Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755556AbXI1Slc (ORCPT ); Fri, 28 Sep 2007 14:41:32 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1754649AbXI1SlV (ORCPT ); Fri, 28 Sep 2007 14:41:21 -0400 Received: from netops-testserver-3-out.sgi.com ([192.48.171.28]:56070 "EHLO relay.sgi.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1754746AbXI1SlT (ORCPT ); Fri, 28 Sep 2007 14:41:19 -0400 Date: Fri, 28 Sep 2007 11:41:18 -0700 (PDT) From: Christoph Lameter X-X-Sender: clameter@schroedinger.engr.sgi.com To: Peter Zijlstra cc: Nick Piggin , Christoph Hellwig , Mel Gorman , linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, David Chinner , Jens Axboe Subject: Re: [15/17] SLUB: Support virtual fallback via SLAB_VFALLBACK In-Reply-To: <1191003950.18147.85.camel@lappy> Message-ID: References: <20070919033605.785839297@sgi.com> <20070919033643.763818012@sgi.com> <200709280742.38262.nickpiggin@yahoo.com.au> <1191002119.18147.80.camel@lappy> <1191003950.18147.85.camel@lappy> MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1075 Lines: 23 On Fri, 28 Sep 2007, Peter Zijlstra wrote: > 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. Yes, strict ordering would be much better. On NUMA it may be possible to completely forbid merging. We can fall back to other nodes if necessary. 12M is not much on a NUMA system. But this shows that (unsurprisingly) we may have issues on systems with a small amounts of memory and we may not want to use higher orders on such systems. The case you got may be good to use as a testcase for the virtual fallback. Hmmmm... Maybe it is possible to allocate the stack as a virtual compound page. Got some script/code to produce that problem? - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/