+ chan->switch_timer_enabled = 1;
+
+ lib_ring_buffer_setup_timer_thread();
+
+ sev.sigev_notify = SIGEV_SIGNAL;
+ sev.sigev_signo = LTTNG_UST_RB_SIG;
+ sev.sigev_value.sival_ptr = chan;
+ ret = timer_create(CLOCKID, &sev, &chan->switch_timer);
+ if (ret == -1) {
+ PERROR("timer_create");
+ }
+
+ its.it_value.tv_sec = chan->switch_timer_interval / 1000000;
+ its.it_value.tv_nsec = chan->switch_timer_interval % 1000000;
+ its.it_interval.tv_sec = its.it_value.tv_sec;
+ its.it_interval.tv_nsec = its.it_value.tv_nsec;
+
+ ret = timer_settime(chan->switch_timer, 0, &its, NULL);
+ if (ret == -1) {
+ PERROR("timer_settime");
+ }
+}
+
+/*
+ * Called with ust_lock() held.
+ */
+static
+void lib_ring_buffer_channel_switch_timer_stop(struct channel *chan)
+{
+ sigset_t pending_set;
+ int sig_is_pending, ret;
+
+ if (!chan->switch_timer_interval || !chan->switch_timer_enabled)
+ return;
+
+ ret = timer_delete(chan->switch_timer);
+ if (ret == -1) {
+ PERROR("timer_delete");
+ }
+
+ /*
+ * Ensure we don't have any signal queued for this channel.
+ */
+ for (;;) {
+ ret = sigemptyset(&pending_set);
+ if (ret == -1) {
+ PERROR("sigemptyset");
+ }
+ ret = sigpending(&pending_set);
+ if (ret == -1) {
+ PERROR("sigpending");
+ }
+ sig_is_pending = sigismember(&pending_set, LTTNG_UST_RB_SIG);
+ if (!sig_is_pending)
+ break;
+ caa_cpu_relax();
+ }
+
+ /*
+ * From this point, no new signal handler will be fired that
+ * would try to access "chan". However, we still need to wait
+ * for any currently executing handler to complete.
+ */
+ cmm_smp_mb();
+ CMM_STORE_SHARED(timer_signal.qs_done, 0);
+ cmm_smp_mb();
+
+ /*
+ * Kill with LTTNG_UST_RB_SIG_TEARDOWN, so signal management
+ * thread wakes up.
+ */
+ kill(getpid(), LTTNG_UST_RB_SIG_TEARDOWN);
+
+ while (!CMM_LOAD_SHARED(timer_signal.qs_done))
+ caa_cpu_relax();
+ cmm_smp_mb();
+
+ chan->switch_timer = 0;
+ chan->switch_timer_enabled = 0;