cpufreq: Simplify __cpufreq_remove_dev()
__cpufreq_remove_dev() is called on multiple occasions: cpufreq_driver
unregister and cpu removals.
Current implementation of this routine is overly complex without much need. If
the cpu to be removed is the policy->cpu, we remove the policy first and add all
other cpus again from policy->cpus and then finally call __cpufreq_remove_dev()
again to remove the cpu to be deleted. Haahhhh..
There exist a simple solution to removal of a cpu:
- Simply use the old policy structure
- update its fields like: policy->cpu, etc.
- notify any users of cpufreq, which depend on changing policy->cpu
Hence this patch, which tries to implement the above theory. It is tested well
by myself on ARM big.LITTLE TC2 SoC, which has 5 cores (2 A15 and 3 A7). Both
A15's share same struct policy and all A7's share same policy structure.
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Tested-by: Shawn Guo <shawn.guo@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
diff --git a/include/linux/cpufreq.h b/include/linux/cpufreq.h
index a55b88e..52be2d0 100644
--- a/include/linux/cpufreq.h
+++ b/include/linux/cpufreq.h
@@ -93,7 +93,9 @@
cpumask_var_t related_cpus; /* CPUs with any coordination */
unsigned int shared_type; /* ANY or ALL affected CPUs
should set cpufreq */
- unsigned int cpu; /* cpu nr of registered CPU */
+ unsigned int cpu; /* cpu nr of CPU managing this policy */
+ unsigned int last_cpu; /* cpu nr of previous CPU that managed
+ * this policy */
struct cpufreq_cpuinfo cpuinfo;/* see above */
unsigned int min; /* in kHz */
@@ -112,10 +114,11 @@
struct completion kobj_unregister;
};
-#define CPUFREQ_ADJUST (0)
-#define CPUFREQ_INCOMPATIBLE (1)
-#define CPUFREQ_NOTIFY (2)
-#define CPUFREQ_START (3)
+#define CPUFREQ_ADJUST (0)
+#define CPUFREQ_INCOMPATIBLE (1)
+#define CPUFREQ_NOTIFY (2)
+#define CPUFREQ_START (3)
+#define CPUFREQ_UPDATE_POLICY_CPU (4)
#define CPUFREQ_SHARED_TYPE_NONE (0) /* None */
#define CPUFREQ_SHARED_TYPE_HW (1) /* HW does needed coordination */
@@ -405,6 +408,7 @@
void cpufreq_frequency_table_get_attr(struct cpufreq_frequency_table *table,
unsigned int cpu);
+void cpufreq_frequency_table_update_policy_cpu(struct cpufreq_policy *policy);
void cpufreq_frequency_table_put_attr(unsigned int cpu);
#endif /* _LINUX_CPUFREQ_H */