From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-wr0-f197.google.com (mail-wr0-f197.google.com [209.85.128.197]) by kanga.kvack.org (Postfix) with ESMTP id 9D2A66B0033 for ; Wed, 25 Oct 2017 23:53:29 -0400 (EDT) Received: by mail-wr0-f197.google.com with SMTP id r79so954233wrb.7 for ; Wed, 25 Oct 2017 20:53:29 -0700 (PDT) Received: from mail-sor-f65.google.com (mail-sor-f65.google.com. [209.85.220.65]) by mx.google.com with SMTPS id 3sor1948873wrv.84.2017.10.25.20.53.27 for (Google Transport Security); Wed, 25 Oct 2017 20:53:27 -0700 (PDT) MIME-Version: 1.0 In-Reply-To: References: <150543458765.3781.10192373650821598320@takondra-t460s> <20170915143619.2ifgex2jxck2xt5u@dhcp22.suse.cz> <150549651001.4512.15084374619358055097@takondra-t460s> <20170918163434.GA11236@cmpxchg.org> From: vinayak menon Date: Thu, 26 Oct 2017 09:23:26 +0530 Message-ID: Subject: Re: Detecting page cache trashing state Content-Type: text/plain; charset="UTF-8" Sender: owner-linux-mm@kvack.org List-ID: To: "Ruslan Ruslichenko -X (rruslich - GLOBALLOGIC INC at Cisco)" Cc: Johannes Weiner , Taras Kondratiuk , Michal Hocko , "linux-mm@kvack.org" , xe-linux-external@cisco.com, linux-kernel@vger.kernel.org On Thu, Sep 28, 2017 at 9:19 PM, Ruslan Ruslichenko -X (rruslich - GLOBALLOGIC INC at Cisco) wrote: > Hi Johannes, > > Hopefully I was able to rebase the patch on top v4.9.26 (latest supported > version by us right now) > and test a bit. > The overall idea definitely looks promising, although I have one question on > usage. > Will it be able to account the time which processes spend on handling major > page faults > (including fs and iowait time) of refaulting page? > > As we have one big application which code space occupies big amount of place > in page cache, > when the system under heavy memory usage will reclaim some of it, the > application will > start constantly thrashing. Since it code is placed on squashfs it spends > whole CPU time > decompressing the pages and seem memdelay counters are not detecting this > situation. > Here are some counters to indicate this: > > 19:02:44 CPU %user %nice %system %iowait %steal %idle > 19:02:45 all 0.00 0.00 100.00 0.00 0.00 0.00 > > 19:02:44 pgpgin/s pgpgout/s fault/s majflt/s pgfree/s pgscank/s > pgscand/s pgsteal/s %vmeff > 19:02:45 15284.00 0.00 428.00 352.00 19990.00 0.00 0.00 > 15802.00 0.00 > > And as nobody actively allocating memory anymore looks like memdelay > counters are not > actively incremented: > > [:~]$ cat /proc/memdelay > 268035776 > 6.13 5.43 3.58 > 1.90 1.89 1.26 > > Just in case, I have attached the v4.9.26 rebased patched. > Looks like this 4.9 version does not contain the accounting in lock_page. -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org