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 13F0AC2D0C3 for ; Mon, 16 Dec 2019 23:10:36 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id D6A8620CC7 for ; Mon, 16 Dec 2019 23:10:35 +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="A860KQ4K" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727189AbfLPXKf (ORCPT ); Mon, 16 Dec 2019 18:10:35 -0500 Received: from mail-io1-f67.google.com ([209.85.166.67]:33657 "EHLO mail-io1-f67.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726591AbfLPXKe (ORCPT ); Mon, 16 Dec 2019 18:10:34 -0500 Received: by mail-io1-f67.google.com with SMTP id z8so7068452ioh.0 for ; Mon, 16 Dec 2019 15:10:34 -0800 (PST) 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=dCnC/jfvEWt+z7fAdBW+xSdl7SEaUneQSHaq+EB0tW8=; b=A860KQ4K3o5h8+6NmyV0mWqxB7G9iucprwDUlid50DJIt930o0EdvyrIQmDddU8BU/ bII7+rThzGEDdo1NoanT+8dfcEbll4RsPU/2r2erpSocVBIUD8HBJv/ZJ1ydcHCtI1Np V5hqkNOaMZx3TmRNaZ1sCyvu6URHi990RaWsTjZd+axtL0dF6DkRNbqZoRcqmNkY3QEg /8Ycnsxw0i50SdGvYuPFBq+MGZ3yMfzTwU5bQEeG8LS4MaZ+3mbDQgvVmTM7dSPBmjhD lNQlUwedlAFoXrSrY7l3oXi86KE2p/ZLiYZxfh48oTu9MZ9P07dNtHABxC7j6VZJvVAt 3M8g== 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=dCnC/jfvEWt+z7fAdBW+xSdl7SEaUneQSHaq+EB0tW8=; b=gGKBA3TKgYImGA63gweHiUcvOxampnQkVEZu+h4/qdrwalQVLR0oyLWgmdKLY+tHau Z8Fk3Dh8fUziMGeXK7fNBMs1nkCH+7YG0I97xjBpwyX00tcrfy8jG9BLfehm91dUL5DH oWVJsAlpVLrdfOdT+b056OKwOAp7fs731FVTXQ7m4bJgO0oa3tAzOtRyxM1J7g0wIh/s 7x3SudTIKsxqwqxmKudVI/GKFM/xXBwXBA+gawTHJCkZU0burRVk0AaXvcBajADMM1iE tWCfWzwYxB9He1aNH8mbQ2gbg268aq4mytaMh+8a0JLWfodaltNk7Atcsh/mssaWlThY GRKw== X-Gm-Message-State: APjAAAX4zJPIWDi7RAQ9vwGTzTYTsFrLAO+77Ch82sPgvUY8dimcS1An 4SR+sH/r3sYzaZnBp+zyU6bGvg== X-Google-Smtp-Source: APXvYqzbm6Awsl5NFoCXB4S8ZwNWX05gmf9fBekjP0vGzfoTbJRwv3EC4ru2y7C/PxbU2pyATedezQ== X-Received: by 2002:a5d:875a:: with SMTP id k26mr1430389iol.45.1576537833871; Mon, 16 Dec 2019 15:10:33 -0800 (PST) Received: from [192.168.1.159] ([65.144.74.34]) by smtp.gmail.com with ESMTPSA id h71sm6259626ila.30.2019.12.16.15.10.33 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Mon, 16 Dec 2019 15:10:33 -0800 (PST) Subject: Re: [PATCH block/for-5.5-fixes] iocost: over-budget forced IOs should schedule async delay To: Tejun Heo Cc: linux-block@vger.kernel.org, kernel-team@fb.com, linux-kernel@vger.kernel.org, cgroups@vger.kernel.org, Josef Bacik References: <20191216213400.GA2914998@devbig004.ftw2.facebook.com> From: Jens Axboe Message-ID: Date: Mon, 16 Dec 2019 16:10:32 -0700 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.2.2 MIME-Version: 1.0 In-Reply-To: <20191216213400.GA2914998@devbig004.ftw2.facebook.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 12/16/19 2:34 PM, Tejun Heo wrote: > When over-budget IOs are force-issued through root cgroup, > iocg_kick_delay() adjusts the async delay accordingly but doesn't > actually schedule async throttle for the issuing task. This bug is > pretty well masked because sooner or later the offending threads are > gonna get directly throttled on regular IOs or have async delay > scheduled by mem_cgroup_throttle_swaprate(). > > However, it can affect control quality on filesystem metadata heavy > operations. Let's fix it by invoking blkcg_schedule_throttle() when > iocg_kick_delay() says async delay is needed. Applied, thanks Tejun. -- Jens Axboe