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Index: sys/vm/vm_page.h
===================================================================
--- sys/vm/vm_page.h
+++ sys/vm/vm_page.h
@@ -613,11 +613,16 @@
void vm_page_bits_set(vm_page_t m, vm_page_bits_t *bits, vm_page_bits_t set);
bool vm_page_blacklist_add(vm_paddr_t pa, bool verbose);
void vm_page_change_lock(vm_page_t m, struct mtx **mtx);
-vm_page_t vm_page_grab (vm_object_t, vm_pindex_t, int);
+vm_page_t vm_page_grab(vm_object_t, vm_pindex_t, int);
+vm_page_t vm_page_grab_unlocked(vm_object_t, vm_pindex_t, int);
int vm_page_grab_pages(vm_object_t object, vm_pindex_t pindex, int allocflags,
vm_page_t *ma, int count);
+int vm_page_grab_pages_unlocked(vm_object_t object, vm_pindex_t pindex,
+ int allocflags, vm_page_t *ma, int count);
int vm_page_grab_valid(vm_page_t *mp, vm_object_t object, vm_pindex_t pindex,
int allocflags);
+int vm_page_grab_valid_unlocked(vm_page_t *mp, vm_object_t object,
+ vm_pindex_t pindex, int allocflags);
void vm_page_deactivate(vm_page_t);
void vm_page_deactivate_noreuse(vm_page_t);
void vm_page_dequeue(vm_page_t m);
@@ -628,8 +633,10 @@
int vm_page_insert (vm_page_t, vm_object_t, vm_pindex_t);
void vm_page_invalid(vm_page_t m);
void vm_page_launder(vm_page_t m);
-vm_page_t vm_page_lookup (vm_object_t, vm_pindex_t);
+vm_page_t vm_page_lookup(vm_object_t, vm_pindex_t);
+vm_page_t vm_page_lookup_unlocked(vm_object_t, vm_pindex_t, int allocflags);
vm_page_t vm_page_next(vm_page_t m);
+vm_page_t vm_page_next_unlocked(vm_page_t m, int allocflags);
void vm_page_pqbatch_drain(void);
void vm_page_pqbatch_submit(vm_page_t m, uint8_t queue);
bool vm_page_pqstate_commit(vm_page_t m, vm_page_astate_t *old,
Index: sys/vm/vm_page.c
===================================================================
--- sys/vm/vm_page.c
+++ sys/vm/vm_page.c
@@ -830,19 +830,38 @@
}
static bool
-vm_page_acquire_flags(vm_page_t m, int allocflags)
+vm_page_trybusy_flags(vm_page_t m, int allocflags)
{
- bool locked;
if ((allocflags & (VM_ALLOC_SBUSY | VM_ALLOC_IGN_SBUSY)) != 0)
- locked = vm_page_trysbusy(m);
+ return (vm_page_trysbusy(m));
else
- locked = vm_page_tryxbusy(m);
+ return (vm_page_tryxbusy(m));
+}
+
+static inline bool
+vm_page_acquire_flags(vm_page_t m, int allocflags)
+{
+ bool locked;
+
+ locked = vm_page_trybusy_flags(m, allocflags);
if (locked && (allocflags & VM_ALLOC_WIRED) != 0)
vm_page_wire(m);
return (locked);
}
+static inline void
+vm_page_busy_return(vm_page_t m, int allocflags)
+{
+
+ if ((allocflags & VM_ALLOC_NOBUSY) != 0) {
+ if ((allocflags & VM_ALLOC_IGN_SBUSY) != 0)
+ vm_page_sunbusy(m);
+ else
+ vm_page_xunbusy(m);
+ }
+}
+
/*
* vm_page_busy_sleep_flags
*
@@ -1650,6 +1669,59 @@
return (vm_radix_lookup(&object->rtree, pindex));
}
+/*
+ * This should only be used by lockless functions for releasing short term
+ * incorrect acquires. The page may have been freed after we acquired a
+ * busy lock. In this case busy_lock == VPB_FREED and we have nothing
+ * further to do.
