Edit File: average.h
#ifndef _LINUX_AVERAGE_H #define _LINUX_AVERAGE_H /* 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 */