From 5536805292e64393f57054de66578f17eb1ea994 Mon Sep 17 00:00:00 2001 From: Nick Piggin Date: Tue, 29 May 2012 15:07:34 -0700 Subject: radix-tree: fix preload vector size We are not preallocating a sufficient number of nodes. Signed-off-by: Nick Piggin Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- lib/radix-tree.c | 15 ++++++++++++++- 1 file changed, 14 insertions(+), 1 deletion(-) 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 @@ -72,12 +72,25 @@ 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, }; -- cgit v1.2.3