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authorJens Axboe <axboe@kernel.dk>2021-10-18 10:12:12 -0600
committerJens Axboe <axboe@kernel.dk>2021-10-19 09:21:42 -0600
commitbc490f81731e181b07b8d7577425c06ae91692c8 (patch)
treeabe26a3d3c309e8a5d62e61e50ccd8a13036aebb /block/blk-merge.c
parent480d42dc001bbfe953825a92073012fcd5a99161 (diff)
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block: change plugging to use a singly linked list
Use a singly linked list for the blk_plug. This saves 8 bytes in the blk_plug struct, and makes for faster list manipulations than doubly linked lists. As we don't use the doubly linked lists for anything, singly linked is just fine. This yields a bump in default (merging enabled) performance from 7.0 to 7.1M IOPS, and ~7.5M IOPS with merging disabled. Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Jens Axboe <axboe@kernel.dk>
Diffstat (limited to 'block/blk-merge.c')
-rw-r--r--block/blk-merge.c4
1 files changed, 2 insertions, 2 deletions
diff --git a/block/blk-merge.c b/block/blk-merge.c
index c273b58378ce..3e6fa449caff 100644
--- a/block/blk-merge.c
+++ b/block/blk-merge.c
@@ -1090,11 +1090,11 @@ bool blk_attempt_plug_merge(struct request_queue *q, struct bio *bio,
struct request *rq;
plug = blk_mq_plug(q, bio);
- if (!plug || list_empty(&plug->mq_list))
+ if (!plug || rq_list_empty(plug->mq_list))
return false;
/* check the previously added entry for a quick merge attempt */
- rq = list_last_entry(&plug->mq_list, struct request, queuelist);
+ rq = rq_list_peek(&plug->mq_list);
if (rq->q == q) {
/*
* Only blk-mq multiple hardware queues case checks the rq in