vm_radix: offer pctrie_iterator access

Add to the vm_radix and vm_page interfaces methods to use pctrie
iterators with vm_radix tries.

Reviewed by:	markj
Differential Revision:	https://reviews.freebsd.org/D46663

sys/vm/vm_page.c

@@ -1706,6 +1706,48 @@ vm_page_lookup(vm_object_t object, vm_pindex_t pindex)
 	return (vm_radix_lookup(&object->rtree, pindex));
 }
 
+/*
+ *	vm_page_iter_init:
+ *
+ *	Initialize iterator for vm pages.
+ */
+void
+vm_page_iter_init(struct pctrie_iter *pages, vm_object_t object)
+{
+
+	VM_OBJECT_ASSERT_LOCKED(object);
+	vm_radix_iter_init(pages, &object->rtree);
+}
+
+/*
+ *	vm_page_iter_init:
+ *
+ *	Initialize iterator for vm pages.
+ */
+void
+vm_page_iter_limit_init(struct pctrie_iter *pages, vm_object_t object,
+    vm_pindex_t limit)
+{
+
+	VM_OBJECT_ASSERT_LOCKED(object);
+	vm_radix_iter_limit_init(pages, &object->rtree, limit);
+}
+
+/*
+ *	vm_page_iter_lookup:
+ *
+ *	Returns the page associated with the object/offset pair specified, and
+ *	stores the path to its position; if none is found, NULL is returned.
+ *
+ *	The iter pctrie must be locked.
+ */
+vm_page_t
+vm_page_iter_lookup(struct pctrie_iter *pages, vm_pindex_t pindex)
+{
+
+	return (vm_radix_iter_lookup(pages, pindex));
+}
+
 /*
  *	vm_page_lookup_unlocked:
  *
@@ -1790,6 +1832,22 @@ vm_page_find_least(vm_object_t object, vm_pindex_t pindex)
 	return (m);
 }
 
+/*
+ *	vm_page_iter_lookup_ge:
+ *
+ *	Returns the page associated with the object with least pindex
+ *	greater than or equal to the parameter pindex, or NULL.  Initializes the
+ *	iterator to point to that page.
+ *
+ *	The iter pctrie must be locked.
+ */
+vm_page_t
+vm_page_iter_lookup_ge(struct pctrie_iter *pages, vm_pindex_t pindex)
+{
+
+	return (vm_radix_iter_lookup_ge(pages, pindex));
+}
+
 /*
  * Returns the given page's successor (by pindex) within the object if it is
  * resident; if none is found, NULL is returned.

sys/vm/vm_page.h

@@ -471,6 +471,7 @@ extern struct mtx_padalign pa_lock[];
 
 #include <sys/kassert.h>
 #include <machine/atomic.h>
+struct pctrie_iter;
 
 /*
  * Each pageable resident page falls into one of five lists:
@@ -642,6 +643,7 @@ void vm_page_deactivate_noreuse(vm_page_t);
 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);
+vm_page_t vm_page_iter_lookup_ge(struct pctrie_iter *, vm_pindex_t);
 void vm_page_free_invalid(vm_page_t);
 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);
@@ -651,6 +653,9 @@ 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);
+void vm_page_iter_init(struct pctrie_iter *, vm_object_t);
+void vm_page_iter_limit_init(struct pctrie_iter *, vm_object_t, vm_pindex_t);
+vm_page_t vm_page_iter_lookup(struct pctrie_iter *, vm_pindex_t);
 vm_page_t vm_page_lookup_unlocked(vm_object_t, vm_pindex_t);
 vm_page_t vm_page_next(vm_page_t m);
 void vm_page_pqbatch_drain(void);

sys/vm/vm_radix.h

@@ -56,8 +56,8 @@ vm_radix_is_empty(struct vm_radix *rtree)
 	return (pctrie_is_empty(&rtree->rt_trie));
 }
 
-PCTRIE_DEFINE_SMR(VM_RADIX, vm_page, pindex, vm_radix_node_alloc, vm_radix_node_free,
-    vm_radix_smr);
+PCTRIE_DEFINE_SMR(VM_RADIX, vm_page, pindex, vm_radix_node_alloc,
+    vm_radix_node_free, vm_radix_smr);
 
 /*
  * Inserts the key-value pair into the trie.
@@ -111,6 +111,49 @@ vm_radix_lookup_unlocked(struct vm_radix *rtree, vm_pindex_t index)
 	return (VM_RADIX_PCTRIE_LOOKUP_UNLOCKED(&rtree->rt_trie, index));
 }
 
