From mboxrd@z Thu Jan  1 00:00:00 1970
Return-Path: <linux-kernel-owner@vger.kernel.org>
Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand
	id S1752437AbaEHFQB (ORCPT <rfc822;w@1wt.eu>);
	Thu, 8 May 2014 01:16:01 -0400
Received: from LGEMRELSE7Q.lge.com ([156.147.1.151]:59852 "EHLO
	lgemrelse7q.lge.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org
	with ESMTP id S1751068AbaEHFQA (ORCPT
	<rfc822;linux-kernel@vger.kernel.org>);
	Thu, 8 May 2014 01:16:00 -0400
X-Original-SENDERIP: 10.177.220.145
X-Original-MAILFROM: iamjoonsoo.kim@lge.com
Date: Thu, 8 May 2014 14:17:48 +0900
From: Joonsoo Kim <iamjoonsoo.kim@lge.com>
To: David Rientjes <rientjes@google.com>
Cc: Andrew Morton <akpm@linux-foundation.org>, Mel Gorman <mgorman@suse.de>,
        Rik van Riel <riel@redhat.com>, Vlastimil Babka <vbabka@suse.cz>,
        Greg Thelen <gthelen@google.com>, Hugh Dickins <hughd@google.com>,
        linux-kernel@vger.kernel.org, linux-mm@kvack.org
Subject: Re: [patch v3 6/6] mm, compaction: terminate async compaction when
 rescheduling
Message-ID: <20140508051747.GA9161@js1304-P5Q-DELUXE>
References: <alpine.DEB.2.02.1404301744110.8415@chino.kir.corp.google.com>
 <alpine.DEB.2.02.1405011434140.23898@chino.kir.corp.google.com>
 <alpine.DEB.2.02.1405061920470.18635@chino.kir.corp.google.com>
 <alpine.DEB.2.02.1405061922220.18635@chino.kir.corp.google.com>
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
In-Reply-To: <alpine.DEB.2.02.1405061922220.18635@chino.kir.corp.google.com>
User-Agent: Mutt/1.5.21 (2010-09-15)
Sender: linux-kernel-owner@vger.kernel.org
List-ID: <linux-kernel.vger.kernel.org>
X-Mailing-List: linux-kernel@vger.kernel.org

On Tue, May 06, 2014 at 07:22:52PM -0700, David Rientjes wrote:
> Async compaction terminates prematurely when need_resched(), see
> compact_checklock_irqsave().  This can never trigger, however, if the 
> cond_resched() in isolate_migratepages_range() always takes care of the 
> scheduling.
> 
> If the cond_resched() actually triggers, then terminate this pageblock scan for 
> async compaction as well.

Hello,

I think that same logic would be helpful to cond_resched() in
isolatate_freepages(). And, isolate_freepages() doesn't have exit logic
when it find zone_lock contention. I think that fixing it is also
helpful.

Thanks.