From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932286Ab2ITS5y (ORCPT ); Thu, 20 Sep 2012 14:57:54 -0400 Received: from mx1.redhat.com ([209.132.183.28]:22172 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755357Ab2ITSyl (ORCPT ); Thu, 20 Sep 2012 14:54:41 -0400 Message-ID: <505B6669.2040104@redhat.com> Date: Thu, 20 Sep 2012 14:54:33 -0400 From: Rik van Riel User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:14.0) Gecko/20120717 Thunderbird/14.0 MIME-Version: 1.0 To: Mel Gorman CC: Richard Davies , Shaohua Li , Avi Kivity , QEMU-devel , KVM , Linux-MM , LKML Subject: Re: [PATCH 3/6] mm: compaction: Acquire the zone->lock as late as possible References: <1348149875-29678-1-git-send-email-mgorman@suse.de> <1348149875-29678-4-git-send-email-mgorman@suse.de> In-Reply-To: <1348149875-29678-4-git-send-email-mgorman@suse.de> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 09/20/2012 10:04 AM, Mel Gorman wrote: > Compactions free scanner acquires the zone->lock when checking for PageBuddy > pages and isolating them. It does this even if there are no PageBuddy pages > in the range. > > This patch defers acquiring the zone lock for as long as possible. In the > event there are no free pages in the pageblock then the lock will not be > acquired at all which reduces contention on zone->lock. > > Signed-off-by: Mel Gorman Acked-by: Rik van Riel