From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail138.messagelabs.com (mail138.messagelabs.com [216.82.249.35]) by kanga.kvack.org (Postfix) with SMTP id 896598D0039 for ; Thu, 10 Feb 2011 05:41:14 -0500 (EST) Date: Thu, 10 Feb 2011 11:41:11 +0100 From: Michal Hocko Subject: Re: [patch] vmscan: fix zone shrinking exit when scan work is done Message-ID: <20110210104111.GD26653@tiehlicka.suse.cz> References: <20110209154606.GJ27110@cmpxchg.org> <20110209164656.GA1063@csn.ul.ie> <20110209182846.GN3347@random.random> <20110210102109.GB17873@csn.ul.ie> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20110210102109.GB17873@csn.ul.ie> Sender: owner-linux-mm@kvack.org List-ID: To: Mel Gorman Cc: Andrea Arcangeli , Johannes Weiner , Andrew Morton , Rik van Riel , Kent Overstreet , linux-mm@kvack.org, linux-kernel@vger.kernel.org On Thu 10-02-11 10:21:10, Mel Gorman wrote: > On Wed, Feb 09, 2011 at 07:28:46PM +0100, Andrea Arcangeli wrote: > > On Wed, Feb 09, 2011 at 04:46:56PM +0000, Mel Gorman wrote: > > > On Wed, Feb 09, 2011 at 04:46:06PM +0100, Johannes Weiner wrote: > > > > Hi, > > > > > > > > I think this should fix the problem of processes getting stuck in > > > > reclaim that has been reported several times. > > > > > > I don't think it's the only source but I'm basing this on seeing > > > constant looping in balance_pgdat() and calling congestion_wait() a few > > > weeks ago that I haven't rechecked since. However, this looks like a > > > real fix for a real problem. > > > > Agreed. Just yesterday I spent some time on the lumpy compaction > > changes after wondering about Michal's khugepaged 100% report, and I > > expected some fix was needed in this area (as I couldn't find any bug > > in khugepaged yet, so the lumpy compaction looked the next candidate > > for bugs). > > > > Michal did report that disabling defrag did not help but the stack trace > also showed that it was stuck in shrink_zone() which is what Johannes' > patch targets. It's not unreasonable to test if Johannes' patch solves > Michal's problem. Michal, I know that your workload is a bit random and > may not be reproducible but do you think it'd be possible to determine > if Johannes' patch helps? Sure, I can test it. Nevertheless, I haven't seen the problem again. I have tried to make some memory pressure on the machine but no "luck". -- Michal Hocko SUSE Labs SUSE LINUX s.r.o. Lihovarska 1060/12 190 00 Praha 9 Czech Republic -- 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/ . Fight unfair telecom internet charges in Canada: sign http://stopthemeter.ca/ Don't email: email@kvack.org