Merge master.kernel.org:/home/rmk/linux-2.6-arm
[linux-2.6.git] / kernel / softlockup.c
index 88796c3..0d4c789 100644 (file)
 
 static DEFINE_SPINLOCK(print_lock);
 
-static DEFINE_PER_CPU(unsigned long, touch_timestamp);
-static DEFINE_PER_CPU(unsigned long, print_timestamp);
-static DEFINE_PER_CPU(struct task_struct *, watchdog_task);
+static DEFINE_PER_CPU(unsigned long, softlockup_touch_ts); /* touch timestamp */
+static DEFINE_PER_CPU(unsigned long, softlockup_print_ts); /* print timestamp */
+static DEFINE_PER_CPU(struct task_struct *, softlockup_watchdog);
+static DEFINE_PER_CPU(bool, softlock_touch_sync);
 
 static int __read_mostly did_panic;
 int __read_mostly softlockup_thresh = 60;
@@ -70,31 +71,37 @@ static void __touch_softlockup_watchdog(void)
 {
        int this_cpu = raw_smp_processor_id();
 
-       __raw_get_cpu_var(touch_timestamp) = get_timestamp(this_cpu);
+       __raw_get_cpu_var(softlockup_touch_ts) = get_timestamp(this_cpu);
 }
 
 void touch_softlockup_watchdog(void)
 {
-       __raw_get_cpu_var(touch_timestamp) = 0;
+       __raw_get_cpu_var(softlockup_touch_ts) = 0;
 }
 EXPORT_SYMBOL(touch_softlockup_watchdog);
 
+void touch_softlockup_watchdog_sync(void)
+{
+       __raw_get_cpu_var(softlock_touch_sync) = true;
+       __raw_get_cpu_var(softlockup_touch_ts) = 0;
+}
+
 void touch_all_softlockup_watchdogs(void)
 {
        int cpu;
 
        /* Cause each CPU to re-update its timestamp rather than complain */
        for_each_online_cpu(cpu)
-               per_cpu(touch_timestamp, cpu) = 0;
+               per_cpu(softlockup_touch_ts, cpu) = 0;
 }
 EXPORT_SYMBOL(touch_all_softlockup_watchdogs);
 
 int proc_dosoftlockup_thresh(struct ctl_table *table, int write,
-                            struct file *filp, void __user *buffer,
+                            void __user *buffer,
                             size_t *lenp, loff_t *ppos)
 {
        touch_all_softlockup_watchdogs();
-       return proc_dointvec_minmax(table, write, filp, buffer, lenp, ppos);
+       return proc_dointvec_minmax(table, write, buffer, lenp, ppos);
 }
 
 /*
@@ -104,28 +111,36 @@ int proc_dosoftlockup_thresh(struct ctl_table *table, int write,
 void softlockup_tick(void)
 {
        int this_cpu = smp_processor_id();
-       unsigned long touch_timestamp = per_cpu(touch_timestamp, this_cpu);
-       unsigned long print_timestamp;
+       unsigned long touch_ts = per_cpu(softlockup_touch_ts, this_cpu);
+       unsigned long print_ts;
        struct pt_regs *regs = get_irq_regs();
        unsigned long now;
 
        /* Is detection switched off? */
-       if (!per_cpu(watchdog_task, this_cpu) || softlockup_thresh <= 0) {
+       if (!per_cpu(softlockup_watchdog, this_cpu) || softlockup_thresh <= 0) {
                /* Be sure we don't false trigger if switched back on */
-               if (touch_timestamp)
-                       per_cpu(touch_timestamp, this_cpu) = 0;
+               if (touch_ts)
+                       per_cpu(softlockup_touch_ts, this_cpu) = 0;
                return;
        }
 
