- Don't allow watchdogd(8) to be swapped out.

On machines with huge amount of swap and high IO activity,
  watchdogd(8) may wait for a swap memory longer than timeout and
  sometimes fires.

Approved by:	kib (mentor)
MFC after:	1 week

usr.sbin/watchdogd/watchdogd.c

@@ -118,6 +118,8 @@ main(int argc, char *argv[])
 		pidfile_write(pfh);
 		if (madvise(0, 0, MADV_PROTECT) != 0)
 			warn("madvise failed");
+		if (mlockall(MCL_FUTURE) != 0)
+			warn("mlockall failed");
 
 		watchdog_loop();