On 09.12.16 21:15:12, Yisheng Xie wrote: > For invalid pages, their zone and node information is not initialized, and it > do have risk to trigger the BUG_ON, so I have a silly question, > why not just change the BUG_ON:
We need to get the page handling correct. Modifying the BUG_ON() just hides that something is wrong. -Robert > ----------- > diff --git a/mm/page_alloc.c b/mm/page_alloc.c > index 6de9440..af199b8 100644 > --- a/mm/page_alloc.c > +++ b/mm/page_alloc.c > @@ -1860,12 +1860,13 @@ int move_freepages(struct zone *zone, > * Remove at a later date when no bug reports exist related to > * grouping pages by mobility > */ > - VM_BUG_ON(page_zone(start_page) != page_zone(end_page)); > + VM_BUG_ON(early_pfn_valid(start_page) && early_pfn_valid(end_page) && > + page_zone(start_page) != page_zone(end_page)); > #endif > > for (page = start_page; page <= end_page;) { > /* Make sure we are not inadvertently changing nodes */ > - VM_BUG_ON_PAGE(page_to_nid(page) != zone_to_nid(zone), page); > + VM_BUG_ON_PAGE(early_pfn_valid(page) && (page_to_nid(page) != > zone_to_nid(zone)), page); > > if (!pfn_valid_within(page_to_pfn(page))) { > page++;