#ifndef _LTTNG_RING_BUFFER_VATOMIC_H
#define _LTTNG_RING_BUFFER_VATOMIC_H
/*
* libringbuffer/vatomic.h
*
* Copyright (C) 2010-2012 - Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to deal
* in the Software without restriction, including without limitation the rights
* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
* copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in
* all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
* SOFTWARE.
*/
#include <assert.h>
#include <urcu/uatomic.h>
/*
* Same data type (long) accessed differently depending on configuration.
* v field is for non-atomic access (protected by mutual exclusion).
* In the fast-path, the ring_buffer_config structure is constant, so the
* compiler can statically select the appropriate branch.
* local_t is used for per-cpu and per-thread buffers.
* atomic_long_t is used for globally shared buffers.
*/
union v_atomic {
long a; /* accessed through uatomic */
long v;
};
static inline
long v_read(const struct lttng_ust_lib_ring_buffer_config *config, union v_atomic *v_a)
{
assert(config->sync != RING_BUFFER_SYNC_PER_CPU);
return uatomic_read(&v_a->a);
}
static inline
void v_set(const struct lttng_ust_lib_ring_buffer_config *config, union v_atomic *v_a,
long v)
{
assert(config->sync != RING_BUFFER_SYNC_PER_CPU);
uatomic_set(&v_a->a, v);
}
static inline
void v_add(const struct lttng_ust_lib_ring_buffer_config *config, long v, union v_atomic *v_a)
{
assert(config->sync != RING_BUFFER_SYNC_PER_CPU);
uatomic_add(&v_a->a, v);
}
static inline
void v_inc(const struct lttng_ust_lib_ring_buffer_config *config, union v_atomic *v_a)
{
assert(config->sync != RING_BUFFER_SYNC_PER_CPU);
uatomic_inc(&v_a->a);
}
/*
* Non-atomic decrement. Only used by reader, apply to reader-owned subbuffer.
*/
static inline
void _v_dec(const struct lttng_ust_lib_ring_buffer_config *config, union v_atomic *v_a)
{
--v_a->v;
}
static inline
long v_cmpxchg(const struct lttng_ust_lib_ring_buffer_config *config, union v_atomic *v_a,
long old, long _new)
{
assert(config->sync != RING_BUFFER_SYNC_PER_CPU);
return uatomic_cmpxchg(&v_a->a, old, _new);
}
#endif /* _LTTNG_RING_BUFFER_VATOMIC_H */