^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1) // SPDX-License-Identifier: GPL-2.0
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2) /*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 3) * Floating proportions with flexible aging period
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 4) *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 5) * Copyright (C) 2011, SUSE, Jan Kara <jack@suse.cz>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 6) *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 7) * The goal of this code is: Given different types of event, measure proportion
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 8) * of each type of event over time. The proportions are measured with
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 9) * exponentially decaying history to give smooth transitions. A formula
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 10) * expressing proportion of event of type 'j' is:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 11) *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 12) * p_{j} = (\Sum_{i>=0} x_{i,j}/2^{i+1})/(\Sum_{i>=0} x_i/2^{i+1})
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 13) *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 14) * Where x_{i,j} is j's number of events in i-th last time period and x_i is
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 15) * total number of events in i-th last time period.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 16) *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 17) * Note that p_{j}'s are normalised, i.e.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 18) *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 19) * \Sum_{j} p_{j} = 1,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 20) *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 21) * This formula can be straightforwardly computed by maintaining denominator
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 22) * (let's call it 'd') and for each event type its numerator (let's call it
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 23) * 'n_j'). When an event of type 'j' happens, we simply need to do:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 24) * n_j++; d++;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 25) *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 26) * When a new period is declared, we could do:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 27) * d /= 2
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 28) * for each j
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 29) * n_j /= 2
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 30) *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 31) * To avoid iteration over all event types, we instead shift numerator of event
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 32) * j lazily when someone asks for a proportion of event j or when event j
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 33) * occurs. This can bit trivially implemented by remembering last period in
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 34) * which something happened with proportion of type j.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 35) */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 36) #include <linux/flex_proportions.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 37)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 38) int fprop_global_init(struct fprop_global *p, gfp_t gfp)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 39) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 40) int err;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 41)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 42) p->period = 0;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 43) /* Use 1 to avoid dealing with periods with 0 events... */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 44) err = percpu_counter_init(&p->events, 1, gfp);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 45) if (err)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 46) return err;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 47) seqcount_init(&p->sequence);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 48) return 0;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 49) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 50)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 51) void fprop_global_destroy(struct fprop_global *p)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 52) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 53) percpu_counter_destroy(&p->events);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 54) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 55)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 56) /*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 57) * Declare @periods new periods. It is upto the caller to make sure period
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 58) * transitions cannot happen in parallel.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 59) *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 60) * The function returns true if the proportions are still defined and false
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 61) * if aging zeroed out all events. This can be used to detect whether declaring
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 62) * further periods has any effect.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 63) */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 64) bool fprop_new_period(struct fprop_global *p, int periods)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 65) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 66) s64 events;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 67) unsigned long flags;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 68)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 69) local_irq_save(flags);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 70) events = percpu_counter_sum(&p->events);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 71) /*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 72) * Don't do anything if there are no events.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 73) */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 74) if (events <= 1) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 75) local_irq_restore(flags);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 76) return false;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 77) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 78) write_seqcount_begin(&p->sequence);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 79) if (periods < 64)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 80) events -= events >> periods;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 81) /* Use addition to avoid losing events happening between sum and set */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 82) percpu_counter_add(&p->events, -events);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 83) p->period += periods;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 84) write_seqcount_end(&p->sequence);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 85) local_irq_restore(flags);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 86)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 87) return true;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 88) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 89)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 90) /*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 91) * ---- SINGLE ----
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 92) */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 93)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 94) int fprop_local_init_single(struct fprop_local_single *pl)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 95) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 96) pl->events = 0;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 97) pl->period = 0;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 98) raw_spin_lock_init(&pl->lock);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 99) return 0;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 100) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 101)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 102) void fprop_local_destroy_single(struct fprop_local_single *pl)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 103) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 104) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 105)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 106) static void fprop_reflect_period_single(struct fprop_global *p,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 107) struct fprop_local_single *pl)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 108) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 109) unsigned int period = p->period;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 110) unsigned long flags;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 111)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 112) /* Fast path - period didn't change */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 113) if (pl->period == period)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 114) return;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 115) raw_spin_lock_irqsave(&pl->lock, flags);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 116) /* Someone updated pl->period while we were spinning? */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 117) if (pl->period >= period) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 118) raw_spin_unlock_irqrestore(&pl->lock, flags);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 119) return;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 120) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 121) /* Aging zeroed our fraction? */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 122) if (period - pl->period < BITS_PER_LONG)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 123) pl->events >>= period - pl->period;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 124) else
