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* block: don't include blk-mq.h in blk.hChristoph Hellwig2021-11-291-0/+1
| | | | | | | | | No needed, shift a blk-stat.h include into the source file that needs it instead. Signed-off-by: Christoph Hellwig <hch@lst.de> Link: https://lore.kernel.org/r/20211123185312.1432157-6-hch@lst.de Signed-off-by: Jens Axboe <axboe@kernel.dk>
* block: convert the rest of block to bdev_get_queuePavel Begunkov2021-10-181-1/+1
| | | | | | | | | Convert bdev->bd_disk->queue to bdev_get_queue(), it's uses a cached queue pointer and so is faster. Signed-off-by: Pavel Begunkov <asml.silence@gmail.com> Link: https://lore.kernel.org/r/addf6ea988c04213697ba3684c853e4ed7642a39.1634219547.git.asml.silence@gmail.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
* block: move blk-throtl fast path inlineJens Axboe2021-10-181-158/+3
| | | | | | | | Even if no policies are defined, we spend ~2% of the total IO time checking. Move the fast path inline. Acked-by: Tejun Heo <tj@kernel.org> Signed-off-by: Jens Axboe <axboe@kernel.dk>
* blk-throttle: fix UAF by deleteing timer in blk_throtl_exit()Li Jinlin2021-09-071-0/+1
| | | | | | | | | | | | | The pending timer has been set up in blk_throtl_init(). However, the timer is not deleted in blk_throtl_exit(). This means that the timer handler may still be running after freeing the timer, which would result in a use-after-free. Fix by calling del_timer_sync() to delete the timer in blk_throtl_exit(). Signed-off-by: Li Jinlin <lijinlin3@huawei.com> Link: https://lore.kernel.org/r/20210907121242.2885564-1-lijinlin3@huawei.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
* blk-throtl: optimize IOPS throttle for large IO scenariosChunguang Xu2021-08-151-0/+32
| | | | | | | | | | | | | | | | | | | | | | | | After patch 54efd50 (block: make generic_make_request handle arbitrarily sized bios), the IO through io-throttle may be larger, and these IOs may be further split into more small IOs. However, IOPS throttle does not seem to be aware of this change, which makes the calculation of IOPS of large IOs incomplete, resulting in disk-side IOPS that does not meet expectations. Maybe we should fix this problem. We can reproduce it by set max_sectors_kb of disk to 128, set blkio.write_iops_throttle to 100, run a dd instance inside blkio and use iostat to watch IOPS: dd if=/dev/zero of=/dev/sdb bs=1M count=1000 oflag=direct As a result, without this change the average IOPS is 1995, with this change the IOPS is 98. Signed-off-by: Chunguang Xu <brookxu@tencent.com> Acked-by: Tejun Heo <tj@kernel.org> Link: https://lore.kernel.org/r/65869aaad05475797d63b4c3fed4f529febe3c26.1627876014.git.brookxu@tencent.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
* block: store a block_device pointer in struct bioChristoph Hellwig2021-01-251-1/+1
| | | | | | | | | | | Replace the gendisk pointer in struct bio with a pointer to the newly improved struct block device. From that the gendisk can be trivially accessed with an extra indirection, but it also allows to directly look up all information related to partition remapping. Signed-off-by: Christoph Hellwig <hch@lst.de> Acked-by: Tejun Heo <tj@kernel.org> Signed-off-by: Jens Axboe <axboe@kernel.dk>
* blk-throttle: don't check whether or not lower limit is valid if ↵Yu Kuai2020-12-021-0/+6
| | | | | | | | | | | | | | | CONFIG_BLK_DEV_THROTTLING_LOW is off blk_throtl_update_limit_valid() will search for descendants to see if 'LIMIT_LOW' of bps/iops and READ/WRITE is nonzero. However, they're always zero if CONFIG_BLK_DEV_THROTTLING_LOW is not set, furthermore, a lot of time will be wasted to iterate descendants. Thus do nothing in blk_throtl_update_limit_valid() in such situation. Signed-off-by: Yu Kuai <yukuai3@huawei.com> Acked-by: Tejun Heo <tj@kernel.org> Signed-off-by: Jens Axboe <axboe@kernel.dk>
