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=-2.4 required=3.0 tests=DKIM_SIGNED, MAILING_LIST_MULTI,SPF_PASS,T_DKIM_INVALID,URIBL_BLOCKED,USER_AGENT_MUTT 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 EF95DC3279B for ; Mon, 2 Jul 2018 21:14:04 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 9C61924E2F for ; Mon, 2 Jul 2018 21:14:04 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="eYX166Fp" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 9C61924E2F Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=kernel.org Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753388AbeGBVOC (ORCPT ); Mon, 2 Jul 2018 17:14:02 -0400 Received: from mail-yb0-f195.google.com ([209.85.213.195]:45593 "EHLO mail-yb0-f195.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753087AbeGBVOA (ORCPT ); Mon, 2 Jul 2018 17:14:00 -0400 Received: by mail-yb0-f195.google.com with SMTP id h127-v6so5609261ybg.12; Mon, 02 Jul 2018 14:14:00 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=sender:date:from:to:cc:subject:message-id:references:mime-version :content-disposition:in-reply-to:user-agent; bh=7/6lZy8CsUNIIIhuX98vCeKoNgj0huEvr8rgBZq2pwg=; b=eYX166FpSypCS3ugz2utPN7fdWlg1PAlNN0+g15O0RQeq8a3B/+RTP2iVVvBzxkCoJ EfipudezyG/6nXgcT3tOg6kh1MaU8ZSHqrCKGI7wwYJ+cCTJ+lRKIip/sLVGLhZ9Ir7D 2HseFKxlRMFMX1tpO6TPX9Zq3tfGXkNgUGU+F34G90x4EpHK/V7WccT6TE5xrMCapPPt hoNKh2MG45jzGbaPGm714agavzpiSU86xk2+zcI8Cyl/C6Sk0Ht2/OrNUfePxYVdnsBJ 5A8R0N9NktkYhRUnRhVXehgbJs3lgGMAJ+8BXpPB9ZZDRZJRCfOjP8bVpSGSDOdYeqr8 syuw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:sender:date:from:to:cc:subject:message-id :references:mime-version:content-disposition:in-reply-to:user-agent; bh=7/6lZy8CsUNIIIhuX98vCeKoNgj0huEvr8rgBZq2pwg=; b=kTTFhh0tS7g7anQP8w4nBV46koewWMQnqNTPyLmRH4/bSFFrqz4B1qyVD/mPsCmdBh b4AyEO7z8Hfpu4iGgIeTxaroQMCCTQL7o7tFijr04hb6Qo2bTUelb0F5w2v53AJeKytv M2EaOC/91u2L8IH8zJIXNLzaqImdTGM3ItTKfxopRVKwQiXyEPKK+l9vUKHExCIxtusJ eOjGJ2aLc9bfHggZUm0awxyasTletpNCKlkvdo/YrxC+7BbQ0GkGEGUs2P3hDDt6i66D btDWFw4477RAHntffEIdWnC0xvx7dVBzacJOoUbKqSQ8oX7gbAMlTYpIluOfXJlgro7A uEpA== X-Gm-Message-State: APt69E1XSeugC0Cgim7mGngG7Gzbmoool/zoTCLHl+iPTb9Y97a2MIAg YObqYJ3Qa+gYszbidsCxisc= X-Google-Smtp-Source: AAOMgpeawQYAmQqtjw7RLwZP9Px5svHjU4WOegMCnxLVtBGDweQug4N+DegFze4SJFSfQjKUXJ0V+g== X-Received: by 2002:a25:6e54:: with SMTP id j81-v6mr8861944ybc.430.1530566039900; Mon, 02 Jul 2018 14:13:59 -0700 (PDT) Received: from localhost ([2620:10d:c091:200::2b6f]) by smtp.gmail.com with ESMTPSA id q131-v6sm9151328ywq.8.2018.07.02.14.13.58 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Mon, 02 Jul 2018 14:13:59 -0700 (PDT) Date: Mon, 2 Jul 2018 14:13:57 -0700 From: Tejun Heo To: Josef Bacik Cc: axboe@kernel.dk, kernel-team@fb.com, linux-block@vger.kernel.org, akpm@linux-foundation.org, hannes@cmpxchg.org, linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org, Josef Bacik Subject: Re: [PATCH 14/14] skip readahead if the cgroup is congested Message-ID: <20180702211357.GN533219@devbig577.frc2.facebook.com> References: <20180629192542.26649-1-josef@toxicpanda.com> <20180629192542.26649-15-josef@toxicpanda.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20180629192542.26649-15-josef@toxicpanda.com> User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, Jun 29, 2018 at 03:25:42PM -0400, Josef Bacik wrote: > From: Josef Bacik > > We noticed in testing we'd get pretty bad latency stalls under heavy > pressure because read ahead would try to do its thing while the cgroup > was under severe pressure. If we're under this much pressure we want to > do as little IO as possible so we can still make progress on real work > if we're a throttled cgroup, so just skip readahead if our group is > under pressure. > > Signed-off-by: Josef Bacik Acked-by: Tejun Heo Thanks. -- tejun