2.6.31-stable review patch. If anyone has any objections, please let us know. ------------------ From: Ingo Molnar commit b417c9fd8690637f0c91479435ab3e2bf450c038 upstream. 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 Cc: Huang Ying Cc: Andi Kleen LKML-Reference: Signed-off-by: Ingo Molnar Signed-off-by: Greg Kroah-Hartman --- arch/x86/kernel/cpu/mcheck/therm_throt.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) --- a/arch/x86/kernel/cpu/mcheck/therm_throt.c +++ b/arch/x86/kernel/cpu/mcheck/therm_throt.c @@ -42,6 +42,7 @@ struct thermal_state { u64 next_check; unsigned long throttle_count; + unsigned long last_throttle_count; }; static DEFINE_PER_CPU(struct thermal_state, thermal_state); @@ -120,11 +121,12 @@ static int therm_throt_process(bool is_t if (is_throttled) state->throttle_count++; - if (!(was_throttled ^ is_throttled) && - time_before64(now, state->next_check)) + if (time_before64(now, state->next_check) && + state->throttle_count != state->last_throttle_count) return 0; state->next_check = now + CHECK_INTERVAL; + state->last_throttle_count = state->throttle_count; /* if we just entered the thermal event */ if (is_throttled) { -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/