Re: lockdep complaints in slab allocator

[Pekka Enberg <penberg@cs.helsinki.fi>]

Matt Mackall wrote:
> This seems like a lot of work to paper over a lockdep false positive in
> code that should be firmly in the maintenance end of its lifecycle? I'd
> rather the fix or papering over happen in lockdep.

True that. Is __raw_spin_lock() out of question, Peter?-) Passing the 
state is pretty invasive because of the kmem_cache_free() call in 
slab_destroy(). We re-enter the slab allocator from the outer edges 
which makes spin_lock_nested() very inconvenient.

> Introducing extra cacheline pressure by passing to_destroy around also
> seems like a good way to trickle away SLAB's narrow remaining
> performance advantages.

We can probably fix that to affect CONFIG_NUMA only which sucks already.

			Pekka