From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from psmtp.com (na3sys010amx130.postini.com [74.125.245.130]) by kanga.kvack.org (Postfix) with SMTP id 0CF756B004A for ; Mon, 9 Apr 2012 20:49:29 -0400 (EDT) Message-ID: <4F838390.1080909@redhat.com> Date: Mon, 09 Apr 2012 20:49:20 -0400 From: Rik van Riel MIME-Version: 1.0 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: owner-linux-mm@kvack.org List-ID: To: Minchan Kim Cc: Alexey Ivanov , "gnehzuil.lzheng@gmail.com" , "linux-kernel@vger.kernel.org" , "linux-mm@kvack.org" , yinghan@google.com On 04/09/2012 08:31 PM, Minchan Kim wrote: > 2012-04-10 i??i ? 8:50, Alexey Ivanov i?' e,?: > >> 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 -- 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/ . Fight unfair telecom internet charges in Canada: sign http://stopthemeter.ca/ Don't email: email@kvack.org