Re: [PATCH 2/4] block: avoid to merge splitted bio

From: Jeff Moyer
Date: Thu Oct 15 2015 - 11:15:51 EST


Ming Lei <ming.lei@xxxxxxxxxxxxx> writes:

> The splitted bio has been already too fat to merge, so mark it
> as NOMERGE.
>
> Signed-off-by: Ming Lei <ming.lei@xxxxxxxxxxxxx>

Reviewed-by: Jeff Moyer <jmoyer@xxxxxxxxxx>

> ---
> block/blk-merge.c | 3 +++
> 1 file changed, 3 insertions(+)
>
> diff --git a/block/blk-merge.c b/block/blk-merge.c
> index 22293fd..de5716d8 100644
> --- a/block/blk-merge.c
> +++ b/block/blk-merge.c
> @@ -139,6 +139,9 @@ void blk_queue_split(struct request_queue *q, struct bio **bio,
> bio_set_flag(res, BIO_SEG_VALID);
>
> if (split) {
> + /* there isn't chance to merge the splitted bio */
> + split->bi_rw |= REQ_NOMERGE;
> +
> bio_chain(split, *bio);
> generic_make_request(*bio);
> *bio = split;
--
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