Subject: Re: [PATCH] netfilter: per-cpu spin-lock with recursion (v0.8)

From: Peter Zijlstra <[email-masked]>
Date: Fri, 17 Apr 2009 19:08:15 +0200

On Fri, 2009-04-17 at 08:14 +0200, Eric Dumazet wrote:
> > Also, please dont call this a 'recursive lock', since it is not a general
> > recursive lock, as pointed by Linus and Paul.
> > 
> > Second question is about MAX_LOCK_DEPTH
> 
> I meant here the ~256 limit we have on preempt_count, not related to LOCKDEP

Very good point, so 256 nested spin_lock() instances will make the
kernel unhappy -- since we now (almost?) support up to 4096 cpus, this
seems like a no-no.