Merge branch 'for-3.11' of git://linux-nfs.org/~bfields/linux
[linux-2.6.git] / include / linux / flex_proportions.h
blob4ebc49fae391ab1c8a9c1b8c769755d04db52b86
1 /*
2 * Floating proportions with flexible aging period
4 * Copyright (C) 2011, SUSE, Jan Kara <jack@suse.cz>
5 */
7 #ifndef _LINUX_FLEX_PROPORTIONS_H
8 #define _LINUX_FLEX_PROPORTIONS_H
10 #include <linux/percpu_counter.h>
11 #include <linux/spinlock.h>
12 #include <linux/seqlock.h>
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.
20 #define FPROP_FRAC_SHIFT 10
21 #define FPROP_FRAC_BASE (1UL << FPROP_FRAC_SHIFT)
24 * ---- Global proportion definitions ----
26 struct 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;
35 int fprop_global_init(struct fprop_global *p);
36 void fprop_global_destroy(struct fprop_global *p);
37 bool fprop_new_period(struct fprop_global *p, int periods);
40 * ---- SINGLE ----
42 struct 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 */
50 #define INIT_FPROP_LOCAL_SINGLE(name) \
51 { .lock = __RAW_SPIN_LOCK_UNLOCKED(name.lock), \
54 int fprop_local_init_single(struct fprop_local_single *pl);
55 void fprop_local_destroy_single(struct fprop_local_single *pl);
56 void __fprop_inc_single(struct fprop_global *p, struct fprop_local_single *pl);
57 void fprop_fraction_single(struct fprop_global *p,
58 struct fprop_local_single *pl, unsigned long *numerator,
59 unsigned long *denominator);
61 static inline
62 void fprop_inc_single(struct fprop_global *p, struct fprop_local_single *pl)
64 unsigned long flags;
66 local_irq_save(flags);
67 __fprop_inc_single(p, pl);
68 local_irq_restore(flags);
72 * ---- PERCPU ----
74 struct 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 */
82 int fprop_local_init_percpu(struct fprop_local_percpu *pl);
83 void fprop_local_destroy_percpu(struct fprop_local_percpu *pl);
84 void __fprop_inc_percpu(struct fprop_global *p, struct fprop_local_percpu *pl);
85 void __fprop_inc_percpu_max(struct fprop_global *p, struct fprop_local_percpu *pl,
86 int max_frac);
87 void fprop_fraction_percpu(struct fprop_global *p,
88 struct fprop_local_percpu *pl, unsigned long *numerator,
89 unsigned long *denominator);
91 static inline
92 void fprop_inc_percpu(struct fprop_global *p, struct fprop_local_percpu *pl)
94 unsigned long flags;
96 local_irq_save(flags);
97 __fprop_inc_percpu(p, pl);
98 local_irq_restore(flags);
101 #endif