1 | /* SPDX-License-Identifier: GPL-2.0 */ |
2 | /* |
3 | * Floating proportions with flexible aging period |
4 | * |
5 | * Copyright (C) 2011, SUSE, Jan Kara <jack@suse.cz> |
6 | */ |
7 | |
8 | #ifndef _LINUX_FLEX_PROPORTIONS_H |
9 | #define _LINUX_FLEX_PROPORTIONS_H |
10 | |
11 | #include <linux/percpu_counter.h> |
12 | #include <linux/spinlock.h> |
13 | #include <linux/seqlock.h> |
14 | #include <linux/gfp.h> |
15 | |
16 | /* |
17 | * When maximum proportion of some event type is specified, this is the |
18 | * precision with which we allow limitting. Note that this creates an upper |
19 | * bound on the number of events per period like |
20 | * ULLONG_MAX >> FPROP_FRAC_SHIFT. |
21 | */ |
22 | #define FPROP_FRAC_SHIFT 10 |
23 | #define FPROP_FRAC_BASE (1UL << FPROP_FRAC_SHIFT) |
24 | |
25 | /* |
26 | * ---- Global proportion definitions ---- |
27 | */ |
28 | struct fprop_global { |
29 | /* Number of events in the current period */ |
30 | struct percpu_counter events; |
31 | /* Current period */ |
32 | unsigned int period; |
33 | /* Synchronization with period transitions */ |
34 | seqcount_t sequence; |
35 | }; |
36 | |
37 | int fprop_global_init(struct fprop_global *p, gfp_t gfp); |
38 | void fprop_global_destroy(struct fprop_global *p); |
39 | bool fprop_new_period(struct fprop_global *p, int periods); |
40 | |
41 | /* |
42 | * ---- PERCPU ---- |
43 | */ |
44 | struct fprop_local_percpu { |
45 | /* the local events counter */ |
46 | struct percpu_counter events; |
47 | /* Period in which we last updated events */ |
48 | unsigned int period; |
49 | raw_spinlock_t lock; /* Protect period and numerator */ |
50 | }; |
51 | |
52 | int fprop_local_init_percpu(struct fprop_local_percpu *pl, gfp_t gfp); |
53 | void fprop_local_destroy_percpu(struct fprop_local_percpu *pl); |
54 | void __fprop_add_percpu(struct fprop_global *p, struct fprop_local_percpu *pl, |
55 | long nr); |
56 | void __fprop_add_percpu_max(struct fprop_global *p, |
57 | struct fprop_local_percpu *pl, int max_frac, long nr); |
58 | void fprop_fraction_percpu(struct fprop_global *p, |
59 | struct fprop_local_percpu *pl, unsigned long *numerator, |
60 | unsigned long *denominator); |
61 | |
62 | static inline |
63 | void fprop_inc_percpu(struct fprop_global *p, struct fprop_local_percpu *pl) |
64 | { |
65 | unsigned long flags; |
66 | |
67 | local_irq_save(flags); |
68 | __fprop_add_percpu(p, pl, nr: 1); |
69 | local_irq_restore(flags); |
70 | } |
71 | |
72 | #endif |
73 | |