On Mon, Feb 27, 2017 at 03:35:34PM +0100, Michal Hocko wrote: > 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 <mho...@suse.com> > > Cc: Minchan Kim <minc...@kernel.org> > > Cc: Hugh Dickins <hu...@google.com> > > Cc: Rik van Riel <r...@redhat.com> > > Cc: Mel Gorman <mgor...@techsingularity.net> > > Cc: Andrew Morton <a...@linux-foundation.org> > > Acked-by: Johannes Weiner <han...@cmpxchg.org> > > Signed-off-by: Shaohua Li <s...@fb.com> > > 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...
Just check a page which isn't lazyfree but wrongly enters here without swap entry. Or maybe you suggest we delete this statement? Thanks, Shaohua
