Messages in this thread | | | Subject | Re: lockdep complaints in slab allocator | From | Pekka Enberg <> | Date | Mon, 23 Nov 2009 21:50:14 +0200 |
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On Mon, 23 Nov 2009, Pekka Enberg wrote: > > That turns out to be _very_ hard. How about something like the following > > untested patch which delays slab_destroy() while we're under nc->lock.
On Mon, 2009-11-23 at 13:30 -0600, Christoph Lameter wrote: > Code changes to deal with a diagnostic issue?
OK, fair enough. If I suffer permanent brain damage from staring at the SLAB code for too long, I hope you and Matt will chip in to pay for my medication.
I think I was looking at the wrong thing here. The problem is in cache_free_alien() so the comment in slab_destroy() isn't relevant. Looking at init_lock_keys() we already do special lockdep annotations but there's a catch (as explained in a comment on top of on_slab_alc_key):
* We set lock class for alien array caches which are up during init. * The lock annotation will be lost if all cpus of a node goes down and * then comes back up during hotplug
Paul said he was running CPU hotplug so maybe that explains the problem?
Pekka
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