Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755624AbaDGXfY (ORCPT ); Mon, 7 Apr 2014 19:35:24 -0400 Received: from zene.cmpxchg.org ([85.214.230.12]:58471 "EHLO zene.cmpxchg.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754637AbaDGXfX (ORCPT ); Mon, 7 Apr 2014 19:35:23 -0400 Date: Mon, 7 Apr 2014 19:35:11 -0400 From: Johannes Weiner To: Mel Gorman Cc: Andrew Morton , Robert Haas , Josh Berkus , Andres Freund , Christoph Lameter , Linux-MM , LKML Subject: Re: [PATCH 1/2] mm: Disable zone_reclaim_mode by default Message-ID: <20140407233511.GO4407@cmpxchg.org> References: <1396910068-11637-1-git-send-email-mgorman@suse.de> <1396910068-11637-2-git-send-email-mgorman@suse.de> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1396910068-11637-2-git-send-email-mgorman@suse.de> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Apr 07, 2014 at 11:34:27PM +0100, 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. > > Signed-off-by: Mel Gorman Acked-by: Johannes Weiner -- 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/