On Wed, Dec 21, 2011 at 03:57:16PM -0800, Hugh Dickins wrote: > 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; Looks good. I might remember why it was done now ;) Cheers, Dave. -- Dave Chinner david@xxxxxxxxxxxxx -- 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>