PB_migrate_isolate
get_pfnblock_bit(page, page_to_pfn(page), PB_migrate_isolate)
clear_pfnblock_bit(page, page_to_pfn(page), PB_migrate_isolate)
set_pfnblock_bit(page, page_to_pfn(page), PB_migrate_isolate)
#define MIGRATETYPE_AND_ISO_MASK (MIGRATETYPE_MASK | BIT(PB_migrate_isolate))
if (flags & BIT(PB_migrate_isolate))
flags |= BIT(PB_migrate_isolate);