Re: [RFC PATCH v2 04/47] hugetlb: only adjust address ranges when VMAs want PMD sharing

[Peter Xu]

On Fri, Oct 21, 2022 at 04:36:20PM +0000, James Houghton wrote:
> Currently this check is overly aggressive. For some userfaultfd VMAs,
> VMA sharing is disabled, yet we still widen the address range, which is
> used for flushing TLBs and sending MMU notifiers.
> 
> This is done now, as HGM VMAs also have sharing disabled, yet would
> still have flush ranges adjusted. Overaggressively flushing TLBs and
> triggering MMU notifiers is particularly harmful with lots of
> high-granularity operations.
> 
> Signed-off-by: James Houghton <jthoughton@xxxxxxxxxx>

Acked-by: Peter Xu <peterx@xxxxxxxxxx>

-- 
Peter Xu