* blk-throttle: Re-use the throtl_set_slice_end()Baolin Wang2020-10-081-1/+1
| | | | | | | Re-use throtl_set_slice_end() to remove duplicate code. Signed-off-by: Baolin Wang <baolin.wang@linux.alibaba.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
* blk-throttle: Open code __throtl_de/enqueue_tg()Baolin Wang2020-10-081-17/+9
| | | | | | | | | The __throtl_de/enqueue_tg() functions are only be called by throtl_de/enqueue_tg(), thus we can just open code them to make code more readable. Signed-off-by: Baolin Wang <baolin.wang@linux.alibaba.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
* blk-throttle: Move service tree validation out of the throtl_rb_first()Baolin Wang2020-10-081-4/+5
| | | | | | | | | | | | | The throtl_schedule_next_dispatch() will validate if the service queue is empty before calling update_min_dispatch_time(), and the update_min_dispatch_time() will call throtl_rb_first(), which will validate service queue again. Thus we can move the service queue validation out of the throtl_rb_first() to remove the redundant validation in the fast path. Signed-off-by: Baolin Wang <baolin.wang@linux.alibaba.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
* blk-throttle: Move the list operation after list validationBaolin Wang2020-10-081-2/+4
| | | | | | | We should move the list operation after validation. Signed-off-by: Baolin Wang <baolin.wang@linux.alibaba.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
* blk-throttle: Fix IO hang for a corner caseBaolin Wang2020-10-081-4/+4
| | | | | | | | | It can not scale up in throtl_adjusted_limit() if we set bps or iops is 1, which will cause IO hang when enable low limit. Thus we should treat 1 as a illegal value to avoid this issue. Signed-off-by: Baolin Wang <baolin.wang@linux.alibaba.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
* blk-throttle: Avoid tracking latency if low limit is invalidBaolin Wang2020-10-081-1/+3
| | | | | | | | | The IO latency tracking is only for LOW limit, so we should add a validation to avoid redundant latency tracking if the LOW limit is not valid. Signed-off-by: Baolin Wang <baolin.wang@linux.alibaba.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
* blk-throttle: Avoid getting the current time if tg->last_finish_time is 0Baolin Wang2020-10-081-2/+6
| | | | | | | | | | We only update the tg->last_finish_time when the low limitaion is enabled, so we can move the tg->last_finish_time validation a little forward to avoid getting the unnecessary current time stamp if the the low limitation is not enabled. Signed-off-by: Baolin Wang <baolin.wang@linux.alibaba.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
* blk-throttle: Remove a meaningless parameter for throtl_downgrade_state()Baolin Wang2020-10-081-3/+3
| | | | | | | | | The throtl_downgrade_state() is always used to change to LIMIT_LOW limitation, thus remove the latter meaningless parameter which indicates the limitation index. Signed-off-by: Baolin Wang <baolin.wang@linux.alibaba.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
* blk-throttle: Avoid checking bps/iops limitation if bps or iops is unlimitedBaolin Wang2020-09-151-0/+12
| | | | | | | Do not need check the bps or iops limitation if bps or iops is unlimited. Signed-off-by: Baolin Wang <baolin.wang@linux.alibaba.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
* blk-throttle: Avoid calculating bps/iops limitation repeatedlyBaolin Wang2020-09-151-9/+10
| | | | | | | | | | | | | | | The tg_may_dispatch() will call tg_with_in_bps_limit() and tg_with_in_iops_limit() to check if we can dispatch a bio or not, which will calculate bps/iops limitation multiple times. But tg_may_dispatch() is always called under queue lock, which means the bps/iops limitation will not change in tg_may_dispatch(). So we can calculate the bps/iops limitation only once, and pass them to tg_with_in_bps_limit() and tg_with_in_iops_limit() to avoid calculating bps/iops limitation repeatedly. Signed-off-by: Baolin Wang <baolin.wang@linux.alibaba.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
