Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758176AbYHDO4S (ORCPT ); Mon, 4 Aug 2008 10:56:18 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1754192AbYHDO4I (ORCPT ); Mon, 4 Aug 2008 10:56:08 -0400 Received: from viefep18-int.chello.at ([213.46.255.22]:65530 "EHLO viefep19-int.chello.at" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1753984AbYHDO4H (ORCPT ); Mon, 4 Aug 2008 10:56:07 -0400 X-SourceIP: 80.57.229.25 Subject: Re: [RFC][PATCH 7/7] lockdep: spin_lock_nest_lock() From: Peter Zijlstra To: Dave Jones Cc: Roland Dreier , Linus Torvalds , David Miller , jeremy@goop.org, hugh@veritas.com, mingo@elte.hu, akpm@linux-foundation.org, linux-kernel@vger.kernel.org, Andrea Arcangeli In-Reply-To: <20080804145318.GA17867@redhat.com> References: <20080804130317.994042639@chello.nl> <20080804131012.246115111@chello.nl> <1217859571.3589.7.camel@twins> <1217860332.3589.11.camel@twins> <20080804145318.GA17867@redhat.com> Content-Type: text/plain Date: Mon, 04 Aug 2008 16:56:03 +0200 Message-Id: <1217861763.3589.13.camel@twins> Mime-Version: 1.0 X-Mailer: Evolution 2.22.3.1 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1315 Lines: 31 On Mon, 2008-08-04 at 10:53 -0400, Dave Jones wrote: > On Mon, Aug 04, 2008 at 04:32:12PM +0200, Peter Zijlstra wrote: > > On Mon, 2008-08-04 at 07:26 -0700, Roland Dreier wrote: > > > > No more than 48 locks (mutexes, rwlocks, spinlock, RCU, everything > > > > covered by lockdep) held by any one code-path; including nested > > > > interrupt contexts. > > > > > > Does that mean that something like the new mm_take_all_locks() operation > > > is going to explode if someone tries to use it with lockdep on? > > > > Gah - yes, clearly nobody tried this.. :-/ > > > > Just looking at the code it will not only run into this limit, but it > > would warn about recursion on the second file/anon vma due to utter lack > > of annotation. > > > > Why are people still developing without lockdep? > > More puzzling, is why hasn't this triggered in the Fedora rawhide kernels, > which do have lockdep enabled. My guess is that the kvm thing attaches before there are any vma, and leaves after all the vma are gone. So it would never actually trigger. -- 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/