Re: Linux 2.6.25-rc2

[Pekka Enberg]

Hi Mathieu,

On Feb 19, 2008 4:02 PM, Mathieu Desnoyers <mathieu.desnoyers@xxxxxxxxxx> wrote:
> > Since this shows mostly with network card drivers, I think the most
> > plausible cause would be an IRQ nesting over kmem_cache_alloc_node and
> > calling it.

On Feb 19, 2008 4:21 PM, Pekka Enberg <penberg@xxxxxxxxxxxxxx> wrote:
> Yes, this can happen. Are you saying it is not safe to be in the
> lockless path when an IRQ triggers?

Hmm. The barrier() in slab_free() looks fishy. The comment says it's
there to make sure we've retrieved c->freelist before c->page but then
it uses a _compiler barrier_ which doesn't affect the CPU and the
reads may still be re-ordered... Not sure if that matters here though.
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