On Tue, 2017-04-11 at 17:54 +1000, Alexey Kardashevskiy wrote: > The CMA pages migration code does not support compound pages at > the moment so it performs few tests before proceeding to actual page > migration. > > One of the tests - PageTransHuge() - has VM_BUG_ON_PAGE(PageTail()) as > it is designed to be called on head pages only. Since we also test for > PageCompound(), and it contains PageTail() and PageHead(), we can > simplify the check by leaving just PageCompound() and therefore avoid > possible VM_BUG_ON_PAGE. > > Fixes: 2e5bbb5461f1 ("KVM: PPC: Book3S HV: Migrate pinned pages out of CMA") > Cc: stable@xxxxxxxxxxxxxxx # v4.9+ > Signed-off-by: Alexey Kardashevskiy <aik@xxxxxxxxx> > Acked-by: Balbir Singh <bsingharora@xxxxxxxxx> > --- > > Changes: > v2: > * instead of moving PageCompound() to the beginning, this just drops > PageHuge() and PageTransHuge() > Looks good! My Acked-by is already present Balbir Singh.