Author: kib
Date: Thu Jul 30 18:28:34 2015
New Revision: 286086
URL: https://svnweb.freebsd.org/changeset/base/286086
Log:
Do not pretend that vm_fault(9) supports unwiring the address. Rename
the VM_FAULT_CHANGE_WIRING flag to VM_FAULT_WIRE. Assert that the
flag is only passed when faulting on the wired map entry. Remove the
vm_page_unwire() call, which should be never reachable.
Since VM_FAULT_WIRE flag implies wired map entry, the TRYPAGER() macro
is reduced to the testing of the fs.object having a default pager.
Inline the check.
Suggested and reviewed by: alc
Tested by: pho (previous version)
MFC after: 1 week
Modified:
head/sys/vm/vm_fault.c
head/sys/vm/vm_map.c
head/sys/vm/vm_map.h
Modified: head/sys/vm/vm_fault.c
==============================================================================
--- head/sys/vm/vm_fault.c Thu Jul 30 18:08:08 2015 (r286085)
+++ head/sys/vm/vm_fault.c Thu Jul 30 18:28:34 2015 (r286086)
@@ -193,7 +193,7 @@ 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)
@@ -244,15 +244,6 @@ 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,
@@ -361,9 +352,12 @@ 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 &&
@@ -509,10 +503,12 @@ 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);
@@ -873,7 +870,7 @@ 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);
@@ -994,7 +991,7 @@ 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);
@@ -1004,11 +1001,9 @@ 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, PQ_ACTIVE);
+ 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: head/sys/vm/vm_map.c
==============================================================================
--- head/sys/vm/vm_map.c Thu Jul 30 18:08:08 2015 (r286085)
+++ head/sys/vm/vm_map.c Thu Jul 30 18:28:34 2015 (r286086)
@@ -2591,7 +2591,7 @@ 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: head/sys/vm/vm_map.h
==============================================================================
--- head/sys/vm/vm_map.h Thu Jul 30 18:08:08 2015 (r286085)
+++ head/sys/vm/vm_map.h Thu Jul 30 18:28:34 2015 (r286086)
@@ -326,9 +326,9 @@ 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
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