From mboxrd@z Thu Jan 1 00:00:00 1970 From: Peter Zijlstra Subject: Re: [15/17] SLUB: Support virtual fallback via SLAB_VFALLBACK Date: Fri, 28 Sep 2007 20:25:50 +0200 Message-ID: <1191003950.18147.85.camel@lappy> References: <20070919033605.785839297@sgi.com> <20070919033643.763818012@sgi.com> <200709280742.38262.nickpiggin@yahoo.com.au> <1191002119.18147.80.camel@lappy> Mime-Version: 1.0 Content-Type: text/plain Content-Transfer-Encoding: 7bit Cc: Nick Piggin , Christoph Hellwig , Mel Gorman , linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, David Chinner , Jens Axboe To: Christoph Lameter Return-path: Received: from pentafluge.infradead.org ([213.146.154.40]:45670 "EHLO pentafluge.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751797AbXI1SaS (ORCPT ); Fri, 28 Sep 2007 14:30:18 -0400 In-Reply-To: Sender: linux-fsdevel-owner@vger.kernel.org List-Id: linux-fsdevel.vger.kernel.org On Fri, 2007-09-28 at 11:20 -0700, Christoph Lameter wrote: > > start 2 processes that each mmap a separate 64M file, and which does > > sequential writes on them. start a 3th process that does the same with > > 64M anonymous. > > > > wait for a while, and you'll see order=1 failures. > > Really? That means we can no longer even allocate stacks for forking. > > Its surprising that neither lumpy reclaim nor the mobility patches can > deal with it? Lumpy reclaim should be able to free neighboring pages to > avoid the order 1 failure unless there are lots of pinned pages. > > I guess then that lots of pages are pinned through I/O? memory got massively fragemented, as anti-frag gets easily defeated. setting min_free_kbytes to 12M does seem to solve it - it forces 2 max order blocks to stay available, so we don't mix types. however 12M on 128M is rather a lot. its still on my todo list to look at it further..