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Index: sys/compat/linuxkpi/common/src/linux_compat.c
===================================================================
--- sys/compat/linuxkpi/common/src/linux_compat.c
+++ sys/compat/linuxkpi/common/src/linux_compat.c
@@ -508,10 +508,7 @@
page = vm_page_getfake(paddr, vm_obj->memattr);
VM_OBJECT_WLOCK(vm_obj);
- vm_page_replace_checked(page, vm_obj,
- (*mres)->pindex, *mres);
-
- vm_page_free(*mres);
+ vm_page_replace(page, vm_obj, (*mres)->pindex, *mres);
*mres = page;
}
vm_page_valid(page);
Index: sys/dev/drm2/ttm/ttm_bo_vm.c
===================================================================
--- sys/dev/drm2/ttm/ttm_bo_vm.c
+++ sys/dev/drm2/ttm/ttm_bo_vm.c
@@ -237,6 +237,7 @@
goto retry;
}
m1 = vm_page_lookup(vm_obj, OFF_TO_IDX(offset));
+ /* XXX This looks like it should just be vm_page_replace? */
if (m1 == NULL) {
if (vm_page_insert(m, vm_obj, OFF_TO_IDX(offset))) {
vm_page_xunbusy(m);
@@ -255,6 +256,7 @@
vm_page_valid(m);
if (*mres != NULL) {
KASSERT(*mres != m, ("losing %p %p", *mres, m));
+ vm_page_xunbusy(*mres);
vm_page_free(*mres);
}
*mres = m;
Index: sys/dev/netmap/netmap_freebsd.c
===================================================================
--- sys/dev/netmap/netmap_freebsd.c
+++ sys/dev/netmap/netmap_freebsd.c
@@ -1022,12 +1022,10 @@
vm_paddr_t paddr;
vm_page_t page;
vm_memattr_t memattr;
- vm_pindex_t pidx;
nm_prdis("object %p offset %jd prot %d mres %p",
object, (intmax_t)offset, prot, mres);
memattr = object->memattr;
- pidx = OFF_TO_IDX(offset);
paddr = netmap_mem_ofstophys(na->nm_mem, offset);
if (paddr == 0)
return VM_PAGER_FAIL;
@@ -1052,9 +1050,8 @@
VM_OBJECT_WUNLOCK(object);
page = vm_page_getfake(paddr, memattr);
VM_OBJECT_WLOCK(object);
- vm_page_free(*mres);
+ vm_page_replace(page, object, (*mres)->pindex, *mres);
*mres = page;
- vm_page_insert(page, object, pidx);
}
vm_page_valid(page);
return (VM_PAGER_OK);
Index: sys/dev/xen/gntdev/gntdev.c
===================================================================
--- sys/dev/xen/gntdev/gntdev.c
+++ sys/dev/xen/gntdev/gntdev.c
@@ -806,7 +806,7 @@
{
struct gntdev_gmap *gmap = object->handle;
vm_pindex_t pidx, ridx;
- vm_page_t page, oldm;
+ vm_page_t page;
vm_ooffset_t relative_offset;
if (gmap->map == NULL)
@@ -829,15 +829,12 @@
KASSERT(vm_page_wired(page), ("page %p is not wired", page));
KASSERT(!vm_page_busied(page), ("page %p is busy", page));
- if (*mres != NULL) {
- oldm = *mres;
- vm_page_free(oldm);
- *mres = NULL;
- }
-
vm_page_busy_acquire(page, 0);
vm_page_valid(page);
- vm_page_insert(page, object, pidx);
+ if (*mres != NULL)
+ vm_page_replace(page, object, pidx, *mres);
+ else
+ vm_page_insert(page, object, pidx);
*mres = page;
return (VM_PAGER_OK);
}
Index: sys/dev/xen/privcmd/privcmd.c
===================================================================
--- sys/dev/xen/privcmd/privcmd.c
+++ sys/dev/xen/privcmd/privcmd.c
@@ -154,7 +154,7 @@
{
struct privcmd_map *map = object->handle;
vm_pindex_t pidx;
- vm_page_t page, oldm;
+ vm_page_t page;
if (map->mapped != true)
return (VM_PAGER_FAIL);
@@ -172,15 +172,13 @@
KASSERT(vm_page_wired(page), ("page %p not wired", page));
KASSERT(!vm_page_busied(page), ("page %p is busy", page));
- if (*mres != NULL) {
- oldm = *mres;
- vm_page_free(oldm);
- *mres = NULL;
- }
-
vm_page_busy_acquire(page, 0);
vm_page_valid(page);
- vm_page_insert(page, object, pidx);
+
+ if (*mres != NULL)
+ vm_page_replace(page, object, pidx, *mres);
+ else
+ vm_page_insert(page, object, pidx);
*mres = page;
return (VM_PAGER_OK);
}
Index: sys/vm/device_pager.c
===================================================================
--- sys/vm/device_pager.c
+++ sys/vm/device_pager.c
@@ -236,7 +236,6 @@
KASSERT((m->oflags & VPO_UNMANAGED) == 0, ("unmanaged %p", m));
pmap_remove_all(m);
(void)vm_page_remove(m);
- vm_page_xunbusy(m);
} else if (object->type == OBJT_DEVICE)
dev_pager_free_page(object, m);
}
@@ -271,8 +270,12 @@
* Free up our fake pages.
