From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755245AbdJSOc5 (ORCPT ); Thu, 19 Oct 2017 10:32:57 -0400 Received: from outbound-smtp12.blacknight.com ([46.22.139.17]:47765 "EHLO outbound-smtp12.blacknight.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755224AbdJSOcy (ORCPT ); Thu, 19 Oct 2017 10:32:54 -0400 Date: Thu, 19 Oct 2017 15:32:52 +0100 From: Mel Gorman To: Vlastimil Babka Cc: Andrew Morton , Linux-MM , Linux-FSDevel , LKML , Jan Kara , Andi Kleen , Dave Hansen , Dave Chinner Subject: Re: [PATCH 8/8] mm: Remove __GFP_COLD Message-ID: <20171019143252.bviqsb7qxppzz32j@techsingularity.net> References: <20171018075952.10627-1-mgorman@techsingularity.net> <20171018075952.10627-9-mgorman@techsingularity.net> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-15 Content-Disposition: inline In-Reply-To: User-Agent: NeoMutt/20170421 (1.8.2) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Oct 19, 2017 at 03:42:12PM +0200, Vlastimil Babka wrote: > From b002266c1a826805a50087db851f93e7a87ceb2f Mon Sep 17 00:00:00 2001 > From: Vlastimil Babka > Date: Tue, 17 Oct 2017 16:03:02 +0200 > Subject: [PATCH] mm, page_alloc: simplify list handling in rmqueue_bulk() > > The rmqueue_bulk() function fills an empty pcplist with pages from the free > list. It tries to preserve increasing order by pfn to the caller, because it > leads to better performance with some I/O controllers, as explained in > e084b2d95e48 ("page-allocator: preserve PFN ordering when __GFP_COLD is set"). > > To preserve the order, it's sufficient to add pages to the tail of the list > as they are retrieved. The current code instead adds to the head of the list, > but then updates the list head pointer to the last added page, in each step. > This does result in the same order, but is needlessly confusing and potentially > wasteful, with no apparent benefit. This patch simplifies the code and adjusts > comment accordingly. > > Signed-off-by: Vlastimil Babka Acked-by: Mel Gorman -- Mel Gorman SUSE Labs