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[CPUFREQ] Fix handling for CPU hotplug

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This patch adds proper logic to cpufreq driver in order to handle
CPU Hotplug.

When CPUs go on/offline, the affected CPUs data, cpufreq_policy->cpus,
is not updated properly. This causes sysfs directories and symlinks to
be in an incorrect state after few CPU on/offlines.

Signed-off-by: Jacob Shin <jacob.shin@amd.com>
Signed-off-by: Dave Jones <davej@redhat.com>
This commit is contained in:
Dave Jones 2006-03-05 03:37:23 -05:00
parent 2a1c1c877e
commit 8ff69732d4
1 changed files with 49 additions and 2 deletions
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51
drivers/cpufreq/cpufreq.c
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@ -6,6 +6,8 @@
*
* Oct 2005 - Ashok Raj <ashok.raj@intel.com>
* Added handling for CPU hotplug
* Feb 2006 - Jacob Shin <jacob.shin@amd.com>
* Fix handling for CPU hotplug -- affected CPUs
*
* 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
@ -573,8 +575,12 @@ static int cpufreq_add_dev (struct sys_device * sys_dev)
struct cpufreq_policy new_policy;
struct cpufreq_policy *policy;
struct freq_attr **drv_attr;
struct sys_device *cpu_sys_dev;
unsigned long flags;
unsigned int j;
#ifdef CONFIG_SMP
struct cpufreq_policy *managed_policy;
#endif
if (cpu_is_offline(cpu))
return 0;
@ -587,8 +593,7 @@ 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)) {
dprintk("CPU already managed, adding link\n");
sysfs_create_link(&sys_dev->kobj, &policy->kobj, "cpufreq");
cpufreq_cpu_put(policy);
cpufreq_debug_enable_ratelimit();
return 0;
}
@ -623,6 +628,32 @@ static int cpufreq_add_dev (struct sys_device * sys_dev)
goto err_out;
}
#ifdef CONFIG_SMP
for_each_cpu_mask(j, policy->cpus) {
if (cpu == j)
continue;
/* check for existing affected CPUs. They may not be aware
* of it due to CPU Hotplug.
*/
managed_policy = cpufreq_cpu_get(j);
if (unlikely(managed_policy)) {
spin_lock_irqsave(&cpufreq_driver_lock, flags);
managed_policy->cpus = policy->cpus;
cpufreq_cpu_data[cpu] = managed_policy;
spin_unlock_irqrestore(&cpufreq_driver_lock, flags);
dprintk("CPU already managed, adding link\n");
sysfs_create_link(&sys_dev->kobj,
&managed_policy->kobj, "cpufreq");
cpufreq_debug_enable_ratelimit();
mutex_unlock(&policy->lock);
ret = 0;
goto err_out_driver_exit; /* call driver->exit() */
}
}
#endif
memcpy(&new_policy, policy, sizeof(struct cpufreq_policy));
/* prepare interface data */
@ -650,6 +681,21 @@ static int cpufreq_add_dev (struct sys_device * sys_dev)
for_each_cpu_mask(j, policy->cpus)
cpufreq_cpu_data[j] = policy;
spin_unlock_irqrestore(&cpufreq_driver_lock, flags);
/* symlink affected CPUs */
for_each_cpu_mask(j, policy->cpus) {
if (j == cpu)
continue;
if (!cpu_online(j))
continue;
dprintk("CPU already managed, adding link\n");
cpufreq_cpu_get(cpu);
cpu_sys_dev = get_cpu_sysdev(j);
sysfs_create_link(&cpu_sys_dev->kobj, &policy->kobj,
"cpufreq");
}
policy->governor = NULL; /* to assure that the starting sequence is
* run in cpufreq_set_policy */
mutex_unlock(&policy->lock);
@ -728,6 +774,7 @@ static int cpufreq_remove_dev (struct sys_device * sys_dev)
*/
if (unlikely(cpu != data->cpu)) {
dprintk("removing link\n");
cpu_clear(cpu, data->cpus);
spin_unlock_irqrestore(&cpufreq_driver_lock, flags);
sysfs_remove_link(&sys_dev->kobj, "cpufreq");
cpufreq_cpu_put(data);