gcc/libcilkrts/runtime/spin_mutex.h

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/* spin_mutex.h -*-C++-*-
*
*************************************************************************
*
* @copyright
* Copyright (C) 2009-2013, Intel Corporation
* All rights reserved.
*
* @copyright
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* * Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* * Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in
* the documentation and/or other materials provided with the
* distribution.
* * Neither the name of Intel Corporation nor the names of its
* contributors may be used to endorse or promote products derived
* from this software without specific prior written permission.
*
* @copyright
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
* A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
* HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
* BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
* OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
* AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY
* WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE.
**************************************************************************/
/**
* @file spin_mutex.h
*
* @brief Support for Cilk runtime mutexes.
*
* Cilk runtime mutexes are implemented as simple spin loops.
*
* This file is similar to a worker_mutex, except it does not have an
* owner field.
*
* TBD: This class, worker_mutex, and os_mutex overlap quite a bit in
* functionality. Can we unify these mutexes somehow?
*/
#ifndef INCLUDED_SPIN_MUTEX_DOT_H
#define INCLUDED_SPIN_MUTEX_DOT_H
#include <cilk/common.h>
#include "rts-common.h"
#include "cilk_malloc.h"
__CILKRTS_BEGIN_EXTERN_C
/**
* Mutexes are treated as an abstract data type within the Cilk
* runtime system. They are implemented as simple spin loops.
*/
typedef struct spin_mutex {
/** Mutex spin loop variable. 0 if unowned, 1 if owned. */
volatile int lock;
/** Padding so the mutex takes up a cache line. */
char pad[64/sizeof(int) - 1];
} spin_mutex;
/**
* @brief Create a new Cilk spin_mutex.
*
* @return Returns an initialized spin mutex.
*/
COMMON_PORTABLE
spin_mutex* spin_mutex_create();
/**
* @brief Initialize a Cilk spin_mutex.
*
* @param m Spin_Mutex to be initialized.
*/
COMMON_PORTABLE
void spin_mutex_init(spin_mutex *m);
/**
* @brief Acquire a Cilk spin_mutex.
*
* If statistics are being gathered, the time spent
* acquiring the spin_mutex will be attributed to the specified worker.
*
* @param m Spin_Mutex to be initialized.
*/
COMMON_PORTABLE
void spin_mutex_lock(struct spin_mutex *m);
/**
* @brief Attempt to lock a Cilk spin_mutex and fail if it isn't available.
*
* @param m Spin_Mutex to be acquired.
*
* @return 1 if the spin_mutex was acquired.
* @return 0 if the spin_mutex was not acquired.
*/
COMMON_PORTABLE
int spin_mutex_trylock(struct spin_mutex *m);
/**
* @brief Release a Cilk spin_mutex.
*
* @param m Spin_Mutex to be released.
*/
COMMON_PORTABLE
void spin_mutex_unlock(struct spin_mutex *m);
/**
* @brief Deallocate a Cilk spin_mutex. Currently does nothing.
*
* @param m Spin_Mutex to be deallocated.
*/
COMMON_PORTABLE
void spin_mutex_destroy(struct spin_mutex *m);
__CILKRTS_END_EXTERN_C
#endif // ! defined(INCLUDED_SPIN_MUTEX_DOT_H)