svn commit: r222992 - head/sys/vm

[Konstantin Belousov]

Author: kib
Date: Sat Jun 11 20:15:19 2011
New Revision: 222992
URL: http://svn.freebsd.org/changeset/base/222992

Log:
  Assert that page is VPO_BUSY or page owner object is locked in
  vm_page_undirty(). The assert is not precise due to VPO_BUSY owner
  to tracked, so assertion does not catch the case when VPO_BUSY is
  owned by other thread.
  
  Reviewed by:	alc

Modified:
  head/sys/vm/vm_page.c
  head/sys/vm/vm_page.h

Modified: head/sys/vm/vm_page.c
==============================================================================
--- head/sys/vm/vm_page.c	Sat Jun 11 20:13:28 2011	(r222991)
+++ head/sys/vm/vm_page.c	Sat Jun 11 20:15:19 2011	(r222992)
@@ -2636,6 +2636,23 @@ vm_page_cowsetup(vm_page_t m)
 	return (0);
 }
 
+#ifdef INVARIANTS
+void
+vm_page_object_lock_assert(vm_page_t m)
+{
+
+	/*
+	 * Certain of the page's fields may only be modified by the
+	 * holder of the containing object's lock or the setter of the
+	 * page's VPO_BUSY flag.  Unfortunately, the setter of the
+	 * VPO_BUSY flag is not recorded, and thus cannot be checked
+	 * here.
+	 */
+	if (m->object != NULL && (m->oflags & VPO_BUSY) == 0)
+		VM_OBJECT_LOCK_ASSERT(m->object, MA_OWNED);
+}
+#endif
+
 #include "opt_ddb.h"
 #ifdef DDB
 #include <sys/kernel.h>

Modified: head/sys/vm/vm_page.h
==============================================================================
--- head/sys/vm/vm_page.h	Sat Jun 11 20:13:28 2011	(r222991)
+++ head/sys/vm/vm_page.h	Sat Jun 11 20:15:19 2011	(r222992)
@@ -383,6 +383,13 @@ void vm_page_cowfault (vm_page_t);
 int vm_page_cowsetup(vm_page_t);
 void vm_page_cowclear (vm_page_t);
 
+#ifdef INVARIANTS
+void vm_page_object_lock_assert(vm_page_t m);
+#define	VM_PAGE_OBJECT_LOCK_ASSERT(m)	vm_page_object_lock_assert(m)
+#else
+#define	VM_PAGE_OBJECT_LOCK_ASSERT(m)	(void)0
+#endif
+
 /*
  *	vm_page_sleep_if_busy:
  *
@@ -412,6 +419,8 @@ vm_page_sleep_if_busy(vm_page_t m, int a
 static __inline void
 vm_page_undirty(vm_page_t m)
 {
+
+	VM_PAGE_OBJECT_LOCK_ASSERT(m);
 	m->dirty = 0;
 }