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-rw-r--r--kernel/include/linux/proportions.h137
1 files changed, 137 insertions, 0 deletions
diff --git a/kernel/include/linux/proportions.h b/kernel/include/linux/proportions.h
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index 000000000..00e8e8fa7
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+++ b/kernel/include/linux/proportions.h
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+/*
+ * 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>
+#include <linux/gfp.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, gfp_t gfp);
+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;
+ raw_spinlock_t lock; /* protect the snapshot state */
+};
+
+int prop_local_init_percpu(struct prop_local_percpu *pl, gfp_t gfp);
+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);
+}
+
+/*
+ * Limit the time part in order to ensure there are some bits left for the
+ * cycle counter and fraction multiply.
+ */
+#if BITS_PER_LONG == 32
+#define PROP_MAX_SHIFT (3*BITS_PER_LONG/4)
+#else
+#define PROP_MAX_SHIFT (BITS_PER_LONG/2)
+#endif
+
+#define PROP_FRAC_SHIFT (BITS_PER_LONG - PROP_MAX_SHIFT - 1)
+#define PROP_FRAC_BASE (1UL << PROP_FRAC_SHIFT)
+
+void __prop_inc_percpu_max(struct prop_descriptor *pd,
+ struct prop_local_percpu *pl, long frac);
+
+
+/*
+ * ----- 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
+ */
+ unsigned long period;
+ int shift;
+ raw_spinlock_t lock; /* protect the snapshot state */
+};
+
+#define INIT_PROP_LOCAL_SINGLE(name) \
+{ .lock = __RAW_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 */