe <axboe@kernel.dk> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2012-09-09block: Ues bi_pool for bio_integrity_alloc()Kent Overstreet
Now that bios keep track of where they were allocated from, bio_integrity_alloc_bioset() becomes redundant. Remove bio_integrity_alloc_bioset() and drop bio_set argument from the related functions and make them use bio->bi_pool. Signed-off-by: Kent Overstreet <koverstreet@google.com> CC: Jens Axboe <axboe@kernel.dk> CC: Martin K. Petersen <martin.petersen@oracle.com> Acked-by: Tejun Heo <tj@kernel.org> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2012-08-30block: rate-limit the error message from failing commandsYi Zou
When performing a cable pull test w/ active stress I/O using fio over a dual port Intel 82599 FCoE CNA, w/ 256LUNs on one port and about 32LUNs on the other, it is observed that the system becomes not usable due to scsi-ml being busy printing the error messages for all the failing commands. I don't believe this problem is specific to FCoE and these commands are anyway failing due to link being down (DID_NO_CONNECT), just rate-limit the messages here to solve this issue. v2->v1: use __ratelimit() as Tomas Henzl mentioned as the proper way for rate-limit per function. However, in this case, the failed i/o gets to blk_end_request_err() and then blk_update_request(), which also has to be rate-limited, as added in the v2 of this patch. v3-v2: resolved conflict to apply on current 3.6-rc3 upstream tip. Signed-off-by: Yi Zou <yi.zou@intel.com> Cc: www.Open-FCoE.org <devel@open-fcoe.org> Cc: Tomas Henzl <thenzl@redhat.com> Cc: <linux-scsi@vger.kernel.org> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2012-08-21workqueue: deprecate __cancel_delayed_work()Tejun Heo
Now that cancel_delayed_work() can be safely called from IRQ handlers, there's no reason to use __cancel_delayed_work(). Use cancel_delayed_work() instead of __cancel_delayed_work() and mark the latter deprecated. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Jens Axboe <axboe@kernel.dk> Cc: Jiri Kosina <jkosina@suse.cz> Cc: Roland Dreier <roland@kernel.org> Cc: Tomi Valkeinen <tomi.valkeinen@ti.com>
2012-08-21workqueue: use mod_delayed_work() instead of __cancel + queueTejun Heo
Now that mod_delayed_work() is safe to call from IRQ handlers, __cancel_delayed_work() followed by queue_delayed_work() can be replaced with mod_delayed_work(). Most conversions are straight-forward except for the following. * net/core/link_watch.c: linkwatch_schedule_work() was doing a quite elaborate dancing around its delayed_work. Collapse it such that linkwatch_work is queued for immediate execution if LW_URGENT and existing timer is kept otherwise. Signed-off-by: Tejun Heo <tj@kernel.org> Cc: "David S. Miller" <davem@davemloft.net> Cc: Tomi Valkeinen <tomi.valkeinen@ti.com>
2012-07-31blk: pass from_schedule to non-request unplug functions.NeilBrown
This will allow md/raid to know why the unplug was called, and will be able to act according - if !from_schedule it is safe to perform tasks which could themselves schedule. Signed-off-by: NeilBrown <neilb@suse.de> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2012-07-31block: stack unplugShaohua Li
MD raid1 prepares to dispatch request in unplug callback. If make_request in low level queue also uses unplug callback to dispatch request, the low level queue's unplug callback will not be called. Recheck the callback list helps this case. Signed-off-by: Shaohua Li <shli@fusionio.com> Signed-off-by: NeilBrown <neilb@suse.de> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2012-07-31blk: centralize non-request unplug handling.NeilBrown
Both md and umem has similar code for getting notified on an blk_finish_plug event. Centralize this code in block/ and allow each driver to provide its distinctive difference. Signed-off-by: NeilBrown <neilb@suse.de> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2012-06-26blkcg: implement per-blkg request allocationTejun Heo
