Subject: Re: [PATCH 1/3] Increase lockdep limits: MAX_STACK_TRACE_ENTRIES
From: Peter Zijlstra <a.p.zijlstra@chello.nl>
To: Dave Jones <davej@redhat.com>
Cc: Joao Correia <joaomiguelcorreia@gmail.com>,
       LKML <linux-kernel@vger.kernel.org>,
       =?ISO-8859-1?Q?Am=E9rico?= Wang <xiyou.wangcong@gmail.com>,
       Frederic Weisbecker <fweisbec@gmail.com>,
       Arjan van de Ven <arjan@linux.intel.com>,
       Catalin Marinas <catalin.marinas@arm.com>,
       "joerg.roedel" <joerg.roedel@amd.com>
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Date: Thu, 09 Jul 2009 19:07:31 +0200
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On Thu, 2009-07-09 at 12:10 -0400, Dave Jones wrote:
> On Thu, Jul 09, 2009 at 10:02:36AM +0200, Peter Zijlstra wrote:
>  > On Thu, 2009-07-09 at 00:39 -0400, Dave Jones wrote:
>  > > On Wed, Jul 08, 2009 at 08:36:04PM +0200, Peter Zijlstra wrote:
>  > >  > Looking at a lockdep dump hch gave me I can see that that is certainly
>  > >  > possible, I see tons of very deep callchains.
>  > >  > 
>  > >  > /me wonders if we're getting significantly deeper..
>  > > 
>  > > Looking at /proc/lockdep, I'm curious..
>  > > Take a look at http://davej.fedorapeople.org/lockdep
>  > > scroll down to c12c0924
>  > > 
>  > > What's up with all those old_style_spin_init's ?
>  > 
>  > What kernel are you running?
> 
> ..31rc2
> 
>  > Does your lib/dma_debug.c:dma_debug_init()
>  > have spin_lock_init() in that HASH_SIZE loop?
> 
> it's doing it by hand..
> 
>  717         for (i = 0; i < HASH_SIZE; ++i) {
>  718                 INIT_LIST_HEAD(&dma_entry_hash[i].list);
>  719                 dma_entry_hash[i].lock = SPIN_LOCK_UNLOCKED;
>  720         }

Hmm, that's the problem, it should read:

        for (i = 0; i < HASH_SIZE; ++i) {
                INIT_LIST_HEAD(&dma_entry_hash[i].list);
                spin_lock_init(&dma_entry_hash[i].lock);
        }

and does in -tip, so maybe Ingo took that patch, but I thought Joerg
would push that Linus wards. Joerg?

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