From: Ming Lei ming.lei@redhat.com
mainline inclusion from mainline-v5.13-rc1 commit 580dca8143d215977811bd2ff881e1e4f6ff39f0 category: performance bugzilla: 187991,https://gitee.com/openeuler/kernel/issues/I66VDN CVE: NA
Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?i...
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Yanhui found that write performance is degraded a lot after applying hctx shared tagset on one test machine with megaraid_sas. And turns out it is caused by none scheduler which becomes default elevator caused by hctx shared tagset patchset.
Given more scsi HBAs will apply hctx shared tagset, and the similar performance exists for them too.
So keep previous behavior by still using default mq-deadline for queues which apply hctx shared tagset, just like before.
Fixes: 32bc15afed04 ("blk-mq: Facilitate a shared sbitmap per tagset") Reported-by: Yanhui Ma yama@redhat.com Cc: John Garry john.garry@huawei.com Cc: Hannes Reinecke hare@suse.de Signed-off-by: Ming Lei ming.lei@redhat.com Reviewed-by: Martin K. Petersen martin.petersen@oracle.com Reviewed-by: Bart Van Assche bvanassche@acm.org Reviewed-by: John Garry john.garry@huawei.com Link: https://lore.kernel.org/r/20210406031933.767228-1-ming.lei@redhat.com Signed-off-by: Jens Axboe axboe@kernel.dk
Conflict: block/elevator.c
Signed-off-by: Zhong Jinghua zhongjinghua@huawei.com Reviewed-by: Hou Tao houtao1@huawei.com Signed-off-by: Zheng Zengkai zhengzengkai@huawei.com --- block/elevator.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/block/elevator.c b/block/elevator.c index 76f70f679a1b..b66afb571e15 100644 --- a/block/elevator.c +++ b/block/elevator.c @@ -630,7 +630,8 @@ static struct elevator_type *elevator_get_default(struct request_queue *q) if (q->tag_set && q->tag_set->flags & BLK_MQ_F_NO_SCHED_BY_DEFAULT) return NULL;
- if (q->nr_hw_queues != 1) + if (q->nr_hw_queues != 1 && + !blk_mq_is_sbitmap_shared(q->tag_set->flags)) return NULL;
return elevator_get(q, "mq-deadline", false);