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path: root/drivers/cpufreq/cpufreq.c
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Diffstat (limited to 'drivers/cpufreq/cpufreq.c')
-rw-r--r--drivers/cpufreq/cpufreq.c85
1 files changed, 67 insertions, 18 deletions
diff --git a/drivers/cpufreq/cpufreq.c b/drivers/cpufreq/cpufreq.c
index 109d62ccf65..6c6121b85a5 100644
--- a/drivers/cpufreq/cpufreq.c
+++ b/drivers/cpufreq/cpufreq.c
@@ -4,6 +4,9 @@
* Copyright (C) 2001 Russell King
* (C) 2002 - 2003 Dominik Brodowski <linux@brodo.de>
*
+ * Oct 2005 - Ashok Raj <ashok.raj@intel.com>
+ * Added handling for CPU hotplug
+ *
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
@@ -36,13 +39,6 @@ static struct cpufreq_policy *cpufreq_cpu_data[NR_CPUS];
static DEFINE_SPINLOCK(cpufreq_driver_lock);
-/* we keep a copy of all ->add'ed CPU's struct sys_device here;
- * as it is only accessed in ->add and ->remove, no lock or reference
- * count is necessary.
- */
-static struct sys_device *cpu_sys_devices[NR_CPUS];
-
-
/* internal prototypes */
static int __cpufreq_governor(struct cpufreq_policy *policy, unsigned int event);
static void handle_update(void *data);
@@ -574,6 +570,9 @@ static int cpufreq_add_dev (struct sys_device * sys_dev)
unsigned long flags;
unsigned int j;
+ if (cpu_is_offline(cpu))
+ return 0;
+
cpufreq_debug_disable_ratelimit();
dprintk("adding CPU %u\n", cpu);
@@ -582,7 +581,6 @@ static int cpufreq_add_dev (struct sys_device * sys_dev)
* CPU because it is in the same boat. */
policy = cpufreq_cpu_get(cpu);
if (unlikely(policy)) {
- cpu_sys_devices[cpu] = sys_dev;
dprintk("CPU already managed, adding link\n");
sysfs_create_link(&sys_dev->kobj, &policy->kobj, "cpufreq");
cpufreq_debug_enable_ratelimit();
@@ -657,7 +655,6 @@ static int cpufreq_add_dev (struct sys_device * sys_dev)
}
module_put(cpufreq_driver->owner);
- cpu_sys_devices[cpu] = sys_dev;
dprintk("initialization complete\n");
cpufreq_debug_enable_ratelimit();
@@ -682,7 +679,7 @@ err_out:
nomem_out:
module_put(cpufreq_driver->owner);
- module_out:
+module_out:
cpufreq_debug_enable_ratelimit();
return ret;
}
@@ -698,6 +695,7 @@ static int cpufreq_remove_dev (struct sys_device * sys_dev)
unsigned int cpu = sys_dev->id;
unsigned long flags;
struct cpufreq_policy *data;
+ struct sys_device *cpu_sys_dev;
#ifdef CONFIG_SMP
unsigned int j;
#endif
@@ -710,7 +708,6 @@ static int cpufreq_remove_dev (struct sys_device * sys_dev)
if (!data) {
spin_unlock_irqrestore(&cpufreq_driver_lock, flags);
- cpu_sys_devices[cpu] = NULL;
cpufreq_debug_enable_ratelimit();
return -EINVAL;
}
@@ -725,14 +722,12 @@ static int cpufreq_remove_dev (struct sys_device * sys_dev)
dprintk("removing link\n");
spin_unlock_irqrestore(&cpufreq_driver_lock, flags);
sysfs_remove_link(&sys_dev->kobj, "cpufreq");
- cpu_sys_devices[cpu] = NULL;
cpufreq_cpu_put(data);
cpufreq_debug_enable_ratelimit();
return 0;
}
#endif
- cpu_sys_devices[cpu] = NULL;
if (!kobject_get(&data->kobj)) {
spin_unlock_irqrestore(&cpufreq_driver_lock, flags);
@@ -761,7 +756,8 @@ static int cpufreq_remove_dev (struct sys_device * sys_dev)
if (j == cpu)
continue;
dprintk("removing link for cpu %u\n", j);
- sysfs_remove_link(&cpu_sys_devices[j]->kobj, "cpufreq");
+ cpu_sys_dev = get_cpu_sysdev(j);
+ sysfs_remove_link(&cpu_sys_dev->kobj, "cpufreq");
cpufreq_cpu_put(data);
}
}
@@ -772,7 +768,6 @@ static int cpufreq_remove_dev (struct sys_device * sys_dev)
down(&data->lock);
if (cpufreq_driver->target)
__cpufreq_governor(data, CPUFREQ_GOV_STOP);
- cpufreq_driver->target = NULL;
up(&data->lock);
kobject_unregister(&data->kobj);
@@ -1119,17 +1114,30 @@ int __cpufreq_driver_target(struct cpufreq_policy *policy,
unsigned int relation)
{
int retval = -EINVAL;
- lock_cpu_hotplug();
+
+ /*
+ * Converted the lock_cpu_hotplug to preempt_disable()
+ * and preempt_enable(). This is a bit kludgy and relies on how cpu
+ * hotplug works. All we need is a guarantee that cpu hotplug won't make
+ * progress on any cpu. Once we do preempt_disable(), this would ensure
+ * that hotplug threads don't get onto this cpu, thereby delaying
+ * the cpu remove process.