* blk-throttle: Define readable macros instead of static variablesBaolin Wang2020-09-151-5/+5
| | | | | | | | | The 'throtl_grp_quantum' and 'throtl_quantum' are both read-only variables, thus better to use readable macros instead of static variables, which can also save some spaces for .bss area. Signed-off-by: Baolin Wang <baolin.wang@linux.alibaba.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
* blk-throttle: Use readable READ/WRITE macrosBaolin Wang2020-09-151-2/+2
| | | | | | | Use readable READ/WRITE macros instead of magic numbers. Signed-off-by: Baolin Wang <baolin.wang@linux.alibaba.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
* blk-throttle: Fix some comments' typosBaolin Wang2020-09-151-7/+7
| | | | | | | Fix some comments' typos. Signed-off-by: Baolin Wang <baolin.wang@linux.alibaba.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
* block: rename generic_make_request to submit_bio_noacctChristoph Hellwig2020-07-011-2/+2
| | | | | | | | | generic_make_request has always been very confusingly misnamed, so rename it to submit_bio_noacct to make it clear that it is submit_bio minus accounting and a few checks. Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Jens Axboe <axboe@kernel.dk>
* blk-cgroup: remove a dead check in blk_throtl_bioChristoph Hellwig2020-06-291-1/+1
| | | | | | | | bios must have a valid block group by the time they are submitted. Acked-by: Tejun Heo <tj@kernel.org> Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Jens Axboe <axboe@kernel.dk>
* blk-cgroup: remove blkcg_bio_issue_checkChristoph Hellwig2020-06-291-2/+3
| | | | | | | | | | | | blkcg_bio_issue_check is a giant inline function that does three entirely different things. Factor out the blk-cgroup related bio initalization into a new helper, and the open code the sequence in the only caller, relying on the fact that all the actual functionality is stubbed out for non-cgroup builds. Acked-by: Tejun Heo <tj@kernel.org> Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Jens Axboe <axboe@kernel.dk>
* blk-cgroup: move rcu locking from blkcg_bio_issue_check to blk_throtl_bioChristoph Hellwig2020-06-291-1/+2
| | | | | | | | | The only thing in blkcg_bio_issue_check that needs to be under rcu_read_lock is blk_throtl_bio, so move the locking there. Acked-by: Tejun Heo <tj@kernel.org> Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Jens Axboe <axboe@kernel.dk>
* blk-throttle: remove tg_drain_biosGuoqing Jiang2020-05-301-22/+0
| | | | | | | | After blk_throtl_drain is removed, there is no caller of tg_drain_bios, so remove it as well. Signed-off-by: Guoqing Jiang <guoqing.jiang@cloud.ionos.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
* blk-throttle: remove blk_throtl_drainGuoqing Jiang2020-05-301-41/+0
| | | | | | | | After the commit 5addeae1bedc4 ("blk-cgroup: remove blkcg_drain_queue"), there is no caller of blk_throtl_drain, so let's remove it. Signed-off-by: Guoqing Jiang <guoqing.jiang@cloud.ionos.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
* blk-cgroup: separate out blkg_rwstat under CONFIG_BLK_CGROUP_RWSTATTejun Heo2019-11-071-0/+1
| | | | | | | | | blkg_rwstat is now only used by bfq-iosched and blk-throtl when on cgroup1. Let's move it into its own files and gate it behind a config option. Signed-off-by: Tejun Heo <tj@kernel.org> Signed-off-by: Jens Axboe <axboe@kernel.dk>
* blk-throtl: stop using blkg->stat_bytes and ->stat_iosTejun Heo2019-11-071-9/+61
