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Date:      Thu, 11 Jul 2013 05:47:27 +0000 (UTC)
From:      Konstantin Belousov <kib@FreeBSD.org>
To:        src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-head@freebsd.org
Subject:   svn commit: r253189 - head/sys/vm
Message-ID:  <201307110547.r6B5lRda042534@svn.freebsd.org>
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Author: kib
Date: Thu Jul 11 05:47:26 2013
New Revision: 253189
URL: http://svnweb.freebsd.org/changeset/base/253189

Log:
  Never remove user-wired pages from an object when doing
  msync(MS_INVALIDATE).  The vm_fault_copy_entry() requires that object
  range which corresponds to the user-wired vm_map_entry, is always
  fully populated.
  
  Add OBJPR_NOTWIRED flag for vm_object_page_remove() to request the
  preserving behaviour, use it when calling vm_object_page_remove() from
  vm_object_sync().
  
  Reported and tested by:	pho
  Reviewed by:	alc
  Sponsored by:	The FreeBSD Foundation
  MFC after:	2 weeks

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

Modified: head/sys/vm/vm_object.c
==============================================================================
--- head/sys/vm/vm_object.c	Thu Jul 11 05:38:39 2013	(r253188)
+++ head/sys/vm/vm_object.c	Thu Jul 11 05:47:26 2013	(r253189)
@@ -1054,9 +1054,9 @@ vm_object_sync(vm_object_t object, vm_oo
 			 */
 			flags = OBJPR_NOTMAPPED;
 		else if (old_msync)
-			flags = 0;
+			flags = OBJPR_NOTWIRED;
 		else
-			flags = OBJPR_CLEANONLY;
+			flags = OBJPR_CLEANONLY | OBJPR_NOTWIRED;
 		vm_object_page_remove(object, OFF_TO_IDX(offset),
 		    OFF_TO_IDX(offset + size + PAGE_MASK), flags);
 	}
@@ -1892,7 +1892,8 @@ again:
 		vm_page_lock(p);
 		if ((wirings = p->wire_count) != 0 &&
 		    (wirings = pmap_page_wired_mappings(p)) != p->wire_count) {
-			if ((options & OBJPR_NOTMAPPED) == 0) {
+			if ((options & (OBJPR_NOTWIRED | OBJPR_NOTMAPPED)) ==
+			    0) {
 				pmap_remove_all(p);
 				/* Account for removal of wired mappings. */
 				if (wirings != 0)
@@ -1902,8 +1903,7 @@ again:
 				p->valid = 0;
 				vm_page_undirty(p);
 			}
-			vm_page_unlock(p);
-			continue;
+			goto next;
 		}
 		if (vm_page_sleep_if_busy(p, TRUE, "vmopar"))
 			goto again;
@@ -1912,12 +1912,12 @@ again:
 		if ((options & OBJPR_CLEANONLY) != 0 && p->valid != 0) {
 			if ((options & OBJPR_NOTMAPPED) == 0)
 				pmap_remove_write(p);
-			if (p->dirty) {
-				vm_page_unlock(p);
-				continue;
-			}
+			if (p->dirty)
+				goto next;
 		}
 		if ((options & OBJPR_NOTMAPPED) == 0) {
+			if ((options & OBJPR_NOTWIRED) != 0 && wirings != 0)
+				goto next;
 			pmap_remove_all(p);
 			/* Account for removal of wired mappings. */
 			if (wirings != 0) {
@@ -1929,6 +1929,7 @@ again:
 			}
 		}
 		vm_page_free(p);
+next:
 		vm_page_unlock(p);
 	}
 	vm_object_pip_wakeup(object);

Modified: head/sys/vm/vm_object.h
==============================================================================
--- head/sys/vm/vm_object.h	Thu Jul 11 05:38:39 2013	(r253188)
+++ head/sys/vm/vm_object.h	Thu Jul 11 05:47:26 2013	(r253189)
@@ -205,6 +205,7 @@ struct vm_object {
  */
 #define	OBJPR_CLEANONLY	0x1		/* Don't remove dirty pages. */
 #define	OBJPR_NOTMAPPED	0x2		/* Don't unmap pages. */
+#define	OBJPR_NOTWIRED	0x4		/* Don't remove wired pages. */
 
 TAILQ_HEAD(object_q, vm_object);

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