psi: introduce state_mask to represent stalled psi states

[linux-2.6-microblaze.git] / kernel / time / tick-common.c

diff --git a/kernel/time/tick-common.c b/kernel/time/tick-common.c
index df40146..59225b4 100644 (file)
--- a/kernel/time/tick-common.c
+++ b/kernel/time/tick-common.c
@@ -46,6 +46,14 @@ ktime_t tick_period;
  *    procedure also covers cpu hotplug.
  */
 int tick_do_timer_cpu __read_mostly = TICK_DO_TIMER_BOOT;
+#ifdef CONFIG_NO_HZ_FULL
+/*
+ * tick_do_timer_boot_cpu indicates the boot CPU temporarily owns
+ * tick_do_timer_cpu and it should be taken over by an eligible secondary
+ * when one comes online.
+ */
+static int tick_do_timer_boot_cpu __read_mostly = -1;
+#endif
 
 /*
  * Debugging: see timer_list.c
@@ -149,7 +157,7 @@ void tick_setup_periodic(struct clock_event_device *dev, int broadcast)
            !tick_broadcast_oneshot_active()) {
                clockevents_switch_state(dev, CLOCK_EVT_STATE_PERIODIC);
        } else {
-               unsigned long seq;
+               unsigned int seq;
                ktime_t next;
 
                do {
@@ -167,6 +175,26 @@ void tick_setup_periodic(struct clock_event_device *dev, int broadcast)
        }
 }
 
+#ifdef CONFIG_NO_HZ_FULL
+static void giveup_do_timer(void *info)
+{
+       int cpu = *(unsigned int *)info;
+
+       WARN_ON(tick_do_timer_cpu != smp_processor_id());
+
+       tick_do_timer_cpu = cpu;
+}
+
+static void tick_take_do_timer_from_boot(void)
+{
+       int cpu = smp_processor_id();
+       int from = tick_do_timer_boot_cpu;
+
+       if (from >= 0 && from != cpu)
+               smp_call_function_single(from, giveup_do_timer, &cpu, 1);
+}
+#endif
+
 /*
  * Setup the tick device
  */
@@ -186,12 +214,26 @@ static void tick_setup_device(struct tick_device *td,
                 * this cpu:
                 */
                if (tick_do_timer_cpu == TICK_DO_TIMER_BOOT) {
-                       if (!tick_nohz_full_cpu(cpu))
-                               tick_do_timer_cpu = cpu;
-                       else
-                               tick_do_timer_cpu = TICK_DO_TIMER_NONE;
+                       tick_do_timer_cpu = cpu;
+
                        tick_next_period = ktime_get();
                        tick_period = NSEC_PER_SEC / HZ;
+#ifdef CONFIG_NO_HZ_FULL
+                       /*
+                        * The boot CPU may be nohz_full, in which case set
+                        * tick_do_timer_boot_cpu so the first housekeeping
+                        * secondary that comes up will take do_timer from
+                        * us.
+                        */
+                       if (tick_nohz_full_cpu(cpu))
+                               tick_do_timer_boot_cpu = cpu;
+
+               } else if (tick_do_timer_boot_cpu != -1 &&
+                                               !tick_nohz_full_cpu(cpu)) {
+                       tick_take_do_timer_from_boot();
+                       tick_do_timer_boot_cpu = -1;
+                       WARN_ON(tick_do_timer_cpu != cpu);
+#endif
                }
 
                /*