+/*
+ * Initialize an iterator for vm_radix.
+ */
+static __inline void
+vm_radix_iter_init(struct pctrie_iter *pages, struct vm_radix *rtree)
+{
+	pctrie_iter_init(pages, &rtree->rt_trie);
+}
+
+/*
+ * Initialize an iterator for vm_radix.
+ */
+static __inline void
+vm_radix_iter_limit_init(struct pctrie_iter *pages, struct vm_radix *rtree,
+    vm_pindex_t limit)
+{
+	pctrie_iter_limit_init(pages, &rtree->rt_trie, limit);
+}
+
+/*
+ * Returns the value stored at the index.
+ * Requires that access be externally synchronized by a lock.
+ *
+ * If the index is not present, NULL is returned.
+ */
+static __inline vm_page_t
+vm_radix_iter_lookup(struct pctrie_iter *pages, vm_pindex_t index)
+{
+	return (VM_RADIX_PCTRIE_ITER_LOOKUP(pages, index));
+}
+
+/*
+ * Returns the value stored 'stride' steps beyond the current position.
+ * Requires that access be externally synchronized by a lock.
+ *
+ * If the index is not present, NULL is returned.
+ */
+static __inline vm_page_t
+vm_radix_iter_stride(struct pctrie_iter *pages, int stride)
+{
+	return (VM_RADIX_PCTRIE_ITER_STRIDE(pages, stride));
+}
+
 /*
  * Returns the page with the least pindex that is greater than or equal to the
  * specified pindex, or NULL if there are no such pages.
@@ -146,7 +189,7 @@ vm_radix_remove(struct vm_radix *rtree, vm_pindex_t index)
 }
 
 /*
- * Remove and free all the nodes from the radix tree.
+ * Reclaim all the interior nodes from the radix tree.
  */
 static __inline void
 vm_radix_reclaim_allnodes(struct vm_radix *rtree)
@@ -154,6 +197,80 @@ vm_radix_reclaim_allnodes(struct vm_radix *rtree)
 	VM_RADIX_PCTRIE_RECLAIM(&rtree->rt_trie);
 }
 
+/*
+ * Initialize an iterator pointing to the page with the least pindex that is
+ * greater than or equal to the specified pindex, or NULL if there are no such
+ * pages.  Return the page.
+ *
+ * Requires that access be externally synchronized by a lock.
+ */
+static __inline vm_page_t
+vm_radix_iter_lookup_ge(struct pctrie_iter *pages, vm_pindex_t index)
+{
+	return (VM_RADIX_PCTRIE_ITER_LOOKUP_GE(pages, index));
+}
+
+/*
+ * Update the iterator to point to the page with the least pindex that is 'jump'
+ * or more greater than or equal to the current pindex, or NULL if there are no
+ * such pages.  Return the page.
+ *
+ * Requires that access be externally synchronized by a lock.
+ */
+static __inline vm_page_t
+vm_radix_iter_jump(struct pctrie_iter *pages, vm_pindex_t jump)
+{
+	return (VM_RADIX_PCTRIE_ITER_JUMP_GE(pages, jump));
+}
+
+/*
+ * Update the iterator to point to the page with the least pindex that is one or
+ * more greater than the current pindex, or NULL if there are no such pages.
+ * Return the page.
+ *
+ * Requires that access be externally synchronized by a lock.
+ */
+static __inline vm_page_t
+vm_radix_iter_step(struct pctrie_iter *pages)
+{
+	return (VM_RADIX_PCTRIE_ITER_STEP_GE(pages));
+}
+
+/*
+ * Update the iterator to point to the page with the pindex that is one greater
+ * than the current pindex, or NULL if there is no such page.  Return the page.
+ *
+ * Requires that access be externally synchronized by a lock.
+ */
+static __inline vm_page_t
+vm_radix_iter_next(struct pctrie_iter *pages)
+{
+	return (VM_RADIX_PCTRIE_ITER_NEXT(pages));
+}
+
+/*
+ * Update the iterator to point to the page with the pindex that is one less
+ * than the current pindex, or NULL if there is no such page.  Return the page.
+ *
+ * Requires that access be externally synchronized by a lock.
+ */
+static __inline vm_page_t
+vm_radix_iter_prev(struct pctrie_iter *pages)
+{
+	return (VM_RADIX_PCTRIE_ITER_PREV(pages));
+}
+
+/*
+ * Return the current page.
+ *
+ * Requires that access be externally synchronized by a lock.
+ */
+static __inline vm_page_t
+vm_radix_iter_page(struct pctrie_iter *pages)
+{
+	return (VM_RADIX_PCTRIE_ITER_VALUE(pages));
+}
+
 /*
  * Replace an existing page in the trie with another one.
  * Panics if there is not an old page in the trie at the new page's index.