Re: [PATCH 1/3] perf_event: fix race in perf_swevent_get_recursion_context()

[Xiao Guangrong]

Hi Peter,

Peter Zijlstra wrote:
> On Mon, 2010-01-18 at 21:42 +0800, Xiao Guangrong wrote:
>> It only disable preemption in perf_swevent_get_recursion_context()
>> it can't avoid race of hard-irq and NMI
>>
>> In this patch, we use atomic operation to avoid it and reduce
>> cpu_ctx->recursion size, it also make this patch no need diable
>> preemption
> 
> Uhm why?
> 
> This patch looks terminally broken

Please see my explanation in another mail:
http://lkml.org/lkml/2010/1/18/501

Thanks,
Xiao
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