Function vm_object_pip_sleep

freebsd/vm/vm_object.c:381–387

* Atomically drop the object lock and wait for pip to drain. This protects * from sleep/wakeup races due to identity changes. The lock is not re-acquired * on return. */

 * on return.
 */
static void
vm_object_pip_sleep(vm_object_t object, const char *waitid)
{

	(void)blockcount_sleep(&object->paging_in_progress, &object->lock,
	    waitid, PVM | PDROP);
}

void
vm_object_pip_wait(vm_object_t object, const char *waitid)