+ *
+ * We removed the lock_cpu_hotplug since we need to call this function
+ * via cpu hotplug callbacks, which result in locking the cpu hotplug
+ * thread itself. Agree this is not very clean, cpufreq community
+ * could improve this if required. - Ashok Raj <ashok.raj@intel.com>
+ */
+ preempt_disable();
dprintk("target for CPU %u: %u kHz, relation %u\n", policy->cpu,
target_freq, relation);
if (cpu_online(policy->cpu) && cpufreq_driver->target)
retval = cpufreq_driver->target(policy, target_freq, relation);
- unlock_cpu_hotplug();
+ preempt_enable();
return retval;
}
EXPORT_SYMBOL_GPL(__cpufreq_driver_target);
-
int cpufreq_driver_target(struct cpufreq_policy *policy,
unsigned int target_freq,
unsigned int relation)
@@ -1416,6 +1424,45 @@ int cpufreq_update_policy(unsigned int cpu)
}
EXPORT_SYMBOL(cpufreq_update_policy);
+static int __cpuinit cpufreq_cpu_callback(struct notifier_block *nfb,
+ unsigned long action, void *hcpu)
+{
+ unsigned int cpu = (unsigned long)hcpu;
+ struct cpufreq_policy *policy;
+ struct sys_device *sys_dev;
+
+ sys_dev = get_cpu_sysdev(cpu);
+
+ if (sys_dev) {
+ switch (action) {
+ case CPU_ONLINE:
+ cpufreq_add_dev(sys_dev);
+ break;
+ case CPU_DOWN_PREPARE:
+ /*
+ * We attempt to put this cpu in lowest frequency
+ * possible before going down. This will permit
+ * hardware-managed P-State to switch other related
+ * threads to min or higher speeds if possible.
+ */
+ policy = cpufreq_cpu_data[cpu];
+ if (policy) {
+ cpufreq_driver_target(policy, policy->min,
+ CPUFREQ_RELATION_H);
+ }
+ break;
+ case CPU_DEAD:
+ cpufreq_remove_dev(sys_dev);
+ break;
+ }
+ }
+ return NOTIFY_OK;
+}
+
+static struct notifier_block cpufreq_cpu_notifier =
+{
+ .notifier_call = cpufreq_cpu_callback,
+};
/*********************************************************************
* REGISTER / UNREGISTER CPUFREQ DRIVER *
@@ -1476,6 +1523,7 @@ int cpufreq_register_driver(struct cpufreq_driver *driver_data)
}
if (!ret) {
+ register_cpu_notifier(&cpufreq_cpu_notifier);
dprintk("driver %s up and running\n", driver_data->name);
cpufreq_debug_enable_ratelimit();
}
@@ -1507,6 +1555,7 @@ int cpufreq_unregister_driver(struct cpufreq_driver *driver)
dprintk("unregistering driver %s\n", driver->name);
sysdev_driver_unregister(&cpu_sysdev_class, &cpufreq_sysdev_driver);
+ unregister_cpu_notifier(&cpufreq_cpu_notifier);
spin_lock_irqsave(&cpufreq_driver_lock, flags);
cpufreq_driver = NULL;
generated by cgit v1.2.3-18-g5258 (git 2.32.0) at 2024-11-26 23:49:14 +0000