*/
while ((m = TAILQ_FIRST(&object->un_pager.devp.devp_pglist))
- != NULL)
+ != NULL) {
+ if (vm_page_busy_acquire(m, VM_ALLOC_WAITFAIL) == 0)
+ continue;
+
dev_pager_free_page(object, m);
+ }
}
object->handle = NULL;
object->type = OBJT_DEAD;
@@ -391,8 +394,7 @@
*/
page = vm_page_getfake(paddr, memattr);
VM_OBJECT_WLOCK(object);
- vm_page_replace_checked(page, object, (*mres)->pindex, *mres);
- vm_page_free(*mres);
+ vm_page_replace(page, object, (*mres)->pindex, *mres);
*mres = page;
}
vm_page_valid(page);
Index: sys/vm/sg_pager.c
===================================================================
--- sys/vm/sg_pager.c
+++ sys/vm/sg_pager.c
@@ -129,6 +129,8 @@
* Free up our fake pages.
*/
while ((m = TAILQ_FIRST(&object->un_pager.sgp.sgp_pglist)) != 0) {
+ if (vm_page_busy_acquire(m, VM_ALLOC_WAITFAIL) == 0)
+ continue;
TAILQ_REMOVE(&object->un_pager.sgp.sgp_pglist, m, plinks.q);
vm_page_putfake(m);
}
@@ -193,10 +195,7 @@
page = vm_page_getfake(paddr, memattr);
VM_OBJECT_WLOCK(object);
TAILQ_INSERT_TAIL(&object->un_pager.sgp.sgp_pglist, page, plinks.q);
- vm_page_replace_checked(page, object, offset, m[0]);
- vm_page_lock(m[0]);
- vm_page_free(m[0]);
- vm_page_unlock(m[0]);
+ vm_page_replace(page, object, offset, m[0]);
m[0] = page;
vm_page_valid(page);
Index: sys/vm/vm_fault.c
===================================================================
--- sys/vm/vm_fault.c
+++ sys/vm/vm_fault.c
@@ -180,8 +180,6 @@
VM_OBJECT_ASSERT_WLOCKED(m->object);
if (!vm_page_wired(m))
vm_page_free(m);
- else
- vm_page_xunbusy(m);
*mp = NULL;
}
}
@@ -1228,10 +1226,14 @@
*/
fs.object == fs.first_object->backing_object) {
- (void)vm_page_remove(fs.m);
- vm_page_replace_checked(fs.m, fs.first_object,
+ /*
+ * Remove but keep xbusy for replace. fs.m is
+ * moved into fs.first_object and left busy
+ * while fs.first_m is conditionally freed.
