[CPUFREQ] Rewrite lock in cpufreq to eliminate cpufreq/hotplug related issues
Yet another attempt to resolve cpufreq and hotplug locking issues.
Patchset has 3 patches:
* Rewrite the lock infrastructure of cpufreq using a per cpu rwsem.
* Minor restructuring of work callback in ondemand driver.
* Use the new cpufreq rwsem infrastructure in ondemand work.
This patch:
Convert policy->lock to rwsem and move it to per_cpu area.
This rwsem will protect against both changing/accessing policy
related parameters and CPU hot plug/unplug.
[malattia@linux.it: fix oops in kref_put()]
Cc: Gautham R Shenoy <ego@in.ibm.com>
Signed-off-by: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com>
Cc: Gautham R Shenoy <ego@in.ibm.com>
Signed-off-by: Mattia Dongili <malattia@linux.it>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Dave Jones <davej@redhat.com>
diff --git a/include/linux/cpufreq.h b/include/linux/cpufreq.h
index 7f008f6..0899e2c 100644
--- a/include/linux/cpufreq.h
+++ b/include/linux/cpufreq.h
@@ -84,9 +84,6 @@
unsigned int policy; /* see above */
struct cpufreq_governor *governor; /* see below */
- struct mutex lock; /* CPU ->setpolicy or ->target may
- only be called once a time */
-
struct work_struct update; /* if update_policy() needs to be
* called, but you're in IRQ context */
@@ -172,11 +169,16 @@
unsigned int relation);
-extern int cpufreq_driver_getavg(struct cpufreq_policy *policy);
+extern int __cpufreq_driver_getavg(struct cpufreq_policy *policy);
int cpufreq_register_governor(struct cpufreq_governor *governor);
void cpufreq_unregister_governor(struct cpufreq_governor *governor);
+int lock_policy_rwsem_read(int cpu);
+int lock_policy_rwsem_write(int cpu);
+void unlock_policy_rwsem_read(int cpu);
+void unlock_policy_rwsem_write(int cpu);
+
/*********************************************************************
* CPUFREQ DRIVER INTERFACE *