1 /*
2 * CDDL HEADER START
3 *
4 * This file and its contents are supplied under the terms of the
5 * Common Development and Distribution License ("CDDL"), version 1.0.
6 * You may only use this file in accordance with the terms of version
7 * 1.0 of the CDDL.
8 *
9 * A full copy of the text of the CDDL should have accompanied this
10 * source. A copy of the CDDL is also available via the Internet at
11 * http://www.illumos.org/license/CDDL.
12 *
13 * CDDL HEADER END
14 */
15
16 /*
17 * wmsum counters are a reduced version of aggsum counters, optimized for
18 * write-mostly scenarios. They do not provide optimized read functions,
19 * but instead allow much cheaper add function. The primary usage is
20 * infrequently read statistic counters, not requiring exact precision.
21 *
22 * The FreeBSD implementation is directly mapped into counter(9) KPI.
23 */
24
25 #ifndef _SYS_WMSUM_H
26 #define _SYS_WMSUM_H
27
28 #include <sys/types.h>
29 #include <sys/systm.h>
30 #include <sys/counter.h>
31 #include <sys/malloc.h>
32
33 #ifdef __cplusplus
34 extern "C" {
35 #endif
36
37 #define wmsum_t counter_u64_t
38
39 static inline void
40 wmsum_init(wmsum_t *ws, uint64_t value)
41 {
42
43 *ws = counter_u64_alloc(M_WAITOK);
44 counter_u64_add(*ws, value);
45 }
46
47 static inline void
48 wmsum_fini(wmsum_t *ws)
49 {
50
51 counter_u64_free(*ws);
52 }
53
54 static inline uint64_t
55 wmsum_value(wmsum_t *ws)
56 {
57
58 return (counter_u64_fetch(*ws));
59 }
60
61 static inline void
62 wmsum_add(wmsum_t *ws, int64_t delta)
63 {
64
65 counter_u64_add(*ws, delta);
66 }
67
68 #ifdef __cplusplus
69 }
70 #endif
71
72 #endif /* _SYS_WMSUM_H */
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