From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Jesper Juhl" Subject: Re: 2.6.19-rc6 : Spontaneous reboots, stack overflows - seems to implicate xfs, scsi, networking, SMP Date: Fri, 24 Nov 2006 02:08:53 +0100 Message-ID: <9a8748490611231708w3abf295bw3c007acf5cdcf336@mail.gmail.com> References: <9a8748490611211551v2ebe88fel2bcf25af004c338a@mail.gmail.com> <20061122.201013.112290046.davem@davemloft.net> <20061123070837.GV11034@melbourne.sgi.com> <200611231416.03387.netdev@axxeo.de> <1164307020.3147.3.camel@laptopd505.fenrus.org> <20061124005528.GF11034@melbourne.sgi.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Cc: "Arjan van de Ven" , "Ingo Oeser" , "David Miller" , chatz@melbourne.sgi.com, linux-kernel@vger.kernel.org, xfs@oss.sgi.com, xfs-masters@oss.sgi.com, netdev@vger.kernel.org, linux-scsi@vger.kernel.org Return-path: To: "David Chinner" In-Reply-To: <20061124005528.GF11034@melbourne.sgi.com> Content-Disposition: inline Sender: linux-scsi-owner@vger.kernel.org List-Id: netdev.vger.kernel.org On 24/11/06, David Chinner wrote: > On Thu, Nov 23, 2006 at 07:37:00PM +0100, Arjan van de Ven wrote: > > On Thu, 2006-11-23 at 14:16 +0100, Ingo Oeser wrote: > > > Hi there, > > > > > > David Chinner schrieb: > > > > If the softirqs were run on a different stack, then a lot of these > > > > softirqs DO run on their own stack! > > So they run on a separate stack for 4k stacks on x86? > Yes, with 4K stacks there's sepperate IRQ stack. >>From the help text for CONFIG_4KSTACKS : "If you say Y here the kernel will use a 4Kb stacksize for the kernel stack attached to each process/thread. This facilitates running more threads on a system and also reduces the pressure on the VM subsystem for higher order allocations. This option will also use IRQ stacks to compensate for the reduced stackspace." > They don't run on a separate stack for 8k stacks on x86 - > Jesper's traces show that - so this may indicate an issue > with the methodology used to generate the stack overflow > traces inteh first place. i.e. if 4k stacks use a separate > stack, then most of the reported overflows are spurious > and would not normally occur on 4k stack systems.. > Well, some of the traces show that we were down to ~3K stack free with 8K stacks, so ~5K used. Even with 4K stacks and sepperate stack for IRQs we will still be uncomfortably close to the edge in those cases. Also, I did manage to capture a single line via netconsole while running with 4K stacks : do_IRQ: stack overflow: 492 Unfortunately that was the only line that made it to the remote log server, so I don't have the actual trace for that one. But it does show that there really is an issue when running with 4K stacks, IRQ stacks or no. -- Jesper Juhl Don't top-post http://www.catb.org/~esr/jargon/html/T/top-post.html Plain text mails only, please http://www.expita.com/nomime.html