- 21 Feb, 2022 17 commits
-
-
Mike Snitzer authored
Where possible, switch from early bio-based IO accounting (at the time DM clones each incoming bio) to late IO accounting just before each remapped bio is issued to underlying device via submit_bio_noacct(). Allows more precise bio-based IO accounting for DM targets that use their own workqueues to perform additional processing of each bio in conjunction with their DM_MAPIO_SUBMITTED return from their map function. When a target is updated to use dm_submit_bio_remap() they must also set ti->accounts_remapped_io to true. Use xchg() in start_io_acct(), as suggested by Mikulas, to ensure each IO is only started once. The xchg race only happens if __send_duplicate_bios() sends multiple bios -- that case is reflected via tio->is_duplicate_bio. Given the niche nature of this race, it is best to avoid any xchg performance penalty for normal IO. For IO that was never submitted with dm_bio_submit_remap(), but the target completes the clone with bio_endio, accounting is started then ended and pending_io counter decremented. Reviewed-by:
Mikulas Patocka <mpatocka@redhat.com> Signed-off-by:
Mike Snitzer <snitzer@redhat.com>
-
Mike Snitzer authored
Formally disallow dm_accept_partial_bio() on clones created by __send_duplicate_bios() because their len_ptr points to a shared unsigned int. __send_duplicate_bios() is only used for flush bios and other "abnormal" bios (discards, writezeroes, etc). And dm_accept_partial_bio() already didn't support flush bios. Also refactor __send_changing_extent_only() to reflect it cannot fail. As such __send_changing_extent_only() can update the clone_info before __send_duplicate_bios() is called to fan-out __map_bio() calls. Reviewed-by:
-
Mike Snitzer authored
Remove one 4 byte hole in dm_io struct. Remove two 4 byte holes in dm_target_io struct. Reviewed-by:
-
Mike Snitzer authored
Suggested-by:
Christoph Hellwig <hch@lst.de> Reviewed-by:
-
Mike Snitzer authored
Prep for being able to defer trace_block_bio_remap() until when the bio is remapped and submitted by the DM target. Reviewed-by:
-
Mike Snitzer authored
Commit 8615cb65 ("dm: remove useless loop in __split_and_process_bio") showcased that we no longer loop. Remove the bio_advance() in __split_and_process_bio() that was only needed when looping was possible. Similarly there is no need to advance the bio, using ci->sector cursor, in __send_duplicate_bios(). Reviewed-by:
-
Mike Snitzer authored
Reviewed-by:
-
Mike Snitzer authored
The flush_bio in question was just initialized to be empty, so there is no way bio_has_data() will return true. So remove stale BUG_ON(). Reviewed-by:
-
Mike Snitzer authored
Error path code (for handling DM_MAPIO_REQUEUE and DM_MAPIO_KILL) is effectively identical. Reviewed-by:
-
Mike Snitzer authored
Remove needless branching and indentation. Leaves code to catch malformed op_is_zone_mgmt bios (they shouldn't have a payload). Reviewed-by:
-
Mike Snitzer authored
Fold __clone_and_map_data_bio into its only caller. Reviewed-by:
-
Mike Snitzer authored
Rename __split_and_process_bio to dm_split_and_process_bio. Rename __split_and_process_non_flush to __split_and_process_bio. Also fix a stale comment and whitespace. Reviewed-by:
-
Mike Snitzer authored
Improves alignment and groups related members relative to cachelines. Signed-off-by: -
Mike Snitzer authored
There is no need for dm_io_dec_pending() to copy dm_io fields anymore now that DM provides its own pending_io counters again. The race documented in commit d208b894 ("dm: fix mempool NULL pointer race when completing IO") no longer exists now that block core's in_flight counters aren't used to signal all dm_io is complete. Also, rename {start,end}_io_acct to dm_{start,end}_io_acct. Signed-off-by:
-
Mike Snitzer authored
dm_stats_account_io()'s STAT_PRECISE_TIMESTAMPS support doesn't handle the fact that with commit b879f915 ("dm: properly fix redundant bio-based IO accounting") io->start_time _may_ be in the past (meaning the start_io_acct() was deferred until later). Add a new dm_stats_recalc_precise_timestamps() helper that will set/clear a new 'precise_timestamps' flag in the dm_stats struct based on whether any configured stats enable STAT_PRECISE_TIMESTAMPS. And update DM core's alloc_io() to use dm_stats_record_start() to set stats_aux.duration_ns if stats->precise_timestamps is true. Also, remove unused 'last_sector' and 'last_rw' members from the dm_stats struct. Fixes: b879f915 ("dm: properly fix redundant bio-based IO accounting") Cc: stable@vger.kernel.org Co-developed-by:
-
Mike Snitzer authored
