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Index: head/sys/vm/vm_fault.c
===================================================================
--- head/sys/vm/vm_fault.c
+++ head/sys/vm/vm_fault.c
@@ -151,23 +151,42 @@
"the page fault handler");
static inline void
-release_page(struct faultstate *fs)
+fault_page_release(vm_page_t *mp)
{
+ vm_page_t m;
- if (fs->m != NULL) {
+ m = *mp;
+ if (m != NULL) {
/*
- * fs->m's object lock might not be held, so the page must be
- * kept busy until we are done with it.
+ * We are likely to loop around again and attempt to busy
+ * this page. Deactivating it leaves it available for
+ * pageout while optimizing fault restarts.
*/
- vm_page_lock(fs->m);
- vm_page_deactivate(fs->m);
- vm_page_unlock(fs->m);
- vm_page_xunbusy(fs->m);
- fs->m = NULL;
+ vm_page_lock(m);
+ vm_page_deactivate(m);
+ vm_page_unlock(m);
+ vm_page_xunbusy(m);
+ *mp = NULL;
}
}
static inline void
+fault_page_free(vm_page_t *mp)
+{
+ vm_page_t m;
+
+ m = *mp;
+ if (m != NULL) {
+ VM_OBJECT_ASSERT_WLOCKED(m->object);
+ if (!vm_page_wired(m))
+ vm_page_free(m);
+ else
+ vm_page_xunbusy(m);
+ *mp = NULL;
+ }
+}
+
+static inline void
unlock_map(struct faultstate *fs)
{
@@ -191,13 +210,13 @@
fault_deallocate(struct faultstate *fs)
{
+ fault_page_release(&fs->m);
vm_object_pip_wakeup(fs->object);
if (fs->object != fs->first_object) {
VM_OBJECT_WLOCK(fs->first_object);
- vm_page_free(fs->first_m);
- vm_object_pip_wakeup(fs->first_object);
+ fault_page_free(&fs->first_m);
VM_OBJECT_WUNLOCK(fs->first_object);
- fs->first_m = NULL;
+ vm_object_pip_wakeup(fs->first_object);
}
vm_object_deallocate(fs->first_object);
unlock_map(fs);
@@ -657,7 +676,6 @@
}
vhold(vp);
- release_page(fs);
unlock_and_deallocate(fs);
error = vget(vp, locked | LK_RETRY | LK_CANRECURSE, curthread);
vdrop(vp);
@@ -774,7 +792,7 @@
fs.lookup_still_valid = true;
- fs.first_m = NULL;
+ fs.m = fs.first_m = NULL;
/*
* Search for the page at object/offset.
@@ -782,6 +800,8 @@
fs.object = fs.first_object;
fs.pindex = fs.first_pindex;
while (TRUE) {
+ KASSERT(fs.m == NULL,
+ ("page still set %p at loop start", fs.m));
/*
* If the object is marked for imminent termination,
* we retry here, since the collapse pass has raced
@@ -826,23 +846,15 @@
*/
vm_page_aflag_set(fs.m, PGA_REFERENCED);
if (fs.object != fs.first_object) {
- if (!VM_OBJECT_TRYWLOCK(
- fs.first_object)) {
- VM_OBJECT_WUNLOCK(fs.object);
- VM_OBJECT_WLOCK(fs.first_object);
- VM_OBJECT_WLOCK(fs.object);
- }
- vm_page_free(fs.first_m);
+ fault_page_release(&fs.first_m);
vm_object_pip_wakeup(fs.first_object);
- VM_OBJECT_WUNLOCK(fs.first_object);
- fs.first_m = NULL;
}
unlock_map(&fs);
+ vm_object_pip_wakeup(fs.object);
if (fs.m == vm_page_lookup(fs.object,
fs.pindex)) {
vm_page_sleep_if_busy(fs.m, "vmpfw");
}
- vm_object_pip_wakeup(fs.object);
VM_OBJECT_WUNLOCK(fs.object);
VM_CNT_INC(v_intrans);
vm_object_deallocate(fs.first_object);
@@ -1091,40 +1103,28 @@
* an error.
*/
if (rv == VM_PAGER_ERROR || rv == VM_PAGER_BAD) {
- if (!vm_page_wired(fs.m))
- vm_page_free(fs.m);
- else
- vm_page_xunbusy(fs.m);
- fs.m = NULL;
+ fault_page_free(&fs.m);
unlock_and_deallocate(&fs);
return (KERN_OUT_OF_BOUNDS);
}
- /*
- * The requested page does not exist at this object/
- * offset. Remove the invalid page from the object,
- * waking up anyone waiting for it, and continue on to
- * the next object. However, if this is the top-level
- * object, we must leave the busy page in place to
- * prevent another process from rushing past us, and
- * inserting the page in that object at the same time
- * that we are.
