From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1762134AbYCGLtF (ORCPT ); Fri, 7 Mar 2008 06:49:05 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1757986AbYCGLsz (ORCPT ); Fri, 7 Mar 2008 06:48:55 -0500 Received: from gir.skynet.ie ([193.1.99.77]:34464 "EHLO gir.skynet.ie" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756634AbYCGLsy (ORCPT ); Fri, 7 Mar 2008 06:48:54 -0500 Date: Fri, 7 Mar 2008 11:48:49 +0000 From: Mel Gorman To: Lee Schermerhorn Cc: linux-kernel , linux-mm , Adam Litke , Nishanth Aravamudan , Andrew Morton , Eric Whitney Subject: Re: [BUG] 2.6.25-rc4 hang/softlockups after freeing hugepages Message-ID: <20080307114849.GC26229@csn.ul.ie> References: <1204824183.5294.62.camel@localhost> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-15 Content-Disposition: inline In-Reply-To: <1204824183.5294.62.camel@localhost> User-Agent: Mutt/1.5.13 (2006-08-11) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On (06/03/08 12:23), Lee Schermerhorn didst pronounce: > Test platform: HP Proliant DL585 server - 4 socket, dual core AMD with > 32GB memory. > > I first saw this on 25-rc2-mm1 with Mel's zonelist patches, while > investigating the interaction of hugepages and cpusets. Thinking that > it might be caused by the zonelist patches, I went back to 25-rc2-mm1 > w/o the patches and saw the same thing. It sometimes takes a while for > the softlockups to start appearing, and I wanted to find a fairly > minimal duplicator. Meanwhile 25-rc3 and rc4 have come out, so I tried > the latest upstream kernel and see the same thing. > > To duplicate the problem, I need only: > > + log into the platform as root in one window and: > > echo N >/proc/sys/vm/nr_hugepages > echo 0 >proc/sys/vm/nr_hugepages > Uncool, I am going to try and find a machine to reproduce this one but in case I have no luck, can you try setting the following in your .config which may rattle out something please? CONFIG_DEBUG_SPINLOCK=y CONFIG_DEBUG_MUTEXES=y CONFIG_DEBUG_LOCK_ALLOC=y CONFIG_PROVE_LOCKING=y CONFIG_DEBUG_SPINLOCK_SLEEP=y CONFIG_DEBUG_VM=y and as you have DEBUG_INFO, can you say what line is ffffffff8027b693 ? > In my case, N=64. If I look, before echoing 0, I see 16 hugepages > allocated on each of the 4 nodes, as expected. > > + then in another window, log in again. > > Sometimes it will hang during the 2nd login and I'll never see a shell > prompt. My initial guess was that is is something to do with page_table_lock but as you didn't get to fault in huge pages, it doesn't make much sense. -- Mel Gorman Part-time Phd Student Linux Technology Center University of Limerick IBM Dublin Software Lab