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1/*
2 * Floating proportions with flexible aging period
3 *
4 * Copyright (C) 2011, SUSE, Jan Kara <jack@suse.cz>
5 */
6
7#ifndef _LINUX_FLEX_PROPORTIONS_H
8#define _LINUX_FLEX_PROPORTIONS_H
9
10#include <linux/percpu_counter.h>
11#include <linux/spinlock.h>
12#include <linux/seqlock.h>
13
14/*
15 * When maximum proportion of some event type is specified, this is the
16 * precision with which we allow limitting. Note that this creates an upper
17 * bound on the number of events per period like
18 * ULLONG_MAX >> FPROP_FRAC_SHIFT.
19 */
20#define FPROP_FRAC_SHIFT 10
21#define FPROP_FRAC_BASE (1UL << FPROP_FRAC_SHIFT)
22
23/*
24 * ---- Global proportion definitions ----
25 */
26struct fprop_global {
27 /* Number of events in the current period */
28 struct percpu_counter events;
29 /* Current period */
30 unsigned int period;
31 /* Synchronization with period transitions */
32 seqcount_t sequence;
33};
34
35int fprop_global_init(struct fprop_global *p);
36void fprop_global_destroy(struct fprop_global *p);
37bool fprop_new_period(struct fprop_global *p, int periods);
38
39/*
40 * ---- SINGLE ----
41 */
42struct fprop_local_single {
43 /* the local events counter */
44 unsigned long events;
45 /* Period in which we last updated events */
46 unsigned int period;
47 raw_spinlock_t lock; /* Protect period and numerator */
48};
49
50#define INIT_FPROP_LOCAL_SINGLE(name) \
51{ .lock = __RAW_SPIN_LOCK_UNLOCKED(name.lock), \
52}
53
54int fprop_local_init_single(struct fprop_local_single *pl);
55void fprop_local_destroy_single(struct fprop_local_single *pl);
56void __fprop_inc_single(struct fprop_global *p, struct fprop_local_single *pl);
57void fprop_fraction_single(struct fprop_global *p,
58 struct fprop_local_single *pl, unsigned long *numerator,
59 unsigned long *denominator);
60
61static inline
62void fprop_inc_single(struct fprop_global *p, struct fprop_local_single *pl)
63{
64 unsigned long flags;
65
66 local_irq_save(flags);
67 __fprop_inc_single(p, pl);
68 local_irq_restore(flags);
69}
70
71/*
72 * ---- PERCPU ----
73 */
74struct fprop_local_percpu {
75 /* the local events counter */
76 struct percpu_counter events;
77 /* Period in which we last updated events */
78 unsigned int period;
79 raw_spinlock_t lock; /* Protect period and numerator */
80};
81
82int fprop_local_init_percpu(struct fprop_local_percpu *pl);
83void fprop_local_destroy_percpu(struct fprop_local_percpu *pl);
84void __fprop_inc_percpu(struct fprop_global *p, struct fprop_local_percpu *pl);
85void __fprop_inc_percpu_max(struct fprop_global *p, struct fprop_local_percpu *pl,
86 int max_frac);
87void fprop_fraction_percpu(struct fprop_global *p,
88 struct fprop_local_percpu *pl, unsigned long *numerator,
89 unsigned long *denominator);
90
91static inline
92void fprop_inc_percpu(struct fprop_global *p, struct fprop_local_percpu *pl)
93{
94 unsigned long flags;
95
96 local_irq_save(flags);
97 __fprop_inc_percpu(p, pl);
98 local_irq_restore(flags);
99}
100
101#endif