Re: [PATCH] Make radix_tree_preload alloc one more slot

[Wu Fengguang <fengguang.wu@intel.com>]

Hi Yanhai,

[Nick CCed]

On Thu, Aug 27, 2009 at 08:10:41PM +0800, Zhu Yanhai wrote:
> The operations against radix tree always use paths with RADIX_TREE_MAX_PATH
> + 1 slots, but radix_tree_preload only pre-allocs RADIX_TREE_MAX_PATH
> slots at present, which causes radix_tree_node_alloc tries to do
> kmem_cache_alloc at the last slot even if we don't have gfp_mask &
> __GFP_WAIT in hand.
 
Are you sure?  The comments read:

        /*
         * The radix tree path needs to be one longer than the maximum path
         * since the "list" is null terminated.
         */
        struct radix_tree_path path[RADIX_TREE_MAX_PATH + 1], *pathp = path;

Thanks,
Fengguang


> Signed-off-by: Zhu Yanhai <zhu.yanhai@gmail.com>
> 
> ---
>  lib/radix-tree.c |    2 +-
>  1 files changed, 1 insertions(+), 1 deletions(-)
> 
> diff --git a/lib/radix-tree.c b/lib/radix-tree.c
> index 23abbd9..72225a8 100644
> --- a/lib/radix-tree.c
> +++ b/lib/radix-tree.c
> @@ -79,7 +79,7 @@ static struct kmem_cache *radix_tree_node_cachep;
>   */
>  struct radix_tree_preload {
>  	int nr;
> -	struct radix_tree_node *nodes[RADIX_TREE_MAX_PATH];
> +	struct radix_tree_node *nodes[RADIX_TREE_MAX_PATH + 1];
>  };
>  static DEFINE_PER_CPU(struct radix_tree_preload, radix_tree_preloads) = { 0, };
>  
> -- 
> 1.6.2.2