From: Keith Busch Date: Fri, 14 Nov 2025 18:31:45 +0000 (-0800) Subject: block: consider discard merge last X-Git-Tag: v6.19-rc1~168^2~44 X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=2516c246d01c23a5f5310e9ac78d9f8aad9b1d0e;p=thirdparty%2Fkernel%2Flinux.git block: consider discard merge last If the next discard range is contiguous with the current range being considered, it's cheaper to expand the current range than to append an additional bio. Signed-off-by: Keith Busch Reviewed-by: Chaitanya Kulkarni Signed-off-by: Jens Axboe --- diff --git a/block/blk-merge.c b/block/blk-merge.c index d3115d7469df0..db08bc9060916 100644 --- a/block/blk-merge.c +++ b/block/blk-merge.c @@ -712,10 +712,10 @@ static void blk_account_io_merge_request(struct request *req) static enum elv_merge blk_try_req_merge(struct request *req, struct request *next) { - if (blk_discard_mergable(req)) - return ELEVATOR_DISCARD_MERGE; - else if (blk_rq_pos(req) + blk_rq_sectors(req) == blk_rq_pos(next)) + if (blk_rq_pos(req) + blk_rq_sectors(req) == blk_rq_pos(next)) return ELEVATOR_BACK_MERGE; + else if (blk_discard_mergable(req)) + return ELEVATOR_DISCARD_MERGE; return ELEVATOR_NO_MERGE; } @@ -903,12 +903,12 @@ bool blk_rq_merge_ok(struct request *rq, struct bio *bio) enum elv_merge blk_try_merge(struct request *rq, struct bio *bio) { - if (blk_discard_mergable(rq)) - return ELEVATOR_DISCARD_MERGE; - else if (blk_rq_pos(rq) + blk_rq_sectors(rq) == bio->bi_iter.bi_sector) + if (blk_rq_pos(rq) + blk_rq_sectors(rq) == bio->bi_iter.bi_sector) return ELEVATOR_BACK_MERGE; else if (blk_rq_pos(rq) - bio_sectors(bio) == bio->bi_iter.bi_sector) return ELEVATOR_FRONT_MERGE; + else if (blk_discard_mergable(rq)) + return ELEVATOR_DISCARD_MERGE; return ELEVATOR_NO_MERGE; }