blk-mq: prefetch request in blk_mq_tag_to_rq()
authorJens Axboe <axboe@fb.com>
Thu, 25 Aug 2016 14:07:30 +0000 (08:07 -0600)
committerJens Axboe <axboe@fb.com>
Mon, 29 Aug 2016 14:13:21 +0000 (08:13 -0600)
commit88c7b2b75132c3ff8180b71e4f06cf043a00eac8
treefa40cb8073832b2321b3f28a3fd782c125364dfb
parent8d354f133e86dd03ea7885a91df398c55ff699ff
blk-mq: prefetch request in blk_mq_tag_to_rq()

When drivers or the core calls this function, they usually
dereference the request shortly there after. Prefetch the first
cache line.

Profiling IO workloads shows that this is the most common cache
miss on the block side of things.

Signed-off-by: Jens Axboe <axboe@fb.com>
block/blk-mq.c