svn commit: r286362 - stable/10/sys/vm

[Konstantin Belousov]

Author: kib
Date: Thu Aug  6 08:51:15 2015
New Revision: 286362
URL: https://svnweb.freebsd.org/changeset/base/286362

Log:
  MFC r286086:
  Do not pretend that vm_fault(9) supports unwiring the address.

Modified:
  stable/10/sys/vm/vm_fault.c
  stable/10/sys/vm/vm_map.c
  stable/10/sys/vm/vm_map.h
Directory Properties:
  stable/10/   (props changed)

Modified: stable/10/sys/vm/vm_fault.c
==============================================================================
--- stable/10/sys/vm/vm_fault.c	Thu Aug  6 07:49:34 2015	(r286361)
+++ stable/10/sys/vm/vm_fault.c	Thu Aug  6 08:51:15 2015	(r286362)
@@ -189,7 +189,7 @@ vm_fault_dirty(vm_map_entry_t entry, vm_
 	VM_OBJECT_ASSERT_LOCKED(m->object);
 
 	need_dirty = ((fault_type & VM_PROT_WRITE) != 0 &&
-	    (fault_flags & VM_FAULT_CHANGE_WIRING) == 0) ||
+	    (fault_flags & VM_FAULT_WIRE) == 0) ||
 	    (fault_flags & VM_FAULT_DIRTY) != 0;
 
 	if (set_wd)
@@ -240,15 +240,6 @@ vm_fault_dirty(vm_map_entry_t entry, vm_
 }
 
 /*
- * TRYPAGER - used by vm_fault to calculate whether the pager for the
- *	      current object *might* contain the page.
- *
- *	      default objects are zero-fill, there is no real pager.
- */
-#define TRYPAGER	(fs.object->type != OBJT_DEFAULT && \
-			((fault_flags & VM_FAULT_CHANGE_WIRING) == 0 || wired))
-
-/*
  *	vm_fault:
  *
  *	Handle a page fault occurring at the given address,
@@ -358,9 +349,12 @@ RetryFault:;
 
 	if (wired)
 		fault_type = prot | (fault_type & VM_PROT_COPY);
+	else
+		KASSERT((fault_flags & VM_FAULT_WIRE) == 0,
+		    ("!wired && VM_FAULT_WIRE"));
 
 	if (fs.vp == NULL /* avoid locked vnode leak */ &&
-	    (fault_flags & (VM_FAULT_CHANGE_WIRING | VM_FAULT_DIRTY)) == 0 &&
+	    (fault_flags & (VM_FAULT_WIRE | VM_FAULT_DIRTY)) == 0 &&
 	    /* avoid calling vm_object_set_writeable_dirty() */
 	    ((prot & VM_PROT_WRITE) == 0 ||
 	    (fs.first_object->type != OBJT_VNODE &&
@@ -506,10 +500,12 @@ fast_failed:
 		}
 
 		/*
-		 * Page is not resident, If this is the search termination
+		 * Page is not resident.  If this is the search termination
 		 * or the pager might contain the page, allocate a new page.
+		 * Default objects are zero-fill, there is no real pager.
 		 */
-		if (TRYPAGER || fs.object == fs.first_object) {
+		if (fs.object->type != OBJT_DEFAULT ||
+		    fs.object == fs.first_object) {
 			if (fs.pindex >= fs.object->size) {
 				unlock_and_deallocate(&fs);
 				return (KERN_PROTECTION_FAILURE);
@@ -556,9 +552,10 @@ readrest:
 		 *
 		 * Attempt to fault-in the page if there is a chance that the
 		 * pager has it, and potentially fault in additional pages
-		 * at the same time.
+		 * at the same time.  For default objects simply provide
+		 * zero-filled pages.
 		 */
-		if (TRYPAGER) {
+		if (fs.object->type != OBJT_DEFAULT) {
 			int rv;
 			u_char behavior = vm_map_entry_behavior(fs.entry);
 
@@ -868,7 +865,7 @@ vnode_locked:
 				pmap_copy_page(fs.m, fs.first_m);
 				fs.first_m->valid = VM_PAGE_BITS_ALL;
 				if (wired && (fault_flags &
-				    VM_FAULT_CHANGE_WIRING) == 0) {
+				    VM_FAULT_WIRE) == 0) {
 					vm_page_lock(fs.first_m);
 					vm_page_wire(fs.first_m);
 					vm_page_unlock(fs.first_m);
@@ -989,7 +986,7 @@ vnode_locked:
 	 */
 	pmap_enter(fs.map->pmap, vaddr, fs.m, prot,
 	    fault_type | (wired ? PMAP_ENTER_WIRED : 0), 0);
-	if (faultcount != 1 && (fault_flags & VM_FAULT_CHANGE_WIRING) == 0 &&
+	if (faultcount != 1 && (fault_flags & VM_FAULT_WIRE) == 0 &&
 	    wired == 0)
 		vm_fault_prefault(&fs, vaddr, faultcount, reqpage);
 	VM_OBJECT_WLOCK(fs.object);
@@ -999,11 +996,9 @@ vnode_locked:
 	 * If the page is not wired down, then put it where the pageout daemon
 	 * can find it.
 	 */
-	if (fault_flags & VM_FAULT_CHANGE_WIRING) {
-		if (wired)
-			vm_page_wire(fs.m);
-		else
-			vm_page_unwire(fs.m, 1);
+	if ((fault_flags & VM_FAULT_WIRE) != 0) {
+		KASSERT(wired, ("VM_FAULT_WIRE && !wired"));
+		vm_page_wire(fs.m);
 	} else
 		vm_page_activate(fs.m);
 	if (m_hold != NULL) {

Modified: stable/10/sys/vm/vm_map.c
==============================================================================
--- stable/10/sys/vm/vm_map.c	Thu Aug  6 07:49:34 2015	(r286361)
+++ stable/10/sys/vm/vm_map.c	Thu Aug  6 08:51:15 2015	(r286362)
@@ -2603,7 +2603,7 @@ vm_map_wire(vm_map_t map, vm_offset_t st
 				 * it into the physical map.
 				 */
 				if ((rv = vm_fault(map, faddr, VM_PROT_NONE,
-				    VM_FAULT_CHANGE_WIRING)) != KERN_SUCCESS)
+				    VM_FAULT_WIRE)) != KERN_SUCCESS)
 					break;
 			} while ((faddr += PAGE_SIZE) < saved_end);
 			vm_map_lock(map);

Modified: stable/10/sys/vm/vm_map.h
==============================================================================
--- stable/10/sys/vm/vm_map.h	Thu Aug  6 07:49:34 2015	(r286361)
+++ stable/10/sys/vm/vm_map.h	Thu Aug  6 08:51:15 2015	(r286362)
@@ -327,9 +327,9 @@ long vmspace_resident_count(struct vmspa
 /*
  * vm_fault option flags
  */
-#define VM_FAULT_NORMAL 0		/* Nothing special */
-#define VM_FAULT_CHANGE_WIRING 1	/* Change the wiring as appropriate */
-#define	VM_FAULT_DIRTY 2		/* Dirty the page; use w/VM_PROT_COPY */
+#define	VM_FAULT_NORMAL	0		/* Nothing special */
+#define	VM_FAULT_WIRE	1		/* Wire the mapped page */
+#define	VM_FAULT_DIRTY	2		/* Dirty the page; use w/VM_PROT_COPY */
 
 /*
  * Initially, mappings are slightly sequential.  The maximum window size must