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In order to prepare for lock-less stats update, add support to defer any updates to it until cpufreq_stats_record_transition() is called. The stats were updated from two places earlier: - show_time_in_state(): This can be easily deferred, all we need is to calculate the delta duration again in this routine to show the current state's time-in-state. - store_reset(): This is a bit tricky as we need to clear the stats here and avoid races with simultaneous call to cpufreq_stats_record_transition(). Fix that by deferring the reset of the stats (within the code) to the next call to cpufreq_stats_record_transition(), but since we need to keep showing the right stats until that time, we capture the reset time and account for the time since last time reset was called until the time cpufreq_stats_record_transition() update the stats. User space will continue seeing the stats correctly, everything will be 0 after the stats are reset, apart from the time-in-state of the current state, until the time a frequency switch happens. Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org> [ rjw: Minor changelog edits ] Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.