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SubjectRe: [patch] x86, mm: avoid stale tlb entries by clearing prev mm_cpumask after switching mm
On Wed, Feb 2, 2011 at 12:07 PM, Suresh Siddha
<> wrote:
> For the prev mm that is handing over the cpu to another mm, clear the cpu
> from the mm_cpumask(prev) after the cr3 is changed.
> Otherwise, clearing the mm_cpumask early will avoid the flush tlb IPI's while
> the cr3 and TLB's are still pointing to the prev mm. And this window can lead
> to the stale (global) TLB entries.


This looks pointless. Explain why this matters. Global entries are
never per-mm, so any global entries can never care about the

And for any normal entries it doesn't matter if the IPI gets lost,
since the TLB will be flushed (immediately afterwards) by the cr3

So no, I will not accept this patch, and it shouldn't be marked for
stable. Unless you can show exactly what is the point of it, and
exactly what the bug is.


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