From 64a75a4e0dd7a4f26110e84912933205242d0928 Mon Sep 17 00:00:00 2001 From: John Garry Date: Wed, 2 Nov 2022 15:36:27 +0800 Subject: [PATCH] blk-mq: Relocate shared sbitmap resize in blk_mq_update_nr_requests() mainline inclusion from mainline-v5.16-rc1 commit 8fa044640f128c0cd015f72cda42989a664889fc category: performance bugzilla: 186917, https://gitee.com/openeuler/kernel/issues/I5N1S5 CVE: NA Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=8fa044640f128c0cd015f72cda42989a664889fc -------------------------------- For shared sbitmap, if the call to blk_mq_tag_update_depth() was successful for any hctx when hctx->sched_tags is not set, then it would be successful for all (due to nature in which blk_mq_tag_update_depth() fails). As such, there is no need to call blk_mq_tag_resize_shared_sbitmap() for each hctx. So relocate the call until after the hctx iteration under the !q->elevator check, which is equivalent (to !hctx->sched_tags). Signed-off-by: John Garry Reviewed-by: Ming Lei Reviewed-by: Hannes Reinecke Link: https://lore.kernel.org/r/1633429419-228500-4-git-send-email-john.garry@huawei.com Signed-off-by: Jens Axboe Signed-off-by: Yu Kuai Reviewed-by: Yu Kuai Reviewed-by: Jason Yan Signed-off-by: Zheng Zengkai --- block/blk-mq.c | 12 +++++++----- 1 file changed, 7 insertions(+), 5 deletions(-) diff --git a/block/blk-mq.c b/block/blk-mq.c index 2c2e82163d3b..0f75b7baa026 100644 --- a/block/blk-mq.c +++ b/block/blk-mq.c @@ -3767,8 +3767,6 @@ int blk_mq_update_nr_requests(struct request_queue *q, unsigned int nr) if (!hctx->sched_tags) { ret = blk_mq_tag_update_depth(hctx, &hctx->tags, nr, false); - if (!ret && blk_mq_is_sbitmap_shared(set->flags)) - blk_mq_tag_resize_shared_sbitmap(set, nr); } else { ret = blk_mq_tag_update_depth(hctx, &hctx->sched_tags, nr, true); @@ -3786,9 +3784,13 @@ int blk_mq_update_nr_requests(struct request_queue *q, unsigned int nr) } if (!ret) { q->nr_requests = nr; - if (q->elevator && blk_mq_is_sbitmap_shared(set->flags)) - sbitmap_queue_resize(&q->sched_bitmap_tags, - nr - set->reserved_tags); + if (blk_mq_is_sbitmap_shared(set->flags)) { + if (q->elevator) + sbitmap_queue_resize(&q->sched_bitmap_tags, + nr - set->reserved_tags); + else + blk_mq_tag_resize_shared_sbitmap(set, nr); + } } blk_mq_unquiesce_queue(q); -- GitLab