| Jan Kara | f3109a5 | 2012-05-24 18:59:10 +0200 | [diff] [blame] | 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 | */ |
| 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; |
| 33 | }; |
| 34 | |
| 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); |
| 38 | |
| 39 | /* |
| 40 | * ---- SINGLE ---- |
| 41 | */ |
| 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 */ |
| 48 | }; |
| 49 | |
| 50 | #define INIT_FPROP_LOCAL_SINGLE(name) \ |
| 51 | { .lock = __RAW_SPIN_LOCK_UNLOCKED(name.lock), \ |
| 52 | } |
| 53 | |
| 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); |
| 60 | |
| 61 | static inline |
| 62 | void 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 | */ |
| 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 */ |
| 80 | }; |
| 81 | |
| 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); |
| 90 | |
| 91 | static inline |
| 92 | void 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 |