From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-wm0-f70.google.com (mail-wm0-f70.google.com [74.125.82.70]) by kanga.kvack.org (Postfix) with ESMTP id 15F026B0005 for ; Tue, 26 Apr 2016 13:24:06 -0400 (EDT) Received: by mail-wm0-f70.google.com with SMTP id s63so17775720wme.2 for ; Tue, 26 Apr 2016 10:24:06 -0700 (PDT) Received: from mx2.suse.de (mx2.suse.de. [195.135.220.15]) by mx.google.com with ESMTPS id dg4si31057569wjd.125.2016.04.26.10.24.04 for (version=TLS1 cipher=AES128-SHA bits=128/128); Tue, 26 Apr 2016 10:24:04 -0700 (PDT) Subject: Re: [PATCH 19/28] mm, page_alloc: Reduce cost of fair zone allocation policy retry References: <1460710760-32601-1-git-send-email-mgorman@techsingularity.net> <1460711275-1130-1-git-send-email-mgorman@techsingularity.net> <1460711275-1130-7-git-send-email-mgorman@techsingularity.net> From: Vlastimil Babka Message-ID: <571FA432.1050103@suse.cz> Date: Tue, 26 Apr 2016 19:24:02 +0200 MIME-Version: 1.0 In-Reply-To: <1460711275-1130-7-git-send-email-mgorman@techsingularity.net> Content-Type: text/plain; charset=iso-8859-2; format=flowed Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org List-ID: To: Mel Gorman , Andrew Morton Cc: Jesper Dangaard Brouer , Linux-MM , LKML On 04/15/2016 11:07 AM, Mel Gorman wrote: > The fair zone allocation policy is not without cost but it can be reduced > slightly. This patch removes an unnecessary local variable, checks the > likely conditions of the fair zone policy first, uses a bool instead of > a flags check and falls through when a remote node is encountered instead > of doing a full restart. The benefit is marginal but it's there > > 4.6.0-rc2 4.6.0-rc2 > decstat-v1r20 optfair-v1r20 > Min alloc-odr0-1 377.00 ( 0.00%) 380.00 ( -0.80%) > Min alloc-odr0-2 273.00 ( 0.00%) 273.00 ( 0.00%) > Min alloc-odr0-4 226.00 ( 0.00%) 227.00 ( -0.44%) > Min alloc-odr0-8 196.00 ( 0.00%) 196.00 ( 0.00%) > Min alloc-odr0-16 183.00 ( 0.00%) 183.00 ( 0.00%) > Min alloc-odr0-32 175.00 ( 0.00%) 173.00 ( 1.14%) > Min alloc-odr0-64 172.00 ( 0.00%) 169.00 ( 1.74%) > Min alloc-odr0-128 170.00 ( 0.00%) 169.00 ( 0.59%) > Min alloc-odr0-256 183.00 ( 0.00%) 180.00 ( 1.64%) > Min alloc-odr0-512 191.00 ( 0.00%) 190.00 ( 0.52%) > Min alloc-odr0-1024 199.00 ( 0.00%) 198.00 ( 0.50%) > Min alloc-odr0-2048 204.00 ( 0.00%) 204.00 ( 0.00%) > Min alloc-odr0-4096 210.00 ( 0.00%) 209.00 ( 0.48%) > Min alloc-odr0-8192 213.00 ( 0.00%) 213.00 ( 0.00%) > Min alloc-odr0-16384 214.00 ( 0.00%) 214.00 ( 0.00%) > > The benefit is marginal at best but one of the most important benefits, > avoiding a second search when falling back to another node is not triggered > by this particular test so the benefit for some corner cases is understated. > > Signed-off-by: Mel Gorman Acked-by: Vlastimil Babka -- 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