| | | | | | | | | | | | | When used on cgroup1, blk-throtl uses the blkg->stat_bytes and ->stat_ios from blk-cgroup core to populate four stat knobs. blk-cgroup core is moving away from blkg_rwstat to improve scalability and won't be able to support this usage. It isn't like the sharing gains all that much. Let's break them out to dedicated rwstat counters which are updated when on cgroup1. Signed-off-by: Tejun Heo <tj@kernel.org> Signed-off-by: Jens Axboe <axboe@kernel.dk>
* block: make rq sector size accessible for block statsHou Tao2019-09-161-1/+2
| | | | | | | | | | | | | | | | | | Currently rq->data_len will be decreased by partial completion or zeroed by completion, so when blk_stat_add() is invoked, data_len will be zero and there will never be samples in poll_cb because blk_mq_poll_stats_bkt() will return -1 if data_len is zero. We could move blk_stat_add() back to __blk_mq_complete_request(), but that would make the effort of trying to call ktime_get_ns() once in vain. Instead we can reuse throtl_size field, and use it for both block stats and block throttle, and adjust the logic in blk_mq_poll_stats_bkt() accordingly. Fixes: 4bc6339a583c ("block: move blk_stat_add() to __blk_mq_end_request()") Tested-by: Pavel Begunkov <asml.silence@gmail.com> Signed-off-by: Hou Tao <houtao1@huawei.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
* blkcg: pass @q and @blkcg into blkcg_pol_alloc_pd_fn()Tejun Heo2019-08-291-2/+4
| | | | | | | | | Instead of @node, pass in @q and @blkcg so that the alloc function has more context. This doesn't cause any behavior change and will be used by io.weight implementation. Signed-off-by: Tejun Heo <tj@kernel.org> Signed-off-by: Jens Axboe <axboe@kernel.dk>
* blk-throttle: fix zero wait time for iops throttled groupKonstantin Khlebnikov2019-07-101-6/+3
| | | | | | | | | | | | | | | After commit 991f61fe7e1d ("Blk-throttle: reduce tail io latency when iops limit is enforced") wait time could be zero even if group is throttled and cannot issue requests right now. As a result throtl_select_dispatch() turns into busy-loop under irq-safe queue spinlock. Fix is simple: always round up target time to the next throttle slice. Fixes: 991f61fe7e1d ("Blk-throttle: reduce tail io latency when iops limit is enforced") Signed-off-by: Konstantin Khlebnikov <khlebnikov@yandex-team.ru> Cc: stable@vger.kernel.org # v4.19+ Signed-off-by: Jens Axboe <axboe@kernel.dk>
* block: Fix throtl_pending_timer_fn() kernel-doc headerBart Van Assche2019-05-311-1/+1
| | | | | | | | | | | Commit e99e88a9d2b0 renamed a function argument without updating the corresponding kernel-doc header. Update the kernel-doc header. Reviewed-by: Chaitanya Kulkarni <chiatanya.kulkarni@wdc.com> Reviewed-by: Kees Cook <keescook@chromium.org> Fixes: e99e88a9d2b0 ("treewide: setup_timer() -> timer_setup()") # v4.15. Signed-off-by: Bart Van Assche <bvanassche@acm.org> Signed-off-by: Jens Axboe <axboe@kernel.dk>
* blkcg: consolidate bio_issue_init() to be a part of coreDennis Zhou2018-12-081-8/+0
| | | | | | | | | | | | bio_issue_init among other things initializes the timestamp for an IO. Rather than have this logic handled by policies, this consolidates it to be on the init paths (normal, clone, bounce clone). Signed-off-by: Dennis Zhou <dennis@kernel.org> Acked-by: Tejun Heo <tj@kernel.org> Reviewed-by: Liu Bo <bo.liu@linux.alibaba.com> Reviewed-by: Josef Bacik <josef@toxicpanda.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
* blkcg: associate blkg when associating a deviceDennis Zhou2018-12-081-1/+0
| | | | | | | | | | | | | | | | Previously, blkg association was handled by controller specific code in blk-throttle and blk-iolatency. However, because a blkg represents a relationship between a blkcg and a request_queue, it makes sense to keep the blkg->q and bio->bi_disk->queue consistent. This patch moves association into the bio_set_dev macro(). This should cover the majority of cases where the device is set/changed keeping the two pointers consistent. Fallback code is added to blkcg_bio_issue_check() to catch any missing paths. Signed-off-by: Dennis Zhou <dennis@kernel.org> Reviewed-by: Josef Bacik <josef@toxicpanda.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
