From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1425523AbWLHOs0 (ORCPT ); Fri, 8 Dec 2006 09:48:26 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1425527AbWLHOs0 (ORCPT ); Fri, 8 Dec 2006 09:48:26 -0500 Received: from outpipe-village-512-1.bc.nu ([81.2.110.250]:48660 "EHLO lxorguk.ukuu.org.uk" rhost-flags-OK-FAIL-OK-FAIL) by vger.kernel.org with ESMTP id S1425523AbWLHOsZ (ORCPT ); Fri, 8 Dec 2006 09:48:25 -0500 Date: Fri, 8 Dec 2006 14:56:05 +0000 From: Alan To: Al Boldi Cc: linux-kernel@vger.kernel.org Subject: Re: additional oom-killer tuneable worth submitting? Message-ID: <20061208145605.1a8b0815@localhost.localdomain> In-Reply-To: <200612081658.29338.a1426z@gawab.com> References: <200612081658.29338.a1426z@gawab.com> X-Mailer: Sylpheed-Claws 2.6.0 (GTK+ 2.8.20; x86_64-redhat-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Fri, 8 Dec 2006 16:58:29 +0300 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. > > 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. Alan