mirror of
https://github.com/torvalds/linux.git
synced 2024-12-25 12:21:37 +00:00
watchdog: Use hotplug thread infrastructure
Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Srivatsa S. Bhat <srivatsa.bhat@linux.vnet.ibm.com> Cc: Rusty Russell <rusty@rustcorp.com.au> Reviewed-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Namhyung Kim <namhyung@kernel.org> Link: http://lkml.kernel.org/r/20120716103948.563736676@linutronix.de Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
This commit is contained in:
Thomas Gleixner
parent
3e339b5dae
commit
bcd951cf10
@ -22,6 +22,7 @@
|
||||
#include <linux/notifier.h>
|
||||
#include <linux/module.h>
|
||||
#include <linux/sysctl.h>
|
||||
#include <linux/smpboot.h>
|
||||
|
||||
#include <asm/irq_regs.h>
|
||||
#include <linux/kvm_para.h>
|
||||
@ -29,16 +30,18 @@
|
||||
|
||||
int watchdog_enabled = 1;
|
||||
int __read_mostly watchdog_thresh = 10;
|
||||
static int __read_mostly watchdog_disabled;
|
||||
|
||||
static DEFINE_PER_CPU(unsigned long, watchdog_touch_ts);
|
||||
static DEFINE_PER_CPU(struct task_struct *, softlockup_watchdog);
|
||||
static DEFINE_PER_CPU(struct hrtimer, watchdog_hrtimer);
|
||||
static DEFINE_PER_CPU(bool, softlockup_touch_sync);
|
||||
static DEFINE_PER_CPU(bool, soft_watchdog_warn);
|
||||
static DEFINE_PER_CPU(unsigned long, hrtimer_interrupts);
|
||||
static DEFINE_PER_CPU(unsigned long, soft_lockup_hrtimer_cnt);
|
||||
#ifdef CONFIG_HARDLOCKUP_DETECTOR
|
||||
static DEFINE_PER_CPU(bool, hard_watchdog_warn);
|
||||
static DEFINE_PER_CPU(bool, watchdog_nmi_touch);
|
||||
static DEFINE_PER_CPU(unsigned long, hrtimer_interrupts);
|
||||
static DEFINE_PER_CPU(unsigned long, hrtimer_interrupts_saved);
|
||||
static DEFINE_PER_CPU(struct perf_event *, watchdog_ev);
|
||||
#endif
|
||||
@ -248,13 +251,15 @@ static void watchdog_overflow_callback(struct perf_event *event,
|
||||
__this_cpu_write(hard_watchdog_warn, false);
|
||||
return;
|
||||
}
|
||||
#endif /* CONFIG_HARDLOCKUP_DETECTOR */
|
||||
|
||||
static void watchdog_interrupt_count(void)
|
||||
{
|
||||
__this_cpu_inc(hrtimer_interrupts);
|
||||
}
|
||||
#else
|
||||
static inline void watchdog_interrupt_count(void) { return; }
|
||||
#endif /* CONFIG_HARDLOCKUP_DETECTOR */
|
||||
|
||||
static int watchdog_nmi_enable(unsigned int cpu);
|
||||
static void watchdog_nmi_disable(unsigned int cpu);
|
||||
|
||||
/* watchdog kicker functions */
|
||||
static enum hrtimer_restart watchdog_timer_fn(struct hrtimer *hrtimer)
|
||||
@ -327,49 +332,68 @@ static enum hrtimer_restart watchdog_timer_fn(struct hrtimer *hrtimer)
|
||||
return HRTIMER_RESTART;
|
||||
}
|
||||
|
||||
|
||||
/*
|
||||
* The watchdog thread - touches the timestamp.
