From mboxrd@z Thu Jan 1 00:00:00 1970 Date: Fri, 2 Mar 2007 13:52:43 -0800 From: Andrew Morton Subject: Re: The performance and behaviour of the anti-fragmentation related patches Message-Id: <20070302135243.ada51084.akpm@linux-foundation.org> In-Reply-To: <45E894D7.2040309@redhat.com> References: <20070301101249.GA29351@skynet.ie> <20070301160915.6da876c5.akpm@linux-foundation.org> <45E842F6.5010105@redhat.com> <20070302085838.bcf9099e.akpm@linux-foundation.org> <20070302093501.34c6ef2a.akpm@linux-foundation.org> <45E8624E.2080001@redhat.com> <20070302100619.cec06d6a.akpm@linux-foundation.org> <45E86BA0.50508@redhat.com> <20070302211207.GJ10643@holomorphy.com> <45E894D7.2040309@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org Return-Path: To: Rik van Riel Cc: Bill Irwin , Christoph Lameter , Mel Gorman , npiggin@suse.de, mingo@elte.hu, jschopp@austin.ibm.com, arjan@infradead.org, torvalds@linux-foundation.org, mbligh@mbligh.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org List-ID: On Fri, 02 Mar 2007 16:19:19 -0500 Rik van Riel wrote: > Bill Irwin wrote: > > On Fri, Mar 02, 2007 at 01:23:28PM -0500, Rik van Riel wrote: > >> With 32 CPUs diving into the page reclaim simultaneously, > >> each trying to scan a fraction of memory, this is disastrous > >> for performance. A 256GB system should be even worse. > > > > Thundering herds of a sort pounding the LRU locks from direct reclaim > > have set off the NMI oopser for users here. > > Ditto here. Opterons? > The main reason they end up pounding the LRU locks is the > swappiness heuristic. They scan too much before deciding > that it would be a good idea to actually swap something > out, and with 32 CPUs doing such scanning simultaneously... What kernel version? -- 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