From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id D724DC433F5 for ; Mon, 25 Oct 2021 05:38:54 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id C516060F70 for ; Mon, 25 Oct 2021 05:38:54 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229499AbhJYFlP (ORCPT ); Mon, 25 Oct 2021 01:41:15 -0400 Received: from out30-130.freemail.mail.aliyun.com ([115.124.30.130]:47027 "EHLO out30-130.freemail.mail.aliyun.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230091AbhJYFlP (ORCPT ); Mon, 25 Oct 2021 01:41:15 -0400 X-Alimail-AntiSpam: AC=PASS;BC=-1|-1;BR=01201311R101e4;CH=green;DM=||false|;DS=||;FP=0|-1|-1|-1|0|-1|-1|-1;HT=e01e04400;MF=xiaoguang.wang@linux.alibaba.com;NM=1;PH=DS;RN=3;SR=0;TI=SMTPD_---0UtWqHq3_1635140331; Received: from localhost(mailfrom:xiaoguang.wang@linux.alibaba.com fp:SMTPD_---0UtWqHq3_1635140331) by smtp.aliyun-inc.com(127.0.0.1); Mon, 25 Oct 2021 13:38:52 +0800 From: Xiaoguang Wang To: io-uring@vger.kernel.org Cc: axboe@kernel.dk, asml.silence@gmail.com Subject: [PATCH v3 3/3] io_uring: don't get completion_lock in io_poll_rewait() Date: Mon, 25 Oct 2021 13:38:49 +0800 Message-Id: <20211025053849.3139-4-xiaoguang.wang@linux.alibaba.com> X-Mailer: git-send-email 2.17.2 In-Reply-To: <20211025053849.3139-1-xiaoguang.wang@linux.alibaba.com> References: <20211025053849.3139-1-xiaoguang.wang@linux.alibaba.com> Precedence: bulk List-ID: X-Mailing-List: io-uring@vger.kernel.org In current implementation, if there are not available events, io_poll_rewait() just gets completion_lock, and unlocks it in io_poll_task_func() or io_async_task_func(), which isn't necessary. Change this logic to let io_poll_task_func() or io_async_task_func() get the completion_lock lock. Signed-off-by: Xiaoguang Wang --- fs/io_uring.c | 58 ++++++++++++++++++++++++++-------------------------------- 1 file changed, 26 insertions(+), 32 deletions(-) diff --git a/fs/io_uring.c b/fs/io_uring.c index e4c779dac953..41ff8fdafe55 100644 --- a/fs/io_uring.c +++ b/fs/io_uring.c @@ -5248,10 +5248,7 @@ static inline int __io_async_wake(struct io_kiocb *req, struct io_poll_iocb *pol } static bool io_poll_rewait(struct io_kiocb *req, struct io_poll_iocb *poll) - __acquires(&req->ctx->completion_lock) { - struct io_ring_ctx *ctx = req->ctx; - /* req->task == current here, checking PF_EXITING is safe */ if (unlikely(req->task->flags & PF_EXITING)) WRITE_ONCE(poll->canceled, true); @@ -5262,7 +5259,6 @@ static bool io_poll_rewait(struct io_kiocb *req, struct io_poll_iocb *poll) req->result = vfs_poll(req->file, &pt) & poll->events; } - spin_lock(&ctx->completion_lock); if (!req->result && !READ_ONCE(poll->canceled)) { if (req->opcode == IORING_OP_POLL_ADD) WRITE_ONCE(poll->active, true); @@ -5357,35 +5353,34 @@ static void io_poll_task_func(struct io_kiocb *req, bool *locked) { struct io_ring_ctx *ctx = req->ctx; struct io_kiocb *nxt; + bool done; - if (io_poll_rewait(req, &req->poll)) { - spin_unlock(&ctx->completion_lock); - } else { - bool done; + if (io_poll_rewait(req, &req->poll)) + return; - if (req->poll.done) { - spin_unlock(&ctx->completion_lock); - return; - } - done = __io_poll_complete(req, req->result); - if (done) { - io_poll_remove_double(req); - __io_poll_remove_one(req, io_poll_get_single(req), true); - hash_del(&req->hash_node); - req->poll.done = true; - } else { - req->result = 0; - WRITE_ONCE(req->poll.active, true); - } - io_commit_cqring(ctx); + spin_lock(&ctx->completion_lock); + if (req->poll.done) { spin_unlock(&ctx->completion_lock); - io_cqring_ev_posted(ctx); + return; + } + done = __io_poll_complete(req, req->result); + if (done) { + io_poll_remove_double(req); + __io_poll_remove_one(req, io_poll_get_single(req), true); + hash_del(&req->hash_node); + req->poll.done = true; + } else { + req->result = 0; + WRITE_ONCE(req->poll.active, true); + } + io_commit_cqring(ctx); + spin_unlock(&ctx->completion_lock); + io_cqring_ev_posted(ctx); - if (done) { - nxt = io_put_req_find_next(req); - if (nxt) - io_req_task_submit(nxt, locked); - } + if (done) { + nxt = io_put_req_find_next(req); + if (nxt) + io_req_task_submit(nxt, locked); } } @@ -5507,11 +5502,10 @@ static void io_async_task_func(struct io_kiocb *req, bool *locked) trace_io_uring_task_run(req->ctx, req, req->opcode, req->user_data); - if (io_poll_rewait(req, &apoll->poll)) { - spin_unlock(&ctx->completion_lock); + if (io_poll_rewait(req, &apoll->poll)) return; - } + spin_lock(&ctx->completion_lock); hash_del(&req->hash_node); io_poll_remove_double(req); apoll->poll.done = true; -- 2.14.4.44.g2045bb6