--- /dev/null
+/*
+ * linux/arch/i386/kerne/cpu/mcheck/therm_throt.c
+ *
+ * Thermal throttle event support code (such as syslog messaging and rate
+ * limiting) that was factored out from x86_64 (mce_intel.c) and i386 (p4.c).
+ * This allows consistent reporting of CPU thermal throttle events.
+ *
+ * Maintains a counter in /sys that keeps track of the number of thermal
+ * events, such that the user knows how bad the thermal problem might be
+ * (since the logging to syslog and mcelog is rate limited).
+ *
+ * Author: Dmitriy Zavin (dmitriyz@google.com)
+ *
+ * Credits: Adapted from Zwane Mwaikambo's original code in mce_intel.c.
+ * Inspired by Ross Biro's and Al Borchers' counter code.
+ */
+
+#include <linux/percpu.h>
+#include <linux/sysdev.h>
+#include <linux/cpu.h>
+#include <asm/cpu.h>
+#include <linux/notifier.h>
+#include <linux/jiffies.h>
+#include <asm/therm_throt.h>
+
+/* 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);
+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, \
+ char *buf) \
+{ \
+ unsigned int cpu = dev->id; \
+ ssize_t ret; \
+ \
+ preempt_disable(); /* CPU hotplug */ \
+ if (cpu_online(cpu)) \
+ ret = sprintf(buf, "%lu\n", \
+ per_cpu(thermal_throttle_##name, cpu)); \
+ else \
+ ret = 0; \
+ preempt_enable(); \
+ \
+ return ret; \
+}
+
+define_therm_throt_sysdev_show_func(count);
+define_therm_throt_sysdev_one_ro(count);
+
+static struct attribute *thermal_throttle_attrs[] = {
+ &attr_count.attr,
+ NULL
+};
+
+static struct attribute_group thermal_throttle_attr_group = {
+ .attrs = thermal_throttle_attrs,
+ .name = "thermal_throttle"
+};
+#endif /* CONFIG_SYSFS */
+
+/***
+ * therm_throt_process - Process thermal throttling event from interrupt
+ * @curr: Whether the condition is current or not (boolean), since the
+ * thermal interrupt normally gets called both when the thermal
+ * event begins and once the event has ended.
+ *
+ * This function is called by the thermal interrupt after the
+ * IRQ has been acknowledged.
+ *
+ * It will take care of rate limiting and printing messages to the syslog.
+ *
+ * Returns: 0 : Event should NOT be further logged, i.e. still in
+ * "timeout" from previous log message.
+ * 1 : Event should be logged further, and a message has been
+ * printed to the syslog.
+ */
+int therm_throt_process(int curr)
+{
+ unsigned int cpu = smp_processor_id();
+ __u64 tmp_jiffs = get_jiffies_64();
+
+ if (curr)
+ __get_cpu_var(thermal_throttle_count)++;
+
+ if (time_before64(tmp_jiffs, __get_cpu_var(next_check)))
+ return 0;
+
+ __get_cpu_var(next_check) = tmp_jiffs + CHECK_INTERVAL;
+
+ /* if we just entered the thermal event */
+ if (curr) {
+ printk(KERN_CRIT "CPU%d: Temperature above threshold, "
+ "cpu clock throttled (total events = %lu)\n", cpu,
+ __get_cpu_var(thermal_throttle_count));
+
+ add_taint(TAINT_MACHINE_CHECK);
+ } else {
+ printk(KERN_CRIT "CPU%d: Temperature/speed normal\n", cpu);
+ }
+
+ return 1;
+}
+
+#ifdef CONFIG_SYSFS
+/* Add/Remove thermal_throttle interface for CPU device */
+static __cpuinit int thermal_throttle_add_dev(struct sys_device *sys_dev)
+{
+ return sysfs_create_group(&sys_dev->kobj, &thermal_throttle_attr_group);
+}
+
+static __cpuinit void thermal_throttle_remove_dev(struct sys_device *sys_dev)
+{
+ return sysfs_remove_group(&sys_dev->kobj, &thermal_throttle_attr_group);
+}
+
+/* Mutex protecting device creation against CPU hotplug */
+static DEFINE_MUTEX(therm_cpu_lock);
+
+/* Get notified when a cpu comes on/off. Be hotplug friendly. */
+static __cpuinit int thermal_throttle_cpu_callback(struct notifier_block *nfb,
+ unsigned long action,
+ void *hcpu)
+{
+ unsigned int cpu = (unsigned long)hcpu;
+ struct sys_device *sys_dev;
+ int err;
+
+ sys_dev = get_cpu_sysdev(cpu);
+ mutex_lock(&therm_cpu_lock);
+ switch (action) {
+ case CPU_ONLINE:
+ err = thermal_throttle_add_dev(sys_dev);
+ WARN_ON(err);
+ break;
+ case CPU_DEAD:
+ thermal_throttle_remove_dev(sys_dev);
+ break;
+ }
+ mutex_unlock(&therm_cpu_lock);
+ return NOTIFY_OK;
+}
+
+static struct notifier_block thermal_throttle_cpu_notifier =
+{
+ .notifier_call = thermal_throttle_cpu_callback,
+};
+
+static __init int thermal_throttle_init_device(void)
+{
+ unsigned int cpu = 0;
+ int err;
+
+ if (!atomic_read(&therm_throt_en))
+ return 0;
+
+ register_hotcpu_notifier(&thermal_throttle_cpu_notifier);
+
+#ifdef CONFIG_HOTPLUG_CPU
+ mutex_lock(&therm_cpu_lock);
+#endif
+ /* connect live CPUs to sysfs */
+ for_each_online_cpu(cpu) {
+ err = thermal_throttle_add_dev(get_cpu_sysdev(cpu));
+ WARN_ON(err);
+ }
+#ifdef CONFIG_HOTPLUG_CPU
+ mutex_unlock(&therm_cpu_lock);
+#endif
+
+ return 0;
+}
+
+device_initcall(thermal_throttle_init_device);
+#endif /* CONFIG_SYSFS */
git://git.onelab.eu / linux-2.6.git / blobdiff