Update.

2003-05-04  H.J. Lu  <hongjiu.lu@intel.com>

	* malloc/arena.c (arena_get2): Add atomic_write_barrier.
	* malloc/thread-m.h: Include <atomic.h>.
	(atomic_full_barrier): Provide default.
	(atomic_read_barrier): Likewise.
	(atomic_write_barrier): Likewise.
	* sysdeps/ia64/bits/atomic.h (atomic_full_barrier): New #define.

ChangeLog

@@ -1,3 +1,12 @@
+2003-05-04  H.J. Lu  <hongjiu.lu@intel.com>
+
+	* malloc/arena.c (arena_get2): Add atomic_write_barrier.
+	* malloc/thread-m.h: Include <atomic.h>.
+	(atomic_full_barrier): Provide default.
+	(atomic_read_barrier): Likewise.
+	(atomic_write_barrier): Likewise.
+	* sysdeps/ia64/bits/atomic.h (atomic_full_barrier): New #define.
+
 2003-06-30  Ulrich Drepper  <drepper@redhat.com>
 
 	* sysdeps/generic/sysdep.h: Define cfi_rel_offset and CFI_REL_OFFSET.

malloc/arena.c

@@ -1,5 +1,5 @@
 /* Malloc implementation for multiple threads without lock contention.
-   Copyright (C) 2001, 2002 Free Software Foundation, Inc.
+   Copyright (C) 2001, 2002, 2003 Free Software Foundation, Inc.
    This file is part of the GNU C Library.
    Contributed by Wolfram Gloger <wg@malloc.de>, 2001.
 
@@ -758,6 +758,7 @@ arena_get2(a_tsd, size) mstate a_tsd; size_t size;
   /* Add the new arena to the global list.  */
   (void)mutex_lock(&list_lock);
   a->next = main_arena.next;
+  atomic_write_barrier ();
   main_arena.next = a;
   (void)mutex_unlock(&list_lock);
 

malloc/thread-m.h

@@ -31,6 +31,7 @@
 
 #if defined(_LIBC) /* The GNU C library, a special case of Posix threads */
 
+#include <atomic.h>
 #include <bits/libc-lock.h>
 
 #ifdef PTHREAD_MUTEX_INITIALIZER
@@ -306,4 +307,16 @@ typedef void *tsd_key_t;
 
 #endif /* defined(NO_THREADS) */
 
+#ifndef atomic_full_barrier
+# define atomic_full_barrier() __asm ("" ::: "memory")
+#endif
+
+#ifndef atomic_read_barrier
+# define atomic_read_barrier() atomic_full_barrier ()
+#endif
+
+#ifndef atomic_write_barrier
+# define atomic_write_barrier() atomic_full_barrier ()
+#endif
+
 #endif /* !defined(_THREAD_M_H) */

sysdeps/ia64/bits/atomic.h

@@ -122,3 +122,5 @@ typedef uintmax_t uatomic_max_t;
        }								      \
      while (__builtin_expect (__val != __oldval, 0));			      \
      __oldval & __mask; })
+
+#define atomic_full_barrier() __sync_synchronize ()