From owner-svn-src-head@FreeBSD.ORG  Thu Jun  3 10:11:46 2010
Return-Path: <owner-svn-src-head@FreeBSD.ORG>
Delivered-To: svn-src-head@freebsd.org
Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34])
	by hub.freebsd.org (Postfix) with ESMTP id 6A4691065674;
	Thu,  3 Jun 2010 10:11:46 +0000 (UTC) (envelope-from kib@FreeBSD.org)
Received: from svn.freebsd.org (unknown [IPv6:2001:4f8:fff6::2c])
	by mx1.freebsd.org (Postfix) with ESMTP id 5A4E88FC1C;
	Thu,  3 Jun 2010 10:11:46 +0000 (UTC)
Received: from svn.freebsd.org (localhost [127.0.0.1])
	by svn.freebsd.org (8.14.3/8.14.3) with ESMTP id o53ABk2X041468;
	Thu, 3 Jun 2010 10:11:46 GMT (envelope-from kib@svn.freebsd.org)
Received: (from kib@localhost)
	by svn.freebsd.org (8.14.3/8.14.3/Submit) id o53ABk0x041466;
	Thu, 3 Jun 2010 10:11:46 GMT (envelope-from kib@svn.freebsd.org)
Message-Id: <201006031011.o53ABk0x041466@svn.freebsd.org>
From: Konstantin Belousov <kib@FreeBSD.org>
Date: Thu, 3 Jun 2010 10:11:46 +0000 (UTC)
To: src-committers@freebsd.org, svn-src-all@freebsd.org,
	svn-src-head@freebsd.org
X-SVN-Group: head
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit
Cc: 
Subject: svn commit: r208772 - head/sys/vm
X-BeenThere: svn-src-head@freebsd.org
X-Mailman-Version: 2.1.5
Precedence: list
List-Id: SVN commit messages for the src tree for head/-current
	<svn-src-head.freebsd.org>
List-Unsubscribe: <http://lists.freebsd.org/mailman/listinfo/svn-src-head>,
	<mailto:svn-src-head-request@freebsd.org?subject=unsubscribe>
List-Archive: <http://lists.freebsd.org/pipermail/svn-src-head>
List-Post: <mailto:svn-src-head@freebsd.org>
List-Help: <mailto:svn-src-head-request@freebsd.org?subject=help>
List-Subscribe: <http://lists.freebsd.org/mailman/listinfo/svn-src-head>,
	<mailto:svn-src-head-request@freebsd.org?subject=subscribe>
X-List-Received-Date: Thu, 03 Jun 2010 10:11:46 -0000

Author: kib
Date: Thu Jun  3 10:11:45 2010
New Revision: 208772
URL: http://svn.freebsd.org/changeset/base/208772

Log:
  Add assertion and comment in vm_page_flag_set() describing the expectations
  when the PG_WRITEABLE flag is set.
  
  Reviewed by:	alc

Modified:
  head/sys/vm/vm_page.c

Modified: head/sys/vm/vm_page.c
==============================================================================
--- head/sys/vm/vm_page.c	Thu Jun  3 09:54:53 2010	(r208771)
+++ head/sys/vm/vm_page.c	Thu Jun  3 10:11:45 2010	(r208772)
@@ -486,6 +486,14 @@ vm_page_flag_set(vm_page_t m, unsigned s
 {
 
 	mtx_assert(&vm_page_queue_mtx, MA_OWNED);
+	/*
+	 * For a managed page, the PG_WRITEABLE flag can be set only if
+	 * the page is VPO_BUSY.  Currently this flag is only set by
+	 * pmap_enter().
+	 */
+	KASSERT((bits & PG_WRITEABLE) == 0 ||
+	    (m->flags & (PG_UNMANAGED | PG_FICTITIOUS)) != 0 ||
+	    (m->oflags & VPO_BUSY) != 0, ("PG_WRITEABLE and !VPO_BUSY"));
 	m->flags |= bits;
 }