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| author | Mark Brown <broonie@kernel.org> | 2015-09-16 20:44:25 +0100 |
|---|---|---|
| committer | Mark Brown <broonie@kernel.org> | 2015-09-16 20:44:25 +0100 |
| commit | 92243b6fc8fcb16bf401b055f7a0ba79f70a4115 (patch) | |
| tree | 08e9fa205efb9bfab23b6ea59fc0a3eaa3fed82b /include/linux/average.h | |
| parent | a394d635193b641f2c86ead5ada5b115d57c51f8 (diff) | |
| parent | 6ff33f3902c3b1c5d0db6b1e2c70b6d76fba357f (diff) | |
Merge tag 'v4.3-rc1' into spi-fix-doc
Linux 4.3-rc1
Diffstat (limited to 'include/linux/average.h')
| -rw-r--r-- | include/linux/average.h | 61 |
1 files changed, 38 insertions, 23 deletions
diff --git a/include/linux/average.h b/include/linux/average.h index c6028fd742c1..d04aa58280de 100644 --- a/include/linux/average.h +++ b/include/linux/average.h @@ -3,28 +3,43 @@ /* Exponentially weighted moving average (EWMA) */ -/* For more documentation see lib/average.c */ - -struct ewma { - unsigned long internal; - unsigned long factor; - unsigned long weight; -}; - -extern void ewma_init(struct ewma *avg, unsigned long factor, - unsigned long weight); - -extern struct ewma *ewma_add(struct ewma *avg, unsigned long val); - -/** - * ewma_read() - Get average value - * @avg: Average structure - * - * Returns the average value held in @avg. - */ -static inline unsigned long ewma_read(const struct ewma *avg) -{ - return avg->internal >> avg->factor; -} +#define DECLARE_EWMA(name, _factor, _weight) \ + struct ewma_##name { \ + unsigned long internal; \ + }; \ + static inline void ewma_##name##_init(struct ewma_##name *e) \ + { \ + BUILD_BUG_ON(!__builtin_constant_p(_factor)); \ + BUILD_BUG_ON(!__builtin_constant_p(_weight)); \ + BUILD_BUG_ON_NOT_POWER_OF_2(_factor); \ + BUILD_BUG_ON_NOT_POWER_OF_2(_weight); \ + e->internal = 0; \ + } \ + static inline unsigned long \ + ewma_##name##_read(struct ewma_##name *e) \ + { \ + BUILD_BUG_ON(!__builtin_constant_p(_factor)); \ + BUILD_BUG_ON(!__builtin_constant_p(_weight)); \ + BUILD_BUG_ON_NOT_POWER_OF_2(_factor); \ + BUILD_BUG_ON_NOT_POWER_OF_2(_weight); \ + return e->internal >> ilog2(_factor); \ + } \ + static inline void ewma_##name##_add(struct ewma_##name *e, \ + unsigned long val) \ + { \ + unsigned long internal = ACCESS_ONCE(e->internal); \ + unsigned long weight = ilog2(_weight); \ + unsigned long factor = ilog2(_factor); \ + \ + BUILD_BUG_ON(!__builtin_constant_p(_factor)); \ + BUILD_BUG_ON(!__builtin_constant_p(_weight)); \ + BUILD_BUG_ON_NOT_POWER_OF_2(_factor); \ + BUILD_BUG_ON_NOT_POWER_OF_2(_weight); \ + \ + ACCESS_ONCE(e->internal) = internal ? \ + (((internal << weight) - internal) + \ + (val << factor)) >> weight : \ + (val << factor); \ + } #endif /* _LINUX_AVERAGE_H */ |