1 files changed, 119 insertions, 0 deletions
diff --git a/include/linux/proportions.h b/include/linux/proportions.h
new file mode 100644
index 00000000000..2c3b3cad92b
--- /dev/null
+++ b/include/linux/proportions.h
@@ -0,0 +1,119 @@
+/*
+ * FLoating proportions
+ *
+ *  Copyright (C) 2007 Red Hat, Inc., Peter Zijlstra <pzijlstr@redhat.com>
+ *
+ * This file contains the public data structure and API definitions.
+ */
+
+#ifndef _LINUX_PROPORTIONS_H
+#define _LINUX_PROPORTIONS_H
+
+#include <linux/percpu_counter.h>
+#include <linux/spinlock.h>
+#include <linux/mutex.h>
+
+struct prop_global {
+	/*
+	 * The period over which we differentiate
+	 *
+	 *   period = 2^shift
+	 */
+	int shift;
+	/*
+	 * The total event counter aka 'time'.
+	 *
+	 * Treated as an unsigned long; the lower 'shift - 1' bits are the
+	 * counter bits, the remaining upper bits the period counter.
+	 */
+	struct percpu_counter events;
+};
+
+/*
+ * global proportion descriptor
+ *
+ * this is needed to consitently flip prop_global structures.
+ */
+struct prop_descriptor {
+	int index;
+	struct prop_global pg[2];
+	struct mutex mutex;		/* serialize the prop_global switch */
+};
+
+int prop_descriptor_init(struct prop_descriptor *pd, int shift);
+void prop_change_shift(struct prop_descriptor *pd, int new_shift);
+
+/*
+ * ----- PERCPU ------
+ */
+
+struct prop_local_percpu {
+	/*
+	 * the local events counter
+	 */
+	struct percpu_counter events;
+
+	/*
+	 * snapshot of the last seen global state
+	 */
+	int shift;
+	unsigned long period;
+	spinlock_t lock;		/* protect the snapshot state */
+};
+
+int prop_local_init_percpu(struct prop_local_percpu *pl);
+void prop_local_destroy_percpu(struct prop_local_percpu *pl);
+void __prop_inc_percpu(struct prop_descriptor *pd, struct prop_local_percpu *pl);
+void prop_fraction_percpu(struct prop_descriptor *pd, struct prop_local_percpu *pl,
+		long *numerator, long *denominator);
+
+static inline
+void prop_inc_percpu(struct prop_descriptor *pd, struct prop_local_percpu *pl)
+{
+	unsigned long flags;
+
+	local_irq_save(flags);
+	__prop_inc_percpu(pd, pl);
+	local_irq_restore(flags);
+}
+
+/*
+ * ----- SINGLE ------
+ */
+
+struct prop_local_single {
+	/*
+	 * the local events counter
+	 */
+	unsigned long events;
+
+	/*
+	 * snapshot of the last seen global state
+	 * and a lock protecting this state
+	 */
+	int shift;
+	unsigned long period;
+	spinlock_t lock;		/* protect the snapshot state */
+};
+
+#define INIT_PROP_LOCAL_SINGLE(name)			\
+{	.lock = __SPIN_LOCK_UNLOCKED(name.lock),	\
+}
+
+int prop_local_init_single(struct prop_local_single *pl);
+void prop_local_destroy_single(struct prop_local_single *pl);
+void __prop_inc_single(struct prop_descriptor *pd, struct prop_local_single *pl);
+void prop_fraction_single(struct prop_descriptor *pd, struct prop_local_single *pl,
+		long *numerator, long *denominator);
+
+static inline
+void prop_inc_single(struct prop_descriptor *pd, struct prop_local_single *pl)
+{
+	unsigned long flags;
+
+	local_irq_save(flags);
+	__prop_inc_single(pd, pl);
+	local_irq_restore(flags);
+}
+
+#endif /* _LINUX_PROPORTIONS_H */