Function vm_page_astate_fcmpset

freebsd/vm/vm_page.h:818–830

* Atomically compare and set a page's atomic state. */

 *	Atomically compare and set a page's atomic state.
 */
static inline bool
vm_page_astate_fcmpset(vm_page_t m, vm_page_astate_t *old, vm_page_astate_t new)
{

	KASSERT(new.queue == PQ_INACTIVE || (new.flags & PGA_REQUEUE_HEAD) == 0,
	    ("%s: invalid head requeue request for page %p", __func__, m));
	KASSERT((new.flags & PGA_ENQUEUED) == 0 || new.queue != PQ_NONE,
	    ("%s: setting PGA_ENQUEUED with PQ_NONE in page %p", __func__, m));
	KASSERT(new._bits != old->_bits,
	    ("%s: bits are unchanged", __func__));

	return (atomic_fcmpset_32(&m->a._bits, &old->_bits, new._bits) != 0);
}

/*
 *	Clear the given bits in the specified page.