[PATCH 2/8] x86: use exit_lazy_tlb rather than membarrier_mm_sync_core_before_usermode

[Andy Lutomirski]

> On Dec 5, 2020, at 7:59 PM, Nicholas Piggin <npiggin at gmail.com> wrote:
>

> I'm still going to persue shoot-lazies for the merge window. As you
> see it's about a dozen lines and a if (IS_ENABLED(... in core code.
> Your change is common code, but a significant complexity (which
> affects all archs) so needs a lot more review and testing at this
> point.

I don't think it's ready for this merge window.  I read the early
patches again, and I think they make the membarrier code worse, not
better.  I'm not fundamentally opposed to the shoot-lazies concept,
but it needs more thought and it needs a cleaner foundation.