Re: [PATCH v1 3/6] blk-mq: check bio_mergeable() early before merging

From: Jeff Moyer
Date: Mon Oct 19 2015 - 11:12:01 EST


Ming Lei <ming.lei@xxxxxxxxxxxxx> writes:

> It isn't necessary to try to merge the bio which is marked
> as NOMERGE.
>
> Signed-off-by: Ming Lei <ming.lei@xxxxxxxxxxxxx>

Reviewed-by: Jeff Moyer <jmoyer@xxxxxxxxxx>

> ---
> block/blk-mq.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/block/blk-mq.c b/block/blk-mq.c
> index 546b3b8..d55d022 100644
> --- a/block/blk-mq.c
> +++ b/block/blk-mq.c
> @@ -1140,7 +1140,7 @@ 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:
--
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