--6TrnltStXW4iwmi0
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline

On Sun, Aug 12, 2007 at 10:57:24PM -0400, Thor Lancelot Simon wrote:
> The kernel is -current as of today, cross-compiled on macppc for various
> obscure reasons.  Any ideas what causes this?  I am a bit curious about
> Opteron erratum 106: 
> 
> http://lists.freebsd.org/pipermail/freebsd-amd64/2005-May/004693.html

Can you try the attached patch? I think it makes condition (3)
impossible and shouldn't hurt for the common case.

Joerg

--6TrnltStXW4iwmi0
Content-Type: text/plain; charset=us-ascii
Content-Disposition: attachment; filename="lock.h.diff"

Index: lock.h
===================================================================
RCS file: /home/joerg/repo/netbsd/src/sys/arch/x86/include/lock.h,v
retrieving revision 1.14
diff -u -r1.14 lock.h
--- lock.h	10 Feb 2007 16:19:39 -0000	1.14
+++ lock.h	13 Aug 2007 09:08:41 -0000
@@ -49,6 +49,30 @@
 
 #include <machine/cpufunc.h>
 
+#ifdef _KERNEL
+void	mb_read(void);
+void	mb_write(void);
+void	mb_memory(void);
+#else	/* _KERNEL */
+static __inline void
+mb_read(void)
+{
+	x86_lfence();
+}
+
+static __inline void
+mb_write(void)
+{
+	__insn_barrier();
+}
+
+static __inline void
+mb_memory(void)
+{
+	x86_mfence();
+}
+#endif	/* _KERNEL */
+
 #ifdef LOCKDEBUG
 
 extern void __cpu_simple_lock_init(__cpu_simple_lock_t *);
@@ -80,11 +104,16 @@
 static __inline void
 __cpu_simple_lock(__cpu_simple_lock_t *lockp)
 {
+	int count = 100;
 
 	while (x86_atomic_testset_b(lockp, __SIMPLELOCK_LOCKED)
 	    != __SIMPLELOCK_UNLOCKED) {
 		do {
 			x86_pause();
+			if (--count) {
+				mb_memory();
+				count = 100;
+			}
 		} while (*lockp == __SIMPLELOCK_LOCKED);
 	}
 	__insn_barrier();
@@ -166,28 +195,4 @@
 #define	SPINLOCK_SPIN_HOOK	/* nothing */
 #define	SPINLOCK_BACKOFF_HOOK	x86_pause()
 
-#ifdef _KERNEL
-void	mb_read(void);
-void	mb_write(void);
-void	mb_memory(void);
-#else	/* _KERNEL */
-static __inline void
-mb_read(void)
-{
-	x86_lfence();
-}
-
-static __inline void
-mb_write(void)
-{
-	__insn_barrier();
-}
-
-static __inline void
-mb_memory(void)
-{
-	x86_mfence();
-}
-#endif	/* _KERNEL */
-
 #endif /* _X86_LOCK_H_ */

--6TrnltStXW4iwmi0--