+ */
+static void
+vm_page_busy_release(vm_page_t m)
+{
+ u_int x;
+
+ x = m->busy_lock;
+ for (;;) {
+ if (x == VPB_FREED)
+ break;
+ if ((x & VPB_BIT_SHARED) != 0 && VPB_SHARERS(x) > 1) {
+ if (atomic_fcmpset_int(&m->busy_lock, &x,
+ x - VPB_ONE_SHARER))
+ break;
+ continue;
+ }
+ if (!atomic_fcmpset_rel_int(&m->busy_lock, &x, VPB_UNBUSIED))
+ continue;
+ if ((x & VPB_BIT_WAITERS) != 0)
+ wakeup(m);
+ break;
+ }
+}
+
+vm_page_t
+vm_page_lookup_unlocked(vm_object_t object, vm_pindex_t pindex, int allocflags)
+{
+ vm_page_t m;
+
+ for (;;) {
+ m = vm_radix_lookup_unlocked(&object->rtree, pindex);
+ if (m == NULL)
+ break;
+ if (!vm_page_trybusy_flags(m, allocflags)) {
+ m = NULL;
+ break;
+ }
+ if (m->object == object && m->pindex == pindex) {
+ if ((allocflags & VM_ALLOC_WIRED) != 0)
+ vm_page_wire(m);
+ vm_page_busy_return(m, allocflags);
+ return (m);
+ }
+ vm_page_busy_release(m);
+ }
+ return (NULL);
+}
+
/*
* vm_page_find_least:
*
@@ -1689,6 +1761,35 @@
return (next);
}
+vm_page_t
+vm_page_next_unlocked(vm_page_t m, int allocflags)
+{
+ vm_object_t object;
+ vm_page_t next;
+ vm_pindex_t pindex;
+
+ MPASS(vm_page_busied(m) || vm_page_wired(m));
+
+ object = m->object;
+ pindex = m->pindex + 1;
+ for (;;) {
+ next = TAILQ_NEXT(m, listq);
+ if (next == NULL || next->pindex != pindex)
+ break;
+ if (!vm_page_trybusy_flags(next, allocflags))
+ break;
+ if (next->object == object && next->pindex == pindex) {
+ if ((allocflags & VM_ALLOC_WIRED) != 0)
+ vm_page_wire(next);
+ vm_page_busy_return(next, allocflags);
+ return (next);
+ }
+ vm_page_busy_release(next);
+ cpu_spinwait();
+ }
+ return (NULL);
+}
+
/*
* Returns the given page's predecessor (by pindex) within the object if it is
* resident; if none is found, NULL is returned.
@@ -4313,12 +4414,23 @@
pmap_zero_page(m);
out:
- if ((allocflags & VM_ALLOC_NOBUSY) != 0) {
- if ((allocflags & VM_ALLOC_IGN_SBUSY) != 0)
- vm_page_sunbusy(m);
- else
- vm_page_xunbusy(m);
- }
+ vm_page_busy_return(m, allocflags);
+
+ return (m);
+}
+
+vm_page_t
+vm_page_grab_unlocked(vm_object_t object, vm_pindex_t pindex, int allocflags)
+{
+ vm_page_t m;
+
+ m = vm_page_lookup_unlocked(object, pindex, allocflags);
+ if (m != NULL)
+ return (m);
+ VM_OBJECT_WLOCK(object);
+ m = vm_page_grab(object, pindex, allocflags);
+ VM_OBJECT_WUNLOCK(object);
+
return (m);
}
@@ -4334,7 +4446,6 @@
{
vm_page_t m;
vm_page_t ma[VM_INITIAL_PAGEIN];
- bool sleep, xbusy;
int after, i, pflags, rv;
KASSERT((allocflags & VM_ALLOC_SBUSY) == 0 ||
@@ -4348,7 +4459,6 @@
pflags |= VM_ALLOC_WAITFAIL;
retrylookup:
- xbusy = false;
if ((m = vm_page_lookup(object, pindex)) != NULL) {
/*
* If the page is fully valid it can only become invalid
@@ -4359,41 +4469,27 @@
* However, we will not end up with an invalid page and a
* shared lock.
*/
- if (!vm_page_all_valid(m) ||
- (allocflags & (VM_ALLOC_IGN_SBUSY | VM_ALLOC_SBUSY)) == 0) {
- sleep = !vm_page_tryxbusy(m);
- xbusy = true;
- } else
- sleep = !vm_page_trysbusy(m);
- if (sleep) {
+ if (!vm_page_trybusy_flags(m,
+ vm_page_all_valid(m) ? allocflags : 0)) {
(void)vm_page_busy_sleep_flags(object, m, "pgrbwt",
allocflags);
goto retrylookup;
}
- if ((allocflags & VM_ALLOC_NOCREAT) != 0 &&
- !vm_page_all_valid(m)) {
- if (xbusy)
- vm_page_xunbusy(m);
- else
- vm_page_sunbusy(m);
+ if (vm_page_all_valid(m))
+ goto out;
+ if ((allocflags & VM_ALLOC_NOCREAT) != 0) {
+ vm_page_busy_release(m);
*mp = NULL;
return (VM_PAGER_FAIL);
}
- if ((allocflags & VM_ALLOC_WIRED) != 0)
- vm_page_wire(m);
- if (vm_page_all_valid(m))
- goto out;
