Re: [PATCH 0/6] x86/cpu hotplug: Wake up offline CPU via mwait ornmi

[Peter Zijlstra]

On Wed, 2012-06-06 at 08:23 -0700, Arjan van de Ven wrote:
> btw TLB invalidation I think is a red herring in this discussion
> (other than "global PTEs" kind of kernel pte changes);
> at least on x86 this is not happening for a long time; if a CPU is
> really idle (which means the CPU internally flushes the tlbs anyway),
> Linux also switches to the kernel PTE set so there's no need for a flush
> later on. 

This is about isolation, not idle. If you share a mm across your
isolation barrier you get TLB invalidates, its unavoidable. The solution
is not sharing the mm -- which is a perfectly usable solution.
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