From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from psmtp.com (na3sys010amx122.postini.com [74.125.245.122]) by kanga.kvack.org (Postfix) with SMTP id AF5566B0033 for ; Mon, 19 Aug 2013 12:55:10 -0400 (EDT) Message-ID: <52124DE7.8070502@intel.com> Date: Mon, 19 Aug 2013 09:55:03 -0700 From: Dave Hansen MIME-Version: 1.0 Subject: Re: [PATCH 2/2] mm: add overcommit_kbytes sysctl variable References: <1376925478-15506-1-git-send-email-jmarchan@redhat.com> <1376925478-15506-2-git-send-email-jmarchan@redhat.com> In-Reply-To: <1376925478-15506-2-git-send-email-jmarchan@redhat.com> Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org List-ID: To: Jerome Marchand Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org On 08/19/2013 08:17 AM, Jerome Marchand wrote: > Some applications that run on HPC clusters are designed around the > availability of RAM and the overcommit ratio is fine tuned to get the > maximum usage of memory without swapping. With growing memory, the > 1%-of-all-RAM grain provided by overcommit_ratio has become too coarse > for these workload (on a 2TB machine it represents no less than > 20GB). > > This patch adds the new overcommit_kbytes sysctl variable that allow a > much finer grain. Instead of introducing yet another tunable, why don't we just make the ratio that comes in from the user more fine-grained? sysctl overcommit_ratio=0.2 We change the internal 'sysctl_overcommit_ratio' to store tenths or hundreths of a percent (or whatever), then parse the input as two integers. I don't think we need fully correct floating point parsing and rounding here, so it shouldn't be too much of a chore. It'd probably end up being less code than you have as it stands. -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org