From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([208.118.235.92]:46642) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1TF7Ol-0002f1-6O for qemu-devel@nongnu.org; Fri, 21 Sep 2012 13:52:19 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1TF7Ok-0000XY-6X for qemu-devel@nongnu.org; Fri, 21 Sep 2012 13:52:19 -0400 Received: from mx1.redhat.com ([209.132.183.28]:21091) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1TF7Oj-0000XU-V5 for qemu-devel@nongnu.org; Fri, 21 Sep 2012 13:52:18 -0400 Date: Fri, 21 Sep 2012 14:52:05 -0300 From: Rafael Aquini 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> Subject: Re: [Qemu-devel] [PATCH 6/9] mm: compaction: Acquire the zone->lock as late as possible List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Mel Gorman Cc: Richard Davies , KVM , QEMU-devel , LKML , Linux-MM , Avi Kivity , Andrew Morton , Shaohua Li 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