diff options
Diffstat (limited to 'kernel/softlockup.c')
| -rw-r--r-- | kernel/softlockup.c | 209 |
1 files changed, 0 insertions, 209 deletions
diff --git a/kernel/softlockup.c b/kernel/softlockup.c deleted file mode 100644 index edeeef3a6a3..00000000000 --- a/kernel/softlockup.c +++ /dev/null @@ -1,209 +0,0 @@ -/* - * Detect Soft Lockups - * - * started by Ingo Molnar, Copyright (C) 2005, 2006 Red Hat, Inc. - * - * this code detects soft lockups: incidents in where on a CPU - * the kernel does not reschedule for 10 seconds or more. - */ -#include <linux/mm.h> -#include <linux/cpu.h> -#include <linux/init.h> -#include <linux/delay.h> -#include <linux/freezer.h> -#include <linux/kthread.h> -#include <linux/notifier.h> -#include <linux/module.h> - -#include <asm/irq_regs.h> - -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 int did_panic; -int softlockup_thresh = 10; - -static int -softlock_panic(struct notifier_block *this, unsigned long event, void *ptr) -{ - did_panic = 1; - - return NOTIFY_DONE; -} - -static struct notifier_block panic_block = { - .notifier_call = softlock_panic, -}; - -/* - * Returns seconds, approximately. We don't need nanosecond - * resolution, and we don't need to waste time with a big divide when - * 2^30ns == 1.074s. - */ -static unsigned long get_timestamp(int this_cpu) -{ - return cpu_clock(this_cpu) >> 30; /* 2^30 ~= 10^9 */ -} - -void touch_softlockup_watchdog(void) -{ - int this_cpu = raw_smp_processor_id(); - - __raw_get_cpu_var(touch_timestamp) = get_timestamp(this_cpu); -} -EXPORT_SYMBOL(touch_softlockup_watchdog); - -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; -} -EXPORT_SYMBOL(touch_all_softlockup_watchdogs); - -/* - * This callback runs from the timer interrupt, and checks - * whether the watchdog thread has hung or not: - */ -void softlockup_tick(void) -{ - int this_cpu = smp_processor_id(); - unsigned long touch_timestamp = per_cpu(touch_timestamp, this_cpu); - unsigned long print_timestamp; - struct pt_regs *regs = get_irq_regs(); - unsigned long now; - - if (touch_timestamp == 0) { - touch_softlockup_watchdog(); - return; - } - - print_timestamp = per_cpu(print_timestamp, this_cpu); - - /* report at most once a second */ - if ((print_timestamp >= touch_timestamp && - print_timestamp < (touch_timestamp + 1)) || - did_panic || !per_cpu(watchdog_task, this_cpu)) { - return; - } - - /* do not print during early bootup: */ - if (unlikely(system_state != SYSTEM_RUNNING)) { - touch_softlockup_watchdog(); - return; - } - - now = get_timestamp(this_cpu); - - /* Wake up the high-prio watchdog task every second: */ - if (now > (touch_timestamp + 1)) - wake_up_process(per_cpu(watchdog_task, this_cpu)); - - /* Warn about unreasonable 10+ seconds delays: */ - if (now <= (touch_timestamp + softlockup_thresh)) - return; - - per_cpu(print_timestamp, this_cpu) = touch_timestamp; - - spin_lock(&print_lock); - printk(KERN_ERR "BUG: soft lockup - CPU#%d stuck for %lus! [%s:%d]\n", - this_cpu, now - touch_timestamp, - current->comm, current->pid); - if (regs) - show_regs(regs); - else - dump_stack(); - spin_unlock(&print_lock); -} - -/* - * The watchdog thread - runs every second and touches the timestamp. - */ -static int watchdog(void *__bind_cpu) -{ - struct sched_param param = { .sched_priority = MAX_RT_PRIO-1 }; - - sched_setscheduler(current, SCHED_FIFO, ¶m); - - /* initialize timestamp */ - touch_softlockup_watchdog(); - - /* - * Run briefly once per second to reset the softlockup timestamp. - * If this gets delayed for more than 10 seconds then the - * debug-printout triggers in softlockup_tick(). - */ - while (!kthread_should_stop()) { - set_current_state(TASK_INTERRUPTIBLE); - touch_softlockup_watchdog(); - schedule(); - } - - return 0; -} - -/* - * Create/destroy watchdog threads as CPUs come and go: - */ -static int __cpuinit -cpu_callback(struct notifier_block *nfb, unsigned long action, void *hcpu) -{ - int hotcpu = (unsigned long)hcpu; - struct task_struct *p; - - switch (action) { - case CPU_UP_PREPARE: - case CPU_UP_PREPARE_FROZEN: - BUG_ON(per_cpu(watchdog_task, 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; - kthread_bind(p, hotcpu); - break; - case CPU_ONLINE: - case CPU_ONLINE_FROZEN: - wake_up_process(per_cpu(watchdog_task, hotcpu)); - break; -#ifdef CONFIG_HOTPLUG_CPU - case CPU_UP_CANCELED: - case CPU_UP_CANCELED_FROZEN: - if (!per_cpu(watchdog_task, hotcpu)) - break; - /* Unbind so it can run. Fall thru. */ - kthread_bind(per_cpu(watchdog_task, hotcpu), - any_online_cpu(cpu_online_map)); - case CPU_DEAD: - case CPU_DEAD_FROZEN: - p = per_cpu(watchdog_task, hotcpu); - per_cpu(watchdog_task, hotcpu) = NULL; - kthread_stop(p); - break; -#endif /* CONFIG_HOTPLUG_CPU */ - } - return NOTIFY_OK; -} - -static struct notifier_block __cpuinitdata cpu_nfb = { - .notifier_call = cpu_callback -}; - -__init void spawn_softlockup_task(void) -{ - void *cpu = (void *)(long)smp_processor_id(); - int err = cpu_callback(&cpu_nfb, CPU_UP_PREPARE, cpu); - - BUG_ON(err == NOTIFY_BAD); - cpu_callback(&cpu_nfb, CPU_ONLINE, cpu); - register_cpu_notifier(&cpu_nfb); - - atomic_notifier_chain_register(&panic_notifier_list, &panic_block); -} |