locking/x86: Tweak the comment about use of wmb() for IO

On x86, we *do* still use the non-NOP rmb()/wmb() for IO barriers,
but even that is generally questionable.

Leave them around as historial unless somebody can point to a
case where they care about the performance, but tweak the
comment so people don't think they are strictly required in all
cases.

Signed-off-by: Michael S. Tsirkin <[email protected]>
Acked-by: Peter Zijlstra (Intel) <[email protected]>
Cc: Andrew Morton <[email protected]>
Cc: Andrey Konovalov <[email protected]>
Cc: Andy Lutomirski <[email protected]>
Cc: Andy Lutomirski <[email protected]>
Cc: Borislav Petkov <[email protected]>
Cc: Borislav Petkov <[email protected]>
Cc: Brian Gerst <[email protected]>
Cc: Davidlohr Bueso <[email protected]>
Cc: Davidlohr Bueso <[email protected]>
Cc: Denys Vlasenko <[email protected]>
Cc: H. Peter Anvin <[email protected]>
Cc: Linus Torvalds <[email protected]>
Cc: Paul E. McKenney <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: Thomas Gleixner <[email protected]>
Cc: virtualization <[email protected]>
Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Ingo Molnar <[email protected]>

diff --git a/arch/x86/include/asm/barrier.h b/arch/x86/include/asm/barrier.h
index a29174599a983187f1cce733d67d4d8bd14804ab..bfb28caf97b1be1f2d6aa8893bd905a39030e310 100644 (file)
--- a/arch/x86/include/asm/barrier.h
+++ b/arch/x86/include/asm/barrier.h
@@ -6,7 +6,7 @@
 
 /*
  * Force strict CPU ordering.
- * And yes, this is required on UP too when we're talking
+ * And yes, this might be required on UP too when we're talking
  * to devices.
  */