- */
- if (fs.object != fs.first_object) {
- if (!vm_page_wired(fs.m))
- vm_page_free(fs.m);
- else
- vm_page_xunbusy(fs.m);
- fs.m = NULL;
- }
}
/*
- * We get here if the object has default pager (or unwiring)
- * or the pager doesn't have the page.
+ * The requested page does not exist at this object/
+ * offset. Remove the invalid page from the object,
+ * waking up anyone waiting for it, and continue on to
+ * the next object. However, if this is the top-level
+ * object, we must leave the busy page in place to
+ * prevent another process from rushing past us, and
+ * inserting the page in that object at the same time
+ * that we are.
*/
- if (fs.object == fs.first_object)
+ if (fs.object == fs.first_object) {
fs.first_m = fs.m;
+ fs.m = NULL;
+ } else
+ fault_page_free(&fs.m);
/*
* Move on to the next object. Lock the next object before
@@ -1142,9 +1142,11 @@
fs.object = fs.first_object;
fs.pindex = fs.first_pindex;
- fs.m = fs.first_m;
VM_OBJECT_WLOCK(fs.object);
}
+ MPASS(fs.first_m != NULL);
+ MPASS(fs.m == NULL);
+ fs.m = fs.first_m;
fs.first_m = NULL;
/*
@@ -1161,6 +1163,7 @@
faultcount = 1;
break; /* break to PAGE HAS BEEN FOUND */
} else {
+ MPASS(fs.first_m != NULL);
KASSERT(fs.object != next_object,
("object loop %p", next_object));
VM_OBJECT_WLOCK(next_object);
@@ -1257,7 +1260,7 @@
/*
* We no longer need the old page or object.
*/
- release_page(&fs);
+ fault_page_release(&fs.m);
}
/*
* fs.object != fs.first_object due to above
@@ -1295,7 +1298,6 @@
*/
if (!fs.lookup_still_valid) {
if (!vm_map_trylock_read(fs.map)) {
- release_page(&fs);
unlock_and_deallocate(&fs);
goto RetryFault;
}
@@ -1310,7 +1312,6 @@
* pageout will grab it eventually.
*/
if (result != KERN_SUCCESS) {
- release_page(&fs);
unlock_and_deallocate(&fs);
/*
@@ -1323,7 +1324,6 @@
}
if ((retry_object != fs.first_object) ||
(retry_pindex != fs.first_pindex)) {
- release_page(&fs);
unlock_and_deallocate(&fs);
goto RetryFault;
}
@@ -1339,7 +1339,6 @@
prot &= retry_prot;
fault_type &= retry_prot;
if (prot == 0) {
- release_page(&fs);
unlock_and_deallocate(&fs);
goto RetryFault;
}
@@ -1400,6 +1399,7 @@
vm_page_wire(fs.m);
}
vm_page_xunbusy(fs.m);
+ fs.m = NULL;
/*
* Unlock everything, and return
Index: head/sys/vm/vm_object.c
===================================================================
--- head/sys/vm/vm_object.c
+++ head/sys/vm/vm_object.c
@@ -1477,6 +1477,18 @@
goto retry;
}
+ /*
+ * The page was left invalid. Likely placed there by
+ * an incomplete fault. Just remove and ignore.
+ */
+ if (vm_page_none_valid(m)) {
+ if (vm_page_remove(m))
+ vm_page_free(m);
+ else
+ vm_page_xunbusy(m);
+ continue;
+ }
+
/* vm_page_rename() will dirty the page. */
if (vm_page_rename(m, new_object, idx)) {
vm_page_xunbusy(m);
@@ -1688,8 +1700,18 @@
continue;
}
- KASSERT(pp == NULL || !vm_page_none_valid(pp),
- ("unbusy invalid page %p", pp));
+ if (pp != NULL && vm_page_none_valid(pp)) {
+ /*
+ * The page was invalid in the parent. Likely placed
+ * there by an incomplete fault. Just remove and
+ * ignore. p can replace it.
+ */
+ if (vm_page_remove(pp))
+ vm_page_free(pp);
+ else
+ vm_page_xunbusy(pp);
+ pp = NULL;
+ }
if (pp != NULL || vm_pager_has_page(object, new_pindex, NULL,
NULL)) {

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