From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail191.messagelabs.com (mail191.messagelabs.com [216.82.242.19]) by kanga.kvack.org (Postfix) with ESMTP id 372706B003D for ; Mon, 14 Dec 2009 11:19:53 -0500 (EST) Date: Mon, 14 Dec 2009 17:19:44 +0100 From: Andi Kleen Subject: Re: [PATCH] vmscan: limit concurrent reclaimers in shrink_zone Message-ID: <20091214161944.GB16474@basil.fritz.box> References: <20091210185626.26f9828a@cuia.bos.redhat.com> <87pr6hya86.fsf@basil.nowhere.org> <1260800599.6666.4.camel@dhcp-100-19-198.bos.redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1260800599.6666.4.camel@dhcp-100-19-198.bos.redhat.com> Sender: owner-linux-mm@kvack.org To: Larry Woodman Cc: Andi Kleen , Rik van Riel , kosaki.motohiro@jp.fujitsu.com, akpm@linux-foundation.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, aarcange@redhat.com List-ID: On Mon, Dec 14, 2009 at 09:23:19AM -0500, Larry Woodman wrote: > On Mon, 2009-12-14 at 14:08 +0100, Andi Kleen wrote: > > Rik van Riel writes: > > > > > +max_zone_concurrent_reclaim: > > > + > > > +The number of processes that are allowed to simultaneously reclaim > > > +memory from a particular memory zone. > > > + > > > +With certain workloads, hundreds of processes end up in the page > > > +reclaim code simultaneously. This can cause large slowdowns due > > > +to lock contention, freeing of way too much memory and occasionally > > > +false OOM kills. > > > + > > > +To avoid these problems, only allow a smaller number of processes > > > +to reclaim pages from each memory zone simultaneously. > > > + > > > +The default value is 8. > > > > I don't like the hardcoded number. Is the same number good for a 128MB > > embedded system as for as 1TB server? Seems doubtful. > > > > This should be perhaps scaled with memory size and number of CPUs? > > Remember this a per-zone number. A zone could be 64MB or 32GB. And the system could have 1 or 1024 CPUs. -Andi -- ak@linux.intel.com -- Speaking for myself only. -- 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