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=-7.5 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 698FEC4338F for ; Wed, 25 Aug 2021 15:38:52 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 3DC0F6109E for ; Wed, 25 Aug 2021 15:38:52 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233573AbhHYPjh (ORCPT ); Wed, 25 Aug 2021 11:39:37 -0400 Received: from out30-131.freemail.mail.aliyun.com ([115.124.30.131]:40459 "EHLO out30-131.freemail.mail.aliyun.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232625AbhHYPjh (ORCPT ); Wed, 25 Aug 2021 11:39:37 -0400 X-Alimail-AntiSpam: AC=PASS;BC=-1|-1;BR=01201311R151e4;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_---0UlsgCvf_1629905929; Received: from B-25KNML85-0107.local(mailfrom:haoxu@linux.alibaba.com fp:SMTPD_---0UlsgCvf_1629905929) by smtp.aliyun-inc.com(127.0.0.1); Wed, 25 Aug 2021 23:38:49 +0800 Subject: Re: [PATCH] io_uring: don't free request to slab To: Pavel Begunkov , Jens Axboe Cc: io-uring@vger.kernel.org, Joseph Qi References: <20210825114003.231641-1-haoxu@linux.alibaba.com> <03767556-ac49-b550-6e73-3b00b3b66753@gmail.com> From: Hao Xu Message-ID: <2157392c-5bdc-c5bd-cce9-c9c8ac1fe165@linux.alibaba.com> Date: Wed, 25 Aug 2021 23:38:49 +0800 User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.15; rv:78.0) Gecko/20100101 Thunderbird/78.12.0 MIME-Version: 1.0 In-Reply-To: <03767556-ac49-b550-6e73-3b00b3b66753@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 2021/8/25 下午9:28, Pavel Begunkov 写道: > On 8/25/21 12:40 PM, Hao Xu wrote: >> It's not neccessary to free the request back to slab when we fail to >> get sqe, just update state->free_reqs pointer. > > It's a bit hackish because depends on the request being drawn > from the array in a particular way. How about returning it It seems a req is always allocated from state->reqs, so it should be ok? I actually didn't understand 'hackish' here, do you mean io_submit_sqes() shouldn't move state->free_reqs which is req caches' internal implementation? > into state->free_list. That thing is as cold as it can get, > only buggy apps can hit it. >