Commit b417c9fd authored Sep 22, 2009 by Ingo Molnar

x86: mce: Fix thermal throttling message storm



If a system switches back and forth between hot and cold mode,
the MCE code will print a stream of critical kernel messages.

Extend the throttling code to properly notice this, by
only printing the first hot + cold transition and omitting
the rest up to CHECK_INTERVAL (5 minutes).

This way we'll only get a single incident of:

 [  102.356584] CPU0: Temperature above threshold, cpu clock throttled (total events = 1)
 [  102.357000] Disabling lock debugging due to kernel taint
 [  102.369223] CPU0: Temperature/speed normal

Every 5 minutes. The 'total events' count tells the number of cold/hot
transitions detected, should overheating occur after 5 minutes again:

[  402.357580] CPU0: Temperature above threshold, cpu clock throttled (total events = 24891)
[  402.358001] CPU0: Temperature/speed normal
[  450.704142] Machine check events logged

Cc: Hidetoshi Seto <seto.hidetoshi@jp.fujitsu.com>
Cc: Huang Ying <ying.huang@intel.com>
Cc: Andi Kleen <ak@linux.intel.com>
LKML-Reference: <new-submission>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

parent 39676840

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

+4 −2

Original line number	Original line	Diff line number	Diff line
	@@ -42,6 +42,7 @@ struct thermal_state {

	u64 next_check;		u64 next_check;
	unsigned long throttle_count;		unsigned long throttle_count;
			unsigned long last_throttle_count;
	};		};

	static DEFINE_PER_CPU(struct thermal_state, thermal_state);		static DEFINE_PER_CPU(struct thermal_state, thermal_state);
	@@ -120,11 +121,12 @@ static int therm_throt_process(bool is_throttled)
	if (is_throttled)		if (is_throttled)
	state->throttle_count++;		state->throttle_count++;

	if (!(was_throttled ^ is_throttled) &&		if (time_before64(now, state->next_check) &&
	time_before64(now, state->next_check))		state->throttle_count != state->last_throttle_count)
	return 0;		return 0;

	state->next_check = now + CHECK_INTERVAL;		state->next_check = now + CHECK_INTERVAL;
			state->last_throttle_count = state->throttle_count;

	/* if we just entered the thermal event */		/* if we just entered the thermal event */
	if (is_throttled) {		if (is_throttled) {