X-Git-Url: https://git.openpandora.org/cgi-bin/gitweb.cgi?a=blobdiff_plain;f=lib%2Fproportions.c;h=4f387a643d723c3853bec845ef0a90018a0e00f0;hb=c19e80808b34b3de5c20884f11f58c3b6988daff;hp=9508d9a7af3ef9ba482925a9d1cdc34ef2fddd0e;hpb=b297d520b9af536d5580ac505dd316be4cf5560c;p=pandora-kernel.git

diff --git a/lib/proportions.c b/lib/proportions.c
index 9508d9a7af3e..4f387a643d72 100644
--- a/lib/proportions.c
+++ b/lib/proportions.c
@@ -73,12 +73,6 @@
 #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;
@@ -267,6 +261,38 @@ void __prop_inc_percpu(struct prop_descriptor *pd, struct prop_local_percpu *pl)
 	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
  *