PATCH: Add memory barrier to malloc

[H. J. Lu]

On Sat, May 03, 2003 at 11:38:27PM -0700, Ulrich Drepper wrote:
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> H. J. Lu wrote:
> 
> > I only found atomic_compare_and_exchange_val_acq and
> > atomic_compare_and_exchange_bool_acq in sysdeps/generic/bits/atomic.h.
> 
> Look at include/atomic.h.
> 

Here is the new patch.


H.J.
-------------- next part --------------
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.

--- libc/malloc/arena.c.barrier	2002-12-26 16:36:41.000000000 -0800
+++ libc/malloc/arena.c	2003-05-03 23:56:59.000000000 -0700
@@ -758,6 +758,7 @@ arena_get2(a_tsd, size) mstate a_tsd; si
   /* 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);
 
--- libc/malloc/thread-m.h.barrier	2003-04-07 08:09:36.000000000 -0700
+++ libc/malloc/thread-m.h	2003-05-04 00:22:29.000000000 -0700
@@ -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
@@ -317,4 +318,16 @@ 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) */
--- libc/sysdeps/ia64/bits/atomic.h.barrier	2003-03-26 08:22:03.000000000 -0800
+++ libc/sysdeps/ia64/bits/atomic.h	2003-05-04 00:25:31.000000000 -0700
@@ -127,3 +127,5 @@ typedef uintmax_t uatomic_max_t;
        }								      \
      while (__builtin_expect (__val != __oldval, 0));			      \
      __oldval & __mask; })
+
+#define atomic_full_barrier() __sync_synchronize ()