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 #include <linux/gfp.h> 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 36 int fprop_global_init(struct fprop_global *p, gfp_t gfp); 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 83 int fprop_local_init_percpu(struct fprop_local_percpu *pl, gfp_t gfp); 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 103