+ */
+ vm_page_remove_xbusy(fs.m);
+ vm_page_replace(fs.m, fs.first_object,
fs.first_pindex, fs.first_m);
- vm_page_free(fs.first_m);
vm_page_dirty(fs.m);
#if VM_NRESERVLEVEL > 0
/*
Index: sys/vm/vm_kern.c
===================================================================
--- sys/vm/vm_kern.c
+++ sys/vm/vm_kern.c
@@ -586,6 +586,7 @@
#endif
for (; offset < end; offset += PAGE_SIZE, m = next) {
next = vm_page_next(m);
+ vm_page_busy_acquire(m, 0);
vm_page_unwire_noq(m);
vm_page_free(m);
}
Index: sys/vm/vm_object.c
===================================================================
--- sys/vm/vm_object.c
+++ sys/vm/vm_object.c
@@ -1484,8 +1484,6 @@
if (vm_page_none_valid(m)) {
if (vm_page_remove(m))
vm_page_free(m);
- else
- vm_page_xunbusy(m);
continue;
}
@@ -1675,8 +1673,6 @@
("freeing mapped page %p", p));
if (vm_page_remove(p))
vm_page_free(p);
- else
- vm_page_xunbusy(p);
continue;
}
@@ -1708,8 +1704,6 @@
*/
if (vm_page_remove(pp))
vm_page_free(pp);
- else
- vm_page_xunbusy(pp);
pp = NULL;
}
@@ -1728,8 +1722,6 @@
("freeing mapped page %p", p));
if (vm_page_remove(p))
vm_page_free(p);
- else
- vm_page_xunbusy(p);
if (pp != NULL)
vm_page_xunbusy(pp);
continue;
Index: sys/vm/vm_page.h
===================================================================
--- sys/vm/vm_page.h
+++ sys/vm/vm_page.h
@@ -622,7 +622,6 @@
void vm_page_dequeue(vm_page_t m);
void vm_page_dequeue_deferred(vm_page_t m);
vm_page_t vm_page_find_least(vm_object_t, vm_pindex_t);
-bool vm_page_free_prep(vm_page_t m);
vm_page_t vm_page_getfake(vm_paddr_t paddr, vm_memattr_t memattr);
void vm_page_initfake(vm_page_t m, vm_paddr_t paddr, vm_memattr_t memattr);
int vm_page_insert (vm_page_t, vm_object_t, vm_pindex_t);
@@ -646,9 +645,10 @@
void vm_page_release(vm_page_t m, int flags);
void vm_page_release_locked(vm_page_t m, int flags);
bool vm_page_remove(vm_page_t);
+bool vm_page_remove_xbusy(vm_page_t);
int vm_page_rename(vm_page_t, vm_object_t, vm_pindex_t);
-vm_page_t vm_page_replace(vm_page_t mnew, vm_object_t object,
- vm_pindex_t pindex);
+void vm_page_replace(vm_page_t mnew, vm_object_t object,
+ vm_pindex_t pindex, vm_page_t mold);
void vm_page_requeue(vm_page_t m);
int vm_page_sbusied(vm_page_t m);
vm_page_t vm_page_scan_contig(u_long npages, vm_page_t m_start,
@@ -681,7 +681,6 @@
void vm_page_test_dirty(vm_page_t);
vm_page_bits_t vm_page_bits(int base, int size);
void vm_page_zero_invalid(vm_page_t m, boolean_t setvalid);
-void vm_page_free_toq(vm_page_t m);
void vm_page_free_pages_toq(struct spglist *free, bool update_wire_count);
void vm_page_dirty_KBI(vm_page_t m);
@@ -902,21 +901,6 @@
m->dirty = 0;
}
-static inline void
-vm_page_replace_checked(vm_page_t mnew, vm_object_t object, vm_pindex_t pindex,
- vm_page_t mold)
-{
- vm_page_t mret;
-
- mret = vm_page_replace(mnew, object, pindex);
- KASSERT(mret == mold,
- ("invalid page replacement, mold=%p, mret=%p", mold, mret));
-
- /* Unused if !INVARIANTS. */
- (void)mold;
- (void)mret;
-}
-
/*
* vm_page_queue:
*
Index: sys/vm/vm_page.c
===================================================================
--- sys/vm/vm_page.c
+++ sys/vm/vm_page.c
@@ -181,6 +181,8 @@
static void vm_page_clear_dirty_mask(vm_page_t m, vm_page_bits_t pagebits);
static void vm_page_dequeue_complete(vm_page_t m);
static void vm_page_enqueue(vm_page_t m, uint8_t queue);
+static bool vm_page_free_prep(vm_page_t m);
+static void vm_page_free_toq(vm_page_t m);
static void vm_page_init(void *dummy);
static int vm_page_insert_after(vm_page_t m, vm_object_t object,
vm_pindex_t pindex, vm_page_t mpred);
