From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-wr0-f200.google.com (mail-wr0-f200.google.com [209.85.128.200]) by kanga.kvack.org (Postfix) with ESMTP id B7B116B0253 for ; Mon, 18 Sep 2017 12:34:44 -0400 (EDT) Received: by mail-wr0-f200.google.com with SMTP id b9so1004856wra.3 for ; Mon, 18 Sep 2017 09:34:44 -0700 (PDT) Received: from gum.cmpxchg.org (gum.cmpxchg.org. [85.214.110.215]) by mx.google.com with ESMTPS id q7si3593524edl.274.2017.09.18.09.34.43 for (version=TLS1_2 cipher=ECDHE-RSA-CHACHA20-POLY1305 bits=256/256); Mon, 18 Sep 2017 09:34:43 -0700 (PDT) Date: Mon, 18 Sep 2017 09:34:34 -0700 From: Johannes Weiner Subject: Re: Detecting page cache trashing state Message-ID: <20170918163434.GA11236@cmpxchg.org> References: <150543458765.3781.10192373650821598320@takondra-t460s> <20170915143619.2ifgex2jxck2xt5u@dhcp22.suse.cz> <150549651001.4512.15084374619358055097@takondra-t460s> MIME-Version: 1.0 Content-Type: multipart/mixed; boundary="xHFwDpU9dbj6ez1V" Content-Disposition: inline In-Reply-To: <150549651001.4512.15084374619358055097@takondra-t460s> Sender: owner-linux-mm@kvack.org List-ID: To: Taras Kondratiuk Cc: Michal Hocko , linux-mm@kvack.org, xe-linux-external@cisco.com, Ruslan Ruslichenko , linux-kernel@vger.kernel.org --xHFwDpU9dbj6ez1V Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Hi Taras, On Fri, Sep 15, 2017 at 10:28:30AM -0700, Taras Kondratiuk wrote: > Quoting Michal Hocko (2017-09-15 07:36:19) > > On Thu 14-09-17 17:16:27, Taras Kondratiuk wrote: > > > Has somebody faced similar issue? How are you solving it? > > > > Yes this is a pain point for a _long_ time. And we still do not have a > > good answer upstream. Johannes has been playing in this area [1]. > > The main problem is that our OOM detection logic is based on the ability > > to reclaim memory to allocate new memory. And that is pretty much true > > for the pagecache when you are trashing. So we do not know that > > basically whole time is spent refaulting the memory back and forth. > > We do have some refault stats for the page cache but that is not > > integrated to the oom detection logic because this is really a > > non-trivial problem to solve without triggering early oom killer > > invocations. > > > > [1] http://lkml.kernel.org/r/20170727153010.23347-1-hannes@cmpxchg.org > > Thanks Michal. memdelay looks promising. We will check it. Great, I'm obviously interested in more users of it :) Please find attached the latest version of the patch series based on v4.13. It needs a bit more refactoring in the scheduler bits before resubmission, but it already contains a couple of fixes and improvements since the first version I sent out. Let me know if you need help rebasing to a different kernel version. --xHFwDpU9dbj6ez1V Content-Type: text/x-diff; charset=us-ascii Content-Disposition: attachment; filename="0001-sched-loadavg-consolidate-LOAD_INT-LOAD_FRAC-macros.patch" --xHFwDpU9dbj6ez1V--