+++ /dev/null
-From: Johannes Berg <johannes.berg@intel.com>
-Date: Wed, 15 Feb 2017 09:49:26 +0100
-Subject: [PATCH] batman-adv: average: change to declare precision, not factor
-
-Declaring the factor is counter-intuitive, and people are prone
-to using small(-ish) values even when that makes no sense.
-
-Change the DECLARE_EWMA() macro to take the fractional precision,
-in bits, rather than a factor, and update all users.
-
-While at it, add some more documentation.
-
-Acked-by: David S. Miller <davem@davemloft.net>
-Signed-off-by: Johannes Berg <johannes.berg@intel.com>
-[sven@narfation.org: Added compatibility code]
-Signed-off-by: Sven Eckelmann <sven@narfation.org>
----
- compat-include/linux/average.h | 67 +++++++++++++++++++++++++++---------------
- net/batman-adv/types.h | 2 +-
- 2 files changed, 45 insertions(+), 24 deletions(-)
-
-diff --git a/compat-include/linux/average.h b/compat-include/linux/average.h
-index ec022cb6..a1e3c254 100644
---- a/compat-include/linux/average.h
-+++ b/compat-include/linux/average.h
-@@ -26,49 +26,70 @@
-
- #include <linux/bug.h>
-
--#if LINUX_VERSION_CODE < KERNEL_VERSION(4, 3, 0)
-+#if LINUX_VERSION_CODE >= KERNEL_VERSION(4, 3, 0)
-+#undef DECLARE_EWMA
-+#endif /* < KERNEL_VERSION(4, 3, 0) */
-
--/* Exponentially weighted moving average (EWMA) */
-+/*
-+ * Exponentially weighted moving average (EWMA)
-+ *
-+ * This implements a fixed-precision EWMA algorithm, with both the
-+ * precision and fall-off coefficient determined at compile-time
-+ * and built into the generated helper funtions.
-+ *
-+ * The first argument to the macro is the name that will be used
-+ * for the struct and helper functions.
-+ *
-+ * The second argument, the precision, expresses how many bits are
-+ * used for the fractional part of the fixed-precision values.
-+ *
-+ * The third argument, the weight reciprocal, determines how the
-+ * new values will be weighed vs. the old state, new values will
-+ * get weight 1/weight_rcp and old values 1-1/weight_rcp. Note
-+ * that this parameter must be a power of two for efficiency.
-+ */
-
--#define DECLARE_EWMA(name, _factor, _weight) \
-+#define DECLARE_EWMA(name, _precision, _weight_rcp) \
- 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); \
-+ BUILD_BUG_ON(!__builtin_constant_p(_precision)); \
-+ BUILD_BUG_ON(!__builtin_constant_p(_weight_rcp)); \
-+ /* \
-+ * Even if you want to feed it just 0/1 you should have \
-+ * some bits for the non-fractional part... \
-+ */ \
-+ BUILD_BUG_ON((_precision) > 30); \
-+ BUILD_BUG_ON_NOT_POWER_OF_2(_weight_rcp); \
- 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); \
-+ BUILD_BUG_ON(!__builtin_constant_p(_precision)); \
-+ BUILD_BUG_ON(!__builtin_constant_p(_weight_rcp)); \
-+ BUILD_BUG_ON((_precision) > 30); \
-+ BUILD_BUG_ON_NOT_POWER_OF_2(_weight_rcp); \
-+ return e->internal >> (_precision); \
- } \
- 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); \
-+ unsigned long weight_rcp = ilog2(_weight_rcp); \
-+ unsigned long precision = _precision; \
- \
-- 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); \
-+ BUILD_BUG_ON(!__builtin_constant_p(_precision)); \
-+ BUILD_BUG_ON(!__builtin_constant_p(_weight_rcp)); \
-+ BUILD_BUG_ON((_precision) > 30); \
-+ BUILD_BUG_ON_NOT_POWER_OF_2(_weight_rcp); \
- \
- ACCESS_ONCE(e->internal) = internal ? \
-- (((internal << weight) - internal) + \
-- (val << factor)) >> weight : \
-- (val << factor); \
-+ (((internal << weight_rcp) - internal) + \
-+ (val << precision)) >> weight_rcp : \
-+ (val << precision); \
- }
-
--#endif /* < KERNEL_VERSION(4, 3, 0) */
--
- #endif /* _NET_BATMAN_ADV_COMPAT_LINUX_AVERAGE_H */
-diff --git a/net/batman-adv/types.h b/net/batman-adv/types.h
-index 8f64a5c0..66b25e41 100644
---- a/net/batman-adv/types.h
-+++ b/net/batman-adv/types.h
-@@ -402,7 +402,7 @@ struct batadv_gw_node {
- struct rcu_head rcu;
- };
-
--DECLARE_EWMA(throughput, 1024, 8)
-+DECLARE_EWMA(throughput, 10, 8)
-
- /**
- * struct batadv_hardif_neigh_node_bat_v - B.A.T.M.A.N. V private neighbor
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