1 /* spin_mutex.h -*-C++-*- 2 * 3 ************************************************************************* 4 * 5 * @copyright 6 * Copyright (C) 2009-2013, Intel Corporation 7 * All rights reserved. 8 * 9 * @copyright 10 * Redistribution and use in source and binary forms, with or without 11 * modification, are permitted provided that the following conditions 12 * are met: 13 * 14 * * Redistributions of source code must retain the above copyright 15 * notice, this list of conditions and the following disclaimer. 16 * * Redistributions in binary form must reproduce the above copyright 17 * notice, this list of conditions and the following disclaimer in 18 * the documentation and/or other materials provided with the 19 * distribution. 20 * * Neither the name of Intel Corporation nor the names of its 21 * contributors may be used to endorse or promote products derived 22 * from this software without specific prior written permission. 23 * 24 * @copyright 25 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS 26 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT 27 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR 28 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT 29 * HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, 30 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, 31 * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS 32 * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED 33 * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 34 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY 35 * WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 36 * POSSIBILITY OF SUCH DAMAGE. 37 **************************************************************************/ 38 39 /** 40 * @file spin_mutex.h 41 * 42 * @brief Support for Cilk runtime mutexes. 43 * 44 * Cilk runtime mutexes are implemented as simple spin loops. 45 * 46 * This file is similar to a worker_mutex, except it does not have an 47 * owner field. 48 * 49 * TBD: This class, worker_mutex, and os_mutex overlap quite a bit in 50 * functionality. Can we unify these mutexes somehow? 51 */ 52 #ifndef INCLUDED_SPIN_MUTEX_DOT_H 53 #define INCLUDED_SPIN_MUTEX_DOT_H 54 55 #include <cilk/common.h> 56 #include "rts-common.h" 57 #include "cilk_malloc.h" 58 59 __CILKRTS_BEGIN_EXTERN_C 60 61 /** 62 * Mutexes are treated as an abstract data type within the Cilk 63 * runtime system. They are implemented as simple spin loops. 64 */ 65 typedef struct spin_mutex { 66 /** Mutex spin loop variable. 0 if unowned, 1 if owned. */ 67 volatile int lock; 68 69 /** Padding so the mutex takes up a cache line. */ 70 char pad[64/sizeof(int) - 1]; 71 } spin_mutex; 72 73 74 /** 75 * @brief Create a new Cilk spin_mutex. 76 * 77 * @return Returns an initialized spin mutex. 78 */ 79 COMMON_PORTABLE 80 spin_mutex* spin_mutex_create(); 81 82 /** 83 * @brief Initialize a Cilk spin_mutex. 84 * 85 * @param m Spin_Mutex to be initialized. 86 */ 87 COMMON_PORTABLE 88 void spin_mutex_init(spin_mutex *m); 89 90 /** 91 * @brief Acquire a Cilk spin_mutex. 92 * 93 * If statistics are being gathered, the time spent 94 * acquiring the spin_mutex will be attributed to the specified worker. 95 * 96 * @param m Spin_Mutex to be initialized. 97 */ 98 COMMON_PORTABLE 99 void spin_mutex_lock(struct spin_mutex *m); 100 /** 101 * @brief Attempt to lock a Cilk spin_mutex and fail if it isn't available. 102 * 103 * @param m Spin_Mutex to be acquired. 104 * 105 * @return 1 if the spin_mutex was acquired. 106 * @return 0 if the spin_mutex was not acquired. 107 */ 108 COMMON_PORTABLE 109 int spin_mutex_trylock(struct spin_mutex *m); 110 111 /** 112 * @brief Release a Cilk spin_mutex. 113 * 114 * @param m Spin_Mutex to be released. 115 */ 116 COMMON_PORTABLE 117 void spin_mutex_unlock(struct spin_mutex *m); 118 119 /** 120 * @brief Deallocate a Cilk spin_mutex. Currently does nothing. 121 * 122 * @param m Spin_Mutex to be deallocated. 123 */ 124 COMMON_PORTABLE 125 void spin_mutex_destroy(struct spin_mutex *m); 126 127 __CILKRTS_END_EXTERN_C 128 129 #endif // ! defined(INCLUDED_SPIN_MUTEX_DOT_H) 130