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=-15.2 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 BED49C433B4 for ; Wed, 28 Apr 2021 06:38:49 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 7F05861420 for ; Wed, 28 Apr 2021 06:38:49 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230490AbhD1GjN (ORCPT ); Wed, 28 Apr 2021 02:39:13 -0400 Received: from out30-45.freemail.mail.aliyun.com ([115.124.30.45]:33566 "EHLO out30-45.freemail.mail.aliyun.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232712AbhD1GjN (ORCPT ); Wed, 28 Apr 2021 02:39:13 -0400 X-Alimail-AntiSpam: AC=PASS;BC=-1|-1;BR=01201311R711e4;CH=green;DM=||false|;DS=||;FP=0|-1|-1|-1|0|-1|-1|-1;HT=e01e04400;MF=haoxu@linux.alibaba.com;NM=1;PH=DS;RN=4;SR=0;TI=SMTPD_---0UX2Q1dq_1619591907; Received: from B-25KNML85-0107.local(mailfrom:haoxu@linux.alibaba.com fp:SMTPD_---0UX2Q1dq_1619591907) by smtp.aliyun-inc.com(127.0.0.1); Wed, 28 Apr 2021 14:38:27 +0800 Subject: Re: [PATCH 5.13] io_uring: don't set IORING_SQ_NEED_WAKEUP when sqthread is dying From: Hao Xu To: Pavel Begunkov , Jens Axboe Cc: io-uring@vger.kernel.org, Joseph Qi References: <1619527526-103300-1-git-send-email-haoxu@linux.alibaba.com> <24c7503d-769f-953e-854f-5090b4bfca3b@gmail.com> <68ce18b8-7bbd-f655-c745-f7cfaac76457@linux.alibaba.com> Message-ID: Date: Wed, 28 Apr 2021 14:38:26 +0800 User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.15; rv:78.0) Gecko/20100101 Thunderbird/78.9.1 MIME-Version: 1.0 In-Reply-To: <68ce18b8-7bbd-f655-c745-f7cfaac76457@linux.alibaba.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 2021/4/27 下午10:35, Hao Xu 写道: > 在 2021/4/27 下午9:13, Pavel Begunkov 写道: >> On 4/27/21 1:45 PM, Hao Xu wrote: >>> we don't need to re-fork the sqthread over exec, so no need to set >>> IORING_SQ_NEED_WAKEUP when sqthread is dying. >> >> It forces users to call io_uring_enter() for it to return >> -EOWNERDEAD. Consider that scenario with the ring given >> away to some other task not in current group, e.g. via socket. >> > Ah, I see. Thank you Pavel. Here I've a question: for processes that aren't in same group, io_uring is now designed that sqthread cannot be shared between these processes? But It seems if users do fork(), they can still call io_uring_enter() in the forked task? >> if (ctx->flags & IORING_SETUP_SQPOLL) { >>     io_cqring_overflow_flush(ctx, false); >> >>     ret = -EOWNERDEAD; >>     if (unlikely(ctx->sq_data->thread == NULL)) { >>         goto out; >>     } >>     ... >> } >> >> btw, can use a comment >> >>> >>> Signed-off-by: Hao Xu >>> --- >>>   fs/io_uring.c | 2 -- >>>   1 file changed, 2 deletions(-) >>> >>> diff --git a/fs/io_uring.c b/fs/io_uring.c >>> index 6b578c380e73..92dcd1c21516 100644 >>> --- a/fs/io_uring.c >>> +++ b/fs/io_uring.c >>> @@ -6897,8 +6897,6 @@ static int io_sq_thread(void *data) >>>       io_uring_cancel_sqpoll(sqd); >>>       sqd->thread = NULL; >>> -    list_for_each_entry(ctx, &sqd->ctx_list, sqd_list) >>> -        io_ring_set_wakeup_flag(ctx); >>>       io_run_task_work(); >>>       io_run_task_work_head(&sqd->park_task_work); >>>       mutex_unlock(&sqd->lock); >>> >>