On 10/13/2017 02:00 PM, Michal Hocko wrote: > From: Michal Hocko <mho...@suse.com> > > Reserved pages should be completely ignored by the core mm because they > have a special meaning for their owners. has_unmovable_pages doesn't > check those so we rely on other tests (reference count, or PageLRU) to > fail on such pages. Althought this happens to work it is safer to simply > check for those explicitly and do not rely on the owner of the page > to abuse those fields for special purposes. > > Please note that this is more of a further fortification of the code > rahter than a fix of an existing issue. > > Signed-off-by: Michal Hocko <mho...@suse.com> > --- > mm/page_alloc.c | 3 +++ > 1 file changed, 3 insertions(+) > > diff --git a/mm/page_alloc.c b/mm/page_alloc.c > index ad0294ab3e4f..a8800b0a5619 100644 > --- a/mm/page_alloc.c > +++ b/mm/page_alloc.c > @@ -7365,6 +7365,9 @@ bool has_unmovable_pages(struct zone *zone, struct page > *page, int count, > > page = pfn_to_page(check); > > + if (PageReferenced(page))
"Referenced" != "Reserved" > + return true; > + > /* > * Hugepages are not in LRU lists, but they're movable. > * We need not scan over tail pages bacause we don't >
