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1 | #ifndef _LTTNG_RING_BUFFER_VATOMIC_H |
2 | #define _LTTNG_RING_BUFFER_VATOMIC_H | |
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3 | |
4 | /* | |
e92f3e28 | 5 | * libringbuffer/vatomic.h |
852c2936 | 6 | * |
e92f3e28 | 7 | * Copyright (C) 2010-2012 - Mathieu Desnoyers <mathieu.desnoyers@efficios.com> |
852c2936 | 8 | * |
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9 | * Permission is hereby granted, free of charge, to any person obtaining a copy |
10 | * of this software and associated documentation files (the "Software"), to deal | |
11 | * in the Software without restriction, including without limitation the rights | |
12 | * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell | |
13 | * copies of the Software, and to permit persons to whom the Software is | |
14 | * furnished to do so, subject to the following conditions: | |
a60d70e6 | 15 | * |
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16 | * The above copyright notice and this permission notice shall be included in |
17 | * all copies or substantial portions of the Software. | |
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18 | * |
19 | * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR | |
20 | * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, | |
21 | * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE | |
22 | * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER | |
23 | * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, | |
24 | * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE | |
25 | * SOFTWARE. | |
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26 | */ |
27 | ||
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28 | #include <assert.h> |
29 | #include <urcu/uatomic.h> | |
30 | ||
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31 | /* |
32 | * Same data type (long) accessed differently depending on configuration. | |
33 | * v field is for non-atomic access (protected by mutual exclusion). | |
34 | * In the fast-path, the ring_buffer_config structure is constant, so the | |
35 | * compiler can statically select the appropriate branch. | |
36 | * local_t is used for per-cpu and per-thread buffers. | |
37 | * atomic_long_t is used for globally shared buffers. | |
38 | */ | |
39 | union v_atomic { | |
14641deb | 40 | long a; /* accessed through uatomic */ |
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41 | long v; |
42 | }; | |
43 | ||
44 | static inline | |
4cfec15c | 45 | long v_read(const struct lttng_ust_lib_ring_buffer_config *config, union v_atomic *v_a) |
852c2936 | 46 | { |
14641deb | 47 | return uatomic_read(&v_a->a); |
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48 | } |
49 | ||
50 | static inline | |
4cfec15c | 51 | void v_set(const struct lttng_ust_lib_ring_buffer_config *config, union v_atomic *v_a, |
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52 | long v) |
53 | { | |
14641deb | 54 | uatomic_set(&v_a->a, v); |
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55 | } |
56 | ||
57 | static inline | |
4cfec15c | 58 | void v_add(const struct lttng_ust_lib_ring_buffer_config *config, long v, union v_atomic *v_a) |
852c2936 | 59 | { |
14641deb | 60 | uatomic_add(&v_a->a, v); |
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61 | } |
62 | ||
63 | static inline | |
4cfec15c | 64 | void v_inc(const struct lttng_ust_lib_ring_buffer_config *config, union v_atomic *v_a) |
852c2936 | 65 | { |
14641deb | 66 | uatomic_inc(&v_a->a); |
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67 | } |
68 | ||
69 | /* | |
70 | * Non-atomic decrement. Only used by reader, apply to reader-owned subbuffer. | |
71 | */ | |
72 | static inline | |
4cfec15c | 73 | void _v_dec(const struct lttng_ust_lib_ring_buffer_config *config, union v_atomic *v_a) |
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74 | { |
75 | --v_a->v; | |
76 | } | |
77 | ||
78 | static inline | |
4cfec15c | 79 | long v_cmpxchg(const struct lttng_ust_lib_ring_buffer_config *config, union v_atomic *v_a, |
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80 | long old, long _new) |
81 | { | |
14641deb | 82 | return uatomic_cmpxchg(&v_a->a, old, _new); |
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83 | } |
84 | ||
e92f3e28 | 85 | #endif /* _LTTNG_RING_BUFFER_VATOMIC_H */ |