From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S964917AbXBOHuV (ORCPT ); Thu, 15 Feb 2007 02:50:21 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S964920AbXBOHuV (ORCPT ); Thu, 15 Feb 2007 02:50:21 -0500 Received: from ebiederm.dsl.xmission.com ([166.70.28.69]:39014 "EHLO ebiederm.dsl.xmission.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S964917AbXBOHuU (ORCPT ); Thu, 15 Feb 2007 02:50:20 -0500 From: ebiederm@xmission.com (Eric W. Biederman) To: Nadia Derbey Cc: Andrew Morton , linux-kernel@vger.kernel.org Subject: Re: [RFC][PATCH 6/6] automatic tuning applied to some kernel components References: <20070116061516.899460000@bull.net> <20070116063030.761795000@bull.net> <20070122115638.835b26a1.akpm@osdl.org> <45B61E50.6020607@bull.net> <45CC68BA.4010403@bull.net> <45D17F8D.3020207@bull.net> <45D406BF.2060009@bull.net> Date: Thu, 15 Feb 2007 00:49:55 -0700 In-Reply-To: <45D406BF.2060009@bull.net> (Nadia Derbey's message of "Thu, 15 Feb 2007 08:07:43 +0100") Message-ID: User-Agent: Gnus/5.110006 (No Gnus v0.6) Emacs/21.4 (gnu/linux) MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Nadia Derbey writes: > But, what do you do with Oracle that's asking maxfiles to be set to 0x10000, > while the default value might be enough for a system that's not running Oracle. > I'm afraid that giving boot time values to the max_* tunables we will loose all > the benefits from /proc (or /sys): it is impossible to anticipate what an OS > will be used for. So allowing such things to be changed without having to reboot > the machine is in my mind quite a powerful feature we should keep taking > adavntage of. I'm not saying remove user spaces' ability to set the denial-of-service limits. I'm saying if they need to be frequently changed we need to update the default so they are higher by default. There really is no cost in moving those values up and down it is just an arbitrary integer used in comparisons. But if we can make a good guess that still catches runaway programs before they kill the machine but also allows more programs to work out of the box we are in better shape. Eric