* blkcg: introduce common blkg association logicDennis Zhou2018-12-081-3/+3
| | | | | | | | | | | | | | | There are 3 ways blkg association can happen: association with the current css, with the page css (swap), or from the wbc css (writeback). This patch handles how association is done for the first case where we are associating bsaed on the current css. If there is already a blkg associated, the css will be reused and association will be redone as the request_queue may have changed. Signed-off-by: Dennis Zhou <dennis@kernel.org> Reviewed-by: Josef Bacik <josef@toxicpanda.com> Acked-by: Tejun Heo <tj@kernel.org> Signed-off-by: Jens Axboe <axboe@kernel.dk>
* blkcg: convert blkg_lookup_create() to find closest blkgDennis Zhou2018-12-081-3/+1
| | | | | | | | | | | | | | | | | There are several scenarios where blkg_lookup_create() can fail such as the blkcg dying, request_queue is dying, or simply being OOM. Most handle this by simply falling back to the q->root_blkg and calling it a day. This patch implements the notion of closest blkg. During blkg_lookup_create(), if it fails to create, return the closest blkg found or the q->root_blkg. blkg_try_get_closest() is introduced and used during association so a bio is always attached to a blkg. Signed-off-by: Dennis Zhou <dennis@kernel.org> Acked-by: Tejun Heo <tj@kernel.org> Reviewed-by: Josef Bacik <josef@toxicpanda.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
* block: add queue_is_mq() helperJens Axboe2018-11-161-1/+1
| | | | | | | | | | | | | Various spots check for q->mq_ops being non-NULL, but provide a helper to do this instead. Where the ->mq_ops != NULL check is redundant, remove it. Since mq == rq-based now that legacy is gone, get rid of the queue_is_rq_based() and just use queue_is_mq() everywhere. Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Jens Axboe <axboe@kernel.dk>
* block: remove the queue_lock indirectionChristoph Hellwig2018-11-151-11/+11
| | | | | | | | | | | | With the legacy request path gone there is no good reason to keep queue_lock as a pointer, we can always use the embedded lock now. Reviewed-by: Hannes Reinecke <hare@suse.com> Signed-off-by: Christoph Hellwig <hch@lst.de> Fixed floppy and blk-cgroup missing conversions and half done edits. Signed-off-by: Jens Axboe <axboe@kernel.dk>
* block: remove queue_lockdep_assert_heldChristoph Hellwig2018-11-151-1/+0
| | | | | | | | | The only remaining user unconditionally drops and reacquires the lock, which means we really don't need any additional (conditional) annotation. Reviewed-by: Hannes Reinecke <hare@suse.com> Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Jens Axboe <axboe@kernel.dk>
* block: remove QUEUE_FLAG_BYPASS and ->bypassChristoph Hellwig2018-11-151-3/+0
| | | | | | | | Unused since the removal of the legacy request code. Reviewed-by: Hannes Reinecke <hare@suse.com> Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Jens Axboe <axboe@kernel.dk>
* blkcg: revert blkcg cleanups seriesDennis Zhou2018-11-021-1/+12
| | | | | | | | | | | | | | | | | | | | | This reverts a series committed earlier due to null pointer exception bug report in [1]. It seems there are edge case interactions that I did not consider and will need some time to understand what causes the adverse interactions. The original series can be found in [2] with a follow up series in [3]. [1] https://www.spinics.net/lists/cgroups/msg20719.html [2] https://lore.kernel.org/lkml/20180911184137.35897-1-dennisszhou@gmail.com/ [3] https://lore.kernel.org/lkml/20181020185612.51587-1-dennis@kernel.org/ This reverts the following commits: d459d853c2ed, b2c3fa546705, 101246ec02b5, b3b9f24f5fcc, e2b0989954ae, f0fcb3ec89f3, c839e7a03f92, bdc2491708c4, 74b7c02a9bc1, 5bf9a1f3b4ef, a7b39b4e961c, 07b05bcc3213, 49f4c2dc2b50, 27e6fa996c53 Signed-off-by: Dennis Zhou <dennis@kernel.org> Signed-off-by: Jens Axboe <axboe@kernel.dk>
