Ming Lei <ming....@canonical.com> writes:
> It isn't necessary to try to merge the bio which is marked
> as NOMERGE.
>
> Signed-off-by: Ming Lei <ming....@canonical.com>
> ---
> block/blk-mq.c | 5 ++++-
> 1 file changed, 4 insertions(+), 1 deletion(-)
>
> diff --git a/block/blk-mq.c b/block/blk-mq.c
> index 546b3b8..deb5f4c 100644
> --- a/block/blk-mq.c
> +++ b/block/blk-mq.c
> @@ -671,6 +671,9 @@ static bool blk_mq_attempt_merge(struct request_queue *q,
> struct request *rq;
> int checked = 8;
>
> + if (!bio_mergeable(bio))
> + return false;
> +
> list_for_each_entry_reverse(rq, &ctx->rq_list, queuelist) {
> int el_ret;
>
> @@ -1140,7 +1143,7 @@ static inline bool blk_mq_merge_queue_io(struct
> blk_mq_hw_ctx *hctx,
> struct blk_mq_ctx *ctx,
> struct request *rq, struct bio *bio)
> {
> - if (!hctx_allow_merges(hctx)) {
> + if (!hctx_allow_merges(hctx) || !bio_mergeable(bio)) {
> blk_mq_bio_to_request(rq, bio);
> spin_lock(&ctx->lock);
> insert_rq:
blk_mq_attempt_merge is only called from blk_mq_merge_queue_io. So, by
adding the conditional in blk_mq_merge_queue_io, you don't need any
change in blk_mq_attempt_merge.
Also, why haven't you updated the non-multiqueue code paths similarly?
Cheers,
Jeff
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