diff options
Diffstat (limited to 'lib')
| -rw-r--r-- | lib/radix-tree.c | 106 |
1 files changed, 31 insertions, 75 deletions
diff --git a/lib/radix-tree.c b/lib/radix-tree.c index 75c9e6197b5b..58f79fee8c71 100644 --- a/lib/radix-tree.c +++ b/lib/radix-tree.c @@ -39,12 +39,6 @@ /* - * The height_to_maxindex array needs to be one deeper than the maximum - * path as height 0 holds only 1 entry. - */ -static unsigned long height_to_maxindex[RADIX_TREE_MAX_PATH + 1] __read_mostly; - -/* * Radix tree node cache. */ static struct kmem_cache *radix_tree_node_cachep; @@ -218,8 +212,7 @@ radix_tree_find_next_bit(const unsigned long *addr, } #ifndef __KERNEL__ -static void dump_node(struct radix_tree_node *node, - unsigned shift, unsigned long index) +static void dump_node(struct radix_tree_node *node, unsigned long index) { unsigned long i; @@ -229,8 +222,8 @@ static void dump_node(struct radix_tree_node *node, node->shift, node->count, node->parent); for (i = 0; i < RADIX_TREE_MAP_SIZE; i++) { - unsigned long first = index | (i << shift); - unsigned long last = first | ((1UL << shift) - 1); + unsigned long first = index | (i << node->shift); + unsigned long last = first | ((1UL << node->shift) - 1); void *entry = node->slots[i]; if (!entry) continue; @@ -243,8 +236,7 @@ static void dump_node(struct radix_tree_node *node, pr_debug("radix entry %p offset %ld indices %ld-%ld\n", entry, i, first, last); } else { - dump_node(indirect_to_ptr(entry), - shift - RADIX_TREE_MAP_SHIFT, first); + dump_node(indirect_to_ptr(entry), first); } } } @@ -252,13 +244,12 @@ static void dump_node(struct radix_tree_node *node, /* For debug */ static void radix_tree_dump(struct radix_tree_root *root) { - pr_debug("radix root: %p height %d rnode %p tags %x\n", - root, root->height, root->rnode, + pr_debug("radix root: %p rnode %p tags %x\n", + root, root->rnode, root->gfp_mask >> __GFP_BITS_SHIFT); if (!radix_tree_is_indirect_ptr(root->rnode)) return; - dump_node(indirect_to_ptr(root->rnode), - (root->height - 1) * RADIX_TREE_MAP_SHIFT, 0); + dump_node(indirect_to_ptr(root->rnode), 0); } #endif @@ -411,14 +402,8 @@ int radix_tree_maybe_preload(gfp_t gfp_mask) EXPORT_SYMBOL(radix_tree_maybe_preload); /* - * Return the maximum key which can be store into a - * radix tree with height HEIGHT. + * The maximum index which can be stored in a radix tree */ -static inline unsigned long radix_tree_maxindex(unsigned int height) -{ - return height_to_maxindex[height]; -} - static inline unsigned long shift_maxindex(unsigned int shift) { return (RADIX_TREE_MAP_SIZE << shift) - 1; @@ -450,24 +435,22 @@ static unsigned radix_tree_load_root(struct radix_tree_root *root, * Extend a radix tree so it can store key @index. */ static int radix_tree_extend(struct radix_tree_root *root, - unsigned long index) + unsigned long index, unsigned int shift) { struct radix_tree_node *slot; - unsigned int height; + unsigned int maxshift; int tag; - /* Figure out what the height should be. */ - height = root->height + 1; - while (index > radix_tree_maxindex(height)) - height++; + /* Figure out what the shift should be. */ + maxshift = shift; + while (index > shift_maxindex(maxshift)) + maxshift += RADIX_TREE_MAP_SHIFT; - if (root->rnode == NULL) { - root->height = height; + slot = root->rnode; + if (!slot) goto out; - } do { - unsigned int newheight; struct radix_tree_node *node = radix_tree_node_alloc(root); if (!node) @@ -479,14 +462,11 @@ static int radix_tree_extend(struct radix_tree_root *root, tag_set(node, tag, 0); } - /* Increase the height. */ - newheight = root->height; - BUG_ON(newheight > BITS_PER_LONG); - node->shift = newheight * RADIX_TREE_MAP_SHIFT; + BUG_ON(shift > BITS_PER_LONG); + node->shift = shift; node->offset = 0; node->count = 1; node->parent = NULL; - slot = root->rnode; if (radix_tree_is_indirect_ptr(slot)) { slot = indirect_to_ptr(slot); slot->parent = node; @@ -495,10 +475,11 @@ static int radix_tree_extend(struct radix_tree_root *root, node->slots[0] = slot; node = ptr_to_indirect(node); rcu_assign_pointer(root->rnode, node); - root->height = ++newheight; - } while (height > root->height); + shift += RADIX_TREE_MAP_SHIFT; + slot = node; + } while (shift <= maxshift); out: - return height * RADIX_TREE_MAP_SHIFT; + return maxshift + RADIX_TREE_MAP_SHIFT; } /** @@ -531,15 +512,13 @@ int __radix_tree_create(struct radix_tree_root *root, unsigned long index, /* Make sure the tree is high enough. */ if (max > maxindex) { - int error = radix_tree_extend(root, max); + int error = radix_tree_extend(root, max, shift); if (error < 0) return error; shift = error; slot = root->rnode; - if (order == shift) { + if (order == shift) shift += RADIX_TREE_MAP_SHIFT; - root->height++; - } } offset = 0; /* uninitialised var warning */ @@ -1412,32 +1391,32 @@ unsigned long radix_tree_locate_item(struct radix_tree_root *root, void *item) #endif /* CONFIG_SHMEM && CONFIG_SWAP */ /** - * radix_tree_shrink - shrink height of a radix tree to minimal + * radix_tree_shrink - shrink radix tree to minimum height * @root radix tree root */ static inline bool radix_tree_shrink(struct radix_tree_root *root) { bool shrunk = false; - /* try to shrink tree height */ - while (root->height > 0) { + for (;;) { struct radix_tree_node *to_free = root->rnode; struct radix_tree_node *slot; - BUG_ON(!radix_tree_is_indirect_ptr(to_free)); + if (!radix_tree_is_indirect_ptr(to_free)) + break; to_free = indirect_to_ptr(to_free); /* * The candidate node has more than one child, or its child - * is not at the leftmost slot, or it is a multiorder entry, - * we cannot shrink. + * is not at the leftmost slot, or the child is a multiorder + * entry, we cannot shrink. */ if (to_free->count != 1) break; slot = to_free->slots[0]; if (!slot) break; - if (!radix_tree_is_indirect_ptr(slot) && (root->height > 1)) + if (!radix_tree_is_indirect_ptr(slot) && to_free->shift) break; if (radix_tree_is_indirect_ptr(slot)) { @@ -1454,7 +1433,6 @@ static inline bool radix_tree_shrink(struct radix_tree_root *root) * one (root->rnode) as far as dependent read barriers go. */ root->rnode = slot; - root->height--; /* * We have a dilemma here. The node's slot[0] must not be @@ -1515,7 +1493,6 @@ bool __radix_tree_delete_node(struct radix_tree_root *root, parent->count--; } else { root_tag_clear_all(root); - root->height = 0; root->rnode = NULL; } @@ -1631,26 +1608,6 @@ radix_tree_node_ctor(void *arg) INIT_LIST_HEAD(&node->private_list); } -static __init unsigned long __maxindex(unsigned int height) -{ - unsigned int width = height * RADIX_TREE_MAP_SHIFT; - int shift = RADIX_TREE_INDEX_BITS - width; - - if (shift < 0) - return ~0UL; - if (shift >= BITS_PER_LONG) - return 0UL; - return ~0UL >> shift; -} - -static __init void radix_tree_init_maxindex(void) -{ - unsigned int i; - - for (i = 0; i < ARRAY_SIZE(height_to_maxindex); i++) - height_to_maxindex[i] = __maxindex(i); -} - static int radix_tree_callback(struct notifier_block *nfb, unsigned long action, void *hcpu) { @@ -1677,6 +1634,5 @@ void __init radix_tree_init(void) sizeof(struct radix_tree_node), 0, SLAB_PANIC | SLAB_RECLAIM_ACCOUNT, radix_tree_node_ctor); - radix_tree_init_maxindex(); hotcpu_notifier(radix_tree_callback, 0); } |