Re: [PATCH v14 052/138] mm: Add folio_raw_mapping()

Matthew Wilcox
2021-08-14T16:52:01Z

On Tue, Aug 10, 2021 at 09:42:13PM +0100, David Howells wrote:
> Matthew Wilcox (Oracle) <willy@infradead.org> wrote:
>
> > Convert __page_rmapping to folio_raw_mapping and move it to mm/internal.h.
> > It's only a couple of instructions (load and mask), so it's definitely
> > going to be cheaper to inline it than call it. Leave page_rmapping
> > out of line.
> >
> > Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
>
> I assume you're going to call it from another source file at some point,
> otherwise this is unnecessary.

Yes, it gets called from mm/ksm.c in a later patch in this series.
__page_rmapping() assumes it's being passed a head page and
folio_raw_mapping() asserts that. Eventually, page_rmapping() can
go away (and maybe it should have been moved to folio-compat.c),
but I'm not inclined to do that now.

> Apart from that,
>
> Reviewed-by: David Howells <dhowells@redhat.com>
>