Currently, request_queue has one request_list to allocate requests from regardless of blkcg of the IO being issued. When the unified request pool is used up, cfq proportional IO limits become meaningless - whoever grabs the next request being freed wins the race regardless of the configured weights. This can be easily demonstrated by creating a blkio cgroup w/ very low weight, put a program which can issue a lot of random direct IOs there and running a sequential IO from a different cgroup. As soon as the request pool is used up, the sequential IO bandwidth crashes. This patch implements per-blkg request_list. Each blkg has its own request_list and any IO allocates its request from the matching blkg making blkcgs completely isolated in terms of request allocation. * Root blkcg uses the request_list embedded in each request_queue, which was renamed to @q->root_rl from @q->rq. While making blkcg rl handling a bit harier, this enables avoiding most overhead for root blkcg. * Queue fullness is properly per request_list but bdi isn't blkcg aware yet, so congestion state currently just follows the root blkcg. As writeback isn't aware of blkcg yet, this works okay for async congestion but readahead may get the wrong signals. It's better than blkcg completely collapsing with shared request_list but needs to be improved with future changes. * After this change, each block cgroup gets a full request pool making resource consumption of each cgroup higher. This makes allowing non-root users to create cgroups less desirable; however, note that allowing non-root users to directly manage cgroups is already severely broken regardless of this patch - each block cgroup consumes kernel memory and skews IO weight (IO weights are not hierarchical). v2: queue-sysfs.txt updated and patch description udpated as suggested by Vivek. v3: blk_get_rl() wasn't checking error return from blkg_lookup_create() and may cause oops on lookup failure. Fix it by falling back to root_rl on blkg lookup failures. This problem was spotted by Rakesh Iyer <rni@google.com>. v4: Updated to accomodate 458f27a982 "block: Avoid missed wakeup in request waitqueue". blk_drain_queue() now wakes up waiters on all blkg->rl on the target queue. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Vivek Goyal <vgoyal@redhat.com> Cc: Wu Fengguang <fengguang.wu@intel.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2012-06-25block: prepare for multiple request_listsTejun Heo
Request allocation is about to be made per-blkg meaning that there'll be multiple request lists. * Make queue full state per request_list. blk_*queue_full() functions are renamed to blk_*rl_full() and takes @rl instead of @q. * Rename blk_init_free_list() to blk_init_rl() and make it take @rl instead of @q. Also add @gfp_mask parameter. * Add blk_exit_rl() instead of destroying rl directly from blk_release_queue(). * Add request_list->q and make request alloc/free functions - blk_free_request(), [__]freed_request(), __get_request() - take @rl instead of @q. This patch doesn't introduce any functional difference. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Vivek Goyal <vgoyal@redhat.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2012-06-25block: add q->nr_rqs[] and move q->rq.elvpriv to q->nr_rqs_elvprivTejun Heo
Add q->nr_rqs[] which currently behaves the same as q->rq.count[] and move q->rq.elvpriv to q->nr_rqs_elvpriv. blk_drain_queue() is updated to use q->nr_rqs[] instead of q->rq.count[]. These counters separates queue-wide request statistics from the request list and allow implementation of per-queue request allocation. While at it, properly indent fields of struct request_list. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Vivek Goyal <vgoyal@redhat.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2012-06-25block: allocate io_context upfrontTejun Heo
