From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: 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 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> Sender: linux-fsdevel-owner@vger.kernel.org List-ID: 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