TAIL_MAPPING     2463 mm/huge_memory.c 	VM_BUG_ON_PAGE(tail > 2 && page_tail->mapping != TAIL_MAPPING,
TAIL_MAPPING      688 mm/page_alloc.c 		p->mapping = TAIL_MAPPING;
TAIL_MAPPING     1092 mm/page_alloc.c 		if (page->mapping != TAIL_MAPPING) {