@@ -1290,8 +1292,7 @@
KASSERT((m->oflags & VPO_UNMANAGED) != 0, ("managed %p", m));
KASSERT((m->flags & PG_FICTITIOUS) != 0,
("vm_page_putfake: bad page %p", m));
- if (vm_page_xbusied(m))
- vm_page_xunbusy(m);
+ vm_page_xunbusy(m);
uma_zfree(fakepg_zone, m);
}
@@ -1579,6 +1580,7 @@
vm_object_t object;
vm_page_t mrem;
+ vm_page_assert_xbusied(m);
object = m->object;
VM_OBJECT_ASSERT_WLOCKED(object);
KASSERT((m->ref_count & VPRC_OBJREF) != 0,
@@ -1615,10 +1617,30 @@
* invalidate any backing storage. Returns true if the object's reference
* was the last reference to the page, and false otherwise.
*
- * The object must be locked.
+ * The object must be locked and the page must be exclusively busied.
+ * The exclusive busy will be released on return. If this is not the
+ * final ref and the caller does not hold a wire reference it may not
+ * continue to access the page.
*/
bool
vm_page_remove(vm_page_t m)
+{
+ bool dropped;
+
+ dropped = vm_page_remove_xbusy(m);
+ vm_page_xunbusy(m);
+
+ return (dropped);
+}
+
+/*
+ * vm_page_remove_xbusy
+ *
+ * Removes the page but leaves the xbusy held. Returns true if this
+ * removed the final ref and false otherwise.
+ */
+bool
+vm_page_remove_xbusy(vm_page_t m)
{
vm_page_object_remove(m);
@@ -1704,13 +1726,24 @@
/*
* Uses the page mnew as a replacement for an existing page at index
* pindex which must be already present in the object.
+ *
+ * Both pages must be exclusively busied on enter. The old page is
+ * unbusied on exit.
+ *
+ * A return value of true means mold is now free. Callers should not
+ * longer access mold if the return value is false unless they hold
+ * a wire ref.
*/
-vm_page_t
-vm_page_replace(vm_page_t mnew, vm_object_t object, vm_pindex_t pindex)
+static bool
+vm_page_replace_hold(vm_page_t mnew, vm_object_t object, vm_pindex_t pindex,
+ vm_page_t mold)
{
- vm_page_t mold;
+ vm_page_t mret;
+ bool dropped;
VM_OBJECT_ASSERT_WLOCKED(object);
+ vm_page_assert_xbusied(mnew);
+ vm_page_assert_xbusied(mold);
KASSERT(mnew->object == NULL && (mnew->ref_count & VPRC_OBJREF) == 0,
("vm_page_replace: page %p already in object", mnew));
@@ -1723,15 +1756,14 @@
mnew->object = object;
mnew->pindex = pindex;
atomic_set_int(&mnew->ref_count, VPRC_OBJREF);
- mold = vm_radix_replace(&object->rtree, mnew);
+ mret = vm_radix_replace(&object->rtree, mnew);
+ KASSERT(mret == mold,
+ ("invalid page replacement, mold=%p, mret=%p", mold, mret));
/* Keep the resident page list in sorted order. */
TAILQ_INSERT_AFTER(&object->memq, mold, mnew, listq);
TAILQ_REMOVE(&object->memq, mold, listq);
-
mold->object = NULL;
- atomic_clear_int(&mold->ref_count, VPRC_OBJREF);
- vm_page_xunbusy(mold);
/*
* The object's resident_page_count does not change because we have
@@ -1740,7 +1772,19 @@
*/
if (pmap_page_is_write_mapped(mnew))
vm_object_set_writeable_dirty(object);
- return (mold);
+ dropped = vm_page_drop(mold, VPRC_OBJREF) == VPRC_OBJREF;
+ vm_page_xunbusy(mold);
+
+ return (dropped);
+}
+
+void
+vm_page_replace(vm_page_t mnew, vm_object_t object, vm_pindex_t pindex,
+ vm_page_t mold)
+{
+
+ if (vm_page_replace_hold(mnew, object, pindex, mold))
+ vm_page_free(mold);
}
/*
@@ -2758,9 +2802,9 @@
m_new->dirty = m->dirty;
m->flags &= ~PG_ZERO;
vm_page_dequeue(m);
- vm_page_replace_checked(m_new, object,
- m->pindex, m);
- if (vm_page_free_prep(m))
+ if (vm_page_replace_hold(m_new, object,
+ m->pindex, m) &&
+ vm_page_free_prep(m))
SLIST_INSERT_HEAD(&free, m,
plinks.s.ss);
@@ -3641,7 +3685,7 @@
* The object must be locked. The page must be locked if it is
* managed.
