From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([208.118.235.92]:58564) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1TEltY-0007sl-ET for qemu-devel@nongnu.org; Thu, 20 Sep 2012 14:54:41 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1TEltX-0001bm-G3 for qemu-devel@nongnu.org; Thu, 20 Sep 2012 14:54:40 -0400 Received: from mx1.redhat.com ([209.132.183.28]:15530) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1TEltX-0001bi-7v for qemu-devel@nongnu.org; Thu, 20 Sep 2012 14:54:39 -0400 Message-ID: <505B6669.2040104@redhat.com> Date: Thu, 20 Sep 2012 14:54:33 -0400 From: Rik van Riel MIME-Version: 1.0 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 Subject: Re: [Qemu-devel] [PATCH 3/6] 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 , Shaohua Li 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