Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757713AbaDHT4z (ORCPT ); Tue, 8 Apr 2014 15:56:55 -0400 Received: from smtp.01.com ([199.36.142.181]:37288 "EHLO smtp.01.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757633AbaDHT4x (ORCPT ); Tue, 8 Apr 2014 15:56:53 -0400 Message-ID: <53445481.3030202@agliodbs.com> Date: Tue, 08 Apr 2014 15:56:49 -0400 From: Josh Berkus Organization: PostgreSQL Experts Inc. User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:24.0) Gecko/20100101 Thunderbird/24.4.0 MIME-Version: 1.0 To: Robert Haas , Christoph Lameter CC: Vlastimil Babka , Mel Gorman , Andrew Morton , Andres Freund , Linux-MM , LKML , sivanich@sgi.com Subject: Re: [PATCH 0/2] Disable zone_reclaim_mode by default References: <1396910068-11637-1-git-send-email-mgorman@suse.de> <5343A494.9070707@suse.cz> In-Reply-To: X-Enigmail-Version: 1.6 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 04/08/2014 03:53 PM, Robert Haas wrote: > In an ideal world, the kernel would put the hottest pages on the local > node and the less-hot pages on remote nodes, moving pages around as > the workload shifts. In practice, that's probably pretty hard. > Fortunately, it's not nearly as important as making sure we don't > unnecessarily hit the disk, which is infinitely slower than any memory > bank. Even if the kernel could do this, we would *still* have to disable it for PostgreSQL, since our double-buffering makes our pages look "cold" to the kernel ... as discussed. -- Josh Berkus PostgreSQL Experts Inc. http://pgexperts.com -- 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/