diff options
| -rw-r--r-- | lib/radix-tree.c | 15 |
1 files changed, 14 insertions, 1 deletions
diff --git a/lib/radix-tree.c b/lib/radix-tree.c index 86516f5588e3..d7c878cc006c 100644 --- a/lib/radix-tree.c +++ b/lib/radix-tree.c @@ -73,11 +73,24 @@ static unsigned long height_to_maxindex[RADIX_TREE_MAX_PATH + 1] __read_mostly; static struct kmem_cache *radix_tree_node_cachep; /* + * The radix tree is variable-height, so an insert operation not only has + * to build the branch to its corresponding item, it also has to build the + * branch to existing items if the size has to be increased (by + * radix_tree_extend). + * + * The worst case is a zero height tree with just a single item at index 0, + * and then inserting an item at index ULONG_MAX. This requires 2 new branches + * of RADIX_TREE_MAX_PATH size to be created, with only the root node shared. + * Hence: + */ +#define RADIX_TREE_PRELOAD_SIZE (RADIX_TREE_MAX_PATH * 2 - 1) + +/* * Per-cpu pool of preloaded nodes */ struct radix_tree_preload { int nr; - struct radix_tree_node *nodes[RADIX_TREE_MAX_PATH]; + struct radix_tree_node *nodes[RADIX_TREE_PRELOAD_SIZE]; }; static DEFINE_PER_CPU(struct radix_tree_preload, radix_tree_preloads) = { 0, }; |