projects / lttng-ust.git / blame
| Commit | Line | Data |
|---|---|---|
| 852c2936 MD |
1 | #ifndef _LINUX_RING_BUFFER_VATOMIC_H |
| 2 | #define _LINUX_RING_BUFFER_VATOMIC_H | |
| 3 | ||
| 4 | /* | |
| 5 | * linux/ringbuffer/vatomic.h | |
| 6 | * | |
| 7 | * Copyright (C) 2010 - Mathieu Desnoyers <mathieu.desnoyers@efficios.com> | |
| 8 | * | |
| 9 | * Dual LGPL v2.1/GPL v2 license. | |
| 10 | */ | |
| 11 | ||
| 852c2936 MD |
12 | /* |
| 13 | * Same data type (long) accessed differently depending on configuration. | |
| 14 | * v field is for non-atomic access (protected by mutual exclusion). | |
| 15 | * In the fast-path, the ring_buffer_config structure is constant, so the | |
| 16 | * compiler can statically select the appropriate branch. | |
| 17 | * local_t is used for per-cpu and per-thread buffers. | |
| 18 | * atomic_long_t is used for globally shared buffers. | |
| 19 | */ | |
| 20 | union v_atomic { | |
| 21 | local_t l; | |
| 22 | atomic_long_t a; | |
| 23 | long v; | |
| 24 | }; | |
| 25 | ||
| 26 | static inline | |
| 27 | long v_read(const struct lib_ring_buffer_config *config, union v_atomic *v_a) | |
| 28 | { | |
| 29 | if (config->sync == RING_BUFFER_SYNC_PER_CPU) | |
| 30 | return local_read(&v_a->l); | |
| 31 | else | |
| 32 | return atomic_long_read(&v_a->a); | |
| 33 | } | |
| 34 | ||
| 35 | static inline | |
| 36 | void v_set(const struct lib_ring_buffer_config *config, union v_atomic *v_a, | |
| 37 | long v) | |
| 38 | { | |
| 39 | if (config->sync == RING_BUFFER_SYNC_PER_CPU) | |
| 40 | local_set(&v_a->l, v); | |
| 41 | else | |
| 42 | atomic_long_set(&v_a->a, v); | |
| 43 | } | |
| 44 | ||
| 45 | static inline | |
| 46 | void v_add(const struct lib_ring_buffer_config *config, long v, union v_atomic *v_a) | |
| 47 | { | |
| 48 | if (config->sync == RING_BUFFER_SYNC_PER_CPU) | |
| 49 | local_add(v, &v_a->l); | |
| 50 | else | |
| 51 | atomic_long_add(v, &v_a->a); | |
| 52 | } | |
| 53 | ||
| 54 | static inline | |
| 55 | void v_inc(const struct lib_ring_buffer_config *config, union v_atomic *v_a) | |
| 56 | { | |
| 57 | if (config->sync == RING_BUFFER_SYNC_PER_CPU) | |
| 58 | local_inc(&v_a->l); | |
| 59 | else | |
| 60 | atomic_long_inc(&v_a->a); | |
| 61 | } | |
| 62 | ||
| 63 | /* | |
| 64 | * Non-atomic decrement. Only used by reader, apply to reader-owned subbuffer. | |
| 65 | */ | |
| 66 | static inline | |
| 67 | void _v_dec(const struct lib_ring_buffer_config *config, union v_atomic *v_a) | |
| 68 | { | |
| 69 | --v_a->v; | |
| 70 | } | |
| 71 | ||
| 72 | static inline | |
| 73 | long v_cmpxchg(const struct lib_ring_buffer_config *config, union v_atomic *v_a, | |
| 74 | long old, long _new) | |
| 75 | { | |
| 76 | if (config->sync == RING_BUFFER_SYNC_PER_CPU) | |
| 77 | return local_cmpxchg(&v_a->l, old, _new); | |
| 78 | else | |
| 79 | return atomic_long_cmpxchg(&v_a->a, old, _new); | |
| 80 | } | |
| 81 | ||
| 82 | #endif /* _LINUX_RING_BUFFER_VATOMIC_H */ |