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=-5.2 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,NICE_REPLY_A,SPF_HELO_NONE, SPF_PASS,UNPARSEABLE_RELAY,USER_AGENT_SANE_1 autolearn=no 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 4AC53C433F5 for ; Sun, 19 Sep 2021 16:10:19 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 17FED610A8 for ; Sun, 19 Sep 2021 16:10:19 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231255AbhISQLn (ORCPT ); Sun, 19 Sep 2021 12:11:43 -0400 Received: from out30-44.freemail.mail.aliyun.com ([115.124.30.44]:36465 "EHLO out30-44.freemail.mail.aliyun.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229933AbhISQLm (ORCPT ); Sun, 19 Sep 2021 12:11:42 -0400 X-Alimail-AntiSpam: AC=PASS;BC=-1|-1;BR=01201311R191e4;CH=green;DM=||false|;DS=||;FP=0|-1|-1|-1|0|-1|-1|-1;HT=e01e04407;MF=haoxu@linux.alibaba.com;NM=1;PH=DS;RN=4;SR=0;TI=SMTPD_---0Uot2qWO_1632067814; Received: from 192.168.31.215(mailfrom:haoxu@linux.alibaba.com fp:SMTPD_---0Uot2qWO_1632067814) by smtp.aliyun-inc.com(127.0.0.1); Mon, 20 Sep 2021 00:10:15 +0800 Subject: Re: [PATCH 5/5] io_uring: leverage completion cache for poll requests From: Hao Xu To: Pavel Begunkov , Jens Axboe Cc: io-uring@vger.kernel.org, Joseph Qi References: <20210917193820.224671-1-haoxu@linux.alibaba.com> <20210917193820.224671-6-haoxu@linux.alibaba.com> <2ab8efb5-7927-cf1a-a1af-f4955f7d94f6@linux.alibaba.com> <166dc3e2-6eea-8354-ef12-07df49ec5aaf@gmail.com> <80237936-9a85-fd65-2b36-724d6caa279d@linux.alibaba.com> Message-ID: <3b49c202-9dc9-10f9-08db-f524f894b46b@linux.alibaba.com> Date: Mon, 20 Sep 2021 00:10:14 +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: <80237936-9a85-fd65-2b36-724d6caa279d@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 2021/9/19 下午11:52, Hao Xu 写道: > 在 2021/9/19 下午8:04, Pavel Begunkov 写道: >> On 9/18/21 7:11 AM, Hao Xu wrote: >>> 在 2021/9/18 上午4:39, Pavel Begunkov 写道: >>>> On 9/17/21 8:38 PM, Hao Xu wrote: >>>>> Leverage completion cache to handle completions of poll requests in a >>>>> batch. >>>>> Good thing is we save compl_nr - 1 completion_lock and >>>>> io_cqring_ev_posted. >>>>> Bad thing is compl_nr extra ifs in flush_completion. >>>> >>>> It does something really wrong breaking all abstractions, we can't go >>>> with this. Can we have one of those below? >>>> - __io_req_complete(issue_flags), forwarding issue_flags from above >>>> - or maybe io_req_task_complete(), if we're in tw >>> Make sense. we may need to remove io_clean_op logic in >> >>> io_req_complete_state(), multishot reqs shouldn't do it, and it's ok for >>> normal reqs since we do it later in __io_submit_flush_completions-> >>> io_req_free_batch->io_dismantle_req->io_clean_op, correct me if I'm >>> wrong. >> >> req->compl.cflags is in the first 64B, i.e. aliased with req->rw and >> others. We need to clean everything left in there before using the >> space, that's what io_clean_op() there is for > True, and that's why we souldn't do it for multishot reqs, since they > are not completed yet, and we won't reuse the req resource until its > final completion. I see what you are saying now..yes, we shouldn't remove that io_clean_op there. >>