Re: [PATCH 08/20] mm: Optimize fullmm TLB flushing

[Peter Zijlstra <a.p.zijlstra@chello.nl>]

On Wed, 2012-06-27 at 15:26 -0700, Linus Torvalds wrote:
> On Wed, Jun 27, 2012 at 2:15 PM, Peter Zijlstra <a.p.zijlstra@chello.nl> wrote:
> > This originated from s390 which does something similar and would allow
> > s390 to use the generic TLB flushing code.
> >
> > The idea is to flush the mm wide cache and tlb a priory and not bother
> > with multiple flushes if the batching isn't large enough.
> >
> > This can be safely done since there cannot be any concurrency on this
> > mm, its either after the process died (exit) or in the middle of
> > execve where the thread switched to the new mm.
> 
> I think we actually *used* to do the final TLB flush from within the
> context of the process that died. That doesn't seem to ever be the
> case any more, but it does worry me a bit. Maybe a
> 
>    VM_BUG_ON(current->active_mm == mm);
> 
> or something for the fullmm case?

OK, added it and am rebooting the test box..

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