Re: [kvm-devel] [patch 2/6] mmu_notifier: Callbacks to invalidate address ranges

Robin Holt
2008-01-31T02:35:34Z

> Well the GRU uses follow_page() instead of get_user_pages. Performance is
> a major issue for the GRU.

Worse, the GRU takes its TLB faults from within an interrupt so we
use follow_page to prevent going to sleep. That said, I think we
could probably use follow_page() with FOLL_GET set to accomplish the
requirements of mmu_notifier invalidate_range call. Doesn't look too
promising for hugetlb pages.

Thanks,
Robin