*/
-bool
+static bool
vm_page_free_prep(vm_page_t m)
{
@@ -3651,6 +3695,9 @@
*/
atomic_thread_fence_acq();
+ if (vm_page_sbusied(m))
+ panic("vm_page_free_prep: freeing shared busy page %p", m);
+
#if defined(DIAGNOSTIC) && defined(PHYS_TO_DMAP)
if (PMAP_HAS_DMAP && (m->flags & PG_ZERO) != 0) {
uint64_t *p;
@@ -3672,9 +3719,6 @@
}
VM_CNT_INC(v_tfree);
- if (vm_page_sbusied(m))
- panic("vm_page_free_prep: freeing shared busy page %p", m);
-
if (m->object != NULL) {
vm_page_object_remove(m);
@@ -3688,10 +3732,11 @@
m, m->ref_count));
m->object = NULL;
m->ref_count -= VPRC_OBJREF;
+ vm_page_xunbusy(m);
}
if (vm_page_xbusied(m))
- vm_page_xunbusy(m);
+ panic("vm_page_free_prep: freeing exclusive busy page %p", m);
/*
* If fictitious remove object association and
@@ -3747,7 +3792,7 @@
* The object must be locked. The page must be locked if it is
* managed.
*/
-void
+static void
vm_page_free_toq(vm_page_t m)
{
struct vm_domain *vmd;
@@ -3884,6 +3929,7 @@
do {
KASSERT(VPRC_WIRE_COUNT(old) > 0,
("vm_page_unwire: wire count underflow for page %p", m));
+ /* XXX && old != 1, why re-insert free page */
if (!locked && VPRC_WIRE_COUNT(old) == 1) {
vm_page_lock(m);
locked = true;
@@ -4092,19 +4138,15 @@
if (object == NULL)
break;
/* Depends on type-stability. */
- if (vm_page_busied(m) || !VM_OBJECT_TRYWLOCK(object)) {
- object = NULL;
+ if (vm_page_busied(m) || !VM_OBJECT_TRYWLOCK(object))
break;
+ if (object == m->object) {
+ vm_page_release_locked(m, flags);
+ VM_OBJECT_WUNLOCK(object);
+ return;
}
- if (object == m->object)
- break;
VM_OBJECT_WUNLOCK(object);
}
- if (__predict_true(object != NULL)) {
- vm_page_release_locked(m, flags);
- VM_OBJECT_WUNLOCK(object);
- return;
- }
}
/*
@@ -4117,6 +4159,7 @@
do {
KASSERT(VPRC_WIRE_COUNT(old) > 0,
("vm_page_unwire: wire count underflow for page %p", m));
+ /* XXX && old != 1, why re-insert free page */
if (!locked && VPRC_WIRE_COUNT(old) == 1) {
vm_page_lock(m);
locked = true;
@@ -4151,7 +4194,7 @@
if (vm_page_unwire_noq(m)) {
if ((flags & VPR_TRYFREE) != 0 &&
(m->object->ref_count == 0 || !pmap_page_is_mapped(m)) &&
- m->dirty == 0 && !vm_page_busied(m)) {
+ m->dirty == 0 && vm_page_tryxbusy(m)) {
vm_page_free(m);
} else {
vm_page_lock(m);

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