Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753655AbaDRPtX (ORCPT ); Fri, 18 Apr 2014 11:49:23 -0400 Received: from cantor2.suse.de ([195.135.220.15]:52831 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751459AbaDRPtV (ORCPT ); Fri, 18 Apr 2014 11:49:21 -0400 Date: Fri, 18 Apr 2014 17:49:18 +0200 From: Michal Hocko To: Mel Gorman Cc: Andrew Morton , Robert Haas , Josh Berkus , Andres Freund , Christoph Lameter , Linux-MM , LKML Subject: Re: [PATCH 0/2] Disable zone_reclaim_mode by default Message-ID: <20140418154918.GD4523@dhcp22.suse.cz> References: <1396910068-11637-1-git-send-email-mgorman@suse.de> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1396910068-11637-1-git-send-email-mgorman@suse.de> User-Agent: Mutt/1.5.23 (2014-03-12) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon 07-04-14 23:34:26, Mel Gorman wrote: > When it was introduced, zone_reclaim_mode made sense as NUMA distances > punished and workloads were generally partitioned to fit into a NUMA > node. NUMA machines are now common but few of the workloads are NUMA-aware > and it's routine to see major performance due to zone_reclaim_mode being > disabled but relatively few can identify the problem. > > Those that require zone_reclaim_mode are likely to be able to detect when > it needs to be enabled and tune appropriately so lets have a sensible > default for the bulk of users. > > Documentation/sysctl/vm.txt | 17 +++++++++-------- > include/linux/mmzone.h | 1 - > mm/page_alloc.c | 17 +---------------- > 3 files changed, 10 insertions(+), 25 deletions(-) Auto-enabling caused so many reports in the past that it is definitely much better to not be clever and let admins enable zone_reclaim where it is appropriate instead. For both patches. Acked-by: Michal Hocko -- Michal Hocko SUSE Labs -- 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/