From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: with ECARTIS (v1.0.0; list xfs); Fri, 31 Aug 2007 08:11:12 -0700 (PDT) Received: from sandeen.net (sandeen.net [209.173.210.139]) by oss.sgi.com (8.12.10/8.12.10/SuSE Linux 0.7) with ESMTP id l7VFB84p004290 for ; Fri, 31 Aug 2007 08:11:10 -0700 Message-ID: <46D82F9A.9090606@sandeen.net> Date: Fri, 31 Aug 2007 10:11:22 -0500 From: Eric Sandeen MIME-Version: 1.0 Subject: Re: [PATCH] Increase lockdep MAX_LOCK_DEPTH References: <46D79C62.1010304@sandeen.net> <1188542389.6112.44.camel@twins> <20070831135042.GD422459@sgi.com> <1188570831.6112.64.camel@twins> <20070831150511.GA734179@sgi.com> <1188572961.6112.72.camel@twins> In-Reply-To: <1188572961.6112.72.camel@twins> Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Sender: xfs-bounce@oss.sgi.com Errors-to: xfs-bounce@oss.sgi.com List-Id: xfs To: Peter Zijlstra Cc: David Chinner , linux-kernel Mailing List , xfs-oss , Ingo Molnar Peter Zijlstra wrote: > On Sat, 2007-09-01 at 01:05 +1000, David Chinner wrote: > >>> Trouble is, we'd like to have a sane upper bound on the amount of held >>> locks at any one time, obviously this is just wanting, because a lot of >>> lock chains also depend on the number of online cpus... >> Sure - this is an obvious case where it is valid to take >30 locks at >> once in a single thread. In fact, worst case here we are taking twice this >> number of locks - we actually take 2 per inode (ilock and flock) so a >> full 32 inode cluster free would take >60 locks in the middle of this >> function and we should be busting this depth couter limit all the >> time. > > I think this started because jeffpc couldn't boot without XFS busting > lockdep :-) > >> Do semaphores (the flush locks) contribute to the lock depth >> counters? > > No, alas, we cannot handle semaphores in lockdep. That explains why 40 was enough for me, I guess :) -Eric