Expand comment on optimization in radix_tree_range_tag_if_tagged(), along the lines proposed by Dave Chinner. Signed-off-by: Hugh Dickins <hughd@xxxxxxxxxx> --- And with -p2, this patch will also apply to the rtth tree. lib/radix-tree.c | 8 +++++++- 1 file changed, 7 insertions(+), 1 deletion(-) --- mmotm/lib/radix-tree.c 2011-12-16 20:40:26.152758485 -0800 +++ linux/lib/radix-tree.c 2011-12-21 14:57:20.073657540 -0800 @@ -703,7 +703,13 @@ unsigned long radix_tree_range_tag_if_ta node = node->parent; } - /* optimization: no need to walk up from this node again */ + /* + * Small optimization: now clear that node pointer. + * Since all of this slot's ancestors now have the tag set + * from setting it above, we have no further need to walk + * back up the tree setting tags, until we update slot to + * point to another radix_tree_node. + */ node = NULL; next: -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Fight unfair telecom internet charges in Canada: sign http://stopthemeter.ca/ Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>