[Emacs-diffs] Changes to emacs/src/gmalloc.c,v

[YAMAMOTO Mitsuharu]

CVSROOT:        /cvsroot/emacs
Module name:    emacs
Changes by:     YAMAMOTO Mitsuharu <mituharu>   07/08/07 08:55:44

Index: gmalloc.c
===================================================================
RCS file: /cvsroot/emacs/emacs/src/gmalloc.c,v
retrieving revision 1.24
retrieving revision 1.25
diff -u -b -r1.24 -r1.25
--- gmalloc.c   29 Jul 2007 10:12:21 -0000      1.24
+++ gmalloc.c   7 Aug 2007 08:55:43 -0000       1.25
@@ -136,6 +136,10 @@
 extern __ptr_t valloc PP ((__malloc_size_t __size));
 #endif
 
+#ifdef USE_PTHREAD
+/* Set up mutexes and make malloc etc. thread-safe.  */
+extern void malloc_enable_thread PP ((void));
+#endif
 
 #ifdef _MALLOC_INTERNAL
 
@@ -242,10 +246,27 @@
 
 #ifdef USE_PTHREAD
 extern pthread_mutex_t _malloc_mutex, _aligned_blocks_mutex;
-#define LOCK()     pthread_mutex_lock (&_malloc_mutex)
-#define UNLOCK()   pthread_mutex_unlock (&_malloc_mutex)
-#define LOCK_ALIGNED_BLOCKS()     pthread_mutex_lock (&_aligned_blocks_mutex)
-#define UNLOCK_ALIGNED_BLOCKS()   pthread_mutex_unlock (&_aligned_blocks_mutex)
+extern int _malloc_thread_enabled_p;
+#define LOCK()                                 \
+  do {                                         \
+    if (_malloc_thread_enabled_p)              \
+      pthread_mutex_lock (&_malloc_mutex);     \
+  } while (0)
+#define UNLOCK()                               \
+  do {                                         \
+    if (_malloc_thread_enabled_p)              \
+      pthread_mutex_unlock (&_malloc_mutex);   \
+  } while (0)
+#define LOCK_ALIGNED_BLOCKS()                          \
+  do {                                                 \
+    if (_malloc_thread_enabled_p)                      \
+      pthread_mutex_lock (&_aligned_blocks_mutex);     \
+  } while (0)
+#define UNLOCK_ALIGNED_BLOCKS()                                \
+  do {                                                 \
+    if (_malloc_thread_enabled_p)                      \
+      pthread_mutex_unlock (&_aligned_blocks_mutex);   \
+  } while (0)
 #else
 #define LOCK()
 #define UNLOCK()
@@ -563,6 +584,47 @@
 #ifdef USE_PTHREAD
 pthread_mutex_t _malloc_mutex = PTHREAD_MUTEX_INITIALIZER;
 pthread_mutex_t _aligned_blocks_mutex = PTHREAD_MUTEX_INITIALIZER;
+int _malloc_thread_enabled_p;
+
+static void
+malloc_atfork_handler_prepare ()
+{
+  LOCK ();
+  LOCK_ALIGNED_BLOCKS ();
+}
+
+static void
+malloc_atfork_handler_parent ()
+{
+  UNLOCK_ALIGNED_BLOCKS ();
+  UNLOCK ();
+}
+
+static void
+malloc_atfork_handler_child ()
+{
+  UNLOCK_ALIGNED_BLOCKS ();
+  UNLOCK ();
+}
+
+/* Set up mutexes and make malloc etc. thread-safe.  */
+void
+malloc_enable_thread ()
+{
+  if (_malloc_thread_enabled_p)
+    return;
+
+  /* Some pthread implementations call malloc for statically
+     initialized mutexes when they are used first.  To avoid such a
+     situation, we initialize mutexes here while their use is
+     disabled in malloc etc.  */
+  pthread_mutex_init (&_malloc_mutex, NULL);
+  pthread_mutex_init (&_aligned_blocks_mutex, NULL);
+  pthread_atfork (malloc_atfork_handler_prepare,
+                 malloc_atfork_handler_parent,
+                 malloc_atfork_handler_child);
+  _malloc_thread_enabled_p = 1;
+}
 #endif
 
 static void
@@ -575,19 +637,6 @@
   if (__malloc_initialize_hook)
     (*__malloc_initialize_hook) ();
 
-  /* We don't use recursive mutex because pthread_mutexattr_init may
-     call malloc internally.  */
-#if 0 /* defined (USE_PTHREAD) */
-  {
-    pthread_mutexattr_t attr;
-
-    pthread_mutexattr_init (&attr);
-    pthread_mutexattr_settype (&attr, PTHREAD_MUTEX_RECURSIVE);
-    pthread_mutex_init (&_malloc_mutex, &attr);
-    pthread_mutexattr_destroy (&attr);
-  }
-#endif
-
   heapsize = HEAP / BLOCKSIZE;
   _heapinfo = (malloc_info *) align (heapsize * sizeof (malloc_info));
   if (_heapinfo == NULL)