[tip:x86/urgent] x86: mce: Clean up thermal throttling state tracking code

tip-bot for Ingo Molnar
2009-09-22T13:35:33Z

Commit-ID: 3967684006f30c253bc6d4a6604d1bad4a7fc672
Gitweb: http://git.kernel.org/tip/3967684006f30c253bc6d4a6604d1bad4a7fc672
Author: Ingo Molnar <mingo@elte.hu>
AuthorDate: Tue, 22 Sep 2009 15:50:24 +0200
Committer: Ingo Molnar <mingo@elte.hu>
CommitDate: Tue, 22 Sep 2009 17:30:41 +0200

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>

---
arch/x86/kernel/cpu/mcheck/therm_throt.c | 63 ++++++++++++++++++-----------
1 files changed, 39 insertions(+), 24 deletions(-)

diff --git a/arch/x86/kernel/cpu/mcheck/therm_throt.c b/arch/x86/kernel/cpu/mcheck/therm_throt.c
index 63a56d1..db80b57 100644
--- 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);
}