pmap_changebit
pmap_changebit(pg, PG_FOW, ~0, cpu_id);
pmap_changebit(pg, PG_FOR | PG_FOW | PG_FOE, ~0, cpu_id);
pmap_changebit(pg, 0, ~faultoff, cpu_id);
void pmap_changebit(struct vm_page *, pt_entry_t, pt_entry_t, cpuid_t);
pmap_changebit(pg, PTE_PROT(TLB_UNCACHABLE), 0);
#define pmap_clear_modify(pg) pmap_changebit(pg, 0, PTE_PROT(TLB_DIRTY))
#define pmap_clear_reference(pg) pmap_changebit(pg, PTE_PROT(TLB_REFTRAP), 0)
boolean_t pmap_changebit(struct vm_page *, pt_entry_t, pt_entry_t);