Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754733AbZIIXrf (ORCPT ); Wed, 9 Sep 2009 19:47:35 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1754620AbZIIXre (ORCPT ); Wed, 9 Sep 2009 19:47:34 -0400 Received: from smtp1.linux-foundation.org ([140.211.169.13]:58500 "EHLO smtp1.linux-foundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752609AbZIIXre (ORCPT ); Wed, 9 Sep 2009 19:47:34 -0400 Date: Wed, 9 Sep 2009 16:46:46 -0700 (PDT) From: Linus Torvalds X-X-Sender: torvalds@localhost.localdomain To: Paul Mackerras cc: Linux Kernel Mailing List Subject: Re: Linux 2.6.31 In-Reply-To: <19112.15202.318732.299671@cargo.ozlabs.ibm.com> Message-ID: References: <19112.15202.318732.299671@cargo.ozlabs.ibm.com> User-Agent: Alpine 2.01 (LFD 1184 2008-12-16) MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1030 Lines: 27 On Thu, 10 Sep 2009, Paul Mackerras wrote: > Linus Torvalds writes: > > > There's also a fair chunk of new debugging/peformance counter stuff: > > memory leak detection ("kmemleak"), memory usage checking ("kmemcheck") > > and performance counters ("perf_counter"). Those new debugging features > > are not likely usable under any real load, but are good for finding kernel > > bugs at a huge performance cost. > > Just to be clear, that last sentence applies to kmemleak and > kmemcheck, but not perf_counters, right? Yes. The perfcounter thing is certainly useful under real loads. But both kmemleak and kmemcheck will probably be pretty unusable if you try to do anything that would stress the machine normally. Kind of like DEBUG_PAGEALLOC, just much worse. Linus -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/