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: Ingo Molnar <mingo@elte.hu>

diff --git a/arch/x86/kernel/cpu/mcheck/therm_throt.c b/arch/x86/kernel/cpu/mcheck/therm_throt.c
index 63a56d147e4a67b55ceea258dfeb20c18b9d1ccf..db80b577f60187e72d15d728748b2733a4ef93d5 100644 (file)
--- a/arch/x86/kernel/cpu/mcheck/therm_throt.c
+++ b/arch/x86/kernel/cpu/mcheck/therm_throt.c
@@ -34,20 +34,30 @@
 /* How long to wait between reporting thermal events */
 #define CHECK_INTERVAL         (300 * HZ)
 
-static DEFINE_PER_CPU(__u64, next_check) = INITIAL_JIFFIES;
-static DEFINE_PER_CPU(unsigned long, thermal_throttle_count);
-static DEFINE_PER_CPU(bool, thermal_throttle_active);
+/*
+ * Current thermal throttling state:
+ */
+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);
 
 #ifdef CONFIG_SYSFS
 #define define_therm_throt_sysdev_one_ro(_name)                                \
        static SYSDEV_ATTR(_name, 0444, therm_throt_sysdev_show_##_name, NULL)
 
 #define define_therm_throt_sysdev_show_func(name)                      \
-static ssize_t therm_throt_sysdev_show_##name(struct sys_device *dev,  \
-                                       struct sysdev_attribute *attr,  \
-                                             char *buf)                \
+                                                                       \
+static ssize_t therm_throt_sysdev_show_##name(                         \
+                       struct sys_device *dev,                         \
+                       struct sysdev_attribute *attr,                  \
+                       char *buf)                                      \
 {                                                                      \
        unsigned int cpu = dev->id;                                     \
        ssize_t ret;                                                    \
@@ -55,7 +65,7 @@ static ssize_t therm_throt_sysdev_show_##name(struct sys_device *dev, \
        preempt_disable();      /* CPU hotplug */                       \
        if (cpu_online(cpu))                                            \
                ret = sprintf(buf, "%lu\n",                             \
-                             per_cpu(thermal_throttle_##name, cpu));   \
+                             per_cpu(thermal_state, cpu).name);        \
        else                                                            \
                ret = 0;                                                \
        preempt_enable();                                               \
@@ -63,11 +73,11 @@ static ssize_t therm_throt_sysdev_show_##name(struct sys_device *dev,       \
        return ret;                                                     \
 }
 
-define_therm_throt_sysdev_show_func(count);
-define_therm_throt_sysdev_one_ro(count);
+define_therm_throt_sysdev_show_func(throttle_count);
+define_therm_throt_sysdev_one_ro(throttle_count);
 
 static struct attribute *thermal_throttle_attrs[] = {
-       &attr_count.attr,
+       &attr_throttle_count.attr,
        NULL
 };
 
@@ -93,33 +103,38 @@ static struct attribute_group thermal_throttle_attr_group = {
  *          1 : Event should be logged further, and a message has been
  *              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();
-       __u64 tmp_jiffs = get_jiffies_64();
-       bool was_throttled = __get_cpu_var(thermal_throttle_active);
-       bool is_throttled = __get_cpu_var(thermal_throttle_active) = curr;
+       struct thermal_state *state;
+       unsigned int this_cpu;
+       bool was_throttled;
+       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)
-               __get_cpu_var(thermal_throttle_count)++;
+               state->throttle_count++;
 
        if (!(was_throttled ^ is_throttled) &&
-           time_before64(tmp_jiffs, __get_cpu_var(next_check)))
+                       time_before64(now, state->next_check))
                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 (is_throttled) {
-               printk(KERN_CRIT "CPU%d: Temperature above threshold, "
-                      "cpu clock throttled (total events = %lu)\n",
-                      cpu, __get_cpu_var(thermal_throttle_count));
+               printk(KERN_CRIT "CPU%d: Temperature above threshold, cpu clock throttled (total events = %lu)\n", this_cpu, state->throttle_count);
 
                add_taint(TAINT_MACHINE_CHECK);
                return 1;
        }
        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;
        }
 
@@ -213,7 +228,7 @@ static void intel_thermal_interrupt(void)
        __u64 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);
 }