From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753465Ab3KGKnz (ORCPT ); Thu, 7 Nov 2013 05:43:55 -0500 Received: from mx4-phx2.redhat.com ([209.132.183.25]:46334 "EHLO mx4-phx2.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751691Ab3KGKnw (ORCPT ); Thu, 7 Nov 2013 05:43:52 -0500 Date: Thu, 7 Nov 2013 05:43:48 -0500 (EST) From: Jerome Marchand To: Dave Hansen Cc: Andrew Morton , linux-mm@kvack.org, linux-kernel@vger.kernel.org Message-ID: <1605509214.19935074.1383821028439.JavaMail.root@redhat.com> In-Reply-To: <527AD5A2.70902@intel.com> 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> <527AD5A2.70902@intel.com> Subject: Re: [PATCH v4 2/2] mm: allow to set overcommit ratio more precisely MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit X-Originating-IP: [10.5.82.12] X-Mailer: Zimbra 8.0.3_GA_5664 (ZimbraWebClient - FF22 (Linux)/8.0.3_GA_5664) Thread-Topic: allow to set overcommit ratio more precisely Thread-Index: X9lNhzCk/L5kqME+glrKuBjQvQRj/w== Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org ----- Original Message ----- > From: "Dave Hansen" > To: "Andrew Morton" , "Jerome Marchand" > Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org > Sent: Thursday, November 7, 2013 12:49:54 AM > Subject: Re: [PATCH v4 2/2] mm: allow to set overcommit ratio more precisely > > 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_. This is not how current *bytes work. Also the *ratio and *bytes value would diverge if the amount of memory changes (e.g. memory hotplug). > > 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. > If everybody agrees on overcommit_kbytes, I can resend my original patch.