Re: percpu related boot crash on x86

From: Eric Dumazet
Date: Thu Jan 20 2011 - 06:12:57 EST


Le jeudi 20 janvier 2011 Ã 11:47 +0100, Peter Zijlstra a Ãcrit :
> On Thu, 2011-01-20 at 10:31 +0200, Pekka Enberg wrote:
> > if (!irqs_disabled())
> >
> > guard around the debugging code to make vfree() always work with IRQs
> > disabled.
>
> That won't be sufficient, __purge_vmap_area_lazy() needs to call
> flush_tlb_kernel_range() occasionally.
>
> There really is a good reason vmalloc()/vfree() don't work with
> interrupts disabled.
>

Hmm, I would try to increase PERCPU_DYNAMIC_RESERVE, or pcpu_mem_alloc()
could try to use kzalloc() even for allocations bigger than one PAGE,
and fallback to vzalloc().

We have more alloc_percpu() uses, we also should try to use first chunk
if possible.



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