Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1161279Ab3DGAsM (ORCPT ); Sat, 6 Apr 2013 20:48:12 -0400 Received: from mail-ia0-f176.google.com ([209.85.210.176]:57067 "EHLO mail-ia0-f176.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1161181Ab3DGAsL (ORCPT ); Sat, 6 Apr 2013 20:48:11 -0400 Message-ID: <5160C244.6080807@gmail.com> Date: Sun, 07 Apr 2013 08:48:04 +0800 From: Simon Jeons User-Agent: Mozilla/5.0 (X11; Linux i686; rv:17.0) Gecko/20130308 Thunderbird/17.0.4 MIME-Version: 1.0 To: Andrew Shewmaker CC: Andrew Morton , linux-mm@kvack.org, linux-kernel@vger.kernel.org, alan@lxorguk.ukuu.org.uk, ric.masonn@gmail.com Subject: Re: [PATCH v7 2/2] mm: replace hardcoded 3% with admin_reserve_pages knob References: <20130325134247.GB1393@localhost.localdomain> <515CF884.8010103@gmail.com> In-Reply-To: Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1610 Lines: 45 Hi Andrew, On 04/05/2013 11:02 PM, Andrew Shewmaker wrote: > On Wed, Apr 3, 2013 at 9:50 PM, Simon Jeons wrote: >>> FAQ >>> > ... >>> * How do you calculate a minimum useful reserve? >>> >>> A user or the admin needs enough memory to login and perform >>> recovery operations, which includes, at a minimum: >>> >>> sshd or login + bash (or some other shell) + top (or ps, kill, etc.) >>> >>> For overcommit 'guess', we can sum resident set sizes (RSS). >>> On x86_64 this is about 8MB. >>> >>> For overcommit 'never', we can take the max of their virtual sizes >>> (VSZ) >>> and add the sum of their RSS. >>> On x86_64 this is about 128MB. >> >> 1.Why has this different between guess and never? > The default, overcommit 'guess' mode, only needs a reserve for > what the recovery programs will typically use. Overcommit 'never' > mode will only successfully launch an app when it can fulfill all of > its requested memory allocations--even if the app only uses a > fraction of what it asks for. VSZ has already cover RSS, is it? why account RSS again? > >> 2.You just test x86/x86_64, other platforms also will use memory overcommit, >> did you test them? > No, I haven't. Unfortunately, I don't currently have any other platforms to test > with. I'll see what I can do. > > Thanks, > > Andrew -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/