PGF_ATTR_MOD
#define PGF_PRESERVE (PGF_ATTR_MOD | PGF_ATTR_REF)
PGF_ATTR_MOD | PGF_ATTR_REF);
} else if (pg->pg_flags & PGF_ATTR_MOD) {
if (pg->pg_flags & PGF_ATTR_MOD) {
atomic_clearbits_int(&pg->pg_flags, PGF_ATTR_MOD);
return (pg->pg_flags & PGF_ATTR_MOD) != 0;
atomic_setbits_int(&pg->pg_flags, PGF_ATTR_MOD | PGF_ATTR_REF);