Messages in this thread Patch in this message |  | | | Subject | [PATCH] rbtree: fix jffs2 build issue due to renamed __rb_parent_color field | | From | David Woodhouse <> | | Date | Wed, 18 Jul 2012 16:16:49 +0100 |
| |
... and clean up the comments to better explain why it's acceptable to do it this way instead of using rb_erase() "properly".
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com> --- On Wed, 2012-07-18 at 12:40 +0100, David Woodhouse wrote: > If you're going to make that comment redundant, you might as well remove > it. And you might as well say that the trees are being *destroyed* > (consumed) at this point, rather than just that there will be no further > insert or erase operations. The comment on ver_insert() confused me too while I was looking at this, so I've improved that as well.
A quick and dirty benchmark shows about a 10% performance improvement when mounting a RAM-backed JFFS2 file system on Westmere. Thanks.
Acked-By: David Woodhouse <David.Woodhouse@intel.com> for the rest of the series.
diff --git a/fs/jffs2/readinode.c b/fs/jffs2/readinode.c index 1ea349f..ae81b01 100644 --- a/fs/jffs2/readinode.c +++ b/fs/jffs2/readinode.c @@ -394,8 +394,11 @@ static int jffs2_add_tn_to_tree(struct jffs2_sb_info *c, } /* Trivial function to remove the last node in the tree. Which by definition - has no right-hand -- so can be removed just by making its only child (if - any) take its place under its parent. */ + has no right-hand child — so can be removed just by making its left-hand + child (if any) take its place under its parent. Since this is only done + when we're consuming the whole tree, there's no need to use rb_erase() + and let it worry about adjusting colours and balancing the tree. That + would just be a waste of time. */ static void eat_last(struct rb_root *root, struct rb_node *node) { struct rb_node *parent = rb_parent(node); @@ -412,12 +415,12 @@ static void eat_last(struct rb_root *root, struct rb_node *node) link = &parent->rb_right; *link = node->rb_left; - /* Colour doesn't matter now. Only the parent pointer. */ if (node->rb_left) - node->rb_left->rb_parent_color = node->rb_parent_color; + node->rb_left->__rb_parent_color = node->__rb_parent_color; } -/* We put this in reverse order, so we can just use eat_last */ +/* We put the version tree in reverse order, so we can use the same eat_last() + function that we use to consume the tmpnode tree (tn_root). */ static void ver_insert(struct rb_root *ver_root, struct jffs2_tmp_dnode_info *tn) { struct rb_node **link = &ver_root->rb_node; -- dwmw2 [unhandled content-type:application/x-pkcs7-signature] |  |