mirror of
https://github.com/FEX-Emu/linux.git
synced 2024-12-26 19:36:41 +00:00
3aef1bde14
On a large SMP box we get a lot of softlockup thread XX started lines. Signed-off-by: Anton Blanchard <anton@samba.org> Acked-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
150 lines
3.5 KiB
C
150 lines
3.5 KiB
C
/*
|
|
* Detect Soft Lockups
|
|
*
|
|
* started by Ingo Molnar, (C) 2005, Red Hat
|
|
*
|
|
* 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/kthread.h>
|
|
#include <linux/notifier.h>
|
|
#include <linux/module.h>
|
|
|
|
static DEFINE_SPINLOCK(print_lock);
|
|
|
|
static DEFINE_PER_CPU(unsigned long, timestamp) = 0;
|
|
static DEFINE_PER_CPU(unsigned long, print_timestamp) = 0;
|
|
static DEFINE_PER_CPU(struct task_struct *, watchdog_task);
|
|
|
|
static int did_panic = 0;
|
|
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,
|
|
};
|
|
|
|
void touch_softlockup_watchdog(void)
|
|
{
|
|
per_cpu(timestamp, raw_smp_processor_id()) = jiffies;
|
|
}
|
|
EXPORT_SYMBOL(touch_softlockup_watchdog);
|
|
|
|
/*
|
|
* This callback runs from the timer interrupt, and checks
|
|
* whether the watchdog thread has hung or not:
|
|
*/
|
|
void softlockup_tick(struct pt_regs *regs)
|
|
{
|
|
int this_cpu = smp_processor_id();
|
|
unsigned long timestamp = per_cpu(timestamp, this_cpu);
|
|
|
|
if (per_cpu(print_timestamp, this_cpu) == timestamp)
|
|
return;
|
|
|
|
/* Do not cause a second panic when there already was one */
|
|
if (did_panic)
|
|
return;
|
|
|
|
if (time_after(jiffies, timestamp + 10*HZ)) {
|
|
per_cpu(print_timestamp, this_cpu) = timestamp;
|
|
|
|
spin_lock(&print_lock);
|
|
printk(KERN_ERR "BUG: soft lockup detected on CPU#%d!\n",
|
|
this_cpu);
|
|
show_regs(regs);
|
|
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 = 99 };
|
|
|
|
sched_setscheduler(current, SCHED_FIFO, ¶m);
|
|
current->flags |= PF_NOFREEZE;
|
|
|
|
set_current_state(TASK_INTERRUPTIBLE);
|
|
|
|
/*
|
|
* Run briefly once per second - if this gets delayed for
|
|
* more than 10 seconds then the debug-printout triggers
|
|
* in softlockup_tick():
|
|
*/
|
|
while (!kthread_should_stop()) {
|
|
msleep_interruptible(1000);
|
|
touch_softlockup_watchdog();
|
|
}
|
|
__set_current_state(TASK_RUNNING);
|
|
|
|
return 0;
|
|
}
|
|
|
|
/*
|
|
* Create/destroy watchdog threads as CPUs come and go:
|
|
*/
|
|
static int __devinit
|
|
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:
|
|
BUG_ON(per_cpu(watchdog_task, hotcpu));
|
|
p = kthread_create(watchdog, hcpu, "watchdog/%d", hotcpu);
|
|
if (IS_ERR(p)) {
|
|
printk("watchdog for %i failed\n", hotcpu);
|
|
return NOTIFY_BAD;
|
|
}
|
|
per_cpu(watchdog_task, hotcpu) = p;
|
|
kthread_bind(p, hotcpu);
|
|
break;
|
|
case CPU_ONLINE:
|
|
|
|
wake_up_process(per_cpu(watchdog_task, hotcpu));
|
|
break;
|
|
#ifdef CONFIG_HOTPLUG_CPU
|
|
case CPU_UP_CANCELED:
|
|
/* Unbind so it can run. Fall thru. */
|
|
kthread_bind(per_cpu(watchdog_task, hotcpu),
|
|
any_online_cpu(cpu_online_map));
|
|
case CPU_DEAD:
|
|
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 __devinitdata cpu_nfb = {
|
|
.notifier_call = cpu_callback
|
|
};
|
|
|
|
__init void spawn_softlockup_task(void)
|
|
{
|
|
void *cpu = (void *)(long)smp_processor_id();
|
|
|
|
cpu_callback(&cpu_nfb, CPU_UP_PREPARE, cpu);
|
|
cpu_callback(&cpu_nfb, CPU_ONLINE, cpu);
|
|
register_cpu_notifier(&cpu_nfb);
|
|
|
|
notifier_chain_register(&panic_notifier_list, &panic_block);
|
|
}
|
|
|