Commit f4e774f5 authored by Johannes Berg's avatar Johannes Berg Committed by David S. Miller

average: remove out-of-line implementation

Since all users are now converted to the inline implementation,
remove the out-of-line implementation entirely.
Signed-off-by: default avatarJohannes Berg <>
Signed-off-by: default avatarDavid S. Miller <>
parent 11ab35ed
......@@ -3,30 +3,6 @@
/* 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; \
......@@ -460,16 +460,6 @@ config ARCH_HAS_ATOMIC64_DEC_IF_POSITIVE
config LRU_CACHE
config AVERAGE
bool "Averaging functions"
This option is provided for the case where no in-kernel-tree
modules require averaging functions, but a module built outside
the kernel tree does. Such modules that use library averaging
functions require Y here.
If unsure, say N.
config CLZ_TAB
* lib/average.c
* This source code is licensed under the GNU General Public License,
* Version 2. See the file COPYING for more details.
#include <linux/export.h>
#include <linux/average.h>
#include <linux/kernel.h>
#include <linux/bug.h>
#include <linux/log2.h>
* DOC: Exponentially Weighted Moving Average (EWMA)
* These are generic functions for calculating Exponentially Weighted Moving
* Averages (EWMA). We keep a structure with the EWMA parameters and a scaled
* up internal representation of the average value to prevent rounding errors.
* The factor for scaling up and the exponential weight (or decay rate) have to
* be specified thru the init fuction. The structure should not be accessed
* directly but only thru the helper functions.
* ewma_init() - Initialize EWMA parameters
* @avg: Average structure
* @factor: Factor to use for the scaled up internal value. The maximum value
* of averages can be ULONG_MAX/(factor*weight). For performance reasons
* factor has to be a power of 2.
* @weight: Exponential weight, or decay rate. This defines how fast the
* influence of older values decreases. For performance reasons weight has
* to be a power of 2.
* Initialize the EWMA parameters for a given struct ewma @avg.
void ewma_init(struct ewma *avg, unsigned long factor, unsigned long weight)
WARN_ON(!is_power_of_2(weight) || !is_power_of_2(factor));
avg->weight = ilog2(weight);
avg->factor = ilog2(factor);
avg->internal = 0;
* ewma_add() - Exponentially weighted moving average (EWMA)
* @avg: Average structure
* @val: Current value
* Add a sample to the average.
struct ewma *ewma_add(struct ewma *avg, unsigned long val)
unsigned long internal = ACCESS_ONCE(avg->internal);
ACCESS_ONCE(avg->internal) = internal ?
(((internal << avg->weight) - internal) +
(val << avg->factor)) >> avg->weight :
(val << avg->factor);
return avg;
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