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authorRafael J. Wysocki <rafael.j.wysocki@intel.com>2016-05-31 22:14:44 +0200
committerRafael J. Wysocki <rafael.j.wysocki@intel.com>2016-06-02 23:24:41 +0200
commit1aefc75b2449eb68a6fc3ca932e2a4ee353b748d (patch)
treedff2ffcc2d7738bcc93bb968f4d370996c63f9c2 /include/linux/cpufreq.h
parent910c6e881c3a610dfd7575b96975d4df21e3a920 (diff)
cpufreq: stats: Make the stats code non-modular
The modularity of cpufreq_stats is quite problematic. First off, the usage of policy notifiers for the initialization and cleanup in the cpufreq_stats module is inherently racy with respect to CPU offline/online and the initialization and cleanup of the cpufreq driver. Second, fast frequency switching (used by the schedutil governor) cannot be enabled if any transition notifiers are registered, so if the cpufreq_stats module (that registers a transition notifier for updating transition statistics) is loaded, the schedutil governor cannot use fast frequency switching. On the other hand, allowing cpufreq_stats to be built as a module doesn't really add much value. Arguably, there's not much reason for that code to be modular at all. For the above reasons, make the cpufreq stats code non-modular, modify the core to invoke functions provided by that code directly and drop the notifiers from it. Make the stats sysfs attributes appear empty if fast frequency switching is enabled as the statistics will not be updated in that case anyway (and returning -EBUSY from those attributes breaks powertop). While at it, clean up Kconfig help for the CPU_FREQ_STAT and CPU_FREQ_STAT_DETAILS options. Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
Diffstat (limited to 'include/linux/cpufreq.h')
-rw-r--r--include/linux/cpufreq.h12
1 files changed, 12 insertions, 0 deletions
diff --git a/include/linux/cpufreq.h b/include/linux/cpufreq.h
index fbd696edf5bd..7ed93c310c08 100644
--- a/include/linux/cpufreq.h
+++ b/include/linux/cpufreq.h
@@ -185,6 +185,18 @@ static inline unsigned int cpufreq_quick_get_max(unsigned int cpu)
static inline void disable_cpufreq(void) { }
#endif
+#ifdef CONFIG_CPU_FREQ_STAT
+void cpufreq_stats_create_table(struct cpufreq_policy *policy);
+void cpufreq_stats_free_table(struct cpufreq_policy *policy);
+void cpufreq_stats_record_transition(struct cpufreq_policy *policy,
+ unsigned int new_freq);
+#else
+static inline void cpufreq_stats_create_table(struct cpufreq_policy *policy) { }
+static inline void cpufreq_stats_free_table(struct cpufreq_policy *policy) { }
+static inline void cpufreq_stats_record_transition(struct cpufreq_policy *policy,
+ unsigned int new_freq) { }
+#endif /* CONFIG_CPU_FREQ_STAT */
+
/*********************************************************************
* CPUFREQ DRIVER INTERFACE *
*********************************************************************/