Re: [patch 1/2] x86_64 page fault NMI-safe

[H. Peter Anvin]

On 07/14/2010 01:07 PM, Andi Kleen wrote:
>>> In fact I'm pretty sure it worked originally. Perhaps it regressed?
>>
>> I'd first ask the obvious to Perf authors: does perf issue vmalloc_sync_all()
>> between percpu data allocation and tracing activation ? The generic ring buffer
>> library I posted last week does it already as a precaution for this very
>> specific reason (making sure NMIs never trigger page faults).
> 
> I suspect the low level per cpu allocation functions should 
> just call it.
> 

Yes, specifically the point at which we allocate new per cpu memory blocks.

	-hpa

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