Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753646Ab0HBIEK (ORCPT ); Mon, 2 Aug 2010 04:04:10 -0400 Received: from ipmail04.adl6.internode.on.net ([150.101.137.141]:17438 "EHLO ipmail04.adl6.internode.on.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753271Ab0HBIEI (ORCPT ); Mon, 2 Aug 2010 04:04:08 -0400 X-IronPort-Anti-Spam-Filtered: true X-IronPort-Anti-Spam-Result: AvsEALIWVkx5LclT/2dsb2JhbACgEHK+foU5BA Date: Mon, 2 Aug 2010 18:03:53 +1000 From: Nick Piggin To: Ingo Molnar Cc: Nick Piggin , Arnaldo Carvalho de Melo , linux-kernel@vger.kernel.org, Arnaldo Carvalho de Melo , Frederic Weisbecker , Mike Galbraith , Peter Zijlstra , Stephane Eranian Subject: Re: [PATCH 11/19] perf record: Release resources at exit Message-ID: <20100802080353.GA8713@amd> References: <1280711334-30000-1-git-send-email-acme@infradead.org> <1280711334-30000-12-git-send-email-acme@infradead.org> <20100802073009.GB7841@amd> <20100802075422.GA24085@elte.hu> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20100802075422.GA24085@elte.hu> User-Agent: Mutt/1.5.20 (2009-06-14) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1421 Lines: 32 On Mon, Aug 02, 2010 at 09:54:22AM +0200, Ingo Molnar wrote: > > * Nick Piggin wrote: > > > On Sun, Aug 01, 2010 at 10:08:46PM -0300, Arnaldo Carvalho de Melo wrote: > > > From: Arnaldo Carvalho de Melo > > > > > > So that we can reduce the noise on valgrind when looking for memory > > > leaks. > > > > Really? That's rather crappy of valgrind. exit is well defined to release > > resources and that's often a more efficient way to do it It finds and > > batches things a lot better, eg. it can avoid all TLB flushing of freeing > > memory that munmap requires. > > That's certainly true but there's no valgrind crappiness here: valgrind simply > can do a better job of finding leaks if there's a well defined "all resources > the app still knows about are freed now" point. "noise" sounds like false positives though. Certainly if this is instead allows valgrind to run in a particular mode that assumes no application resources consumed at exit(2) time, I wouldn't call it crappy :) But you could equally sprinkle in other valgrind specific annotations or semantics at various points in the code to improve its coverage, no? -- 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/