Block layer very lazy allocation of ioc. It waits until the moment ioc is absolutely necessary; unfortunately, that time could be inside queue lock and __get_request() performs unlock - try alloc - retry dancing. Just allocate it up-front on entry to block layer. We're not saving the rain forest by deferring it to the last possible moment and complicating things unnecessarily. This patch is to prepare for further updates to request allocation path. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Vivek Goyal <vgoyal@redhat.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2012-06-25block: refactor get_request[_wait]()Tejun Heo
Currently, there are two request allocation functions - get_request() and get_request_wait(). The former tries to allocate a request once and the latter keeps retrying until it succeeds. The latter wraps the former and keeps retrying until allocation succeeds. The combination of two functions deliver fallible non-wait allocation, fallible wait allocation and unfailing wait allocation. However, given that forward progress is guaranteed, fallible wait allocation isn't all that useful and in fact nobody uses it. This patch simplifies the interface as follows. * get_request() is renamed to __get_request() and is only used by the wrapper function. * get_request_wait() is renamed to get_request(). It now takes @gfp_mask and retries iff it contains %__GFP_WAIT. This patch doesn't introduce any functional change and is to prepare for further updates to request allocation path. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Vivek Goyal <vgoyal@redhat.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2012-06-25mempool: add @gfp_mask to mempool_create_node()Tejun Heo
mempool_create_node() currently assumes %GFP_KERNEL. Its only user, blk_init_free_list(), is about to be updated to use other allocation flags - add @gfp_mask argument to the function. Signed-off-by: Tejun Heo <tj@kernel.org> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Hugh Dickins <hughd@google.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2012-06-15block: Mitigate lock unbalance caused by lock switchingAsias He
Commit 777eb1bf15b8532c396821774bf6451e563438f5 disconnects externally supplied queue_lock before blk_drain_queue(). Switching the lock would introduce lock unbalance because theads which have taken the external lock might unlock the internal lock in the during the queue drain. This patch mitigate this by disconnecting the lock after the queue draining since queue draining makes a lot of request_queue users go away. However, please note, this patch only makes the problem less likely to happen. Anyone who still holds a ref might try to issue a new request on a dead queue after the blk_cleanup_queue() finishes draining, the lock unbalance might still happen in this case. ===================================== [ BUG: bad unlock balance detected! ] 3.4.0+ #288 Not tainted ------------------------------------- fio/17706 is trying to release lock (&(&q->__queue_lock)->rlock) at: [<ffffffff81329372>] blk_queue_bio+0x2a2/0x380 but there are no more locks to release! other info that might help us debug this: 1 lock held by fio/17706: #0: (&(&vblk->lock)->rlock){......}, at: [<ffffffff81327f1a>] get_request_wait+0x19a/0x250 stack backtrace: Pid: 17706, comm: fio Not tainted 3.4.0+ #288 Call Trace: [<ffffffff81329372>] ? blk_queue_bio+0x2a2/0x380 [<ffffffff810dea49>] print_unlock_inbalance_bug+0xf9/0x100 [<ffffffff810dfe4f>] lock_release_non_nested+0x1df/0x330 [<ffffffff811dae24>] ? dio_bio_end_aio+0x34/0xc0 [<ffffffff811d6935>] ? bio_check_pages_dirty+0x85/0xe0 [<ffffffff811daea1>] ? dio_bio_end_aio+0xb1/0xc0 [<ffffffff81329372>] ? blk_queue_bio+0x2a2/0x380 [<ffffffff81329372>] ? blk_queue_bio+0x2a2/0x380 [<ffffffff810e0079>] lock_release+0xd9/0x250 [<ffffffff81a74553>] _raw_spin_unlock_irq+0x23/0x40 [<ffffffff81329372>] blk_queue_bio+0x2a2/0x380 [<ffffffff81328faa>] generic_make_request+0xca/0x100 [<ffffffff81329056>] submit_bio+0x76/0xf0 [<ffffffff8115470c>] ? set_page_dirty_lock+0x3c/0x60 [<ffffffff811d69e1>] ? bio_set_pages_dirty+0x51/0x70 [<ffffffff811dd1a8>] do_blockdev_direct_IO+0xbf8/0xee0 [<ffffffff811d8620>] ? blkdev_get_block+0x80/0x80 [<ffffffff811dd4e5>] __blockdev_direct_IO+0x55/0x60 [<ffffffff811d8620>] ? blkdev_get_block+0x80/0x80 [<ffffffff811d92e7>] blkdev_direct_IO+0x57/0x60 [<ffffffff811d8620>] ? blkdev_get_block+0x80/0x80 [<ffffffff8114c6ae>] generic_file_aio_read+0x70e/0x760 [<ffffffff810df7c5>] ? __lock_acquire+0x215/0x5a0 [<ffffffff811e9924>] ? aio_run_iocb+0x54/0x1a0 [<ffffffff8114bfa0>] ? grab_cache_page_nowait+0xc0/0xc0 [<ffffffff811e82cc>] aio_rw_vect_retry+0x7c/0x1e0 [<ffffffff811e8250>] ? aio_fsync+0x30/0x30 [<ffffffff811e9936>] aio_run_iocb+0x66/0x1a0 [<ffffffff811ea9b0>] do_io_submit+0x6f0/0xb80 [<ffffffff8134de2e>] ? trace_hardirqs_on_thunk+0x3a/0x3f [<ffffffff811eae50>] sys_io_submit+0x10/0x20 [<ffffffff81a7c9e9>] system_call_fastpath+0x16/0x1b Changes since v2: Update commit log to explain how the code is still broken even if we delay the lock switching after the drain. Changes since v1: Update commit log as Tejun suggested. Acked-by: Tejun Heo <tj@kernel.org> Signed-off-by: Asias He <asias@redhat.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2012-06-15block: Avoid missed wakeup in request waitqueueAsias He
After hot-unplug a stressed disk, I found that rl->wait[] is not empty while rl->count[] is empty and there are theads still sleeping on get_request after the queue cleanup. With simple debug code, I found there are exactly nr_sleep - nr_wakeup of theads in D state. So there are missed wakeup. $ dmesg | grep nr_sleep [ 52.917115] ---> nr_sleep=1046, nr_wakeup=873, delta=173 $ vmstat 1 1 173 0 712640 24292 96172 0 0 0 0 419 757 0 0 0 100 0 To quote Tejun: Ah, okay, freed_request() wakes up single waiter with the assumption that after the wakeup there will at least be one successful allocation which in turn will continue the wakeup chain until the wait list is empty - ie. waiter wakeup is dependent on successful request allocation happening after each wakeup. With queue marked dead, any woken up waiter fails the allocation path, so the wakeup chaining is lost and we're left with hung waiters. What we need is wake_up_all() after drain completion. This patch fixes the missed wakeup by waking up all the theads which are sleeping on wait queue after queue drain. Changes in v2: Drop waitqueue_active() optimization Acked-by: Tejun Heo <tj@kernel.org> Signed-off-by: Asias He <asias@redhat.com> Fixed a bug by me, where stacked devices would oops on calling blk_drain_queue() since ->rq.wait[] do not get initialized unless it's a full queue setup. Signed-off-by: Jens Axboe <axboe@kernel.dk>
2012-05-01Merge tag 'v3.4-rc5' into for-3.5/coreJens Axboe
The core branch is behind driver commits that we want to build on for 3.5, hence I'm pulling in a later -rc. Linux 3.4-rc5 Conflicts: Documentation/feature-removal-schedule.txt Signed-off-by: Jens Axboe <axboe@kernel.dk>
2012-04-20block: fix elvpriv allocation failure handlingTejun Heo
Request allocation is mempool backed to guarantee forward progress under memory pressure; unfortunately, this property got broken while adding elvpriv data. Failures during elvpriv allocation, including ioc and icq creation failures, currently make get_request() fail as whole. There's no forward progress guarantee for these allocations - they may fail indefinitely under memory pressure stalling IO and deadlocking the system. This patch updates get_request() such that elvpriv allocation failure doesn't make the whole function fail. If elvpriv allocation fails, the allocation is degraded into !ELVPRIV. This will force the request to ELEVATOR_INSERT_BACK disturbing scheduling but elvpriv alloc failures should be rare (nothing is per-request) and anything is better than deadlocking. Signed-off-by: Tejun Heo <tj@kernel.org> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2012-04-20block: collapse blk_alloc_request() into get_request()Tejun Heo
Allocation failure handling in get_request() is about to be updated. To ease the update, collapse blk_alloc_request() into get_request(). This patch doesn't introduce any functional change. Signed-off-by: Tejun Heo <tj@kernel.org> Signed-off-by: Jens Axboe <axboe@kernel.dk>