From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from psmtp.com (na3sys010amx143.postini.com [74.125.245.143]) by kanga.kvack.org (Postfix) with SMTP id DBAF06B0005 for ; Thu, 11 Apr 2013 13:25:13 -0400 (EDT) Date: Thu, 11 Apr 2013 18:25:08 +0100 From: Mel Gorman Subject: Re: [PATCH] mm: Print the correct method to disable automatic numa migration Message-ID: <20130411172508.GC11656@suse.de> References: <1365622514-26614-1-git-send-email-andi@firstfloor.org> <20130411124803.GK3710@suse.de> <20130411140425.GJ16732@two.firstfloor.org> <20130411141942.GL3710@suse.de> <20130411155304.GK22166@tassilo.jf.intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-15 Content-Disposition: inline In-Reply-To: <20130411155304.GK22166@tassilo.jf.intel.com> Sender: owner-linux-mm@kvack.org List-ID: To: Andi Kleen Cc: Andi Kleen , akpm@linux-foundation.org, linux-mm@kvack.org On Thu, Apr 11, 2013 at 08:53:04AM -0700, Andi Kleen wrote: > > > > David has also already pointed out the problems with NO_NUMA vs -NUMA and > > > > the fact that the option only exists if CONFIG_SCHED_DEBUG which I agree > > > > is unfortunate. Ends up with this sort of mess > > > > > > We just need the sysctl. Are you adding one or should I send > > > another patch with it? > > > > > > > I hadn't planned on it in the short term at least. Originally there was > > I'll send a patch. > Ok. > But are you taking care of the documentation of all the existing knobs? > Which knobs? The sched_features knobs? No, I was not planning on documenting them. Some of them are already partially documented in kernel/sched/features.h but the consequences of tuning them is heavily workload dependant. While this is unsatisfactory, the interface is only intended for debugging. For NUMA balancing, the tuning knob is a kernel parameter and it is already documented in Documentation/kernel-parameters.txt > I think if you had done that earlier you would have noticed > that the current situation is not very satisfying. > > Writing documentation is one of the best ways we have > to sanitize user interfaces. > > > revisited NUMA balancing a long time ago but too many bugs have been > > getting in the way. > > That will likely make everything even worse. > With one exception, the bugs I've been working on are not related to automatic NUMA balancing. -- Mel Gorman SUSE Labs -- 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