From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752711AbaGKIZK (ORCPT ); Fri, 11 Jul 2014 04:25:10 -0400 Received: from bombadil.infradead.org ([198.137.202.9]:49605 "EHLO bombadil.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751875AbaGKIZH (ORCPT ); Fri, 11 Jul 2014 04:25:07 -0400 Date: Fri, 11 Jul 2014 10:25:00 +0200 From: Peter Zijlstra To: Sasha Levin Cc: Hugh Dickins , Heiko Carstens , Vlastimil Babka , akpm@linux-foundation.org, davej@redhat.com, koct9i@gmail.com, lczerner@redhat.com, stable@vger.kernel.org, "linux-mm@kvack.org" , LKML Subject: Re: + shmem-fix-faulting-into-a-hole-while-its-punched-take-2.patch added to -mm tree Message-ID: <20140711082500.GB20603@laptop.programming.kicks-ass.net> References: <53BD1053.5020401@suse.cz> <53BD39FC.7040205@oracle.com> <53BD67DC.9040700@oracle.com> <53BE8B1B.3000808@oracle.com> <53BECBA4.3010508@oracle.com> <53BED7F6.4090502@oracle.com> <53BEE345.4090203@oracle.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <53BEE345.4090203@oracle.com> User-Agent: Mutt/1.5.21 (2012-12-30) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Jul 10, 2014 at 03:02:29PM -0400, Sasha Levin wrote: > What if we move lockdep's acquisition point to after it actually got the > lock? NAK, you want to do deadlock detection _before_ you're stuck in a deadlock. > We'd miss deadlocks, but we don't care about them right now. Anyways, doesn't > lockdep have anything built in to allow us to separate between locks which > we attempt to acquire and locks that are actually acquired? > > (cc PeterZ) > > We can treat locks that are in the process of being acquired the same as > acquired locks to avoid races, but when we print something out it would > be nice to have annotation of the read state of the lock. I'm missing the problem here I think.