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 X-Spam-Level: X-Spam-Status: No, score=-19.1 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,NICE_REPLY_A,SPF_HELO_NONE,SPF_PASS,UNPARSEABLE_RELAY, USER_AGENT_SANE_1 autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 3CDEEC433F5 for ; Sun, 5 Sep 2021 06:25:12 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 08EAA60F21 for ; Sun, 5 Sep 2021 06:25:12 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231793AbhIEG0N (ORCPT ); Sun, 5 Sep 2021 02:26:13 -0400 Received: from out30-44.freemail.mail.aliyun.com ([115.124.30.44]:41609 "EHLO out30-44.freemail.mail.aliyun.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230339AbhIEG0L (ORCPT ); Sun, 5 Sep 2021 02:26:11 -0400 X-Alimail-AntiSpam: AC=PASS;BC=-1|-1;BR=01201311R851e4;CH=green;DM=||false|;DS=||;FP=0|-1|-1|-1|0|-1|-1|-1;HT=e01e04395;MF=haoxu@linux.alibaba.com;NM=1;PH=DS;RN=4;SR=0;TI=SMTPD_---0UnGCEB0_1630823106; Received: from B-25KNML85-0107.local(mailfrom:haoxu@linux.alibaba.com fp:SMTPD_---0UnGCEB0_1630823106) by smtp.aliyun-inc.com(127.0.0.1); Sun, 05 Sep 2021 14:25:06 +0800 Subject: Re: [PATCH 6/6] io_uring: enable multishot mode for accept To: Pavel Begunkov , Jens Axboe Cc: io-uring@vger.kernel.org, Joseph Qi References: <20210903110049.132958-1-haoxu@linux.alibaba.com> <20210903110049.132958-7-haoxu@linux.alibaba.com> <3cdcd28b-4723-32f8-5a0f-59fab8f4af27@gmail.com> From: Hao Xu Message-ID: <1542ac87-c518-3aa4-55ca-061f2761a1db@linux.alibaba.com> Date: Sun, 5 Sep 2021 14:25:06 +0800 User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.15; rv:78.0) Gecko/20100101 Thunderbird/78.13.0 MIME-Version: 1.0 In-Reply-To: <3cdcd28b-4723-32f8-5a0f-59fab8f4af27@gmail.com> Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: io-uring@vger.kernel.org 在 2021/9/5 上午6:43, Pavel Begunkov 写道: > On 9/3/21 12:00 PM, Hao Xu wrote: >> Update io_accept_prep() to enable multishot mode for accept operation. >> >> Signed-off-by: Hao Xu >> --- >> fs/io_uring.c | 14 ++++++++++++-- >> 1 file changed, 12 insertions(+), 2 deletions(-) >> >> diff --git a/fs/io_uring.c b/fs/io_uring.c >> index eb81d37dce78..34612646ae3c 100644 >> --- a/fs/io_uring.c >> +++ b/fs/io_uring.c >> @@ -4861,6 +4861,7 @@ static int io_recv(struct io_kiocb *req, unsigned int issue_flags) >> static int io_accept_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe) >> { >> struct io_accept *accept = &req->accept; >> + bool is_multishot; >> >> if (unlikely(req->ctx->flags & IORING_SETUP_IOPOLL)) >> return -EINVAL; >> @@ -4872,14 +4873,23 @@ static int io_accept_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe) >> accept->flags = READ_ONCE(sqe->accept_flags); >> accept->nofile = rlimit(RLIMIT_NOFILE); >> >> + is_multishot = accept->flags & IORING_ACCEPT_MULTISHOT; >> + if (is_multishot && (req->flags & REQ_F_FORCE_ASYNC)) >> + return -EINVAL; > > Why REQ_F_FORCE_ASYNC is not allowed? It doesn't sound like there > should be any problem, would just eventually go looping > poll_wait + tw Hmm..The arm_poll facility is only on the io_submit_sqes() path. If FORCE_ASYNC is set, the req goes to io_wq_submit_work-->io_issue_sqe. Moreover, I guess theoretically poll based retry and async iowq are two ways for users to handle their sqes, it may not be sane to go to poll based retry path if a user already forcely choose iowq as their prefer way. > >> + >> accept->file_slot = READ_ONCE(sqe->file_index); >> if (accept->file_slot && ((req->open.how.flags & O_CLOEXEC) || >> - (accept->flags & SOCK_CLOEXEC))) >> + (accept->flags & SOCK_CLOEXEC) || is_multishot)) >> return -EINVAL; >> - if (accept->flags & ~(SOCK_CLOEXEC | SOCK_NONBLOCK)) >> + if (accept->flags & ~(SOCK_CLOEXEC | SOCK_NONBLOCK | IORING_ACCEPT_MULTISHOT)) >> return -EINVAL; >> if (SOCK_NONBLOCK != O_NONBLOCK && (accept->flags & SOCK_NONBLOCK)) >> accept->flags = (accept->flags & ~SOCK_NONBLOCK) | O_NONBLOCK; >> + if (is_multishot) { >> + req->flags |= REQ_F_APOLL_MULTISHOT; >> + accept->flags &= ~IORING_ACCEPT_MULTISHOT; >> + } >> + >> return 0; >> } >> >> >