Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757080AbaDHOOK (ORCPT ); Tue, 8 Apr 2014 10:14:10 -0400 Received: from qmta14.emeryville.ca.mail.comcast.net ([76.96.27.212]:44639 "EHLO qmta14.emeryville.ca.mail.comcast.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756782AbaDHOOJ (ORCPT ); Tue, 8 Apr 2014 10:14:09 -0400 Date: Tue, 8 Apr 2014 09:14:05 -0500 (CDT) From: Christoph Lameter X-X-Sender: cl@nuc To: sivanich@sgi.com cc: Mel Gorman , Andrew Morton , Robert Haas , Josh Berkus , Andres Freund , Linux-MM , LKML Subject: Re: [PATCH 1/2] mm: Disable zone_reclaim_mode by default In-Reply-To: <1396910068-11637-2-git-send-email-mgorman@suse.de> Message-ID: References: <1396910068-11637-1-git-send-email-mgorman@suse.de> <1396910068-11637-2-git-send-email-mgorman@suse.de> Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, 7 Apr 2014, Mel Gorman wrote: > zone_reclaim_mode causes processes to prefer reclaiming memory from local > node instead of spilling over to other nodes. This made sense initially when > NUMA machines were almost exclusively HPC and the workload was partitioned > into nodes. The NUMA penalties were sufficiently high to justify reclaiming > the memory. On current machines and workloads it is often the case that > zone_reclaim_mode destroys performance but not all users know how to detect > this. Favour the common case and disable it by default. Users that are > sophisticated enough to know they need zone_reclaim_mode will detect it. Ok that is going to require SGI machines to deal with zone_reclaim configurations on bootup. Dimitri? Any comments? -- 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/