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 fprop_inc_percpu(struct fprop_global * p,struct fprop_local_percpu * pl)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, 1); 69 local_irq_restore(flags); 70 } 71 72 #endif 73