| 1 | #ifndef _LINUX_AVERAGE_H
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| 2 | #define _LINUX_AVERAGE_H
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| 3 |
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| 4 |
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| 5 |
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| 6 | #define DECLARE_EWMA(name, _factor, _weight) \
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| 7 | struct ewma_##name { \
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| 8 | unsigned long internal; \
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| 9 | }; \
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| 10 | static inline void ewma_##name##_init(struct ewma_##name *e) \
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| 11 | { \
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| 12 | BUILD_BUG_ON(!__builtin_constant_p(_factor)); \
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| 13 | BUILD_BUG_ON(!__builtin_constant_p(_weight)); \
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| 14 | BUILD_BUG_ON_NOT_POWER_OF_2(_factor); \
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| 15 | BUILD_BUG_ON_NOT_POWER_OF_2(_weight); \
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| 16 | e->internal = 0; \
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| 17 | } \
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| 18 | static inline unsigned long \
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| 19 | ewma_##name##_read(struct ewma_##name *e) \
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| 20 | { \
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| 21 | BUILD_BUG_ON(!__builtin_constant_p(_factor)); \
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| 22 | BUILD_BUG_ON(!__builtin_constant_p(_weight)); \
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| 23 | BUILD_BUG_ON_NOT_POWER_OF_2(_factor); \
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| 24 | BUILD_BUG_ON_NOT_POWER_OF_2(_weight); \
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| 25 | return e->internal >> ilog2(_factor); \
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| 26 | } \
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| 27 | static inline void ewma_##name##_add(struct ewma_##name *e, \
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| 28 | unsigned long val) \
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| 29 | { \
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| 30 | unsigned long internal = ACCESS_ONCE(e->internal); \
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| 31 | unsigned long weight = ilog2(_weight); \
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| 32 | unsigned long factor = ilog2(_factor); \
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| 33 | \
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| 34 | BUILD_BUG_ON(!__builtin_constant_p(_factor)); \
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| 35 | BUILD_BUG_ON(!__builtin_constant_p(_weight)); \
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| 36 | BUILD_BUG_ON_NOT_POWER_OF_2(_factor); \
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| 37 | BUILD_BUG_ON_NOT_POWER_OF_2(_weight); \
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| 38 | \
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| 39 | ACCESS_ONCE(e->internal) = internal ? \
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| 40 | (((internal << weight) - internal) + \
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| 41 | (val << factor)) >> weight : \
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| 42 | (val << factor); \
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| 43 | }
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| 44 |
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| 45 | #endif
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