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-rw-r--r--lib/average.c64
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diff --git a/lib/average.c b/lib/average.c
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-/*
- * 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;
-}
-EXPORT_SYMBOL(ewma_init);
-
-/**
- * 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;
-}
-EXPORT_SYMBOL(ewma_add);