libcilkrts/runtime/worker_mutex.h

   1 /* worker_mutex.h                  -*-C++-*-
   2  *
   3  *************************************************************************
   4  *
   5  *  Copyright (C) 2009-2016, Intel Corporation
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  37  *  PLEASE NOTE: This file is a downstream copy of a file mainitained in
  38  *  a repository at cilkplus.org. Changes made to this file that are not
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  43  *  https://bitbucket.org/intelcilkruntime/intel-cilk-runtime.git are
  44  *  not tracked.
  45  *
  46  *  We welcome your contributions to this open source project. Thank you
  47  *  for your assistance in helping us improve Cilk Plus.
  48  **************************************************************************/
  49
  50 /**
  51  * @file worker_mutex.h
  52  *
  53  * @brief Support for Cilk runtime mutexes.
  54  *
  55  * Cilk runtime mutexes are implemented as simple spin loops.
  56  */
  57
  58 #ifndef INCLUDED_WORKER_MUTEX_DOT_H
  59 #define INCLUDED_WORKER_MUTEX_DOT_H
  60
  61 #include <cilk/common.h>
  62 #include "rts-common.h"
  63
  64 __CILKRTS_BEGIN_EXTERN_C
  65
  66 /**
  67  * Mutexes are treated as an abstract data type within the Cilk
  68  * runtime system.  They are implemented as simple spin loops and
  69  * owned by a __cilkrts_worker.
  70  */
  71 typedef struct mutex {
  72     /** Mutex spin loop variable. 0 if unowned, 1 if owned. */
  73     volatile int lock;
  74
  75     /** Worker that owns the mutex.  Must be 0 if mutex is unowned. */
  76     __cilkrts_worker *owner;
  77 } mutex;
  78
  79 /**
  80  * @brief Initialize a Cilk mutex.
  81  *
  82  * @param m Mutex to be initialized.
  83  */
  84 COMMON_PORTABLE
  85 void __cilkrts_mutex_init(struct mutex *m);
  86
  87 /**
  88  * @brief Acquire a Cilk mutex.
  89  *
  90  * If statistics are being gathered, the time spent
  91  * acquiring the mutex will be attributed to the specified worker.
  92  *
  93  * @param w Worker that will become the owner of this mutex.
  94  * @param m Mutex to be initialized.
  95  */
  96 COMMON_PORTABLE
  97 void __cilkrts_mutex_lock(__cilkrts_worker *w,
  98                           struct mutex *m);
  99 /**
 100  * @brief Attempt to lock a Cilk mutex and fail if it isn't available.
 101  *
 102  * If statistics are being gathered, the time spent acquiring the
 103  * mutex will be attributed to the specified worker.
 104  *
 105  * @param w Worker that will become the owner of this mutex.
 106  * @param m Mutex to be acquired.
 107  *
 108  * @return 1 if the mutex was acquired.
 109  * @return 0 if the mutex was not acquired.
 110  */
 111 COMMON_PORTABLE
 112 int __cilkrts_mutex_trylock(__cilkrts_worker *w,
 113                             struct mutex *m);
 114
 115 /**
 116  * @brief Release a Cilk mutex.
 117  *
 118  * If statistics are being gathered, the time spent
 119  * acquiring the mutex will be attributed to the specified worker.
 120  *
 121  * @pre The mutex must be owned by the worker.
 122  *
 123  * @param w Worker that owns this mutex.
 124  * @param m Mutex to be released.
 125  */
 126 COMMON_PORTABLE
 127 void __cilkrts_mutex_unlock(__cilkrts_worker *w,
 128                             struct mutex *m);
 129
 130 /**
 131  * @brief Deallocate a Cilk mutex.  Currently does nothing.
 132  *
 133  * @param w Unused.
 134  * @param m Mutex to be deallocated.
 135  */
 136 COMMON_PORTABLE
 137 void __cilkrts_mutex_destroy(__cilkrts_worker *w,
 138                              struct mutex *m);
 139
 140 __CILKRTS_END_EXTERN_C
 141
 142 #endif // ! defined(INCLUDED_WORKER_MUTEX_DOT_H)