#include <linux/proportions.h>
#include <linux/rcupdate.h>
-/*
- * Limit the time part in order to ensure there are some bits left for the
- * cycle counter.
- */
-#define PROP_MAX_SHIFT (3*BITS_PER_LONG/4)
-
int prop_descriptor_init(struct prop_descriptor *pd, int shift)
{
int err;
prop_put_global(pd, pg);
}
+/*
+ * identical to __prop_inc_percpu, except that it limits this pl's fraction to
+ * @frac/PROP_FRAC_BASE by ignoring events when this limit has been exceeded.
+ */
+void __prop_inc_percpu_max(struct prop_descriptor *pd,
+ struct prop_local_percpu *pl, long frac)
+{
+ struct prop_global *pg = prop_get_global(pd);
+
+ prop_norm_percpu(pg, pl);
+
+ if (unlikely(frac != PROP_FRAC_BASE)) {
+ unsigned long period_2 = 1UL << (pg->shift - 1);
+ unsigned long counter_mask = period_2 - 1;
+ unsigned long global_count;
+ long numerator, denominator;
+
+ numerator = percpu_counter_read_positive(&pl->events);
+ global_count = percpu_counter_read(&pg->events);
+ denominator = period_2 + (global_count & counter_mask);
+
+ if (numerator > ((denominator * frac) >> PROP_FRAC_SHIFT))
+ goto out_put;
+ }
+
+ percpu_counter_add(&pl->events, 1);
+ percpu_counter_add(&pg->events, 1);
+
+out_put:
+ prop_put_global(pd, pg);
+}
+
/*
* Obtain a fraction of this proportion
*