PG_DIRECT_MAP_1M
update_page_count(PG_DIRECT_MAP_1M, pages);
update_page_count(PG_DIRECT_MAP_1M, -1);
update_page_count(PG_DIRECT_MAP_1M, PTRS_PER_PMD);
atomic_long_read(&direct_pages_count[PG_DIRECT_MAP_1M]) << 10);
update_page_count(PG_DIRECT_MAP_1M, add ? pages : -pages);