From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755512AbcFQL1Q (ORCPT ); Fri, 17 Jun 2016 07:27:16 -0400 Received: from mx2.suse.de ([195.135.220.15]:52003 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752038AbcFQL1N (ORCPT ); Fri, 17 Jun 2016 07:27:13 -0400 Subject: Re: [PATCH 24/27] mm, page_alloc: Remove fair zone allocation policy To: Mel Gorman , Andrew Morton , Linux-MM References: <1465495483-11855-1-git-send-email-mgorman@techsingularity.net> <1465495483-11855-25-git-send-email-mgorman@techsingularity.net> Cc: Rik van Riel , Johannes Weiner , LKML , Michal Hocko From: Vlastimil Babka Message-ID: <9f30977a-ff07-d783-4c21-e13bd2478aa3@suse.cz> Date: Fri, 17 Jun 2016 13:27:09 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:45.0) Gecko/20100101 Thunderbird/45.1.0 MIME-Version: 1.0 In-Reply-To: <1465495483-11855-25-git-send-email-mgorman@techsingularity.net> Content-Type: text/plain; charset=iso-8859-2; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 06/09/2016 08:04 PM, Mel Gorman wrote: > The fair zone allocation policy interleaves allocation requests between > zones to avoid an age inversion problem whereby new pages are reclaimed > to balance a zone. Reclaim is now node-based so this should no longer be > an issue and the fair zone allocation policy is not free. This patch > removes it. I wonder if fair zone allocation had the side effect of preventing e.g. a small Normal zone to be almost fully occupied by long-lived unreclaimable allocations early in the kernel lifetime. So that might be one thing to watch out for. But otherwise I would agree it should be no longer needed with node-based reclaim. > Signed-off-by: Mel Gorman Acked-by: Vlastimil Babka