libcilkrts/runtime/os_mutex-unix.c

   1 /* os_mutex-unix.c                  -*-C-*-
   2  *
   3  *************************************************************************
   4  *
   5  *  Copyright (C) 2009-2016, Intel Corporation
   6  *  All rights reserved.
   7  *
   8  *  Redistribution and use in source and binary forms, with or without
   9  *  modification, are permitted provided that the following conditions
  10  *  are met:
  11  *
  12  *    * Redistributions of source code must retain the above copyright
  13  *      notice, this list of conditions and the following disclaimer.
  14  *    * Redistributions in binary form must reproduce the above copyright
  15  *      notice, this list of conditions and the following disclaimer in
  16  *      the documentation and/or other materials provided with the
  17  *      distribution.
  18  *    * Neither the name of Intel Corporation nor the names of its
  19  *      contributors may be used to endorse or promote products derived
  20  *      from this software without specific prior written permission.
  21  *
  22  *  THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
  23  *  "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
  24  *  LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
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  30  *  AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  31  *  LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY
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  34  *
  35  *  *********************************************************************
  36  *
  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
  39  *  submitted through the contribution process detailed at
  40  *  http://www.cilkplus.org/submit-cilk-contribution will be lost the next
  41  *  time that a new version is released. Changes only submitted to the
  42  *  GNU compiler collection or posted to the git repository at
  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 #include "os_mutex.h"
  51 #include "bug.h"
  52
  53 #include <stdlib.h>
  54 #include <errno.h>
  55 #include <pthread.h>
  56
  57 // contains notification macros for VTune.
  58 #include "cilk-ittnotify.h"
  59
  60 /*
  61  * OS Mutex functions.
  62  *
  63  * Not to be confused with the spinlock mutexes implemented in cilk_mutex.c
  64  */
  65
  66 struct os_mutex {
  67     pthread_mutex_t mutex;  ///< On Linux, os_mutex is implemented with a pthreads mutex
  68 };
  69
  70 // Unix implementation of the global OS mutex.  This will be created by the
  71 // first call to global_os_mutex_lock() and *NEVER* destroyed.  On gcc-based
  72 // systems there's no way to guarantee the ordering of constructors and
  73 // destructors, so we can't be guaranteed that our destructor for a static
  74 // object will be called *after* any static destructors that may use Cilk
  75 // in the user's application
  76 static struct os_mutex *global_os_mutex = NULL;
  77
  78 /* Sometimes during shared library load malloc doesn't work.
  79    To handle that case, preallocate space for one mutex. */
  80 static struct os_mutex static_mutex;
  81 static int static_mutex_used;
  82
  83 struct os_mutex *__cilkrts_os_mutex_create(void)
  84 {
  85     int status;
  86     struct os_mutex *mutex = (struct os_mutex *)malloc(sizeof(struct os_mutex));
  87     pthread_mutexattr_t attr;
  88
  89     ITT_SYNC_CREATE(mutex, "OS Mutex");
  90
  91     if (!mutex) {
  92         if (static_mutex_used) {
  93             __cilkrts_bug("Cilk RTS library initialization failed");
  94         } else {
  95             static_mutex_used = 1;
  96             mutex = &static_mutex;
  97         }
  98     }
  99
 100     status = pthread_mutexattr_init(&attr);
 101     CILK_ASSERT (status == 0);
 102 #if defined DEBUG || CILK_LIB_DEBUG
 103 #ifdef PTHREAD_MUTEX_ERRORCHECK
 104     status = pthread_mutexattr_settype(&attr, PTHREAD_MUTEX_ERRORCHECK);
 105 #else
 106     status = pthread_mutexattr_settype(&attr, PTHREAD_MUTEX_ERRORCHECK_NP);
 107 #endif
 108     CILK_ASSERT (status == 0);
 109 #endif
 110     status = pthread_mutex_init (&mutex->mutex, &attr);
 111     CILK_ASSERT (status == 0);
 112     pthread_mutexattr_destroy(&attr);
 113
 114     return mutex;
 115 }
 116
 117 void __cilkrts_os_mutex_lock(struct os_mutex *p)
 118 {
 119     int status;
 120     status = pthread_mutex_lock (&p->mutex);
 121     ITT_SYNC_ACQUIRED(p);
 122     if (__builtin_expect(status, 0) == 0)
 123         return;
 124     if (status == EDEADLK)
 125         __cilkrts_bug("Cilk runtime error: deadlock acquiring mutex %p\n",
 126                       p);
 127     else
 128         __cilkrts_bug("Cilk runtime error %d acquiring mutex %p\n",
 129                       status, p);
 130 }
 131
 132 int __cilkrts_os_mutex_trylock(struct os_mutex *p)
 133 {
 134     int status;
 135     status = pthread_mutex_trylock (&p->mutex);
 136     return (status == 0);
 137 }
 138
 139 void __cilkrts_os_mutex_unlock(struct os_mutex *p)
 140 {
 141     int status;
 142     ITT_SYNC_RELEASING(p);
 143     status = pthread_mutex_unlock (&p->mutex);
 144     CILK_ASSERT(status == 0);
 145 }
 146
 147 void __cilkrts_os_mutex_destroy(struct os_mutex *p)
 148 {
 149     pthread_mutex_destroy (&p->mutex);
 150     if (p == &static_mutex) {
 151         static_mutex_used = 0;
 152     } else {
 153         free(p);
 154     }
 155 }
 156
 157 /*
 158  * create_global_os_mutex
 159  *
 160  * Function used with pthread_once to initialize the global OS mutex.  Since
 161  * pthread_once requires a function which takes no parameters and has no
 162  * return value, the global OS mutex will be stored in the static (global
 163  * to the compilation unit) variable "global_os_mutex."
 164  *
 165  *
 166  * global_os_mutex will never be destroyed.
 167  */
 168 static void create_global_os_mutex(void)
 169 {
 170     CILK_ASSERT(NULL == global_os_mutex);
 171     global_os_mutex = __cilkrts_os_mutex_create();
 172 }
 173
 174 void global_os_mutex_lock(void)
 175 {
 176     // pthread_once_t used with pthread_once to guarantee that
 177     // create_global_os_mutex() is only called once
 178     static pthread_once_t global_os_mutex_is_initialized = PTHREAD_ONCE_INIT;
 179
 180     // Execute create_global_os_mutex once in a thread-safe manner
 181     // Note that create_global_os_mutex returns the mutex in the static
 182     // (global to the module) variable "global_os_mutex"
 183     pthread_once(&global_os_mutex_is_initialized,
 184                  create_global_os_mutex);
 185
 186     // We'd better have allocated a global_os_mutex
 187     CILK_ASSERT(NULL != global_os_mutex);
 188
 189     // Acquire the global OS mutex
 190     __cilkrts_os_mutex_lock(global_os_mutex);
 191 }
 192
 193 void global_os_mutex_unlock(void)
 194 {
 195     // We'd better have allocated a global_os_mutex.  This means you should
 196     // have called global_os_mutex_lock() before calling
 197     // global_os_mutex_unlock(), but this is the only check for it.
 198     CILK_ASSERT(NULL != global_os_mutex);
 199
 200     // Release the global OS mutex
 201     __cilkrts_os_mutex_unlock(global_os_mutex);
 202 }
 203
 204 /* End os_mutex-unix.c */