/* SPDX-License-Identifier: GPL-2.0 */ /* * Floating proportions with flexible aging period * * Copyright (C) 2011, SUSE, Jan Kara <jack@suse.cz> */ #ifndef _LINUX_FLEX_PROPORTIONS_H #define _LINUX_FLEX_PROPORTIONS_H #include <linux/percpu_counter.h> #include <linux/spinlock.h> #include <linux/seqlock.h> #include <linux/gfp.h> /* * When maximum proportion of some event type is specified, this is the * precision with which we allow limitting. Note that this creates an upper * bound on the number of events per period like * ULLONG_MAX >> FPROP_FRAC_SHIFT. */ #define FPROP_FRAC_SHIFT 10 #define FPROP_FRAC_BASE (1UL << FPROP_FRAC_SHIFT) /* * ---- Global proportion definitions ---- */ struct fprop_global { /* Number of events in the current period */ struct percpu_counter events; /* Current period */ unsigned int period; /* Synchronization with period transitions */ seqcount_t sequence; }; int fprop_global_init(struct fprop_global *p, gfp_t gfp); void fprop_global_destroy(struct fprop_global *p); bool fprop_new_period(struct fprop_global *p, int periods); /* * ---- SINGLE ---- */ struct fprop_local_single { /* the local events counter */ unsigned long events; /* Period in which we last updated events */ unsigned int period; raw_spinlock_t lock; /* Protect period and numerator */ }; #define INIT_FPROP_LOCAL_SINGLE(name) \ { .lock = __RAW_SPIN_LOCK_UNLOCKED(name.lock), \ } int fprop_local_init_single(struct fprop_local_single *pl); void fprop_local_destroy_single(struct fprop_local_single *pl); void __fprop_inc_single(struct fprop_global *p, struct fprop_local_single *pl); void fprop_fraction_single(struct fprop_global *p, struct fprop_local_single *pl, unsigned long *numerator, unsigned long *denominator); static inline void fprop_inc_single(struct fprop_global *p, struct fprop_local_single *pl) { unsigned long flags; local_irq_save(flags); __fprop_inc_single(p, pl); local_irq_restore(flags); } /* * ---- PERCPU ---- */ struct fprop_local_percpu { /* the local events counter */ struct percpu_counter events; /* Period in which we last updated events */ unsigned int period; raw_spinlock_t lock; /* Protect period and numerator */ }; int fprop_local_init_percpu(struct fprop_local_percpu *pl, gfp_t gfp); void fprop_local_destroy_percpu(struct fprop_local_percpu *pl); void __fprop_inc_percpu(struct fprop_global *p, struct fprop_local_percpu *pl); void __fprop_inc_percpu_max(struct fprop_global *p, struct fprop_local_percpu *pl, int max_frac); void fprop_fraction_percpu(struct fprop_global *p, struct fprop_local_percpu *pl, unsigned long *numerator, unsigned long *denominator); static inline void fprop_inc_percpu(struct fprop_global *p, struct fprop_local_percpu *pl) { unsigned long flags; local_irq_save(flags); __fprop_inc_percpu(p, pl); local_irq_restore(flags); } #endif