From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754060AbYHVOBR (ORCPT ); Fri, 22 Aug 2008 10:01:17 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752578AbYHVOBE (ORCPT ); Fri, 22 Aug 2008 10:01:04 -0400 Received: from casper.infradead.org ([85.118.1.10]:44136 "EHLO casper.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752549AbYHVOBD (ORCPT ); Fri, 22 Aug 2008 10:01:03 -0400 Date: Fri, 22 Aug 2008 07:00:54 -0700 From: Arjan van de Ven To: Andrew Morton Cc: linux-kernel@vger.kernel.org, mingo@elte.hu Subject: Re: PATCH] debug: add notifier chain debugging Message-ID: <20080822070054.5d466be9@infradead.org> In-Reply-To: <20080819210932.9bb348b9.akpm@linux-foundation.org> References: <20080815152938.4bc9d48c@infradead.org> <20080819210932.9bb348b9.akpm@linux-foundation.org> Organization: Intel X-Mailer: Claws Mail 3.5.0 (GTK+ 2.12.11; i386-redhat-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit X-SRS-Rewrite: SMTP reverse-path rewritten from by casper.infradead.org See http://www.infradead.org/rpr.html Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, 19 Aug 2008 21:09:32 -0700 Andrew Morton wrote: > > If we remove the first two checks then surely we can afford to add the > remaining check unconditionally and lose the new config option and its > ifdef. > Andi told me that this notifier is a hotpath for kprobes (systemtap) use models; at which point making this a config option makes sort of sense to get the last bit of performance out of that. Personally I would always want this option on for anything I run, and I suspect (enterprise) distros will just always turn it on as well since it's a good sanity check at low cost. I'd be happy to lose the config (I think we have way too many unneeded ones of those already); I'll make a patch. -- If you want to reach me at my work email, use arjan@linux.intel.com For development, discussion and tips for power savings, visit http://www.lesswatts.org