* blkcg: consolidate bio_issue_init to be a part of coreDennis Zhou (Facebook)2018-09-221-8/+0
| | | | | | | | | | | bio_issue_init among other things initializes the timestamp for an IO. Rather than have this logic handled by policies, this consolidates it to be on the init paths (normal, clone, bounce clone). Signed-off-by: Dennis Zhou <dennisszhou@gmail.com> Acked-by: Tejun Heo <tj@kernel.org> Reviewed-by: Liu Bo <bo.liu@linux.alibaba.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
* blkcg: always associate a bio with a blkgDennis Zhou (Facebook)2018-09-221-4/+1
| | | | | | | | | | | | | | | | | Previously, blkg's were only assigned as needed by blk-iolatency and blk-throttle. bio->css was also always being associated while blkg was being looked up and then thrown away in blkcg_bio_issue_check. This patch begins the cleanup of bio->css and bio->bi_blkg by always associating a blkg in blkcg_bio_issue_check. This tries to create the blkg, but if it is not possible, falls back to using the root_blkg of the request_queue. Therefore, a bio will always be associated with a blkg. The duplicate association logic is removed from blk-throttle and blk-iolatency. Signed-off-by: Dennis Zhou <dennisszhou@gmail.com> Acked-by: Tejun Heo <tj@kernel.org> Signed-off-by: Jens Axboe <axboe@kernel.dk>
* Blk-throttle: update to use rbtree with leftmost node cachedLiu Bo2018-09-211-26/+15
| | | | | | | | As rbtree has native support of caching leftmost node, i.e. rb_root_cached, no need to do the caching by ourselves. Signed-off-by: Liu Bo <bo.liu@linux.alibaba.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
* blkcg: use tryget logic when associating a blkg with a bioDennis Zhou (Facebook)2018-08-311-2/+3
| | | | | | | | | | | | | | | | | | | | | There is a very small change a bio gets caught up in a really unfortunate race between a task migration, cgroup exiting, and itself trying to associate with a blkg. This is due to css offlining being performed after the css->refcnt is killed which triggers removal of blkgs that reach their blkg->refcnt of 0. To avoid this, association with a blkg should use tryget and fallback to using the root_blkg. Fixes: 08e18eab0c579 ("block: add bi_blkg to the bio for cgroups") Reviewed-by: Josef Bacik <josef@toxicpanda.com> Signed-off-by: Dennis Zhou <dennisszhou@gmail.com> Cc: Jiufei Xue <jiufei.xue@linux.alibaba.com> Cc: Joseph Qi <joseph.qi@linux.alibaba.com> Cc: Tejun Heo <tj@kernel.org> Cc: Josef Bacik <josef@toxicpanda.com> Cc: Jens Axboe <axboe@kernel.dk> Signed-off-by: Jens Axboe <axboe@kernel.dk>
* Blk-throttle: reduce tail io latency when iops limit is enforcedLiu Bo2018-08-091-6/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | When an application's iops has exceeded its cgroup's iops limit, surely it is throttled and kernel will set a timer for dispatching, thus IO latency includes the delay. However, the dispatch delay which is calculated by the limit and the elapsed jiffies is suboptimal. As the dispatch delay is only calculated once the application's iops is (iops limit + 1), it doesn't need to wait any longer than the remaining time of the current slice. The difference can be proved by the following fio job and cgroup iops setting, ----- $ echo 4 > /mnt/config/nullb/disk1/mbps # limit nullb's bandwidth to 4MB/s for testing. $ echo "253:1 riops=100 rbps=max" > /sys/fs/cgroup/unified/cg1/io.max $ cat r2.job [global] name=fio-rand-read filename=/dev/nullb1 rw=randread bs=4k direct=1 numjobs=1 