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Commit 8ff69732 authored by Dave Jones's avatar Dave Jones
Browse files

[CPUFREQ] Fix handling for CPU hotplug 



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: default avatarJacob Shin <jacob.shin@amd.com>
Signed-off-by: default avatarDave Jones <davej@redhat.com>
parent 2a1c1c87

drivers/cpufreq/cpufreq.c

+49 −2
Original line number Original line Diff line number Diff line
@@ -6,6 +6,8 @@ 
 *

 *

 *  Oct 2005 - Ashok Raj <ashok.raj@intel.com>

 *  Oct 2005 - Ashok Raj <ashok.raj@intel.com>

 *	Added handling for CPU hotplug

 *	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

 * 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

 * 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 new_policy;

	struct cpufreq_policy *policy;

	struct cpufreq_policy *policy;

	struct freq_attr **drv_attr;

	struct freq_attr **drv_attr;

	struct sys_device *cpu_sys_dev;

	unsigned long flags;

	unsigned long flags;

	unsigned int j;

	unsigned int j;

#ifdef CONFIG_SMP

	struct cpufreq_policy *managed_policy;

#endif





	if (cpu_is_offline(cpu))

	if (cpu_is_offline(cpu))

		return 0;

		return 0;
@@ -587,8 +593,7 @@ static int cpufreq_add_dev (struct sys_device * sys_dev) 
	 * CPU because it is in the same boat. */

	 * CPU because it is in the same boat. */

	policy = cpufreq_cpu_get(cpu);

	policy = cpufreq_cpu_get(cpu);

	if (unlikely(policy)) {

	if (unlikely(policy)) {

		dprintk("CPU already managed, adding link\n");

		cpufreq_cpu_put(policy);

		sysfs_create_link(&sys_dev->kobj, &policy->kobj, "cpufreq");

		cpufreq_debug_enable_ratelimit();

		cpufreq_debug_enable_ratelimit();

		return 0;

		return 0;

	}

	}
@@ -623,6 +628,32 @@ static int cpufreq_add_dev (struct sys_device * sys_dev) 
		goto err_out;

		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));

	memcpy(&new_policy, policy, sizeof(struct cpufreq_policy));





	/* prepare interface data */

	/* prepare interface data */
@@ -650,6 +681,21 @@ static int cpufreq_add_dev (struct sys_device * sys_dev) 
	for_each_cpu_mask(j, policy->cpus)

	for_each_cpu_mask(j, policy->cpus)

		cpufreq_cpu_data[j] = policy;

		cpufreq_cpu_data[j] = policy;

	spin_unlock_irqrestore(&cpufreq_driver_lock, flags);

	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

	policy->governor = NULL; /* to assure that the starting sequence is

				  * run in cpufreq_set_policy */

				  * run in cpufreq_set_policy */

	mutex_unlock(&policy->lock);

	mutex_unlock(&policy->lock);
@@ -728,6 +774,7 @@ static int cpufreq_remove_dev (struct sys_device * sys_dev) 
	 */

	 */

	if (unlikely(cpu != data->cpu)) {

	if (unlikely(cpu != data->cpu)) {

		dprintk("removing link\n");

		dprintk("removing link\n");

		cpu_clear(cpu, data->cpus);

		spin_unlock_irqrestore(&cpufreq_driver_lock, flags);

		spin_unlock_irqrestore(&cpufreq_driver_lock, flags);

		sysfs_remove_link(&sys_dev->kobj, "cpufreq");

		sysfs_remove_link(&sys_dev->kobj, "cpufreq");

		cpufreq_cpu_put(data);

		cpufreq_cpu_put(data);