svn commit: r252579 - user/attilio/vmobj-readlock/sys/vm

[Attilio Rao]

Author: attilio
Date: Wed Jul  3 17:47:48 2013
New Revision: 252579
URL: http://svnweb.freebsd.org/changeset/base/252579

Log:
  Mark the busy_lock as volatile in order to avoid compiler optimizations
  which can result in problems with inlined functions, like
  vm_page_busy_wlocked().
  
  Sponsored by:	EMC / Isilon storage division

Modified:
  user/attilio/vmobj-readlock/sys/vm/vm_page.h

Modified: user/attilio/vmobj-readlock/sys/vm/vm_page.h
==============================================================================
--- user/attilio/vmobj-readlock/sys/vm/vm_page.h	Wed Jul  3 17:39:19 2013	(r252578)
+++ user/attilio/vmobj-readlock/sys/vm/vm_page.h	Wed Jul  3 17:47:48 2013	(r252579)
@@ -159,7 +159,7 @@ struct vm_page {
 	/* so, on normal X86 kernels, they must be at least 8 bits wide */
 	vm_page_bits_t valid;		/* map of valid DEV_BSIZE chunks (O) */
 	vm_page_bits_t dirty;		/* map of dirty DEV_BSIZE chunks (M) */
-	u_int busy_lock;		/* busy owners lock */
+	volatile u_int busy_lock;	/* busy owners lock */
 };
 
 /*