| Message ID | 20230209031930.27354-1-xni@redhat.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | [1/1] block: Merge bio before checking ->cached_rq | expand |
On Thu, Feb 09, 2023 at 11:19:30AM +0800, Xiao Ni wrote: > It checks if plug->cached_rq is empty before merging bio. But the merge action > doesn't have relationship with plug->cached_rq, it trys to merge bio with > requests within plug->mq_list. Now it checks if ->cached_rq is empty before > merging bio. If it's empty, it will miss the merge chances. So move the merge > function before checking ->cached_rq. > > Signed-off-by: Xiao Ni <xni@redhat.com> > --- > block/blk-mq.c | 7 ++++--- > 1 file changed, 4 insertions(+), 3 deletions(-) Looks fine, Reviewed-by: Ming Lei <ming.lei@redhat.com> Thanks, Ming
On Thu, 09 Feb 2023 11:19:30 +0800, Xiao Ni wrote: > It checks if plug->cached_rq is empty before merging bio. But the merge action > doesn't have relationship with plug->cached_rq, it trys to merge bio with > requests within plug->mq_list. Now it checks if ->cached_rq is empty before > merging bio. If it's empty, it will miss the merge chances. So move the merge > function before checking ->cached_rq. > > > [...] Applied, thanks! [1/1] block: Merge bio before checking ->cached_rq commit: 23f3e3272e7a4d9fb870485cd6df1e4f9539282c Best regards,
diff --git a/block/blk-mq.c b/block/blk-mq.c index 9c8dc70020bc..63bd7a34fe6f 100644 --- a/block/blk-mq.c +++ b/block/blk-mq.c @@ -2894,15 +2894,16 @@ static inline struct request *blk_mq_get_cached_request(struct request_queue *q, if (!plug) return NULL; - rq = rq_list_peek(&plug->cached_rq); - if (!rq || rq->q != q) - return NULL; if (blk_mq_attempt_bio_merge(q, *bio, nsegs)) { *bio = NULL; return NULL; } + rq = rq_list_peek(&plug->cached_rq); + if (!rq || rq->q != q) + return NULL; + type = blk_mq_get_hctx_type((*bio)->bi_opf); hctx_type = rq->mq_hctx->type; if (type != hctx_type &&
It checks if plug->cached_rq is empty before merging bio. But the merge action doesn't have relationship with plug->cached_rq, it trys to merge bio with requests within plug->mq_list. Now it checks if ->cached_rq is empty before merging bio. If it's empty, it will miss the merge chances. So move the merge function before checking ->cached_rq. Signed-off-by: Xiao Ni <xni@redhat.com> --- block/blk-mq.c | 7 ++++--- 1 file changed, 4 insertions(+), 3 deletions(-)