From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1425537AbWLHPS6 (ORCPT ); Fri, 8 Dec 2006 10:18:58 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1425542AbWLHPS6 (ORCPT ); Fri, 8 Dec 2006 10:18:58 -0500 Received: from [212.33.164.29] ([212.33.164.29]:32946 "EHLO localhost.localdomain" rhost-flags-FAIL-FAIL-OK-FAIL) by vger.kernel.org with ESMTP id S1425537AbWLHPS5 (ORCPT ); Fri, 8 Dec 2006 10:18:57 -0500 From: Al Boldi To: Alan Subject: Re: additional oom-killer tuneable worth submitting? Date: Fri, 8 Dec 2006 18:19:43 +0300 User-Agent: KMail/1.5 Cc: linux-kernel@vger.kernel.org References: <200612081658.29338.a1426z@gawab.com> <20061208145605.1a8b0815@localhost.localdomain> In-Reply-To: <20061208145605.1a8b0815@localhost.localdomain> MIME-Version: 1.0 Content-Type: text/plain; charset="windows-1256" Content-Transfer-Encoding: 7bit Content-Disposition: inline Message-Id: <200612081819.43991.a1426z@gawab.com> Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Alan wrote: > Al Boldi wrote: > > > That is why we have no-overcommit support. > > > > Alan, I think you know that this isn't really true, due to shared-libs. > > Shared libraries are correctly handled by no-overcommit and in fact they > have almost zero impact on out of memory questions because the shared > parts of the library are file backed and constant. That means they don't > actually cost swap space. What I understood from Arjan is that the problem isn't swapspace, but rather that shared-libs are implement via a COW trick, which always overcommits, no matter what. > > > Now there is an argument for > > > a meaningful rlimit-as to go with it, and together I think they do > > > what you really need. > > > > The problem with rlimit is that it works per process. Tuning this by > > hand may be awkward and/or wasteful. What we need is to rlimit on a > > global basis, by calculating an upperlimit dynamically, such as to avoid > > overcommit/OOM. > > You've just described the existing no overcommit functionality, although > you've forgotten to allow for pre-reserving of stacks and some other > detail that has been found to make it work better as it has been refined. Are you saying there is some new no-overcommit functionality in 2.6.19, or has this been there before? Thanks! -- Al