From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932273Ab2DJAtc (ORCPT ); Mon, 9 Apr 2012 20:49:32 -0400 Received: from mx1.redhat.com ([209.132.183.28]:61914 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932102Ab2DJAtb (ORCPT ); Mon, 9 Apr 2012 20:49:31 -0400 Message-ID: <4F838390.1080909@redhat.com> Date: Mon, 09 Apr 2012 20:49:20 -0400 From: Rik van Riel User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:11.0) Gecko/20120329 Thunderbird/11.0.1 MIME-Version: 1.0 To: Minchan Kim CC: Alexey Ivanov , "gnehzuil.lzheng@gmail.com" , "linux-kernel@vger.kernel.org" , "linux-mm@kvack.org" , yinghan@google.com Subject: Re: mapped pagecache pages vs unmapped pages References: <37371333672160@webcorp7.yandex-team.ru> <4F7E9854.1020904@gmail.com> <12701333991475@webcorp7.yandex-team.ru> <4F8326FD.8020507@redhat.com> <8041334015453@webcorp4.yandex-team.ru> <4F837F6E.3010508@kernel.org> In-Reply-To: <4F837F6E.3010508@kernel.org> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 04/09/2012 08:31 PM, Minchan Kim wrote: > 2012-04-10 오전 8:50, Alexey Ivanov 쓴 글: > >> Did you consider making this ratio tunable, at least manually(i.e. via sysctl)? >> I suppose we are not the only ones with almost-whole-ram-mmaped workload. > > Personally, I think it's not good approach. > It depends on kernel's internal implemenatation which would be changed > in future as we chagend it at 2.6.28. I also believe that a tunable for this is not going to be a very workable approach, for the simple reason that changing the value does not make a predictable change in the effectiveness of working set detection or protection. > In my opinion, kernel just should do best effort to keep active working > set except some critical pages which are code pages. Johannes has some experimental code to measure refaults, and calculate their distance in a multi-zone, multi-cgroup environment. That would allow us to predictably place things in the working set as required. -- All rights reversed