DM handles a flush with data by first issuing an empty flush and then once it completes the REQ_PREFLUSH flag is removed and the payload is issued. The problem fixed by this commit is that both the empty flush bio and the data payload will account the full extent of the data payload. Fix this by factoring out dm_io_acct() and having it wrap all IO accounting to set the size of bio with REQ_PREFLUSH to 0, account the IO, and then restore the original size. Cc: stable@vger.kernel.org Signed-off-by: -
Mike Snitzer authored
Commit d208b894 ("dm: fix mempool NULL pointer race when completing IO") didn't go far enough. When bio_end_io_acct ends the count of in-flight I/Os may reach zero and the DM device may be suspended. There is a possibility that the suspend races with dm_stats_account_io. Fix this by adding percpu "pending_io" counters to track outstanding dm_io. Move kicking of suspend queue to dm_io_dec_pending(). Also, rename md_in_flight_bios() to dm_in_flight_bios() and update it to iterate all pending_io counters. Fixes: d208b894 ("dm: fix mempool NULL pointer race when completing IO") Cc: stable@vger.kernel.org Co-developed-by:
-
- 17 Feb, 2022 20 commits
-
-
Yahu Gao authored
The return value is ioprio * BFQ_WEIGHT_CONVERSION_COEFF or 0. What we want is ioprio or 0. Correct this by changing the calculation. Signed-off-by:
Yahu Gao <gaoyahu19@gmail.com> Acked-by:
Paolo Valente <paolo.valente@linaro.org> Link: https://lore.kernel.org/r/20220107065859.25689-1-gaoyahu19@gmail.comSigned-off-by:
Jens Axboe <axboe@kernel.dk>
-
David Jeffery authored
When blk_mq_delay_run_hw_queues sets an hctx to run in the future, it can reset the delay length for an already pending delayed work run_work. This creates a scenario where multiple hctx may have their queues set to run, but if one runs first and finds nothing to do, it can reset the delay of another hctx and stall the other hctx's ability to run requests. To avoid this I/O stall when an hctx's run_work is already pending, leave it untouched to run at its current designated time rather than extending its delay. The work will still run which keeps closed the race calling blk_mq_delay_run_hw_queues is needed for while also avoiding the I/O stall. Signed-off-by:
David Jeffery <djeffery@redhat.com> Reviewed-by:
Ming Lei <ming.lei@redhat.com> Link: https://lore.kernel.org/r/20220131203337.GA17666@redhatSigned-off-by:
-
Christoph Hellwig authored
Implement the ->free_disk method to free the virtio_blk structure only once the last gendisk reference goes away instead of keeping a local refcount. Signed-off-by:
Stefan Hajnoczi <stefanha@redhat.com> Acked-by:
Michael S. Tsirkin <mst@redhat.com> Link: https://lore.kernel.org/r/20220215094514.3828912-6-hch@lst.deSigned-off-by:
-
Christoph Hellwig authored
Implement the ->free_disk method to free the msb_data structure only once the last gendisk reference goes away instead of keeping a local refcount. Signed-off-by:
-
Christoph Hellwig authored
Use set_disk_ro to propagate the read-only state to the block layer instead of checking for it in ->open and leaking a reference in case of a read-only device. Signed-off-by:
-
Christoph Hellwig authored
Implement the ->free_disk method to free the msb_data structure only once the last gendisk reference goes away instead of keeping a local refcount. Signed-off-by:
-
Christoph Hellwig authored
Add a method to notify the driver that the gendisk is about to be freed. This allows drivers to tie the lifetime of their private data to that of the gendisk and thus deal with device removal races without expensive synchronization and boilerplate code. A new flag is added so that ->free_disk is only called after a successful call to add_disk, which significantly simplifies the error handling path during probing. Signed-off-by:
-
Ming Lei authored
Revert commit 4f1e9630 ("blk-throtl: optimize IOPS throttle for large IO scenarios") since we have another easier way to address this issue and get better iops throttling result. Acked-by:
Tejun Heo <tj@kernel.org> Signed-off-by:
-
Ming Lei authored
We need to throttle split bio in case of IOPS limit even though the split bio has been marked as BIO_THROTTLED since block layer accounts split bio actually. If only throughput throttle is setup, no need to throttle any more if BIO_THROTTLED is set since we have accounted & considered the whole bio bytes already. Add one flag of THROTL_TG_HAS_IOPS_LIMIT for serving this purpose. Acked-by:
-
Ming Lei authored
