Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757430Ab1DMAW3 (ORCPT ); Tue, 12 Apr 2011 20:22:29 -0400 Received: from smtp-out.google.com ([74.125.121.67]:24458 "EHLO smtp-out.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756150Ab1DMAW1 (ORCPT ); Tue, 12 Apr 2011 20:22:27 -0400 DomainKey-Signature: a=rsa-sha1; c=nofws; d=google.com; s=beta; h=date:from:x-x-sender:to:cc:subject:in-reply-to:message-id :references:user-agent:mime-version:content-type; b=Ji/CJdxeDmBCcP4RVt1NiRuYFBFpDKq6IpcbdzqIFmoCQAoBa32qfE1ZgYbesnu4f7 di4XOEn7oF7P5qjHKsyw== Date: Tue, 12 Apr 2011 17:22:21 -0700 (PDT) From: David Rientjes X-X-Sender: rientjes@chino.kir.corp.google.com To: Dave Hansen cc: KOSAKI Motohiro , LKML , linux-mm , Andrew Morton , Christoph Lameter , KAMEZAWA Hiroyuki , Chris McDermott Subject: Re: [PATCH resend^2] mm: increase RECLAIM_DISTANCE to 30 In-Reply-To: <1302557371.7286.16607.camel@nimitz> Message-ID: References: <20110411172004.0361.A69D9226@jp.fujitsu.com> <1302557371.7286.16607.camel@nimitz> User-Agent: Alpine 2.00 (DEB 1167 2008-08-23) MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII X-System-Of-Record: true Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1228 Lines: 25 On Mon, 11 Apr 2011, Dave Hansen wrote: > > This patch raise zone_reclaim_mode threshold to 30. 30 don't have > > specific meaning. but 20 mean one-hop QPI/Hypertransport and such > > relatively cheap 2-4 socket machine are often used for tradiotional > > server as above. The intention is, their machine don't use > > zone_reclaim_mode. > > I know specifically of pieces of x86 hardware that set the information > in the BIOS to '21' *specifically* so they'll get the zone_reclaim_mode > behavior which that implies. > That doesn't seem like an argument against this patch, it's an improper configuration unless the remote memory access has a latency of 2.1x that of a local access between those two nodes. If that's the case, then it's accurately following the ACPI spec and the VM has made its policy decision to enable zone_reclaim_mode as a result. I'm surprised that they'd play with their BIOS to enable this by default, those, when it's an easily tunable sysctl. -- 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/