|
||||
*/
|
||||
static int watchdog(void *unused)
|
||||
static void watchdog_set_prio(unsigned int policy, unsigned int prio)
|
||||
{
|
||||
struct sched_param param = { .sched_priority = prio };
|
||||
|
||||
sched_setscheduler(current, policy, ¶m);
|
||||
}
|
||||
|
||||
static void watchdog_enable(unsigned int cpu)
|
||||
{
|
||||
struct sched_param param = { .sched_priority = 0 };
|
||||
struct hrtimer *hrtimer = &__raw_get_cpu_var(watchdog_hrtimer);
|
||||
|
||||
/* initialize timestamp */
|
||||
__touch_watchdog();
|
||||
if (!watchdog_enabled) {
|
||||
kthread_park(current);
|
||||
return;
|
||||
}
|
||||
|
||||
/* Enable the perf event */
|
||||
watchdog_nmi_enable(cpu);
|
||||
|
||||
/* kick off the timer for the hardlockup detector */
|
||||
hrtimer_init(hrtimer, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
|
||||
hrtimer->function = watchdog_timer_fn;
|
||||
|
||||
/* done here because hrtimer_start can only pin to smp_processor_id() */
|
||||
hrtimer_start(hrtimer, ns_to_ktime(get_sample_period()),
|
||||
HRTIMER_MODE_REL_PINNED);
|
||||
|
||||
set_current_state(TASK_INTERRUPTIBLE);
|
||||
/*
|
||||
* Run briefly (kicked by the hrtimer callback function) once every
|
||||
* get_sample_period() seconds (4 seconds by default) to reset the
|
||||
* softlockup timestamp. If this gets delayed for more than
|
||||
* 2*watchdog_thresh seconds then the debug-printout triggers in
|
||||
* watchdog_timer_fn().
|
||||
*/
|
||||
while (!kthread_should_stop()) {
|
||||
__touch_watchdog();
|
||||
schedule();
|
||||
|
||||
if (kthread_should_stop())
|
||||
break;
|
||||
|
||||
set_current_state(TASK_INTERRUPTIBLE);
|
||||
}
|
||||
/*
|
||||
* Drop the policy/priority elevation during thread exit to avoid a
|
||||
* scheduling latency spike.
|
||||
*/
|
||||
__set_current_state(TASK_RUNNING);
|
||||
sched_setscheduler(current, SCHED_NORMAL, ¶m);
|
||||
return 0;
|
||||
/* initialize timestamp */
|
||||
watchdog_set_prio(SCHED_FIFO, MAX_RT_PRIO - 1);
|
||||
__touch_watchdog();
|
||||
}
|
||||
|
||||
static void watchdog_disable(unsigned int cpu)
|
||||
{
|
||||
struct hrtimer *hrtimer = &__raw_get_cpu_var(watchdog_hrtimer);
|
||||
|
||||
watchdog_set_prio(SCHED_NORMAL, 0);
|
||||
hrtimer_cancel(hrtimer);
|
||||
/* disable the perf event */
|
||||
watchdog_nmi_disable(cpu);
|
||||
}
|
||||
|
||||
static int watchdog_should_run(unsigned int cpu)
|
||||
{
|
||||
return __this_cpu_read(hrtimer_interrupts) !=
|
||||
__this_cpu_read(soft_lockup_hrtimer_cnt);
|
||||
}
|
||||
|
||||
/*
|
||||
* The watchdog thread function - touches the timestamp.
|
||||
*
|
||||
* It only runs once every get_sample_period() seconds (4 seconds by
|
||||
* default) to reset the softlockup timestamp. If this gets delayed
|
||||
* for more than 2*watchdog_thresh seconds then the debug-printout
|
||||
* triggers in watchdog_timer_fn().
