1 files changed, 103 insertions, 0 deletions
diff --git a/include/linux/flex_proportions.h b/include/linux/flex_proportions.h
new file mode 100644
index 000000000..c12df59d3
--- /dev/null
+++ b/include/linux/flex_proportions.h
@@ -0,0 +1,103 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Floating proportions with flexible aging period
+ *
+ *  Copyright (C) 2011, SUSE, Jan Kara <jack@suse.cz>
+ */
+
+#ifndef _LINUX_FLEX_PROPORTIONS_H
+#define _LINUX_FLEX_PROPORTIONS_H
+
+#include <linux/percpu_counter.h>
+#include <linux/spinlock.h>
+#include <linux/seqlock.h>
+#include <linux/gfp.h>
+
+/*
+ * When maximum proportion of some event type is specified, this is the
+ * precision with which we allow limitting. Note that this creates an upper
+ * bound on the number of events per period like
+ *   ULLONG_MAX >> FPROP_FRAC_SHIFT.
+ */
+#define FPROP_FRAC_SHIFT 10
+#define FPROP_FRAC_BASE (1UL << FPROP_FRAC_SHIFT)
+
+/*
+ * ---- Global proportion definitions ----
+ */
+struct fprop_global {
+	/* Number of events in the current period */
+	struct percpu_counter events;
+	/* Current period */
+	unsigned int period;
+	/* Synchronization with period transitions */
+	seqcount_t sequence;
+};
+
+int fprop_global_init(struct fprop_global *p, gfp_t gfp);
+void fprop_global_destroy(struct fprop_global *p);
+bool fprop_new_period(struct fprop_global *p, int periods);
+
+/*
+ *  ---- SINGLE ----
+ */
+struct fprop_local_single {
+	/* the local events counter */
+	unsigned long events;
+	/* Period in which we last updated events */
+	unsigned int period;
+	raw_spinlock_t lock;	/* Protect period and numerator */
+};
+
+#define INIT_FPROP_LOCAL_SINGLE(name)			\
+{	.lock = __RAW_SPIN_LOCK_UNLOCKED(name.lock),	\
+}
+
+int fprop_local_init_single(struct fprop_local_single *pl);
+void fprop_local_destroy_single(struct fprop_local_single *pl);
+void __fprop_inc_single(struct fprop_global *p, struct fprop_local_single *pl);
+void fprop_fraction_single(struct fprop_global *p,
+	struct fprop_local_single *pl, unsigned long *numerator,
+	unsigned long *denominator);
+
+static inline
+void fprop_inc_single(struct fprop_global *p, struct fprop_local_single *pl)
+{
+	unsigned long flags;
+
+	local_irq_save(flags);
+	__fprop_inc_single(p, pl);
+	local_irq_restore(flags);
+}
+
+/*
+ * ---- PERCPU ----
+ */
+struct fprop_local_percpu {
+	/* the local events counter */
+	struct percpu_counter events;
+	/* Period in which we last updated events */
+	unsigned int period;
+	raw_spinlock_t lock;	/* Protect period and numerator */
+};
+
+int fprop_local_init_percpu(struct fprop_local_percpu *pl, gfp_t gfp);
+void fprop_local_destroy_percpu(struct fprop_local_percpu *pl);
+void __fprop_inc_percpu(struct fprop_global *p, struct fprop_local_percpu *pl);
+void __fprop_inc_percpu_max(struct fprop_global *p, struct fprop_local_percpu *pl,
+			    int max_frac);
+void fprop_fraction_percpu(struct fprop_global *p,
+	struct fprop_local_percpu *pl, unsigned long *numerator,
+	unsigned long *denominator);
+
+static inline
+void fprop_inc_percpu(struct fprop_global *p, struct fprop_local_percpu *pl)
+{
+	unsigned long flags;
+
+	local_irq_save(flags);
+	__fprop_inc_percpu(p, pl);
+	local_irq_restore(flags);
+}
+
+#endif