ce enabled, while running 100
> KVM
> guest instances.
>
> This patch fixes the issue by ensuring that the page belongs to a valid PFN
> when we fallback to using the lower limit of the scan range upon failure in
> fast_isolate_freepages().
>
> Fixes: 5a811889de10f1eb ("mm, compaction: use free lists to quickly locate a
> migration target")
> Reported-by: Marc Zyngier
> Signed-off-by: Suzuki K Poulose
Reviewed-by: Mel Gorman
--
Mel Gorman
SUSE Labs
> pfn_to_online_page() here would be better as it does not add pfn_valid() cost
> on
> architectures which does not subscribe to CONFIG_HOLES_IN_ZONE. But
> regardless if
> the compaction is trying to scan pfns in zone holes, then it should be
> avoided.
CONFIG_HOLES_IN_ZONE ty
unmeasurable overall. However,
it is definitely the case that if the PFN you highlight is invalid that
badness happens. If you want to express this as a signed-off patch with
an adjusted changelog then I'd be happy to add
Reviewed-by: Mel Gorman
If you are not comfortable with rewriting t
