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 Linux implementation is directly mapped into percpu_counter KPI.
23 */
24
25 #ifndef _SYS_WMSUM_H
26 #define _SYS_WMSUM_H
27
28 #include <linux/percpu_counter.h>
29
30 #ifdef __cplusplus
31 extern "C" {
32 #endif
33
34 typedef struct percpu_counter wmsum_t;
35
36 static inline void
wmsum_init(wmsum_t * ws,uint64_t value)37 wmsum_init(wmsum_t *ws, uint64_t value)
38 {
39
40 #ifdef HAVE_PERCPU_COUNTER_INIT_WITH_GFP
41 percpu_counter_init(ws, value, GFP_KERNEL);
42 #else
43 percpu_counter_init(ws, value);
44 #endif
45 }
46
47 static inline void
wmsum_fini(wmsum_t * ws)48 wmsum_fini(wmsum_t *ws)
49 {
50
51 percpu_counter_destroy(ws);
52 }
53
54 static inline uint64_t
wmsum_value(wmsum_t * ws)55 wmsum_value(wmsum_t *ws)
56 {
57
58 return (percpu_counter_sum(ws));
59 }
60
61 static inline void
wmsum_add(wmsum_t * ws,int64_t delta)62 wmsum_add(wmsum_t *ws, int64_t delta)
63 {
64
65 #ifdef HAVE_PERCPU_COUNTER_ADD_BATCH
66 percpu_counter_add_batch(ws, delta, INT_MAX / 2);
67 #else
68 __percpu_counter_add(ws, delta, INT_MAX / 2);
69 #endif
70 }
71
72 #ifdef __cplusplus
73 }
74 #endif
75
76 #endif /* _SYS_WMSUM_H */
77