LXR linux/include/linux/flex

   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 */
  28struct 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
  37int fprop_global_init(struct fprop_global *p, gfp_t gfp);
  38void fprop_global_destroy(struct fprop_global *p);
  39bool fprop_new_period(struct fprop_global *p, int periods);
  40
  41/*
  42 *  ---- SINGLE ----
  43 */
  44struct fprop_local_single {
  45        /* the local events counter */
  46        unsigned long 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#define INIT_FPROP_LOCAL_SINGLE(name)                   \
  53{       .lock = __RAW_SPIN_LOCK_UNLOCKED(name.lock),    \
  54}
  55
  56int fprop_local_init_single(struct fprop_local_single *pl);
  57void fprop_local_destroy_single(struct fprop_local_single *pl);
  58void __fprop_inc_single(struct fprop_global *p, struct fprop_local_single *pl);
  59void fprop_fraction_single(struct fprop_global *p,
  60        struct fprop_local_single *pl, unsigned long *numerator,
  61        unsigned long *denominator);
  62
  63static inline
  64void fprop_inc_single(struct fprop_global *p, struct fprop_local_single *pl)
  65{
  66        unsigned long flags;
  67
  68        local_irq_save(flags);
  69        __fprop_inc_single(p, pl);
  70        local_irq_restore(flags);
  71}
  72
  73/*
  74 * ---- PERCPU ----
  75 */
  76struct fprop_local_percpu {
  77        /* the local events counter */
  78        struct percpu_counter events;
  79        /* Period in which we last updated events */
  80        unsigned int period;
  81        raw_spinlock_t lock;    /* Protect period and numerator */
  82};
  83
  84int fprop_local_init_percpu(struct fprop_local_percpu *pl, gfp_t gfp);
  85void fprop_local_destroy_percpu(struct fprop_local_percpu *pl);
  86void __fprop_inc_percpu(struct fprop_global *p, struct fprop_local_percpu *pl);
  87void __fprop_inc_percpu_max(struct fprop_global *p, struct fprop_local_percpu *pl,
  88                            int max_frac);
  89void fprop_fraction_percpu(struct fprop_global *p,
  90        struct fprop_local_percpu *pl, unsigned long *numerator,
  91        unsigned long *denominator);
  92
  93static inline
  94void fprop_inc_percpu(struct fprop_global *p, struct fprop_local_percpu *pl)
  95{
  96        unsigned long flags;
  97
  98        local_irq_save(flags);
  99        __fprop_inc_percpu(p, pl);
 100        local_irq_restore(flags);
 101}
 102
 103#endif
 104