From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from psmtp.com (na3sys010amx187.postini.com [74.125.245.187]) by kanga.kvack.org (Postfix) with SMTP id 4C9636B0033 for ; Tue, 4 Jun 2013 19:37:17 -0400 (EDT) Date: Wed, 5 Jun 2013 08:37:16 +0900 From: Minchan Kim Subject: Re: [v5][PATCH 6/6] mm: vmscan: drain batch list during long operations Message-ID: <20130604233716.GD31006@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> Sender: owner-linux-mm@kvack.org List-ID: 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 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. > > I added some statistics to the __remove_mapping_batch() code to > track how large the lists are that we pass in to it. With this > patch, the average list length drops about 10% (from about 4.1 to > 3.8). The workload here was a make -j4 kernel compile on a VM > with 200MB of RAM. > > I've still got the statistics patch around if anyone is > interested. > > Signed-off-by: Dave Hansen Reviewed-by: Minchan Kim -- Kind regards, Minchan Kim -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org