time_based=1 runtime=60 group_reporting=1 [file1] size=4G ioengine=libaio iodepth=1 rate_iops=50000 norandommap=1 thinktime=4ms ----- wo patch: file1: (g=0): rw=randread, bs=(R) 4096B-4096B, (W) 4096B-4096B, (T) 4096B-4096B, ioengine=libaio, iodepth=1 fio-3.7-66-gedfc Starting 1 process read: IOPS=99, BW=400KiB/s (410kB/s)(23.4MiB/60001msec) slat (usec): min=10, max=336, avg=27.71, stdev=17.82 clat (usec): min=2, max=28887, avg=5929.81, stdev=7374.29 lat (usec): min=24, max=28901, avg=5958.73, stdev=7366.22 clat percentiles (usec): | 1.00th=[ 4], 5.00th=[ 4], 10.00th=[ 4], 20.00th=[ 4], | 30.00th=[ 4], 40.00th=[ 4], 50.00th=[ 6], 60.00th=[11731], | 70.00th=[11863], 80.00th=[11994], 90.00th=[12911], 95.00th=[22676], | 99.00th=[23725], 99.50th=[23987], 99.90th=[23987], 99.95th=[25035], | 99.99th=[28967] w/ patch: file1: (g=0): rw=randread, bs=(R) 4096B-4096B, (W) 4096B-4096B, (T) 4096B-4096B, ioengine=libaio, iodepth=1 fio-3.7-66-gedfc Starting 1 process read: IOPS=100, BW=400KiB/s (410kB/s)(23.4MiB/60005msec) slat (usec): min=10, max=155, avg=23.24, stdev=16.79 clat (usec): min=2, max=12393, avg=5961.58, stdev=5959.25 lat (usec): min=23, max=12412, avg=5985.91, stdev=5951.92 clat percentiles (usec): | 1.00th=[ 3], 5.00th=[ 3], 10.00th=[ 4], 20.00th=[ 4], | 30.00th=[ 4], 40.00th=[ 5], 50.00th=[ 47], 60.00th=[11863], | 70.00th=[11994], 80.00th=[11994], 90.00th=[11994], 95.00th=[11994], | 99.00th=[11994], 99.50th=[11994], 99.90th=[12125], 99.95th=[12125], | 99.99th=[12387] Signed-off-by: Liu Bo <bo.liu@linux.alibaba.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
* block: add bi_blkg to the bio for cgroupsJosef Bacik2018-07-091-14/+7
| | | | | | | | | | | | | | | | | | | | | | | | Currently io.low uses a bi_cg_private to stash its private data for the blkg, however other blkcg policies may want to use this as well. Since we can get the private data out of the blkg, move this to bi_blkg in the bio and make it generic, then we can use bio_associate_blkg() to attach the blkg to the bio. Theoretically we could simply replace the bi_css with this since we can get to all the same information from the blkg, however you have to lookup the blkg, so for example wbc_init_bio() would have to lookup and possibly allocate the blkg for the css it was trying to attach to the bio. This could be problematic and result in us either not attaching the css at all to the bio, or falling back to the root blkcg if we are unable to allocate the corresponding blkg. So for now do this, and in the future if possible we could just replace the bi_css with bi_blkg and update the helpers to do the correct translation. Signed-off-by: Josef Bacik <jbacik@fb.com> Acked-by: Tejun Heo <tj@kernel.org> Signed-off-by: Jens Axboe <axboe@kernel.dk>
* Block: blk-throttle: set low_valid immediately once one cgroup has io.low ↵Liu Bo2018-07-091-1/+3
| | | | | | | | | | configured Once one cgroup has io.low configured, @low_valid becomes true and other cgroups won't switch it back whatsoever. Signed-off-by: Liu Bo <bo.liu@linux.alibaba.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
* blk-throttle: return proper bool type to caller instead of 0/1Chengguang Xu2018-05-301-5/+5
| | | | | | | Change to return true/false only for bool type return code. Signed-off-by: Chengguang Xu <cgxu519@gmx.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
* blk-throttle: fix potential NULL pointer dereference in throtl_select_dispatchLiu Bo2018-05-301-1/+2
| | | | | | | | | | tg in throtl_select_dispatch is used first and then do check. Since tg may be NULL, it has potential NULL pointer dereference risk. So fix it. Signed-off-by: Joseph Qi <joseph.qi@linux.alibaba.com> Signed-off-by: Liu Bo <bo.liu@linux.alibaba.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
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