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authorDominik Brodowski2018-01-30 06:42:37 +0100
committerRafael J. Wysocki2018-02-08 10:21:39 +0100
commitffd81dcfef85a33729f90e4acd2f61a68e56b993 (patch)
tree4160debd7778d436e027edf810e438266953dc11 /Documentation/cpu-freq/cpu-drivers.txt
parentcpufreq: intel_pstate: Enable HWP during system resume on CPU0 (diff)
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cpufreq: Add and use cpufreq_for_each_{valid_,}entry_idx()
Pointer subtraction is slow and tedious. Therefore, replace all instances where cpufreq_for_each_{valid_,}entry loops contained such substractions with an iteration macro providing an index to the frequency_table entry. Suggested-by: Al Viro <viro@ZenIV.linux.org.uk> Link: http://lkml.kernel.org/r/20180120020237.GM13338@ZenIV.linux.org.uk Acked-by: Viresh Kumar <viresh.kumar@linaro.org> Signed-off-by: Dominik Brodowski <linux@dominikbrodowski.net> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Diffstat (limited to 'Documentation/cpu-freq/cpu-drivers.txt')
-rw-r--r--Documentation/cpu-freq/cpu-drivers.txt4
1 files changed, 4 insertions, 0 deletions
diff --git a/Documentation/cpu-freq/cpu-drivers.txt b/Documentation/cpu-freq/cpu-drivers.txt
index 434c49cc7330..61546ac578d6 100644
--- a/Documentation/cpu-freq/cpu-drivers.txt
+++ b/Documentation/cpu-freq/cpu-drivers.txt
@@ -291,3 +291,7 @@ For example:
/* Do something with pos */
pos->frequency = ...
}
+
+If you need to work with the position of pos within driver_freq_table,
+do not subtract the pointers, as it is quite costly. Instead, use the
+macros cpufreq_for_each_entry_idx() and cpufreq_for_each_valid_entry_idx().