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 125) pl->events = 0;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 126) pl->period = period;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 127) raw_spin_unlock_irqrestore(&pl->lock, flags);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 128) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 129)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 130) /* Event of type pl happened */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 131) void __fprop_inc_single(struct fprop_global *p, struct fprop_local_single *pl)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 132) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 133) fprop_reflect_period_single(p, pl);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 134) pl->events++;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 135) percpu_counter_add(&p->events, 1);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 136) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 137)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 138) /* Return fraction of events of type pl */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 139) void fprop_fraction_single(struct fprop_global *p,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 140) struct fprop_local_single *pl,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 141) unsigned long *numerator, unsigned long *denominator)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 142) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 143) unsigned int seq;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 144) s64 num, den;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 145)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 146) do {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 147) seq = read_seqcount_begin(&p->sequence);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 148) fprop_reflect_period_single(p, pl);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 149) num = pl->events;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 150) den = percpu_counter_read_positive(&p->events);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 151) } while (read_seqcount_retry(&p->sequence, seq));
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 152)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 153) /*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 154) * Make fraction <= 1 and denominator > 0 even in presence of percpu
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 155) * counter errors
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 156) */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 157) if (den <= num) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 158) if (num)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 159) den = num;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 160) else
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 161) den = 1;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 162) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 163) *denominator = den;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 164) *numerator = num;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 165) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 166)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 167) /*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 168) * ---- PERCPU ----
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 169) */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 170) #define PROP_BATCH (8*(1+ilog2(nr_cpu_ids)))
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 171)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 172) int fprop_local_init_percpu(struct fprop_local_percpu *pl, gfp_t gfp)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 173) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 174) int err;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 175)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 176) err = percpu_counter_init(&pl->events, 0, gfp);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 177) if (err)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 178) return err;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 179) pl->period = 0;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 180) raw_spin_lock_init(&pl->lock);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 181) return 0;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 182) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 183)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 184) void fprop_local_destroy_percpu(struct fprop_local_percpu *pl)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 185) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 186) percpu_counter_destroy(&pl->events);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 187) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 188)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 189) static void fprop_reflect_period_percpu(struct fprop_global *p,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 190) struct fprop_local_percpu *pl)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 191) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 192) unsigned int period = p->period;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 193) unsigned long flags;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 194)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 195) /* Fast path - period didn't change */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 196) if (pl->period == period)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 197) return;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 198) raw_spin_lock_irqsave(&pl->lock, flags);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 199) /* Someone updated pl->period while we were spinning? */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 200) if (pl->period >= period) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 201) raw_spin_unlock_irqrestore(&pl->lock, flags);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 202) return;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 203) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 204) /* Aging zeroed our fraction? */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 205) if (period - pl->period < BITS_PER_LONG) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 206) s64 val = percpu_counter_read(&pl->events);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 207)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 208) if (val < (nr_cpu_ids * PROP_BATCH))
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 209) val = percpu_counter_sum(&pl->events);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 210)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 211) percpu_counter_add_batch(&pl->events,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 212) -val + (val >> (period-pl->period)), PROP_BATCH);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 213) } else
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 214) percpu_counter_set(&pl->events, 0);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 215) pl->period = period;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 216) raw_spin_unlock_irqrestore(&pl->lock, flags);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 217) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 218)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 219) /* Event of type pl happened */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 220) void __fprop_inc_percpu(struct fprop_global *p, struct fprop_local_percpu *pl)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 221) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 222) fprop_reflect_period_percpu(p, pl);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 223) percpu_counter_add_batch(&pl->events, 1, PROP_BATCH);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 224) percpu_counter_add(&p->events, 1);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 225) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 226)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 227) void fprop_fraction_percpu(struct fprop_global *p,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 228) struct fprop_local_percpu *pl,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 229) unsigned long *numerator, unsigned long *denominator)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 230) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 231) unsigned int seq;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 232) s64 num, den;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 233)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 234) do {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 235) seq = read_seqcount_begin(&p->sequence);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 236) fprop_reflect_period_percpu(p, pl);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 237) num = percpu_counter_read_positive(&pl->events);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 238) den = percpu_counter_read_positive(&p->events);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 239) } while (read_seqcount_retry(&p->sequence, seq));
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 240)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 241) /*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 242) * Make fraction <= 1 and denominator > 0 even in presence of percpu
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 243) * counter errors
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 244) */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 245) if (den <= num) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 246) if (num)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 247) den = num;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 248) else
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 249) den = 1;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 250) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 251) *denominator = den;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 252) *numerator = num;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 253) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 254)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 255) /*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 256) * Like __fprop_inc_percpu() except that event is counted only if the given
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 257) * type has fraction smaller than @max_frac/FPROP_FRAC_BASE
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 258) */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 259) void __fprop_inc_percpu_max(struct fprop_global *p,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 260) struct fprop_local_percpu *pl, int max_frac)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 261) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 262) if (unlikely(max_frac < FPROP_FRAC_BASE)) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 263) unsigned long numerator, denominator;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 264)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 265) fprop_fraction_percpu(p, pl, &numerator, &denominator);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 266) if (numerator >
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 267) (((u64)denominator) * max_frac) >> FPROP_FRAC_SHIFT)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 268) return;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 269) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 270)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 271) __fprop_inc_percpu(p, pl);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 272) }
Orange Pi5 kernel
Deprecated Linux kernel 5.10.110 for OrangePi 5/5B/5+ boards
3 Commits
0 Branches
0 Tags