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authorDave Jones <davej@redhat.com>2006-03-05 03:37:23 -0500
committerDave Jones <davej@redhat.com>2006-03-05 03:37:23 -0500
commit8ff69732d484ea9ccbf242cc49b4fe9538e64c71 (patch)
tree5b65e26af1cbf2f5c54ca9b3b35755ddeb2f40ee /drivers
parent2a1c1c877ecb446dbdf1715248e151db8719a87b (diff)
[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: Jacob Shin <jacob.shin@amd.com> Signed-off-by: Dave Jones <davej@redhat.com>
Diffstat (limited to 'drivers')
-rw-r--r--drivers/cpufreq/cpufreq.c51
1 files changed, 49 insertions, 2 deletions
diff --git a/drivers/cpufreq/cpufreq.c b/drivers/cpufreq/cpufreq.c
index cb7d6e0db75..aed80e6aec6 100644
--- a/drivers/cpufreq/cpufreq.c
+++ b/drivers/cpufreq/cpufreq.c
@@ -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);