1 #ifndef _LTTNG_RING_BUFFER_VATOMIC_H
2 #define _LTTNG_RING_BUFFER_VATOMIC_H
5 * libringbuffer/vatomic.h
7 * Copyright (C) 2010-2012 - Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
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:
16 * The above copyright notice and this permission notice shall be included in
17 * all copies or substantial portions of the Software.
21 #include <urcu/uatomic.h>
24 * Same data type (long) accessed differently depending on configuration.
25 * v field is for non-atomic access (protected by mutual exclusion).
26 * In the fast-path, the ring_buffer_config structure is constant, so the
27 * compiler can statically select the appropriate branch.
28 * local_t is used for per-cpu and per-thread buffers.
29 * atomic_long_t is used for globally shared buffers.
32 long a
; /* accessed through uatomic */
37 long v_read(const struct lttng_ust_lib_ring_buffer_config
*config
, union v_atomic
*v_a
)
39 assert(config
->sync
!= RING_BUFFER_SYNC_PER_CPU
);
40 return uatomic_read(&v_a
->a
);
44 void v_set(const struct lttng_ust_lib_ring_buffer_config
*config
, union v_atomic
*v_a
,
47 assert(config
->sync
!= RING_BUFFER_SYNC_PER_CPU
);
48 uatomic_set(&v_a
->a
, v
);
52 void v_add(const struct lttng_ust_lib_ring_buffer_config
*config
, long v
, union v_atomic
*v_a
)
54 assert(config
->sync
!= RING_BUFFER_SYNC_PER_CPU
);
55 uatomic_add(&v_a
->a
, v
);
59 void v_inc(const struct lttng_ust_lib_ring_buffer_config
*config
, union v_atomic
*v_a
)
61 assert(config
->sync
!= RING_BUFFER_SYNC_PER_CPU
);
66 * Non-atomic decrement. Only used by reader, apply to reader-owned subbuffer.
69 void _v_dec(const struct lttng_ust_lib_ring_buffer_config
*config
, union v_atomic
*v_a
)
75 long v_cmpxchg(const struct lttng_ust_lib_ring_buffer_config
*config
, union v_atomic
*v_a
,
78 assert(config
->sync
!= RING_BUFFER_SYNC_PER_CPU
);
79 return uatomic_cmpxchg(&v_a
->a
, old
, _new
);
82 #endif /* _LTTNG_RING_BUFFER_VATOMIC_H */