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Subject: Re: [PATCH v3] lockdep: Make MAX_STACK_TRACE_ENTRIES configurable.
From: Peter Zijlstra <peterz@infradead.org>
To: John Kacur <jkacur@redhat.com>
Cc: Andrew Morton <akpm@linux-foundation.org>, linux-kernel@vger.kernel.org,
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Date: Wed, 21 Apr 2010 14:24:31 +0200
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On Wed, 2010-04-21 at 14:12 +0200, John Kacur wrote:
> 
>  lock-classes:                         1330 [max: 8191]
>  direct dependencies:                 12754 [max: 16384]
>  indirect dependencies:               33245
>  all direct dependencies:             49074
>  dependency chains:                   19641 [max: 32768]

Right, so each dependency also gets a stack trace, see
add_lock_to_list().

>  dependency chain hlocks:             73246 [max: 163840]
>  in-hardirq chains:                      25
>  in-softirq chains:                       0
>  in-process chains:                   19616
>  stack-trace entries:                262144 [max: 262144]
> 
> 
> I'm looking at more details in /proc/lockdep and friends to see if
> I can find any more details, or something that looks amiss.
> 
It might be useful to add a counter that simply counts all save_trace()
invocations, and maybe split them out according to new_bit in
mark_lock().