IO-Uring Archive on lore.kernel.org
 help / color / Atom feed
From: Pavel Begunkov <asml.silence@gmail.com>
To: Jens Axboe <axboe@kernel.dk>, io-uring@vger.kernel.org
Subject: [PATCH 3/4] io_uring: optimise commit_sqring() for common case
Date: Mon, 30 Dec 2019 21:24:46 +0300
Message-ID: <5f61617ff3347304948d46c5257cc52581f527fe.1577729827.git.asml.silence@gmail.com> (raw)
In-Reply-To: <cover.1577729827.git.asml.silence@gmail.com>

It should be pretty rare to not submitting anything when there is
something in the ring. No need to keep heuristics for this case.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
---
 fs/io_uring.c | 14 ++++++--------
 1 file changed, 6 insertions(+), 8 deletions(-)

diff --git a/fs/io_uring.c b/fs/io_uring.c
index 05d07974a5b3..642aca3f2d1f 100644
--- a/fs/io_uring.c
+++ b/fs/io_uring.c
@@ -4506,14 +4506,12 @@ static void io_commit_sqring(struct io_ring_ctx *ctx)
 {
 	struct io_rings *rings = ctx->rings;
 
-	if (ctx->cached_sq_head != READ_ONCE(rings->sq.head)) {
-		/*
-		 * Ensure any loads from the SQEs are done at this point,
-		 * since once we write the new head, the application could
-		 * write new data to them.
-		 */
-		smp_store_release(&rings->sq.head, ctx->cached_sq_head);
-	}
+	/*
+	 * Ensure any loads from the SQEs are done at this point,
+	 * since once we write the new head, the application could
+	 * write new data to them.
+	 */
+	smp_store_release(&rings->sq.head, ctx->cached_sq_head);
 }
 
 /*
-- 
2.24.0


  parent reply index

Thread overview: 6+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-12-30 18:24 [PATCH 0/4] a bunch of changes for submmission path Pavel Begunkov
2019-12-30 18:24 ` [PATCH 1/4] io_uring: clamp to_submit in io_submit_sqes() Pavel Begunkov
2019-12-30 18:24 ` [PATCH 2/4] io_uring: optimise head checks in io_get_sqring() Pavel Begunkov
2019-12-30 18:24 ` Pavel Begunkov [this message]
2019-12-30 18:24 ` [PATCH 4/4] io_uring: remove extra io_wq_current_is_worker() Pavel Begunkov
2019-12-30 22:24 ` [PATCH 0/4] a bunch of changes for submmission path Jens Axboe

Reply instructions:

You may reply publically to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=5f61617ff3347304948d46c5257cc52581f527fe.1577729827.git.asml.silence@gmail.com \
    --to=asml.silence@gmail.com \
    --cc=axboe@kernel.dk \
    --cc=io-uring@vger.kernel.org \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link

IO-Uring Archive on lore.kernel.org

Archives are clonable:
	git clone --mirror https://lore.kernel.org/io-uring/0 io-uring/git/0.git

	# If you have public-inbox 1.1+ installed, you may
	# initialize and index your mirror using the following commands:
	public-inbox-init -V2 io-uring io-uring/ https://lore.kernel.org/io-uring \
		io-uring@vger.kernel.org
	public-inbox-index io-uring

Example config snippet for mirrors

Newsgroup available over NNTP:
	nntp://nntp.lore.kernel.org/org.kernel.vger.io-uring


AGPL code for this site: git clone https://public-inbox.org/public-inbox.git