LXR linux/include/linux/flex

   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 */
  27struct 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
  36int fprop_global_init(struct fprop_global *p, gfp_t gfp);
  37void fprop_global_destroy(struct fprop_global *p);
  38bool fprop_new_period(struct fprop_global *p, int periods);
  39
  40/*
  41 *  ---- SINGLE ----
  42 */
  43struct 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
  55int fprop_local_init_single(struct fprop_local_single *pl);
  56void fprop_local_destroy_single(struct fprop_local_single *pl);
  57void __fprop_inc_single(struct fprop_global *p, struct fprop_local_single *pl);
  58void fprop_fraction_single(struct fprop_global *p,
  59        struct fprop_local_single *pl, unsigned long *numerator,
  60        unsigned long *denominator);
  61
  62static inline
  63void 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 */
  75struct 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
  83int fprop_local_init_percpu(struct fprop_local_percpu *pl, gfp_t gfp);
  84void fprop_local_destroy_percpu(struct fprop_local_percpu *pl);
  85void __fprop_inc_percpu(struct fprop_global *p, struct fprop_local_percpu *pl);
  86void __fprop_inc_percpu_max(struct fprop_global *p, struct fprop_local_percpu *pl,
  87                            int max_frac);
  88void fprop_fraction_percpu(struct fprop_global *p,
  89        struct fprop_local_percpu *pl, unsigned long *numerator,
  90        unsigned long *denominator);
  91
  92static inline
  93void 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