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f3109a51 JK |
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> | |
20ae0079 | 13 | #include <linux/gfp.h> |
f3109a51 JK |
14 | |
15 | /* | |
16 | * When maximum proportion of some event type is specified, this is the | |
17 | * precision with which we allow limitting. Note that this creates an upper | |
18 | * bound on the number of events per period like | |
19 | * ULLONG_MAX >> FPROP_FRAC_SHIFT. | |
20 | */ | |
21 | #define FPROP_FRAC_SHIFT 10 | |
22 | #define FPROP_FRAC_BASE (1UL << FPROP_FRAC_SHIFT) | |
23 | ||
24 | /* | |
25 | * ---- Global proportion definitions ---- | |
26 | */ | |
27 | struct fprop_global { | |
28 | /* Number of events in the current period */ | |
29 | struct percpu_counter events; | |
30 | /* Current period */ | |
31 | unsigned int period; | |
32 | /* Synchronization with period transitions */ | |
33 | seqcount_t sequence; | |
34 | }; | |
35 | ||
20ae0079 | 36 | int fprop_global_init(struct fprop_global *p, gfp_t gfp); |
f3109a51 JK |
37 | void fprop_global_destroy(struct fprop_global *p); |
38 | bool fprop_new_period(struct fprop_global *p, int periods); | |
39 | ||
40 | /* | |
41 | * ---- SINGLE ---- | |
42 | */ | |
43 | struct fprop_local_single { | |
44 | /* the local events counter */ | |
45 | unsigned long events; | |
46 | /* Period in which we last updated events */ | |
47 | unsigned int period; | |
48 | raw_spinlock_t lock; /* Protect period and numerator */ | |
49 | }; | |
50 | ||
51 | #define INIT_FPROP_LOCAL_SINGLE(name) \ | |
52 | { .lock = __RAW_SPIN_LOCK_UNLOCKED(name.lock), \ | |
53 | } | |
54 | ||
55 | int fprop_local_init_single(struct fprop_local_single *pl); | |
56 | void fprop_local_destroy_single(struct fprop_local_single *pl); | |
57 | void __fprop_inc_single(struct fprop_global *p, struct fprop_local_single *pl); | |
58 | void fprop_fraction_single(struct fprop_global *p, | |
59 | struct fprop_local_single *pl, unsigned long *numerator, | |
60 | unsigned long *denominator); | |
61 | ||
62 | static inline | |
63 | void fprop_inc_single(struct fprop_global *p, struct fprop_local_single *pl) | |
64 | { | |
65 | unsigned long flags; | |
66 | ||
67 | local_irq_save(flags); | |
68 | __fprop_inc_single(p, pl); | |
69 | local_irq_restore(flags); | |
70 | } | |
71 | ||
72 | /* | |
73 | * ---- PERCPU ---- | |
74 | */ | |
75 | struct fprop_local_percpu { | |
76 | /* the local events counter */ | |
77 | struct percpu_counter events; | |
78 | /* Period in which we last updated events */ | |
79 | unsigned int period; | |
80 | raw_spinlock_t lock; /* Protect period and numerator */ | |
81 | }; | |
82 | ||
20ae0079 | 83 | int fprop_local_init_percpu(struct fprop_local_percpu *pl, gfp_t gfp); |
f3109a51 JK |
84 | void fprop_local_destroy_percpu(struct fprop_local_percpu *pl); |
85 | void __fprop_inc_percpu(struct fprop_global *p, struct fprop_local_percpu *pl); | |
86 | void __fprop_inc_percpu_max(struct fprop_global *p, struct fprop_local_percpu *pl, | |
87 | int max_frac); | |
88 | void fprop_fraction_percpu(struct fprop_global *p, | |
89 | struct fprop_local_percpu *pl, unsigned long *numerator, | |
90 | unsigned long *denominator); | |
91 | ||
92 | static inline | |
93 | void fprop_inc_percpu(struct fprop_global *p, struct fprop_local_percpu *pl) | |
94 | { | |
95 | unsigned long flags; | |
96 | ||
97 | local_irq_save(flags); | |
98 | __fprop_inc_percpu(p, pl); | |
99 | local_irq_restore(flags); | |
100 | } | |
101 | ||
102 | #endif |