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852c2936 | 1 | /* |
c0c0989a | 2 | * SPDX-License-Identifier: MIT |
a60d70e6 | 3 | * |
c0c0989a | 4 | * Copyright (C) 2010-2012 Mathieu Desnoyers <mathieu.desnoyers@efficios.com> |
852c2936 MD |
5 | */ |
6 | ||
c0c0989a MJ |
7 | #ifndef _LTTNG_RING_BUFFER_VATOMIC_H |
8 | #define _LTTNG_RING_BUFFER_VATOMIC_H | |
9 | ||
14641deb MD |
10 | #include <assert.h> |
11 | #include <urcu/uatomic.h> | |
12 | ||
852c2936 MD |
13 | /* |
14 | * Same data type (long) accessed differently depending on configuration. | |
15 | * v field is for non-atomic access (protected by mutual exclusion). | |
16 | * In the fast-path, the ring_buffer_config structure is constant, so the | |
17 | * compiler can statically select the appropriate branch. | |
18 | * local_t is used for per-cpu and per-thread buffers. | |
19 | * atomic_long_t is used for globally shared buffers. | |
20 | */ | |
21 | union v_atomic { | |
14641deb | 22 | long a; /* accessed through uatomic */ |
852c2936 MD |
23 | long v; |
24 | }; | |
25 | ||
26 | static inline | |
4cfec15c | 27 | long v_read(const struct lttng_ust_lib_ring_buffer_config *config, union v_atomic *v_a) |
852c2936 | 28 | { |
14641deb MD |
29 | assert(config->sync != RING_BUFFER_SYNC_PER_CPU); |
30 | return uatomic_read(&v_a->a); | |
852c2936 MD |
31 | } |
32 | ||
33 | static inline | |
4cfec15c | 34 | void v_set(const struct lttng_ust_lib_ring_buffer_config *config, union v_atomic *v_a, |
852c2936 MD |
35 | long v) |
36 | { | |
14641deb MD |
37 | assert(config->sync != RING_BUFFER_SYNC_PER_CPU); |
38 | uatomic_set(&v_a->a, v); | |
852c2936 MD |
39 | } |
40 | ||
41 | static inline | |
4cfec15c | 42 | void v_add(const struct lttng_ust_lib_ring_buffer_config *config, long v, union v_atomic *v_a) |
852c2936 | 43 | { |
14641deb MD |
44 | assert(config->sync != RING_BUFFER_SYNC_PER_CPU); |
45 | uatomic_add(&v_a->a, v); | |
852c2936 MD |
46 | } |
47 | ||
48 | static inline | |
4cfec15c | 49 | void v_inc(const struct lttng_ust_lib_ring_buffer_config *config, union v_atomic *v_a) |
852c2936 | 50 | { |
14641deb MD |
51 | assert(config->sync != RING_BUFFER_SYNC_PER_CPU); |
52 | uatomic_inc(&v_a->a); | |
852c2936 MD |
53 | } |
54 | ||
55 | /* | |
56 | * Non-atomic decrement. Only used by reader, apply to reader-owned subbuffer. | |
57 | */ | |
58 | static inline | |
2208d8b5 | 59 | void _v_dec(const struct lttng_ust_lib_ring_buffer_config *config __attribute__((unused)), union v_atomic *v_a) |
852c2936 MD |
60 | { |
61 | --v_a->v; | |
62 | } | |
63 | ||
64 | static inline | |
4cfec15c | 65 | long v_cmpxchg(const struct lttng_ust_lib_ring_buffer_config *config, union v_atomic *v_a, |
852c2936 MD |
66 | long old, long _new) |
67 | { | |
14641deb MD |
68 | assert(config->sync != RING_BUFFER_SYNC_PER_CPU); |
69 | return uatomic_cmpxchg(&v_a->a, old, _new); | |
852c2936 MD |
70 | } |
71 | ||
e92f3e28 | 72 | #endif /* _LTTNG_RING_BUFFER_VATOMIC_H */ |