From mboxrd@z Thu Jan 1 00:00:00 1970 From: Andreas Dilger Date: Wed, 2 Oct 2002 15:56:49 -0600 Subject: Re: [RFC][PATCH] 4KB stack + irq stack for x86 Message-ID: <20021002215649.GY3000@clusterfs.com> References: <3D9B62AC.30607@us.ibm.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <3D9B62AC.30607@us.ibm.com> Sender: owner-linux-mm@kvack.org Return-Path: To: Dave Hansen Cc: linux-kernel@vger.kernel.org, "Martin J. Bligh" , linux-mm@kvack.org List-ID: On Oct 02, 2002 14:18 -0700, Dave Hansen wrote: > I've resynced Ben's patch against 2.5.40. However, I'm getting some > strange failures. The patch is good enough to pass LTP, but > consistently freezes when I run tcpdump on it. > > Although I don't have CONFIG_PREEMPT on, I have the feeling that I > need to disable preemption in common_interrupt() like it was before. > Any insights would be appreciated. I'm a little bit worried about this patch. Have you tried something like NFS-over-ext3-over-LVM-over-MD or so, which can have a deep stack? We hit a bunch of deep stack problems like this (overflowing an 8kB stack) even without interrupts involved when developing Lustre. Granted, we fixed some large stack allocations in the ext3 indexed-directory code and in our own code, but I'm still worried that a 4kB stack is too small. The Stanford checker folks would probably be able to run a test for large stack allocations in 2.5.40 if you asked them nicely, and maybe even do stack depths for call chains. Alternately, you could set up an 8kB stack + IRQ stack and "red-zone" the high page of the current 8kB stack and see if it is ever used. Cheers, Andreas -- Andreas Dilger http://www-mddsp.enel.ucalgary.ca/People/adilger/ http://sourceforge.net/projects/ext2resize/ -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/