From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753569Ab1LUBO7 (ORCPT ); Tue, 20 Dec 2011 20:14:59 -0500 Received: from va3ehsobe003.messaging.microsoft.com ([216.32.180.13]:33801 "EHLO VA3EHSOBE003.bigfish.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752252Ab1LUBO4 (ORCPT ); Tue, 20 Dec 2011 20:14:56 -0500 X-SpamScore: -10 X-BigFish: VPS-10(zzbb2dI1432N98dKzz1202hzzz2fh668h839h93fh) X-Forefront-Antispam-Report: CIP:160.33.98.74;KIP:(null);UIP:(null);IPV:NLI;H:mail7.fw-bc.sony.com;RD:mail7.fw-bc.sony.com;EFVD:NLI Message-ID: <4EF132EA.7000300@am.sony.com> Date: Tue, 20 Dec 2011 17:14:18 -0800 From: Frank Rowand Reply-To: User-Agent: Mozilla/5.0 (X11; U; Linux x86_64; en-US; rv:1.9.2.17) Gecko/20110428 Fedora/3.1.10-1.fc14 Thunderbird/3.1.10 MIME-Version: 1.0 To: Anton Vorontsov CC: David Rientjes , KOSAKI Motohiro , Michal Hocko , =?UTF-8?B?QXJ2ZSBIasO4bm5ldsOlZw==?= , Rik van Riel , Pavel Machek , Greg Kroah-Hartman , Andrew Morton , John Stultz , "linux-mm@kvack.org" , "linux-kernel@vger.kernel.org" , Johannes Weiner , KAMEZAWA Hiroyuki , Alan Cox , Subject: Re: Android low memory killer vs. memory pressure notifications References: <20111219025328.GA26249@oksana.dev.rtsoft.ru> <20111219121255.GA2086@tiehlicka.suse.cz> <20111220145654.GA26881@oksana.dev.rtsoft.ru> <20111221002853.GA11504@oksana.dev.rtsoft.ru> In-Reply-To: <20111221002853.GA11504@oksana.dev.rtsoft.ru> Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 7bit X-OriginatorOrg: am.sony.com Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 12/20/11 16:28, Anton Vorontsov wrote: > On Tue, Dec 20, 2011 at 01:36:00PM -0800, David Rientjes wrote: >> On Tue, 20 Dec 2011, Anton Vorontsov wrote: >> >>> Hm, assuming that metadata is no longer an issue, why do you think avoiding >>> cgroups would be a good idea? >>> >> >> It's helpful for certain end users, particularly those in the embedded >> world, to be able to disable as many config options as possible to reduce >> the size of kernel image as much as possible, so they'll want a minimal >> amount of kernel functionality that allows such notifications. Keep in >> mind that CONFIG_CGROUP_MEM_RES_CTLR is not enabled by default because of >> this (enabling it, CONFIG_RESOURCE_COUNTERS, and CONFIG_CGROUPS increases >> the size of the kernel text by ~1%), > > So for 2MB kernel that's about 20KB of an additional text... This seems > affordable, especially as a trade-off for the things that cgroups may > provide. A comment from http://lkml.indiana.edu/hypermail/linux/kernel/1102.1/00412.html: "I care about 5K. (But honestly, I don't actively hunt stuff less than 10K in size, because there's too many of them to chase, currently)." > > The fact is, for desktop and server Linux, cgroups slowly becomes a > mandatory thing. And the reason for this is that cgroups mechanism > provides some very useful features (in an extensible way, like plugins), > i.e. a way to manage and track processes and its resources -- which is the > main purpose of cgroups. And for embedded and for real-time, some of us do not want cgroups to be a mandatory thing. We want it to remain configurable. My personal interest is in keeping the latency of certain critical paths (especially in the scheduler) short and consistent. -Frank