1 files changed, 119 insertions, 0 deletions

diff --git a/include/linux/proportions.h b/include/linux/proportions.h
new file mode 100644
index 000000000000..2c3b3cad92be
--- /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 */