Re: [tip:perfcounters/core] perf_counter: x86: Fix call-chain support to use NMI-safe methods

[Mathieu Desnoyers <mathieu.desnoyers@xxxxxxxxxx>]

* H. Peter Anvin (hpa@xxxxxxxxx) wrote:
> Mathieu Desnoyers wrote:
> > 
> > I'm just thinking that touching or not vmalloc'd areas should not be the
> > first thing that comes into the mind of someone willing to write a
> > nmi-hooking tracer or oprofile module.
> > 
> 
> But is HAS to be.  Otherwise you're in deadlock city anyway.
> 

Where is the kernel page fault handler grabbing any lock to service
in-kernel page faults exactly ?

Those are usually considered as utterly simple page table fixups,
nothing more.

Mathieu

> 	-hpa
> 

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Mathieu Desnoyers
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