From: Jens Axboe <axboe@kernel.dk>
Date: Tue, 19 Oct 2021 15:32:59 +0000 (-0600)
Subject: block: prefetch request to be initialized
X-Git-Url: http://git.maquefel.me/?a=commitdiff_plain;h=92aff191cc5b15a56d10a7a1a0b4bc5f6e17fcf3;p=linux.git

block: prefetch request to be initialized

Now we have the tags available in __blk_mq_alloc_requests_batch(), we
can start fetching the first request cacheline before calling into the
request initialization.

Signed-off-by: Jens Axboe <axboe@kernel.dk>
Link: https://lore.kernel.org/r/20211019153300.623322-4-axboe@kernel.dk
Signed-off-by: Jens Axboe <axboe@kernel.dk>
---

diff --git a/block/blk-mq.c b/block/blk-mq.c
index e881e12a2691e..7cdb10f96aa6c 100644
--- a/block/blk-mq.c
+++ b/block/blk-mq.c
@@ -405,6 +405,7 @@ __blk_mq_alloc_requests_batch(struct blk_mq_alloc_data *data,
 	for (i = 0; tag_mask; i++) {
 		if (!(tag_mask & (1UL << i)))
 			continue;
+		prefetch(tags->static_rqs[tag]);
 		tag = tag_offset + i;
 		tag_mask &= ~(1UL << i);
 		rq = blk_mq_rq_ctx_init(data, tags, tag, alloc_time_ns);