|
||||
*/
|
||||
static void watchdog(unsigned int cpu)
|
||||
{
|
||||
__this_cpu_write(soft_lockup_hrtimer_cnt,
|
||||
__this_cpu_read(hrtimer_interrupts));
|
||||
__touch_watchdog();
|
||||
}
|
||||
|
||||
#ifdef CONFIG_HARDLOCKUP_DETECTOR
|
||||
/*
|
||||
@ -379,7 +403,7 @@ static int watchdog(void *unused)
|
||||
*/
|
||||
static unsigned long cpu0_err;
|
||||
|
||||
static int watchdog_nmi_enable(int cpu)
|
||||
static int watchdog_nmi_enable(unsigned int cpu)
|
||||
{
|
||||
struct perf_event_attr *wd_attr;
|
||||
struct perf_event *event = per_cpu(watchdog_ev, cpu);
|
||||
@ -433,7 +457,7 @@ out:
|
||||
return 0;
|
||||
}
|
||||
|
||||
static void watchdog_nmi_disable(int cpu)
|
||||
static void watchdog_nmi_disable(unsigned int cpu)
|
||||
{
|
||||
struct perf_event *event = per_cpu(watchdog_ev, cpu);
|
||||
|
||||
@ -447,107 +471,35 @@ static void watchdog_nmi_disable(int cpu)
|
||||
return;
|
||||
}
|
||||
#else
|
||||
static int watchdog_nmi_enable(int cpu) { return 0; }
|
||||
static void watchdog_nmi_disable(int cpu) { return; }
|
||||
static int watchdog_nmi_enable(unsigned int cpu) { return 0; }
|
||||
static void watchdog_nmi_disable(unsigned int cpu) { return; }
|
||||
#endif /* CONFIG_HARDLOCKUP_DETECTOR */
|
||||
|
||||
/* prepare/enable/disable routines */
|
||||
static void watchdog_prepare_cpu(int cpu)
|
||||
{
|
||||
struct hrtimer *hrtimer = &per_cpu(watchdog_hrtimer, cpu);
|
||||
|
||||
WARN_ON(per_cpu(softlockup_watchdog, cpu));
|
||||
hrtimer_init(hrtimer, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
|
||||
hrtimer->function = watchdog_timer_fn;
|
||||
}
|
||||
|
||||
static int watchdog_enable(int cpu)
|
||||
{
|
||||
struct task_struct *p = per_cpu(softlockup_watchdog, cpu);
|
||||
int err = 0;
|
||||
|
||||
/* enable the perf event */
|
||||
err = watchdog_nmi_enable(cpu);
|
||||
|
||||
/* Regardless of err above, fall through and start softlockup */
|
||||
|
||||
/* create the watchdog thread */
|
||||
if (!p) {
|
||||
struct sched_param param = { .sched_priority = MAX_RT_PRIO-1 };
|
||||
p = kthread_create_on_node(watchdog, NULL, cpu_to_node(cpu), "watchdog/%d", cpu);
|
||||
if (IS_ERR(p)) {
|
||||
pr_err("softlockup watchdog for %i failed\n", cpu);
|
||||
if (!err) {
|
||||
/* if hardlockup hasn't already set this */
|
||||
err = PTR_ERR(p);
|
||||
/* and disable the perf event */
|
||||
watchdog_nmi_disable(cpu);
|
||||
}
|
||||
goto out;
|
||||
}
|
||||
sched_setscheduler(p, SCHED_FIFO, ¶m);
|
||||
kthread_bind(p, cpu);
|
||||
per_cpu(watchdog_touch_ts, cpu) = 0;
|
||||
per_cpu(softlockup_watchdog, cpu) = p;
|
||||
wake_up_process(p);
|
||||
}
|
||||
|
||||
out:
|
||||
return err;
|
||||
}
|
||||
|
||||
static void watchdog_disable(int cpu)
|
||||
{
|
||||
struct task_struct *p = per_cpu(softlockup_watchdog, cpu);
|
||||
struct hrtimer *hrtimer = &per_cpu(watchdog_hrtimer, cpu);
|
||||
|
||||
/*
|
||||
* cancel the timer first to stop incrementing the stats
|
||||
* and waking up the kthread
|
||||
*/
|
||||
hrtimer_cancel(hrtimer);
|
||||
|
||||
/* disable the perf event */
|
||||
watchdog_nmi_disable(cpu);
|
||||
|
||||
/* stop the watchdog thread */
|
||||
if (p) {
|
||||
per_cpu(softlockup_watchdog, cpu) = NULL;
|
||||
kthread_stop(p);
|
||||
}
|
||||
}
|
||||
|
||||
/* sysctl functions */
|
||||
#ifdef CONFIG_SYSCTL
|
||||
static void watchdog_enable_all_cpus(void)
|
||||
{
|
||||
int cpu;
|
||||
|
||||
watchdog_enabled = 0;
|
||||
|
||||
