From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758877Ab3FDGF4 (ORCPT ); Tue, 4 Jun 2013 02:05:56 -0400 Received: from LGEMRELSE1Q.lge.com ([156.147.1.111]:44092 "EHLO LGEMRELSE1Q.lge.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753369Ab3FDGFz (ORCPT ); Tue, 4 Jun 2013 02:05:55 -0400 X-AuditID: 9c93016f-b7cfdae000002fc1-4c-51ad83c10239 Date: Tue, 4 Jun 2013 15:05:53 +0900 From: Minchan Kim To: Dave Hansen Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org, akpm@linux-foundation.org, mgorman@suse.de, tim.c.chen@linux.intel.com Subject: Re: [v5][PATCH 6/6] mm: vmscan: drain batch list during long operations Message-ID: <20130604060553.GF14719@blaptop> References: <20130603200202.7F5FDE07@viggo.jf.intel.com> <20130603200210.259954C3@viggo.jf.intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20130603200210.259954C3@viggo.jf.intel.com> User-Agent: Mutt/1.5.21 (2010-09-15) X-Brightmail-Tracker: AAAAAA== Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Jun 03, 2013 at 01:02:10PM -0700, Dave Hansen wrote: > > From: Dave Hansen > > This was a suggestion from Mel: > > http://lkml.kernel.org/r/20120914085634.GM11157@csn.ul.ie > > Any pages we collect on 'batch_for_mapping_removal' will have > their lock_page() held during the duration of their stay on the > list. If some other user is trying to get at them during this > time, they might end up having to wait. > > This ensures that we drain the batch if we are about to perform a > pageout() or congestion_wait(), either of which will take some > time. We expect this to help mitigate the worst of the latency > increase that the batching could cause. Nice idea but I could see drain before pageout but congestion_wait? -- Kind regards, Minchan Kim