path: root/block
diff options
authorMing Lei <>2021-05-14 10:20:52 +0800
committerJens Axboe <>2021-05-14 08:59:08 -0600
commit03f26d8f11403295de445b6e4e0e57ac57755791 (patch)
tree1957af73deaa32dff92ead193f1490b798f47f90 /block
parent6bdf2fbc48f104a84606f6165aa8a20d9a7d9074 (diff)
blk-mq: plug request for shared sbitmap
In case of shared sbitmap, request won't be held in plug list any more sine commit 32bc15afed04 ("blk-mq: Facilitate a shared sbitmap per tagset"), this way makes request merge from flush plug list & batching submission not possible, so cause performance regression. Yanhui reports performance regression when running sequential IO test(libaio, 16 jobs, 8 depth for each job) in VM, and the VM disk is emulated with image stored on xfs/megaraid_sas. Fix the issue by recovering original behavior to allow to hold request in plug list. Cc: Yanhui Ma <> Cc: John Garry <> Cc: Bart Van Assche <> Cc: Fixes: 32bc15afed04 ("blk-mq: Facilitate a shared sbitmap per tagset") Signed-off-by: Ming Lei <> Link: Signed-off-by: Jens Axboe <>
Diffstat (limited to 'block')
1 files changed, 3 insertions, 2 deletions
diff --git a/block/blk-mq.c b/block/blk-mq.c
index 466676bc2f0b..28ef0248efba 100644
--- a/block/blk-mq.c
+++ b/block/blk-mq.c
@@ -2232,8 +2232,9 @@ blk_qc_t blk_mq_submit_bio(struct bio *bio)
/* Bypass scheduler for flush requests */
blk_mq_run_hw_queue(data.hctx, true);
- } else if (plug && (q->nr_hw_queues == 1 || q->mq_ops->commit_rqs ||
- !blk_queue_nonrot(q))) {
+ } else if (plug && (q->nr_hw_queues == 1 ||
+ blk_mq_is_sbitmap_shared(rq->mq_hctx->flags) ||
+ q->mq_ops->commit_rqs || !blk_queue_nonrot(q))) {
* Use plugging if we have a ->commit_rqs() hook as well, as
* we know the driver uses bd->last in a smart fashion.