Commit 111be883 ("block-throttle: avoid double charge") marks bio as BIO_THROTTLED unconditionally if __blk_throtl_bio() is called on this bio, then this bio won't be called into __blk_throtl_bio() any more. This way is to avoid double charge in case of bio splitting. It is reasonable for read/write throughput limit, but not reasonable for IOPS limit because block layer provides io accounting against split bio. Chunguang Xu has already observed this issue and fixed it in commit 4f1e9630 ("blk-throtl: optimize IOPS throttle for large IO scenarios"). However, that patch only covers bio splitting in __blk_queue_split(), and we have other kind of bio splitting, such as bio_split() & submit_bio_noacct() and other ways. This patch tries to fix the issue in one generic way by always charging the bio for iops limit in blk_throtl_bio(). This way is reasonable: re-submission & fast-cloned bio is charged if it is submitted to same disk/queue, and BIO_THROTTLED will be cleared if bio->bi_bdev is changed. This new approach can get much more smooth/stable iops limit compared with commit 4f1e9630 ("blk-throtl: optimize IOPS throttle for large IO scenarios") since that commit can't throttle current split bios actually. Also this way won't cause new double bio iops charge in blk_throtl_dispatch_work_fn() in which blk_throtl_bio() won't be called any more. Reported-by:
Ning Li <lining2020x@163.com> Acked-by:
-
Ming Lei authored
Now submit_bio_checks() is only called by submit_bio_noacct(), so merge it into submit_bio_noacct(). Suggested-by:
Chaitanya Kulkarni <kch@nvidia.com> Link: https://lore.kernel.org/r/20220216044514.2903784-6-ming.lei@redhat.comSigned-off-by:
-
Ming Lei authored
The bio has been checked already before throttling, so no need to check it again before dispatching it from throttle queue. Add a helper of submit_bio_noacct_nocheck() for this purpose. Signed-off-by:
-
Ming Lei authored
submit_bio_checks() won't be called outside of block/blk-core.c any more since commit 9d497e29 ("block: don't protect submit_bio_checks by q_usage_counter"), so mark it as one local helper. Reviewed-by:
-
Ming Lei authored
blk_crypto_bio_prep() is called for both bio based and blk-mq drivers, so move it out of blk-mq.c, then we can unify this kind of handling. Reviewed-by:
-
Ming Lei authored
It is more clean & readable to check bio when starting to submit it, instead of just before calling ->submit_bio() or blk_mq_submit_bio(). Also it provides us chance to optimize bio submission without checking bio. Reviewed-by:
-
Christoph Hellwig authored
Fold dm_dispatch_clone_request into it's only caller, and use a switch statement to single dispatch for the handling of the different return values from blk_insert_cloned_request. Signed-off-by:
-
Christoph Hellwig authored
Both ->start_time_ns and the RQF_IO_STAT are set when the request is allocated using blk_mq_alloc_request by dm-mpath in blk_mq_rq_ctx_init. The block layer also ensures ->start_time_ns is only set when actually needed. Signed-off-by:
-
Christoph Hellwig authored
The request must be submitted to the queue it was allocated for, so remove the extra request_queue argument. Signed-off-by:
-
Christoph Hellwig authored
Fold blk_cloned_rq_check_limits into its only caller. Signed-off-by:
-
Christoph Hellwig authored
The code to stack blk-mq drivers is only used by dm-multipath, and will preferably stay that way. Make it optional and only selected by device mapper, so that the buildbots more easily catch abuses like the one that slipped in in the ufs driver in the last merged window. Another positive side effects is that kernel builds without device mapper shrink a little bit as well. Signed-off-by:
-
- 15 Feb, 2022 3 commits
-
-
Chengming Zhou authored
Don't need to do blkg_iostat_set for top blkg iostat on each CPU, so move it after percpu stat aggregation. Fixes: ef45fe47 ("blk-cgroup: show global disk stats in root cgroup io.stat") Signed-off-by:
Chengming Zhou <zhouchengming@bytedance.com> Acked-by:
-
Chaitanya Kulkarni authored
Based on the comment present in the bdev_get_queue() bdev->bd_queue can never be NULL. Remove the NULL check for the local variable q that is set from bdev_get_queue() for discard, write_same, and write_zeroes. Signed-off-by:
-
Christoph Hellwig authored
This document is completely out of date and extremely misleading. In general the existing kerneldoc comment serve as a much better documentation of the still existing functionality, while the history blurbs are pretty much irrelevant today. Signed-off-by:
Johannes Thumshirn <johannes.thumshirn@wdc.com> Link: https://lore.kernel.org/r/20220215081047.3693582-1-hch@lst.deSigned-off-by:
-
