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| author | Rafael J. Wysocki <rafael.j.wysocki@intel.com> | 2016-05-31 22:14:44 +0200 |
|---|---|---|
| committer | Rafael J. Wysocki <rafael.j.wysocki@intel.com> | 2016-06-02 23:24:41 +0200 |
| commit | 1aefc75b2449eb68a6fc3ca932e2a4ee353b748d (patch) | |
| tree | dff2ffcc2d7738bcc93bb968f4d370996c63f9c2 /drivers/cpufreq/Kconfig | |
| parent | 910c6e881c3a610dfd7575b96975d4df21e3a920 (diff) | |
| download | lwn-1aefc75b2449eb68a6fc3ca932e2a4ee353b748d.tar.gz lwn-1aefc75b2449eb68a6fc3ca932e2a4ee353b748d.zip | |
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 'drivers/cpufreq/Kconfig')
| -rw-r--r-- | drivers/cpufreq/Kconfig | 13 |
1 files changed, 4 insertions, 9 deletions
diff --git a/drivers/cpufreq/Kconfig b/drivers/cpufreq/Kconfig index b7445b6ae5a4..c822d72629d5 100644 --- a/drivers/cpufreq/Kconfig +++ b/drivers/cpufreq/Kconfig @@ -31,23 +31,18 @@ config CPU_FREQ_BOOST_SW depends on THERMAL config CPU_FREQ_STAT - tristate "CPU frequency translation statistics" + bool "CPU frequency transition statistics" default y help - This driver exports CPU frequency statistics information through sysfs - file system. - - To compile this driver as a module, choose M here: the - module will be called cpufreq_stats. + Export CPU frequency statistics information through sysfs. If in doubt, say N. config CPU_FREQ_STAT_DETAILS - bool "CPU frequency translation statistics details" + bool "CPU frequency transition statistics details" depends on CPU_FREQ_STAT help - This will show detail CPU frequency translation table in sysfs file - system. + Show detailed CPU frequency transition table in sysfs. If in doubt, say N. |