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Commit 6298c512 authored by Andi Kleen's avatar Andi Kleen Committed by H. Peter Anvin
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x86, mce: make polling timer interval per CPU 



The polling timer while running per CPU still uses a global next_interval
variable, which lead to some CPUs either polling too fast or too slow.   
This was not a serious problem because all errors get picked up eventually,
but it's still better to avoid it. Turn next_interval into a per cpu variable.

v2: Fix check_interval == 0 case (Hidetoshi Seto)

[ Impact: minor bug fix ]

Signed-off-by: default avatarAndi Kleen <ak@linux.intel.com>
Reviewed-by: default avatarHidetoshi Seto <seto.hidetoshi@jp.fujitsu.com>
Signed-off-by: default avatarH. Peter Anvin <hpa@linux.intel.com>
parent a939b96c

arch/x86/kernel/cpu/mcheck/mce_64.c

+12 −12
Original line number Diff line number Diff line
@@ -452,13 +452,14 @@ void mce_log_therm_throt_event(__u64 status) 
 */



static int check_interval = 5 * 60; /* 5 minutes */

static int next_interval; /* in jiffies */

static DEFINE_PER_CPU(int, next_interval); /* in jiffies */

static void mcheck_timer(unsigned long);

static DEFINE_PER_CPU(struct timer_list, mce_timer);



static void mcheck_timer(unsigned long data)

{

	struct timer_list *t = &per_cpu(mce_timer, data);

	int *n;



	WARN_ON(smp_processor_id() != data);
@@ -470,14 +471,14 @@ static void mcheck_timer(unsigned long data) 
	 * Alert userspace if needed.  If we logged an MCE, reduce the

	 * polling interval, otherwise increase the polling interval.

	 */

	n = &__get_cpu_var(next_interval);

	if (mce_notify_user()) {

		next_interval = max(next_interval/2, HZ/100);

		*n = max(*n/2, HZ/100);

	} else {

		next_interval = min(next_interval * 2,

				(int)round_jiffies_relative(check_interval*HZ));

		*n = min(*n*2, (int)round_jiffies_relative(check_interval*HZ));

	}



	t->expires = jiffies + next_interval;

	t->expires = jiffies + *n;

	add_timer(t);

}
@@ -632,14 +633,13 @@ static void mce_cpu_features(struct cpuinfo_x86 *c) 
static void mce_init_timer(void)

{

	struct timer_list *t = &__get_cpu_var(mce_timer);

	int *n = &__get_cpu_var(next_interval);



	/* data race harmless because everyone sets to the same value */

	if (!next_interval)

		next_interval = check_interval * HZ;

	if (!next_interval)

	*n = check_interval * HZ;

	if (!*n)

		return;

	setup_timer(t, mcheck_timer, smp_processor_id());

	t->expires = round_jiffies(jiffies + next_interval);

	t->expires = round_jiffies(jiffies + *n);

	add_timer(t);

}
@@ -907,7 +907,6 @@ static void mce_cpu_restart(void *data) 
/* Reinit MCEs after user configuration changes */

static void mce_restart(void)

{

	next_interval = check_interval * HZ;

	on_each_cpu(mce_cpu_restart, NULL, 1);

}
@@ -1110,7 +1109,8 @@ static int __cpuinit mce_cpu_callback(struct notifier_block *nfb, 
		break;

	case CPU_DOWN_FAILED:

	case CPU_DOWN_FAILED_FROZEN:

		t->expires = round_jiffies(jiffies + next_interval);

		t->expires = round_jiffies(jiffies +

						__get_cpu_var(next_interval));

		add_timer_on(t, cpu);

		smp_call_function_single(cpu, mce_reenable_cpu, &action, 1);

		break;