From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from psmtp.com (na3sys010amx124.postini.com [74.125.245.124]) by kanga.kvack.org (Postfix) with SMTP id 21C236B002B for ; Thu, 8 Nov 2012 23:22:14 -0500 (EST) Received: from /spool/local by e34.co.us.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted for from ; Thu, 8 Nov 2012 21:22:13 -0700 Received: from d03relay03.boulder.ibm.com (d03relay03.boulder.ibm.com [9.17.195.228]) by d03dlp01.boulder.ibm.com (Postfix) with ESMTP id 7FBF7C40003 for ; Thu, 8 Nov 2012 21:22:07 -0700 (MST) Received: from d03av01.boulder.ibm.com (d03av01.boulder.ibm.com [9.17.195.167]) by d03relay03.boulder.ibm.com (8.13.8/8.13.8/NCO v10.0) with ESMTP id qA94M9IQ243780 for ; Thu, 8 Nov 2012 21:22:09 -0700 Received: from d03av01.boulder.ibm.com (loopback [127.0.0.1]) by d03av01.boulder.ibm.com (8.14.4/8.13.1/NCO v10.0 AVout) with ESMTP id qA94M8SS005269 for ; Thu, 8 Nov 2012 21:22:09 -0700 Message-ID: <509C84ED.8090605@linux.vnet.ibm.com> Date: Thu, 08 Nov 2012 22:22:05 -0600 From: Seth Jennings MIME-Version: 1.0 Subject: Re: kswapd0: excessive CPU usage References: <507688CC.9000104@suse.cz> <106695.1349963080@turing-police.cc.vt.edu> <5076E700.2030909@suse.cz> <118079.1349978211@turing-police.cc.vt.edu> <50770905.5070904@suse.cz> <119175.1349979570@turing-police.cc.vt.edu> <5077434D.7080008@suse.cz> <50780F26.7070007@suse.cz> <20121012135726.GY29125@suse.de> <507BDD45.1070705@suse.cz> <20121015110937.GE29125@suse.de> <5093A3F4.8090108@redhat.com> <5093A631.5020209@suse.cz> <509422C3.1000803@suse.cz> In-Reply-To: <509422C3.1000803@suse.cz> Content-Type: text/plain; charset=ISO-8859-15 Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org List-ID: To: Jiri Slaby Cc: Mel Gorman , Zdenek Kabelac , Valdis.Kletnieks@vt.edu, Jiri Slaby , linux-mm@kvack.org, LKML , Andrew Morton , Rik van Riel , Robert Jennings On 11/02/2012 02:45 PM, Jiri Slaby wrote: > On 11/02/2012 11:53 AM, Jiri Slaby wrote: >> On 11/02/2012 11:44 AM, Zdenek Kabelac wrote: >>>>> Yes, applying this instead of the revert fixes the issue as well. >>> >>> I've applied this patch on 3.7.0-rc3 kernel - and I still see excessive >>> CPU usage - mainly after suspend/resume >>> >>> Here is just simple kswapd backtrace from running kernel: >> >> Yup, this is what we were seeing with the former patch only too. Try to >> apply the other one too: >> https://patchwork.kernel.org/patch/1673231/ >> >> For me I would say, it is fixed by the two patches now. I won't be able >> to report later, since I'm leaving to a conference tomorrow. > > Damn it. It recurred right now, with both patches applied. After I > started a java program which consumed some more memory. Though there are > still 2 gigs free, kswap is spinning: > [] __cond_resched+0x2a/0x40 > [] shrink_slab+0x1c0/0x2d0 > [] kswapd+0x66d/0xb60 > [] kthread+0xc0/0xd0 > [] ret_from_fork+0x7c/0xb0 > [] 0xffffffffffffffff I'm also hitting this issue in v3.7-rc4. It appears that the last release not effected by this issue was v3.3. Bisecting the changes included for v3.4-rc1 showed that this commit introduced the issue: fe2c2a106663130a5ab45cb0e3414b52df2fff0c is the first bad commit commit fe2c2a106663130a5ab45cb0e3414b52df2fff0c Author: Rik van Riel Date: Wed Mar 21 16:33:51 2012 -0700 vmscan: reclaim at order 0 when compaction is enabled ... This is plausible since the issue seems to be in the kswapd + compaction realm. I've yet to figure out exactly what about this commit results in kswapd spinning. I would be interested if someone can confirm this finding. -- Seth -- 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