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1 /* SPDX-License-Identifier: GPL-2.0 */
3 * Floating proportions with flexible aging period
5 * Copyright (C) 2011, SUSE, Jan Kara <jack@suse.cz>
8 #ifndef _LINUX_FLEX_PROPORTIONS_H
9 #define _LINUX_FLEX_PROPORTIONS_H
11 #include <linux/percpu_counter.h>
12 #include <linux/spinlock.h>
13 #include <linux/seqlock.h>
14 #include <linux/gfp.h>
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.
22 #define FPROP_FRAC_SHIFT 10
23 #define FPROP_FRAC_BASE (1UL << FPROP_FRAC_SHIFT)
26 * ---- Global proportion definitions ----
29 /* Number of events in the current period */
30 struct percpu_counter events
;
33 /* Synchronization with period transitions */
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
);
44 struct fprop_local_single
{
45 /* the local events counter */
47 /* Period in which we last updated events */
49 raw_spinlock_t lock
; /* Protect period and numerator */
52 #define INIT_FPROP_LOCAL_SINGLE(name) \
53 { .lock = __RAW_SPIN_LOCK_UNLOCKED(name.lock), \
56 int fprop_local_init_single(struct fprop_local_single
*pl
);
57 void fprop_local_destroy_single(struct fprop_local_single
*pl
);
58 void __fprop_inc_single(struct fprop_global
*p
, struct fprop_local_single
*pl
);
59 void fprop_fraction_single(struct fprop_global
*p
,
60 struct fprop_local_single
*pl
, unsigned long *numerator
,
61 unsigned long *denominator
);
64 void fprop_inc_single(struct fprop_global
*p
, struct fprop_local_single
*pl
)
68 local_irq_save(flags
);
69 __fprop_inc_single(p
, pl
);
70 local_irq_restore(flags
);
76 struct fprop_local_percpu
{
77 /* the local events counter */
78 struct percpu_counter events
;
79 /* Period in which we last updated events */
81 raw_spinlock_t lock
; /* Protect period and numerator */
84 int fprop_local_init_percpu(struct fprop_local_percpu
*pl
, gfp_t gfp
);
85 void fprop_local_destroy_percpu(struct fprop_local_percpu
*pl
);
86 void __fprop_inc_percpu(struct fprop_global
*p
, struct fprop_local_percpu
*pl
);
87 void __fprop_inc_percpu_max(struct fprop_global
*p
, struct fprop_local_percpu
*pl
,
89 void fprop_fraction_percpu(struct fprop_global
*p
,
90 struct fprop_local_percpu
*pl
, unsigned long *numerator
,
91 unsigned long *denominator
);
94 void fprop_inc_percpu(struct fprop_global
*p
, struct fprop_local_percpu
*pl
)
98 local_irq_save(flags
);
99 __fprop_inc_percpu(p
, pl
);
100 local_irq_restore(flags
);