From mboxrd@z Thu Jan 1 00:00:00 1970 From: Trond Myklebust Subject: Re: [RFC, PATCH] locks: remove posix deadlock detection Date: Sun, 28 Oct 2007 17:50:30 -0400 Message-ID: <1193608230.7561.11.camel@heimdal.trondhjem.org> References: <20071017185157.GC3785@mvista.com> <20071018185759.GU3785@mvista.com> <20071026170750.GC13033@fieldses.org> <20071026224707.GO13033@fieldses.org> <20071028173136.GA16905@fieldses.org> <20071028174321.GB16905@fieldses.org> <20071028182732.GK27248@parisc-linux.org> <20071028184052.49abd092@the-village.bc.nu> <20071028201101.GA32359@parisc-linux.org> Mime-Version: 1.0 Content-Type: text/plain Content-Transfer-Encoding: 7bit Cc: Alan Cox , "J. Bruce Fields" , Linus Torvalds , linux-kernel@vger.kernel.org, "George G. Davis" , Andrew Morton , linux-fsdevel@vger.kernel.org To: Matthew Wilcox Return-path: Received: from pat.uio.no ([129.240.10.15]:58934 "EHLO pat.uio.no" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751198AbXJ1Vsk (ORCPT ); Sun, 28 Oct 2007 17:48:40 -0400 In-Reply-To: <20071028201101.GA32359@parisc-linux.org> Sender: linux-fsdevel-owner@vger.kernel.org List-Id: linux-fsdevel.vger.kernel.org On Sun, 2007-10-28 at 14:11 -0600, Matthew Wilcox wrote: > On Sun, Oct 28, 2007 at 06:40:52PM +0000, Alan Cox wrote: > > so we need to fix the bugs - the lock usage and the looping. At that > > point it merely becomes a performance concern to those who use it, which > > is the proper behaviour. If you want a faster non-checking one use > > flock(), or add another flag that is a Linux "don't check for deadlock" > > You can't fix the false EDEADLK detection without solving the halting > problem. Best of luck with that. I can see that it would be difficult to do efficiently, but basically, this boils down to finding a circular path in a graph. That is hardly an unsolvable issue... Trond