From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752572Ab3KFXur (ORCPT ); Wed, 6 Nov 2013 18:50:47 -0500 Received: from mga09.intel.com ([134.134.136.24]:32213 "EHLO mga09.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751908Ab3KFXuq (ORCPT ); Wed, 6 Nov 2013 18:50:46 -0500 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="4.93,535,1378882800"; d="scan'208";a="430993340" Message-ID: <527AD5A2.70902@intel.com> Date: Wed, 06 Nov 2013 15:49:54 -0800 From: Dave Hansen User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:24.0) Gecko/20100101 Thunderbird/24.1.0 MIME-Version: 1.0 To: Andrew Morton , Jerome Marchand CC: linux-mm@kvack.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH v4 2/2] mm: allow to set overcommit ratio more precisely References: <1382101019-23563-1-git-send-email-jmarchan@redhat.com> <1382101019-23563-2-git-send-email-jmarchan@redhat.com> <20131105155319.732dcbefb162c2ee4716ef9d@linux-foundation.org> <1450211196.19341043.1383727340985.JavaMail.root@redhat.com> <20131106143313.1a368250df917fba0faf56fe@linux-foundation.org> In-Reply-To: <20131106143313.1a368250df917fba0faf56fe@linux-foundation.org> Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 11/06/2013 02:33 PM, Andrew Morton wrote: > On Wed, 6 Nov 2013 03:42:20 -0500 (EST) Jerome Marchand wrote: >> That was my first version of this patch (actually "kbytes" to avoid >> overflow). >> Dave raised the issue that it silently breaks the user interface: >> overcommit_ratio is zero while the system behaves differently. > > I don't understand that at all. We keep overcommit_ratio as-is, with > the same default values and add a different way of altering it. That > should be back-compatible? Reading the old thread, I think my main point was that we shouldn't output overcommit_ratio=0 when overcommit_bytes>0. We need to round up for numbers less than 1 so that folks don't think overcommit_ratio is _off_. I was really just trying to talk you in to cramming the extra precision in to the _existing_ sysctl. :) I don't think bytes vs. ratio is really that big of a deal.