BM_PAGE_LAZY_WRITEOUT
clear_bit(BM_PAGE_LAZY_WRITEOUT, &page_private(page));
return (*addr & ((1UL<<BM_PAGE_NEED_WRITEOUT)|(1UL<<BM_PAGE_LAZY_WRITEOUT))) == 0;
set_bit(BM_PAGE_LAZY_WRITEOUT, &page_private(page));
return test_bit(BM_PAGE_LAZY_WRITEOUT, &page_private(page));