From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932690Ab2IURwV (ORCPT ); Fri, 21 Sep 2012 13:52:21 -0400 Received: from mx1.redhat.com ([209.132.183.28]:11683 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932208Ab2IURwT (ORCPT ); Fri, 21 Sep 2012 13:52:19 -0400 Date: Fri, 21 Sep 2012 14:52:05 -0300 From: Rafael Aquini To: Mel Gorman Cc: Andrew Morton , Richard Davies , Shaohua Li , Rik van Riel , Avi Kivity , QEMU-devel , KVM , Linux-MM , LKML Subject: Re: [PATCH 6/9] mm: compaction: Acquire the zone->lock as late as possible Message-ID: <20120921175204.GF6665@optiplex.redhat.com> References: <1348224383-1499-1-git-send-email-mgorman@suse.de> <1348224383-1499-7-git-send-email-mgorman@suse.de> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1348224383-1499-7-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 Fri, Sep 21, 2012 at 11:46:20AM +0100, 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 > --- Acked-by: Rafael Aquini