+++ /dev/null
-/*
- * 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/nmi.h>
-#include <linux/init.h>
-#include <linux/delay.h>
-#include <linux/freezer.h>
-#include <linux/kthread.h>
-#include <linux/lockdep.h>
-#include <linux/notifier.h>
-#include <linux/module.h>
-#include <linux/sysctl.h>
-
-#include <asm/irq_regs.h>
-
-static DEFINE_SPINLOCK(print_lock);
-
-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;
-
-/*
- * Should we panic (and reboot, if panic_timeout= is set) when a
- * soft-lockup occurs:
- */
-unsigned int __read_mostly softlockup_panic =
- CONFIG_BOOTPARAM_SOFTLOCKUP_PANIC_VALUE;
-
-static int __init softlockup_panic_setup(char *str)
-{
- softlockup_panic = simple_strtoul(str, NULL, 0);
-
- return 1;
-}
-__setup("softlockup_panic=", softlockup_panic_setup);
-
-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) >> 30LL; /* 2^30 ~= 10^9 */
-}
-
-static void __touch_softlockup_watchdog(void)
-{
- int this_cpu = raw_smp_processor_id();
-
- __raw_get_cpu_var(softlockup_touch_ts) = get_timestamp(this_cpu);
-}
-
-void touch_softlockup_watchdog(void)
-{
- __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(softlockup_touch_ts, cpu) = 0;
-}
-EXPORT_SYMBOL(touch_all_softlockup_watchdogs);
-
-int proc_dosoftlockup_thresh(struct ctl_table *table, int write,
- void __user *buffer,
- size_t *lenp, loff_t *ppos)
-{
- touch_all_softlockup_watchdogs();
- return proc_dointvec_minmax(table, write, buffer, lenp, ppos);
-}
-
-/*
- * 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_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(softlockup_watchdog, this_cpu) || softlockup_thresh <= 0) {
- /* Be sure we don't false trigger if switched back on */
- if (touch_ts)
- per_cpu(softlockup_touch_ts, this_cpu) = 0;
- return;
- }
-
- 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_ts = per_cpu(softlockup_print_ts, this_cpu);
-
- /* report at most once a second */
- if (print_ts == touch_ts || did_panic)
- 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 twice per
- * threshold timespan.
- */
- if (time_after(now - softlockup_thresh/2, touch_ts))
- wake_up_process(per_cpu(softlockup_watchdog, this_cpu));
-
- /* Warn about unreasonable delays: */
- if (time_before_eq(now - softlockup_thresh, touch_ts))
- return;
-
- 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_ts,
- current->comm, task_pid_nr(current));
- print_modules();
- print_irqtrace_events(current);
- if (regs)
- show_regs(regs);
- else
- dump_stack();
- spin_unlock(&print_lock);
-
- if (softlockup_panic)
- panic("softlockup: hung tasks");
-}
-
-/*
- * 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();
-
- set_current_state(TASK_INTERRUPTIBLE);
- /*
- * Run briefly once per second to reset the softlockup timestamp.
- * If this gets delayed for more than 60 seconds then the
- * debug-printout triggers in softlockup_tick().
- */
- while (!kthread_should_stop()) {
- __touch_softlockup_watchdog();
- schedule();
-
- if (kthread_should_stop())
- break;
-
- set_current_state(TASK_INTERRUPTIBLE);
- }
- __set_current_state(TASK_RUNNING);
-
- 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(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(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(softlockup_watchdog, hotcpu));
- break;
-#ifdef CONFIG_HOTPLUG_CPU
- case CPU_UP_CANCELED:
- case CPU_UP_CANCELED_FROZEN:
- if (!per_cpu(softlockup_watchdog, hotcpu))
- break;
- /* Unbind so it can run. Fall thru. */
- kthread_bind(per_cpu(softlockup_watchdog, hotcpu),
- cpumask_any(cpu_online_mask));
- case CPU_DEAD:
- case CPU_DEAD_FROZEN:
- p = per_cpu(softlockup_watchdog, hotcpu);
- per_cpu(softlockup_watchdog, hotcpu) = NULL;
- kthread_stop(p);
- break;
-#endif /* CONFIG_HOTPLUG_CPU */
- }
- return NOTIFY_OK;
-}
-
-static struct notifier_block __cpuinitdata cpu_nfb = {
- .notifier_call = cpu_callback
-};
-
-static int __initdata nosoftlockup;
-
-static int __init nosoftlockup_setup(char *str)
-{
- nosoftlockup = 1;
- return 1;
-}
-__setup("nosoftlockup", nosoftlockup_setup);
-
-static int __init spawn_softlockup_task(void)
-{
- void *cpu = (void *)(long)smp_processor_id();
- int err;
-
- if (nosoftlockup)
- return 0;
-
- err = cpu_callback(&cpu_nfb, CPU_UP_PREPARE, cpu);
- if (err == NOTIFY_BAD) {
- BUG();
- return 1;
- }
- cpu_callback(&cpu_nfb, CPU_ONLINE, cpu);
- register_cpu_notifier(&cpu_nfb);
-
- atomic_notifier_chain_register(&panic_notifier_list, &panic_block);
-
- return 0;
-}
-early_initcall(spawn_softlockup_task);
projects / platform / upstream / kernel-adaptation-pc.git / commitdiff