+ /*
+ * itimer signal ?
+ *
+ * itimers are process shared and we restart periodic
+ * itimers in the signal delivery path to prevent DoS
+ * attacks in the high resolution timer case. This is
+ * compliant with the old way of self restarting
+ * itimers, as the SIGALRM is a legacy signal and only
+ * queued once. Changing the restart behaviour to
+ * restart the timer in the signal dequeue path is
+ * reducing the timer noise on heavy loaded !highres
+ * systems too.
+ */
+ if (unlikely(signr == SIGALRM)) {
+ struct hrtimer *tmr = &tsk->signal->real_timer;
+
+ if (!hrtimer_is_queued(tmr) &&
+ tsk->signal->it_real_incr.tv64 != 0) {
+ hrtimer_forward(tmr, tmr->base->get_time(),
+ tsk->signal->it_real_incr);
+ hrtimer_restart(tmr);
+ }
+ }
+ }