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=-2.5 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_PASS,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 4D86FC282CA for ; Sun, 27 Jan 2019 16:00:32 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 1EBD92148D for ; Sun, 27 Jan 2019 16:00:32 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726766AbfA0QAa (ORCPT ); Sun, 27 Jan 2019 11:00:30 -0500 Received: from atrey.karlin.mff.cuni.cz ([195.113.26.193]:46803 "EHLO atrey.karlin.mff.cuni.cz" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726313AbfA0QAa (ORCPT ); Sun, 27 Jan 2019 11:00:30 -0500 Received: by atrey.karlin.mff.cuni.cz (Postfix, from userid 512) id 2F557806E1; Sun, 27 Jan 2019 17:00:21 +0100 (CET) Date: Sun, 27 Jan 2019 17:00:27 +0100 From: Pavel Machek To: Mel Gorman Cc: valdis.kletnieks@vt.edu, kernel list , Andrew Morton , vbabka@suse.cz, aarcange@redhat.com, rientjes@google.com, mhocko@kernel.org, zi.yan@cs.rutgers.edu, hannes@cmpxchg.org, jack@suse.cz Subject: Re: [regression -next0117] What is kcompactd and why is he eating 100% of my cpu? Message-ID: <20190127160027.GA9340@amd> References: <20190126200005.GB27513@amd> <12171.1548557813@turing-police.cc.vt.edu> <20190127141556.GB9565@techsingularity.net> MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="3V7upXqbjpZ4EhLz" Content-Disposition: inline In-Reply-To: <20190127141556.GB9565@techsingularity.net> User-Agent: Mutt/1.5.23 (2014-03-12) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org --3V7upXqbjpZ4EhLz Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable Hi! > > > top - 13:38:51 up 1:42, 16 users, load average: 1.41, 1.93, 1.62 > > > Tasks: 182 total, 3 running, 138 sleeping, 0 stopped, 0 zombie > > > %Cpu(s): 2.3 us, 57.8 sy, 0.0 ni, 39.9 id, 0.0 wa, 0.0 hi, 0.0 s= i, 0.0 st > > > KiB Mem: 3020044 total, 2429420 used, 590624 free, 27468 buff= ers > > > KiB Swap: 2097148 total, 0 used, 2097148 free. 1924268 cach= ed Mem > > > > > > PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ C= OMMAND > > > 608 root 20 0 0 0 0 R 99.6 0.0 11:34.38 k= compactd0 > > > 9782 root 20 0 0 0 0 I 7.9 0.0 0:59.02 k= worker/0: > > > 2971 root 20 0 46624 23076 13576 S 4.3 0.8 2:50.22 X= org > >=20 > > I've noticed this as well on earlier kernels (next-20181224 to 20190115) > >=20 > > Some more info: > >=20 > > 1) echo 3 > /proc/sys/vm/drop_caches unwedges kcompactd in 1-3 seconds. > >=20 >=20 > This aspect is curious as it indicates that kcompactd could potentially > be infinite looping but it's not something I've experienced myself. By > any chance is there a preditable reproduction case for this? I seen it exactly once, so not sure how reproducible this is. x86-32 machine, running chromium browser, so yes, there was some swapping involved. Pavel --=20 (english) http://www.livejournal.com/~pavelmachek (cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blo= g.html --3V7upXqbjpZ4EhLz Content-Type: application/pgp-signature; name="signature.asc" Content-Description: Digital signature -----BEGIN PGP SIGNATURE----- Version: GnuPG v1 iEYEARECAAYFAlxN1ZoACgkQMOfwapXb+vJuTgCgwpjtZ7XQM8ZpFRDsMQ0d1STa ojoAoKnruHRBMNcofPvK9++RZExVUG6O =7i05 -----END PGP SIGNATURE----- --3V7upXqbjpZ4EhLz--