On Fri, May 06, 2016 at 05:03:59PM +0200, Andrea Arcangeli wrote: > compound_mapcount() is only called after PageCompound() has already > been checked by the caller, so there's no point to check it again. Gcc > may optimize it away too because it's inline but this will remove the > runtime check for sure and add it'll add an assert instead. > > Signed-off-by: Andrea Arcangeli <[email protected]>
Acked-by: Kirill A. Shutemov <[email protected]> > --- > include/linux/mm.h | 3 +-- > 1 file changed, 1 insertion(+), 2 deletions(-) > > diff --git a/include/linux/mm.h b/include/linux/mm.h > index 263f229..726ba80 100644 > --- a/include/linux/mm.h > +++ b/include/linux/mm.h > @@ -471,8 +471,7 @@ static inline atomic_t *compound_mapcount_ptr(struct page > *page) > > static inline int compound_mapcount(struct page *page) > { > - if (!PageCompound(page)) > - return 0; > + VM_BUG_ON_PAGE(!PageCompound(page), page); > page = compound_head(page); > return atomic_read(compound_mapcount_ptr(page)) + 1; > } -- Kirill A. Shutemov
