From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751812Ab3LLPe1 (ORCPT ); Thu, 12 Dec 2013 10:34:27 -0500 Received: from cantor2.suse.de ([195.135.220.15]:47481 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751395Ab3LLPe0 (ORCPT ); Thu, 12 Dec 2013 10:34:26 -0500 Date: Thu, 12 Dec 2013 15:34:22 +0000 From: Mel Gorman To: Johannes Weiner Cc: Andrew Morton , Dave Hansen , Rik van Riel , Linux-MM , LKML Subject: Re: [RFC PATCH 0/4] Configurable fair allocation zone policy Message-ID: <20131212153422.GJ11295@suse.de> References: <1386860779-2301-1-git-send-email-mgorman@suse.de> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-15 Content-Disposition: inline In-Reply-To: <1386860779-2301-1-git-send-email-mgorman@suse.de> User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Dec 12, 2013 at 03:06:15PM +0000, Mel Gorman wrote: > Commit 81c0a2bb ("mm: page_alloc: fair zone allocator policy") solved a > bug whereby new pages could be reclaimed before old pages because of how > the page allocator and kswapd interacted on the per-zone LRU lists. > > Unfortunately a side-effect missed during review was that it's now very > easy to allocate remote memory on NUMA machines. The problem is that > it is not a simple case of just restoring local allocation policies as > there are genuine reasons why global page aging may be prefereable. It's > still a major change to default behaviour so this patch makes the policy > configurable and sets what I think is a sensible default. > > The patches are on top of some NUMA balancing patches currently in -mm. > The first patch in the series is a patch posted by Johannes that must be > taken into account before any of my patches on top. The last patch of the > series is what alters default behaviour and makes the fair zone allocator > policy configurable. > > Sniff test results based on following kernels > > vanilla 3.13-rc3 stock > instrument-v5r1 NUMA balancing patches just to rule out any conflicts there > lruslabonly-v1r2 Patch 1 only > local-v1r2 Full series > These figures need to be redone. The instrument-v5r1 and later kernels included a debugging patch that increases migration rates to trigger another bug. The figures of local-v1r2 relative to instrument-v5r1 are fine but not relative to 3.13.0-rc3-vanilla -- Mel Gorman SUSE Labs