-       if (touch_timestamp == 0) {
+       if (touch_ts == 0) {
+               if (unlikely(per_cpu(softlock_touch_sync, this_cpu))) {
+                       /*
+                        * If the time stamp was touched atomically
+                        * make sure the scheduler tick is up to date.
+                        */
+                       per_cpu(softlock_touch_sync, this_cpu) = false;
+                       sched_clock_tick();
+               }
                __touch_softlockup_watchdog();
                return;
        }
 
-       print_timestamp = per_cpu(print_timestamp, this_cpu);
+       print_ts = per_cpu(softlockup_print_ts, this_cpu);
 
        /* report at most once a second */
-       if (print_timestamp == touch_timestamp || did_panic)
+       if (print_ts == touch_ts || did_panic)
                return;
 
        /* do not print during early bootup: */
@@ -140,18 +155,18 @@ void softlockup_tick(void)
         * Wake up the high-prio watchdog task twice per
         * threshold timespan.
         */
-       if (now > touch_timestamp + softlockup_thresh/2)
-               wake_up_process(per_cpu(watchdog_task, this_cpu));
+       if (now > touch_ts + softlockup_thresh/2)
+               wake_up_process(per_cpu(softlockup_watchdog, this_cpu));
 
        /* Warn about unreasonable delays: */
-       if (now <= (touch_timestamp + softlockup_thresh))
+       if (now <= (touch_ts + softlockup_thresh))
                return;
 
-       per_cpu(print_timestamp, this_cpu) = touch_timestamp;
+       per_cpu(softlockup_print_ts, this_cpu) = touch_ts;
 
        spin_lock(&print_lock);
        printk(KERN_ERR "BUG: soft lockup - CPU#%d stuck for %lus! [%s:%d]\n",
-                       this_cpu, now - touch_timestamp,
+                       this_cpu, now - touch_ts,
                        current->comm, task_pid_nr(current));
        print_modules();
        print_irqtrace_events(current);
@@ -209,32 +224,32 @@ cpu_callback(struct notifier_block *nfb, unsigned long action, void *hcpu)
        switch (action) {
        case CPU_UP_PREPARE:
        case CPU_UP_PREPARE_FROZEN:
-               BUG_ON(per_cpu(watchdog_task, hotcpu));
+               BUG_ON(per_cpu(softlockup_watchdog, hotcpu));
                p = kthread_create(watchdog, hcpu, "watchdog/%d", hotcpu);
                if (IS_ERR(p)) {
                        printk(KERN_ERR "watchdog for %i failed\n", hotcpu);
                        return NOTIFY_BAD;
                }
-               per_cpu(touch_timestamp, hotcpu) = 0;
-               per_cpu(watchdog_task, hotcpu) = p;
+               per_cpu(softlockup_touch_ts, hotcpu) = 0;
+               per_cpu(softlockup_watchdog, hotcpu) = p;
                kthread_bind(p, hotcpu);
                break;
        case CPU_ONLINE:
        case CPU_ONLINE_FROZEN:
-               wake_up_process(per_cpu(watchdog_task, hotcpu));
+               wake_up_process(per_cpu(softlockup_watchdog, hotcpu));
                break;
 #ifdef CONFIG_HOTPLUG_CPU
        case CPU_UP_CANCELED:
        case CPU_UP_CANCELED_FROZEN:
-               if (!per_cpu(watchdog_task, hotcpu))
+               if (!per_cpu(softlockup_watchdog, hotcpu))
                        break;
                /* Unbind so it can run.  Fall thru. */
-               kthread_bind(per_cpu(watchdog_task, hotcpu),
+               kthread_bind(per_cpu(softlockup_watchdog, hotcpu),
                             cpumask_any(cpu_online_mask));
        case CPU_DEAD:
        case CPU_DEAD_FROZEN:
-               p = per_cpu(watchdog_task, hotcpu);
-               per_cpu(watchdog_task, hotcpu) = NULL;
+               p = per_cpu(softlockup_watchdog, hotcpu);
+               per_cpu(softlockup_watchdog, hotcpu) = NULL;
                kthread_stop(p);
                break;
 #endif /* CONFIG_HOTPLUG_CPU */