} else if ((allocflags & VM_ALLOC_NOCREAT) != 0) {
*mp = NULL;
return (VM_PAGER_FAIL);
- } else if ((m = vm_page_alloc(object, pindex, pflags)) != NULL) {
- xbusy = true;
- } else {
+ } else if ((m = vm_page_alloc(object, pindex, pflags)) == NULL) {
goto retrylookup;
}
vm_page_assert_xbusied(m);
- MPASS(xbusy);
if (vm_pager_has_page(object, pindex, NULL, &after)) {
after = MIN(after, VM_INITIAL_PAGEIN);
after = MIN(after, allocflags >> VM_ALLOC_COUNT_SHIFT);
@@ -4419,8 +4515,6 @@
/* Pager may have replaced a page. */
m = ma[0];
if (rv != VM_PAGER_OK) {
- if ((allocflags & VM_ALLOC_WIRED) != 0)
- vm_page_unwire_noq(m);
for (i = 0; i < after; i++) {
if (!vm_page_wired(ma[i]))
vm_page_free(ma[i]);
@@ -4437,18 +4531,50 @@
vm_page_zero_invalid(m, TRUE);
}
out:
- if ((allocflags & VM_ALLOC_NOBUSY) != 0) {
- if (xbusy)
- vm_page_xunbusy(m);
- else
- vm_page_sunbusy(m);
- }
- if ((allocflags & VM_ALLOC_SBUSY) != 0 && xbusy)
+ if ((allocflags & VM_ALLOC_WIRED) != 0)
+ vm_page_wire(m);
+ if ((allocflags & VM_ALLOC_SBUSY) != 0 && vm_page_xbusied(m))
vm_page_busy_downgrade(m);
+ else if ((allocflags & VM_ALLOC_NOBUSY) != 0)
+ vm_page_busy_release(m);
*mp = m;
return (VM_PAGER_OK);
}
+int
+vm_page_grab_valid_unlocked(vm_page_t *mp, vm_object_t object,
+ vm_pindex_t pindex, int allocflags)
+{
+ vm_page_t m;
+ int flags;
+ int error;
+
+ /*
+ * Attempt a lockless lookup and busy. We need at least an sbusy
+ * before we can inspect the valid field and return a wired page.
+ */
+ if (allocflags & (VM_ALLOC_NOBUSY | VM_ALLOC_SBUSY))
+ flags = VM_ALLOC_SBUSY;
+ else
+ flags = 0;
+ m = vm_page_lookup_unlocked(object, pindex, flags);
+ if (m != NULL) {
+ if (vm_page_all_valid(m)) {
+ if ((allocflags & VM_ALLOC_WIRED) != 0)
+ vm_page_wire(m);
+ if ((allocflags & VM_ALLOC_NOBUSY) != 0)
+ vm_page_sunbusy(m);
+ *mp = m;
+ return (VM_PAGER_OK);
+ }
+ vm_page_busy_release(m);
+ }
+ VM_OBJECT_WLOCK(object);
+ error = vm_page_grab_valid(mp, object, pindex, allocflags);
+ VM_OBJECT_WUNLOCK(object);
+ return (error);
+}
+
/*
* Return the specified range of pages from the given object. For each
* page offset within the range, if a page already exists within the object
@@ -4524,18 +4650,54 @@
pmap_zero_page(m);
vm_page_valid(m);
}
- if ((allocflags & VM_ALLOC_NOBUSY) != 0) {
- if ((allocflags & VM_ALLOC_IGN_SBUSY) != 0)
- vm_page_sunbusy(m);
- else
- vm_page_xunbusy(m);
- }
+ vm_page_busy_return(m, allocflags);
ma[i] = mpred = m;
m = vm_page_next(m);
}
return (i);
}
+int
+vm_page_grab_pages_unlocked(vm_object_t object, vm_pindex_t pindex,
+ int allocflags, vm_page_t *ma, int count)
+{
+ vm_page_t m;
+ int flags;
+ int i;
+
+ i = 0;
+ flags = allocflags;
+ if ((allocflags & VM_ALLOC_NOBUSY) != 0) {
+ flags &= ~VM_ALLOC_NOBUSY;
+ if ((flags & VM_ALLOC_IGN_SBUSY) != 0)
+ flags |= VM_ALLOC_SBUSY;
+ }
+ m = vm_page_lookup_unlocked(object, pindex, flags);
+ while (m != NULL) {
+ if (vm_page_none_valid(m) &&
+ (allocflags & VM_ALLOC_ZERO) != 0) {
+ if ((m->flags & PG_ZERO) == 0)
+ pmap_zero_page(m);
+ vm_page_valid(m);
+ }
+ /* m will still be wired or busy according to flags. */
+ ma[i] = m;
+ vm_page_busy_return(m, allocflags);
+ if (++i == count)
+ break;
+ m = vm_page_next_unlocked(m, flags);
+ }
+ if (i < count) {
+ count -= i;
+ pindex += i;
+ VM_OBJECT_WLOCK(object);
+ i += vm_page_grab_pages(object, pindex, allocflags, &ma[i],
+ count);
+ VM_OBJECT_WUNLOCK(object);
+ }
+ return (i);
+}
+
/*
* Mapping function for valid or dirty bits in a page.
*

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