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=-2.2 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, 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 8546CC432C2 for ; Tue, 24 Sep 2019 11:16:02 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 53F59205F4 for ; Tue, 24 Sep 2019 11:16:02 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=kernel-dk.20150623.gappssmtp.com header.i=@kernel-dk.20150623.gappssmtp.com header.b="DM/bGaSF" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2409594AbfIXLQB (ORCPT ); Tue, 24 Sep 2019 07:16:01 -0400 Received: from mail-pl1-f193.google.com ([209.85.214.193]:32979 "EHLO mail-pl1-f193.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2409582AbfIXLQB (ORCPT ); Tue, 24 Sep 2019 07:16:01 -0400 Received: by mail-pl1-f193.google.com with SMTP id d22so881093pls.0 for ; Tue, 24 Sep 2019 04:16:00 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel-dk.20150623.gappssmtp.com; s=20150623; h=subject:to:cc:references:from:message-id:date:user-agent :mime-version:in-reply-to:content-language:content-transfer-encoding; bh=2Gdf6rrJ78JFoK3177iA9xPZfiz710O7xq5kze1mYLg=; b=DM/bGaSF9mTkDWPUrP+tKjpzReekozk0vkcwm/qn5A4/7oLsirebrYcD+OTSGmkuSv z2d9hoyqAZAfu/YYM9y+K5hvJTXv9gJjL1pRBixF2avzT5VnY1jIXwBbvSK2reOHj59m nlmHWqveukUqFqTXlo3lv7CpU5fN40GjlF4IO9jDoez0QDcBxlm+E9UJJx2jMVaqSAj8 hLwTdGi8YYVcyOnXC61izqAfBVs5PGmi5NzDsNT32fP3UlQpieXAhWh2C4OV9j6r62hg ev22L1hfSXGb/4xi+7uKPUXX3TyIpnLlVnZxstl+QzepJeWBP/2MotvhO9sCUSKc4J5X lTfQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:subject:to:cc:references:from:message-id:date :user-agent:mime-version:in-reply-to:content-language :content-transfer-encoding; bh=2Gdf6rrJ78JFoK3177iA9xPZfiz710O7xq5kze1mYLg=; b=Q2ZR9jxRh/mGkSDmC121yc+e6wfqJYeDXQc5epan3iROMvEIXCp99rvS3rx/YfJHSu rIAxQB6Bg8pWz/IQp+o5Lm53LgNKyT7Ylqwcv9rwhlwByfLJWjV7xj3HVd72iwE0btVb P3mChEe7dHeAfaSyPrQXAgGRK/5URkM1EUQgfx3X8nRAjPEDU63LvNE1VWfWOZaArDm5 C9qWHsZ3bc1izKGszr14bhUPrUkvFOdDa2MiqbcJ/Mrj+imV1Gr+ffA2OIMWSH53zXqK J/tm5PG0Dkh1OgBCMyy/RpuKfBf/piryG5ShD6Ch5HN5SWOrnTOodIoTh8za5RsWzVjo aKyA== X-Gm-Message-State: APjAAAVO3A7bSKkn9WJferLGVb3ETV9dYp0eC5v/02B3mfimwvfeHdSK cBZL+LXWNJ3eyws08TolVQuqkMno/PTNug== X-Google-Smtp-Source: APXvYqxwQZmXXwg08lPwE0Q+7ai01Po6hJAh0bDY6pnXE34tW+a5hjtWjo8g12BFudEkOz4yVBz/NA== X-Received: by 2002:a17:902:8207:: with SMTP id x7mr2410456pln.147.1569323759815; Tue, 24 Sep 2019 04:15:59 -0700 (PDT) Received: from ?IPv6:2600:380:8419:743e:a9a6:f93b:f300:79e6? ([2600:380:8419:743e:a9a6:f93b:f300:79e6]) by smtp.gmail.com with ESMTPSA id v3sm2123221pfn.18.2019.09.24.04.15.56 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Tue, 24 Sep 2019 04:15:58 -0700 (PDT) Subject: Re: [PATCH v2 0/2] Optimise io_uring completion waiting To: Pavel Begunkov , Peter Zijlstra Cc: Ingo Molnar , Ingo Molnar , linux-block@vger.kernel.org, linux-kernel@vger.kernel.org References: <20190923083549.GA42487@gmail.com> <731b2087-7786-5374-68ff-8cba42f0cd68@kernel.dk> <759b9b48-1de3-1d43-3e39-9c530bfffaa0@kernel.dk> <43244626-9cfd-0c0b-e7a1-878363712ef3@gmail.com> <20190924094942.GN2349@hirez.programming.kicks-ass.net> <6f935fb9-6ebd-1df1-0cd0-69e34a16fa7e@kernel.dk> <29e6e06e-351f-c19d-ed7c-51f30c9ca887@kernel.dk> <08193e07-6f05-a496-492d-06ed8ce3aea1@gmail.com> From: Jens Axboe Message-ID: Date: Tue, 24 Sep 2019 13:15:52 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.8.0 MIME-Version: 1.0 In-Reply-To: <08193e07-6f05-a496-492d-06ed8ce3aea1@gmail.com> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 9/24/19 5:11 AM, Pavel Begunkov wrote: > On 24/09/2019 13:34, Jens Axboe wrote: >> On 9/24/19 4:13 AM, Jens Axboe wrote: >>> On 9/24/19 3:49 AM, Peter Zijlstra wrote: >>>> On Tue, Sep 24, 2019 at 10:36:28AM +0200, Jens Axboe wrote: >>>> >>>>> +struct io_wait_queue { >>>>> + struct wait_queue_entry wq; >>>>> + struct io_ring_ctx *ctx; >>>>> + struct task_struct *task; >>>> >>>> wq.private is where the normal waitqueue stores the task pointer. >>>> >>>> (I'm going to rename that) >>> >>> If you do that, then we can just base the io_uring parts on that. >> >> Just took a quick look at it, and ran into block/kyber-iosched.c that >> actually uses the private pointer for something that isn't a task >> struct... >> > > Let reuse autoremove_wake_function anyway. Changed a bit your patch: Yep that should do it, and saves 8 bytes of stack as well. BTW, did you test my patch, this one or the previous? Just curious if it worked for you. -- Jens Axboe