/*
* %CopyrightBegin%
*
* Copyright Ericsson AB 2009-2010. All Rights Reserved.
*
* The contents of this file are subject to the Erlang Public License,
* Version 1.1, (the "License"); you may not use this file except in
* compliance with the License. You should have received a copy of the
* Erlang Public License along with this software. If not, it can be
* retrieved online at http://www.erlang.org/.
*
* Software distributed under the License is distributed on an "AS IS"
* basis, WITHOUT WARRANTY OF ANY KIND, either express or implied. See
* the License for the specific language governing rights and limitations
* under the License.
*
* %CopyrightEnd%
*/
/*
* Author: Rickard Green
*/
#if defined(ETHR_HAVE_LINUX_FUTEX) && defined(ETHR_HAVE_NATIVE_ATOMICS)
/* --- Linux futex implementation of ethread events ------------------------- */
#define ETHR_LINUX_FUTEX_IMPL__
#include <sys/syscall.h>
#include <unistd.h>
#include <linux/futex.h>
#include <sys/time.h>
/*
* Note: Linux futexes operate on 32-bit integers, but
* ethr_native_atomic_t are 64-bits on 64-bit
* platforms. This has to be taken into account.
* Therefore, in each individual value used each
* byte look the same.
*/
#if ETHR_SIZEOF_PTR == 8
#define ETHR_EVENT_OFF_WAITER__ ((ethr_sint_t) 0xffffffffffffffffL)
#define ETHR_EVENT_OFF__ ((ethr_sint_t) 0x7777777777777777L)
#define ETHR_EVENT_ON__ ((ethr_sint_t) 0L)
#elif ETHR_SIZEOF_PTR == 4
#define ETHR_EVENT_OFF_WAITER__ ((ethr_sint_t) 0xffffffffL)
#define ETHR_EVENT_OFF__ ((ethr_sint_t) 0x77777777L)
#define ETHR_EVENT_ON__ ((ethr_sint_t) 0L)
#else
#error ehrm...
#endif
#if defined(FUTEX_WAIT_PRIVATE) && defined(FUTEX_WAKE_PRIVATE)
# define ETHR_FUTEX_WAIT__ FUTEX_WAIT_PRIVATE
# define ETHR_FUTEX_WAKE__ FUTEX_WAKE_PRIVATE
#else
# define ETHR_FUTEX_WAIT__ FUTEX_WAIT
# define ETHR_FUTEX_WAKE__ FUTEX_WAKE
#endif
typedef struct {
ethr_atomic_t futex;
} ethr_event;
#define ETHR_FUTEX__(FTX, OP, VAL) \
(-1 == syscall(__NR_futex, (void *) (FTX), (OP), (int) (VAL), NULL, NULL, 0)\
? errno : 0)
#if defined(ETHR_TRY_INLINE_FUNCS) || defined(ETHR_EVENT_IMPL__)
static void ETHR_INLINE
ETHR_INLINE_FUNC_NAME_(ethr_event_set)(ethr_event *e)
{
ethr_sint_t val;
ETHR_WRITE_MEMORY_BARRIER;
val = ethr_atomic_xchg(&e->futex, ETHR_EVENT_ON__);
if (val == ETHR_EVENT_OFF_WAITER__) {
int res = ETHR_FUTEX__(&e->futex, ETHR_FUTEX_WAKE__, 1);
if (res != 0)
ETHR_FATAL_ERROR__(res);
}
}
static void ETHR_INLINE
ETHR_INLINE_FUNC_NAME_(ethr_event_reset)(ethr_event *e)
{
ethr_atomic_set(&e->futex, ETHR_EVENT_OFF__);
ETHR_MEMORY_BARRIER;
}
#endif
#elif defined(ETHR_PTHREADS)
/* --- Posix mutex/cond implementation of events ---------------------------- */
typedef struct {
ethr_atomic_t state;
pthread_mutex_t mtx;
pthread_cond_t cnd;
} ethr_event;
#define ETHR_EVENT_OFF_WAITER__ -1L
#define ETHR_EVENT_OFF__ 1L
#define ETHR_EVENT_ON__ 0L
#if defined(ETHR_TRY_INLINE_FUNCS) || defined(ETHR_EVENT_IMPL__)
static void ETHR_INLINE
ETHR_INLINE_FUNC_NAME_(ethr_event_set)(ethr_event *e)
{
ethr_sint_t val;
ETHR_WRITE_MEMORY_BARRIER;
val = ethr_atomic_xchg(&e->state, ETHR_EVENT_ON__);
if (val == ETHR_EVENT_OFF_WAITER__) {
int res = pthread_mutex_lock(&e->mtx);
if (res != 0)
ETHR_FATAL_ERROR__(res);
res = pthread_cond_signal(&e->cnd);
if (res != 0)
ETHR_FATAL_ERROR__(res);
res = pthread_mutex_unlock(&e->mtx);
if (res != 0)
ETHR_FATAL_ERROR__(res);
}
}
static void ETHR_INLINE
ETHR_INLINE_FUNC_NAME_(ethr_event_reset)(ethr_event *e)
{
ethr_atomic_set(&e->state, ETHR_EVENT_OFF__);
ETHR_MEMORY_BARRIER;
}
#endif
#endif
int ethr_event_init(ethr_event *e);
int ethr_event_destroy(ethr_event *e);
int ethr_event_wait(ethr_event *e);
int ethr_event_swait(ethr_event *e, int spincount);
#if !defined(ETHR_TRY_INLINE_FUNCS) || defined(ETHR_EVENT_IMPL__)
void ethr_event_set(ethr_event *e);
void ethr_event_reset(ethr_event *e);
#endif
