From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-oa0-f41.google.com (mail-oa0-f41.google.com [209.85.219.41]) by kanga.kvack.org (Postfix) with ESMTP id 19E896B0031 for ; Tue, 8 Apr 2014 15:56:55 -0400 (EDT) Received: by mail-oa0-f41.google.com with SMTP id j17so1621167oag.14 for ; Tue, 08 Apr 2014 12:56:53 -0700 (PDT) Received: from smtp.01.com (smtp.01.com. [199.36.142.181]) by mx.google.com with ESMTP id pu6si2560229oeb.178.2014.04.08.12.56.53 for ; Tue, 08 Apr 2014 12:56:53 -0700 (PDT) Message-ID: <53445481.3030202@agliodbs.com> Date: Tue, 08 Apr 2014 15:56:49 -0400 From: Josh Berkus MIME-Version: 1.0 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: Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org List-ID: To: Robert Haas , Christoph Lameter Cc: Vlastimil Babka , Mel Gorman , Andrew Morton , Andres Freund , Linux-MM , LKML , sivanich@sgi.com 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, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org