Re: [PATCH v2 08/10] mm: rmap: make try_to_unmap() void function

[HORIGUCHI NAOYA(堀口 直也)]

On Tue, Jun 08, 2021 at 09:25:22PM -0700, Hugh Dickins wrote:
> From: Yang Shi <shy828301@xxxxxxxxx>
> 
> Currently try_to_unmap() return bool value by checking page_mapcount(),
> however this may return false positive since page_mapcount() doesn't
> check all subpages of compound page.  The total_mapcount() could be used
> instead, but its cost is higher since it traverses all subpages.
> 
> Actually the most callers of try_to_unmap() don't care about the
> return value at all.  So just need check if page is still mapped by
> page_mapped() when necessary.  And page_mapped() does bail out early
> when it finds mapped subpage.
> 
> Suggested-by: Hugh Dickins <hughd@xxxxxxxxxx>
> Signed-off-by: Yang Shi <shy828301@xxxxxxxxx>
> Acked-by: Minchan Kim <minchan@xxxxxxxxxx>
> Reviewed-by: Shakeel Butt <shakeelb@xxxxxxxxxx>
> Acked-by: Kirill A. Shutemov <kirill.shutemov@xxxxxxxxxxxxxxx>
> Signed-off-by: Hugh Dickins <hughd@xxxxxxxxxx>

Looks good to me, thank you.

Acked-by: Naoya Horiguchi <naoya.horiguchi@xxxxxxx>