for_each_online_cpu(cpu)
|
||||
if (!watchdog_enable(cpu))
|
||||
/* if any cpu succeeds, watchdog is considered
|
||||
enabled for the system */
|
||||
watchdog_enabled = 1;
|
||||
|
||||
if (!watchdog_enabled)
|
||||
pr_err("failed to be enabled on some cpus\n");
|
||||
unsigned int cpu;
|
||||
|
||||
if (watchdog_disabled) {
|
||||
watchdog_disabled = 0;
|
||||
for_each_online_cpu(cpu)
|
||||
kthread_unpark(per_cpu(softlockup_watchdog, cpu));
|
||||
}
|
||||
}
|
||||
|
||||
static void watchdog_disable_all_cpus(void)
|
||||
{
|
||||
int cpu;
|
||||
unsigned int cpu;
|
||||
|
||||
for_each_online_cpu(cpu)
|
||||
watchdog_disable(cpu);
|
||||
|
||||
/* if all watchdogs are disabled, then they are disabled for the system */
|
||||
watchdog_enabled = 0;
|
||||
if (!watchdog_disabled) {
|
||||
watchdog_disabled = 1;
|
||||
for_each_online_cpu(cpu)
|
||||
kthread_park(per_cpu(softlockup_watchdog, cpu));
|
||||
}
|
||||
}
|
||||
|
||||
|
||||
/*
|
||||
* proc handler for /proc/sys/kernel/nmi_watchdog,watchdog_thresh
|
||||
*/
|
||||
@ -557,73 +509,36 @@ int proc_dowatchdog(struct ctl_table *table, int write,
|
||||
{
|
||||
int ret;
|
||||
|
||||
if (watchdog_disabled < 0)
|
||||
return -ENODEV;
|
||||
|
||||
ret = proc_dointvec_minmax(table, write, buffer, lenp, ppos);
|
||||
if (ret || !write)
|
||||
goto out;
|
||||
return ret;
|
||||
|
||||
if (watchdog_enabled && watchdog_thresh)
|
||||
watchdog_enable_all_cpus();
|
||||
else
|
||||
watchdog_disable_all_cpus();
|
||||
|
||||
out:
|
||||
return ret;
|
||||
}
|
||||
#endif /* CONFIG_SYSCTL */
|
||||
|
||||
|
||||
/*
|
||||
* 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;
|
||||
|
||||
switch (action) {
|
||||
case CPU_UP_PREPARE:
|
||||
case CPU_UP_PREPARE_FROZEN:
|
||||
watchdog_prepare_cpu(hotcpu);
|
||||
break;
|
||||
case CPU_ONLINE:
|
||||
case CPU_ONLINE_FROZEN:
|
||||
if (watchdog_enabled)
|
||||
watchdog_enable(hotcpu);
|
||||
break;
|
||||
#ifdef CONFIG_HOTPLUG_CPU
|
||||
case CPU_UP_CANCELED:
|
||||
case CPU_UP_CANCELED_FROZEN:
|
||||
watchdog_disable(hotcpu);
|
||||
break;
|
||||
case CPU_DEAD:
|
||||
case CPU_DEAD_FROZEN:
|
||||
watchdog_disable(hotcpu);
|
||||
break;
|
||||
#endif /* CONFIG_HOTPLUG_CPU */
|
||||
}
|
||||
|
||||
/*
|
||||
* hardlockup and softlockup are not important enough
|
||||
* to block cpu bring up. Just always succeed and
|
||||
* rely on printk output to flag problems.
|
||||
*/
|
||||
return NOTIFY_OK;
|
||||
}
|
||||
|
||||
static struct notifier_block __cpuinitdata cpu_nfb = {
|
||||
.notifier_call = cpu_callback
|
||||
static struct smp_hotplug_thread watchdog_threads = {
|
||||
.store = &softlockup_watchdog,
|
||||
.thread_should_run = watchdog_should_run,
|
||||
.thread_fn = watchdog,
|
||||
.thread_comm = "watchdog/%u",
|
||||
.setup = watchdog_enable,
|
||||
.park = watchdog_disable,
|
||||
.unpark = watchdog_enable,
|
||||
};
|
||||
|
||||
void __init lockup_detector_init(void)
|
||||
{
|
||||
void *cpu = (void *)(long)smp_processor_id();
|
||||
int err;
|
||||
|
||||
err = cpu_callback(&cpu_nfb, CPU_UP_PREPARE, cpu);
|
||||
WARN_ON(notifier_to_errno(err));
|
||||
|
||||
cpu_callback(&cpu_nfb, CPU_ONLINE, cpu);
|
||||
register_cpu_notifier(&cpu_nfb);
|
||||
|
||||
return;
|
||||
if (smpboot_register_percpu_thread(&watchdog_threads)) {
|
||||
pr_err("Failed to create watchdog threads, disabled\n");
|
||||
watchdog_disabled = -ENODEV;
|
||||
}
|
||||
}
|
||||
|
||||
Loading…
Reference in New Issue
Block a user