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Commit 39676840 authored by Ingo Molnar's avatar Ingo Molnar
Browse files

x86: mce: Clean up thermal throttling state tracking code 



Instead of a mess of three separate percpu variables, consolidate
the state into a single structure.

Also clean up therm_throt_process(), use cleaner and more
understandable variable names and a clearer logic.

This, without changing the logic, makes the code more
streamlined, more readable and smaller as well:

   text	   data	    bss	    dec	    hex	filename
   1487	    169	      4	   1660	    67c	therm_throt.o.before
   1432	    176	      4	   1612	    64c	therm_throt.o.after

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: default avatarIngo Molnar <mingo@elte.hu>
parent b8c7f1dc

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

+39 −24
Original line number Original line Diff line number Diff line
@@ -34,9 +34,17 @@ 
/* How long to wait between reporting thermal events */

/* How long to wait between reporting thermal events */

#define CHECK_INTERVAL		(300 * HZ)

#define CHECK_INTERVAL		(300 * HZ)





static DEFINE_PER_CPU(__u64, next_check) = INITIAL_JIFFIES;

/*

static DEFINE_PER_CPU(unsigned long, thermal_throttle_count);

 * Current thermal throttling state:

static DEFINE_PER_CPU(bool, thermal_throttle_active);

 */

struct thermal_state {

	bool			is_throttled;



	u64			next_check;

	unsigned long		throttle_count;

};



static DEFINE_PER_CPU(struct thermal_state, thermal_state);





static atomic_t therm_throt_en	= ATOMIC_INIT(0);

static atomic_t therm_throt_en	= ATOMIC_INIT(0);
@@ -45,7 +53,9 @@ static atomic_t therm_throt_en = ATOMIC_INIT(0); 
	static SYSDEV_ATTR(_name, 0444, therm_throt_sysdev_show_##_name, NULL)

	static SYSDEV_ATTR(_name, 0444, therm_throt_sysdev_show_##_name, NULL)





#define define_therm_throt_sysdev_show_func(name)			\

#define define_therm_throt_sysdev_show_func(name)			\

static ssize_t therm_throt_sysdev_show_##name(struct sys_device *dev,	\

									\

static ssize_t therm_throt_sysdev_show_##name(				\

			struct sys_device *dev,				\

			struct sysdev_attribute *attr,			\

			struct sysdev_attribute *attr,			\

			char *buf)					\

			char *buf)					\

{									\

{									\
@@ -55,7 +65,7 @@ static ssize_t therm_throt_sysdev_show_##name(struct sys_device *dev, \ 
	preempt_disable();	/* CPU hotplug */			\

	preempt_disable();	/* CPU hotplug */			\

	if (cpu_online(cpu))						\

	if (cpu_online(cpu))						\

		ret = sprintf(buf, "%lu\n",				\

		ret = sprintf(buf, "%lu\n",				\

			      per_cpu(thermal_throttle_##name, cpu));	\

			      per_cpu(thermal_state, cpu).name);	\

	else								\

	else								\

		ret = 0;						\

		ret = 0;						\

	preempt_enable();						\

	preempt_enable();						\
@@ -63,11 +73,11 @@ static ssize_t therm_throt_sysdev_show_##name(struct sys_device *dev, \ 
	return ret;							\

	return ret;							\

}

}





define_therm_throt_sysdev_show_func(count);

define_therm_throt_sysdev_show_func(throttle_count);

define_therm_throt_sysdev_one_ro(count);

define_therm_throt_sysdev_one_ro(throttle_count);





static struct attribute *thermal_throttle_attrs[] = {

static struct attribute *thermal_throttle_attrs[] = {

	&attr_count.attr,

	&attr_throttle_count.attr,

	NULL

	NULL

};

};
@@ -93,33 +103,38 @@ static struct attribute_group thermal_throttle_attr_group = { 
 *          1 : Event should be logged further, and a message has been

 *          1 : Event should be logged further, and a message has been

 *              printed to the syslog.

 *              printed to the syslog.

 */

 */

static int therm_throt_process(int curr)

static int therm_throt_process(bool is_throttled)

{

{

	unsigned int cpu = smp_processor_id();

	struct thermal_state *state;

	__u64 tmp_jiffs = get_jiffies_64();

	unsigned int this_cpu;

	bool was_throttled = __get_cpu_var(thermal_throttle_active);

	bool was_throttled;

	bool is_throttled = __get_cpu_var(thermal_throttle_active) = curr;

	u64 now;



	this_cpu = smp_processor_id();

	now = get_jiffies_64();

	state = &per_cpu(thermal_state, this_cpu);



	was_throttled = state->is_throttled;

	state->is_throttled = is_throttled;





	if (is_throttled)

	if (is_throttled)

		__get_cpu_var(thermal_throttle_count)++;

		state->throttle_count++;





	if (!(was_throttled ^ is_throttled) &&

	if (!(was_throttled ^ is_throttled) &&

	    time_before64(tmp_jiffs, __get_cpu_var(next_check)))

			time_before64(now, state->next_check))

		return 0;

		return 0;





	__get_cpu_var(next_check) = tmp_jiffs + CHECK_INTERVAL;

	state->next_check = now + CHECK_INTERVAL;





	/* if we just entered the thermal event */

	/* if we just entered the thermal event */

	if (is_throttled) {

	if (is_throttled) {

		printk(KERN_CRIT "CPU%d: Temperature above threshold, "

		printk(KERN_CRIT "CPU%d: Temperature above threshold, cpu clock throttled (total events = %lu)\n", this_cpu, state->throttle_count);

		       "cpu clock throttled (total events = %lu)\n",

		       cpu, __get_cpu_var(thermal_throttle_count));





		add_taint(TAINT_MACHINE_CHECK);

		add_taint(TAINT_MACHINE_CHECK);

		return 1;

		return 1;

	}

	}

	if (was_throttled) {

	if (was_throttled) {

		printk(KERN_INFO "CPU%d: Temperature/speed normal\n", cpu);

		printk(KERN_INFO "CPU%d: Temperature/speed normal\n", this_cpu);

		return 1;

		return 1;

	}

	}
@@ -213,7 +228,7 @@ static void intel_thermal_interrupt(void) 
	__u64 msr_val;

	__u64 msr_val;





	rdmsrl(MSR_IA32_THERM_STATUS, msr_val);

	rdmsrl(MSR_IA32_THERM_STATUS, msr_val);

	if (therm_throt_process(msr_val & THERM_STATUS_PROCHOT))

	if (therm_throt_process((msr_val & THERM_STATUS_PROCHOT) != 0))

		mce_log_therm_throt_event(msr_val);

		mce_log_therm_throt_event(msr_val);

}

}