On Fri 24-02-17 13:31:45, Shaohua Li wrote:
> There are a few places the code assumes anonymous pages should have
> SwapBacked flag set. MADV_FREE pages are anonymous pages but we are
> going to add them to LRU_INACTIVE_FILE list and clear SwapBacked flag
> for them. The assumption doesn't hold any more, so fix them.
>
> Cc: Michal Hocko <[email protected]>
> Cc: Minchan Kim <[email protected]>
> Cc: Hugh Dickins <[email protected]>
> Cc: Rik van Riel <[email protected]>
> Cc: Mel Gorman <[email protected]>
> Cc: Andrew Morton <[email protected]>
> Acked-by: Johannes Weiner <[email protected]>
> Signed-off-by: Shaohua Li <[email protected]>
Looks good to me.
[...]
> index 96eb85c..c621088 100644
> --- a/mm/rmap.c
> +++ b/mm/rmap.c
> @@ -1416,7 +1416,8 @@ static int try_to_unmap_one(struct page *page, struct
> vm_area_struct *vma,
> * Store the swap location in the pte.
> * See handle_pte_fault() ...
> */
> - VM_BUG_ON_PAGE(!PageSwapCache(page), page);
> + VM_BUG_ON_PAGE(!PageSwapCache(page) &&
> PageSwapBacked(page),
> + page);
just this part makes me scratch my head. I really do not understand what
kind of problem it tries to prevent from, maybe I am missing something
obvoious...
>
> if (!PageDirty(page)) {
> /* It's a freeable page by MADV_FREE */
> --
> 2.9.3
>
--
Michal Hocko
SUSE Labs
