From: Praveen Kumar <kpraveen.lkml@gmail.com>
To: xen-devel@lists.xen.org
Cc: sstabellini@kernel.org, wei.liu2@citrix.com,
George.Dunlap@eu.citrix.com, andrew.cooper3@citrix.com,
dario.faggioli@citrix.com, ian.jackson@eu.citrix.com,
tim@xen.org, Praveen Kumar <kpraveen.lkml@gmail.com>,
jbeulich@suse.com
Subject: [Resend][PATCH 04/17] rbtree: empty nodes have no color
Date: Thu, 1 Jun 2017 02:50:43 +0530 [thread overview]
Message-ID: <20170531212056.10583-5-kpraveen.lkml@gmail.com> (raw)
In-Reply-To: <20170531212056.10583-1-kpraveen.lkml@gmail.com>
Empty nodes have no color. We can make use of this property to simplify the
code emitted by the RB_EMPTY_NODE and RB_CLEAR_NODE macros.
commit 4c199a93a2d36b277a9fd209a0f2793f8460a215 from linux tree.
Signed-off-by: Praveen Kumar <kpraveen.lkml@gmail.com>
---
xen/common/rbtree.c | 4 ++--
xen/include/xen/rbtree.h | 9 ++++++---
2 files changed, 8 insertions(+), 5 deletions(-)
diff --git a/xen/common/rbtree.c b/xen/common/rbtree.c
index 0695edd9f9..81fb746b35 100644
--- a/xen/common/rbtree.c
+++ b/xen/common/rbtree.c
@@ -323,7 +323,7 @@ struct rb_node *rb_next(struct rb_node *node)
{
struct rb_node *parent;
- if (rb_parent(node) == node)
+ if (RB_EMPTY_NODE(node))
return NULL;
/* If we have a right-hand child, go down and then left as far
@@ -352,7 +352,7 @@ struct rb_node *rb_prev(struct rb_node *node)
{
struct rb_node *parent;
- if (rb_parent(node) == node)
+ if (RB_EMPTY_NODE(node))
return NULL;
/* If we have a left-hand child, go down and then right as far
diff --git a/xen/include/xen/rbtree.h b/xen/include/xen/rbtree.h
index f93c4d5823..29071a7e4a 100644
--- a/xen/include/xen/rbtree.h
+++ b/xen/include/xen/rbtree.h
@@ -52,9 +52,12 @@ static inline void rb_set_color(struct rb_node *rb, int color)
#define RB_ROOT (struct rb_root) { NULL, }
#define rb_entry(ptr, type, member) container_of(ptr, type, member)
-#define RB_EMPTY_ROOT(root) ((root)->rb_node == NULL)
-#define RB_EMPTY_NODE(node) (rb_parent(node) == node)
-#define RB_CLEAR_NODE(node) (rb_set_parent(node, node))
+#define RB_EMPTY_ROOT(root) ((root)->rb_node == NULL)
+
+/* 'empty' nodes are nodes that are known not to be inserted in an rbree */
+#define RB_EMPTY_NODE(node) ((node)->rb_parent_color == (unsigned long)(node))
+#define RB_CLEAR_NODE(node) ((node)->rb_parent_color = (unsigned long)(node))
+
extern void rb_insert_color(struct rb_node *, struct rb_root *);
extern void rb_erase(struct rb_node *, struct rb_root *);
--
2.12.0
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next prev parent reply other threads:[~2017-05-31 21:20 UTC|newest]
Thread overview: 34+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-05-31 21:20 [Xen-devel[PATCH Resend v2] xen: common: rbtree: ported updates from linux tree Praveen Kumar
2017-05-31 21:20 ` [Resend][PATCH 01/17] rb_tree: reorganize code in rb_erase() for additional changes Praveen Kumar
2017-05-31 22:40 ` Dario Faggioli
2017-05-31 22:56 ` Andrew Cooper
2017-06-01 8:01 ` Dario Faggioli
2017-06-02 16:28 ` Praveen Kumar
2017-06-08 15:57 ` Jan Beulich
2017-05-31 21:20 ` [Resend][PATCH 02/17] rb_tree: make clear distinction between two different cases in rb_erase() Praveen Kumar
2017-05-31 21:20 ` [Resend][PATCH 03/17] rb_tree: remove redundant if()-condition " Praveen Kumar
2017-05-31 21:20 ` Praveen Kumar [this message]
2017-06-12 16:42 ` [Resend][PATCH 04/17] rbtree: empty nodes have no color Dario Faggioli
2017-06-13 8:21 ` Jan Beulich
2017-05-31 21:20 ` [Resend][PATCH 05/17] rbtree: move some implementation details from rbtree.h to rbtree.c Praveen Kumar
2017-05-31 21:20 ` [Resend][PATCH 06/17] rbtree: break out of rb_insert_color loop after tree rotation Praveen Kumar
2017-06-12 16:41 ` Dario Faggioli
2017-05-31 21:20 ` [Resend][PATCH 07/17] rbtree: adjust root color in rb_insert_color() only when necessary Praveen Kumar
2017-05-31 21:20 ` [Resend][PATCH 08/17] rbtree: low level optimizations in rb_insert_color() Praveen Kumar
2017-05-31 21:20 ` [Resend][PATCH 09/17] rbtree: adjust node color in __rb_erase_color() only when necessary Praveen Kumar
2017-05-31 21:20 ` [Resend][PATCH 10/17] rbtree: optimize case selection logic in __rb_erase_color() Praveen Kumar
2017-05-31 21:20 ` [Resend][PATCH 11/17] rbtree: low level optimizations " Praveen Kumar
2017-05-31 21:20 ` [Resend][PATCH 12/17] rbtree: optimize fetching of sibling node Praveen Kumar
2017-05-31 21:20 ` [Resend][PATCH 13/17] rbtree: add __rb_change_child() helper function Praveen Kumar
2017-06-12 16:14 ` Dario Faggioli
2017-05-31 21:20 ` [Resend][PATCH 14/17] rbtree: place easiest case first in rb_erase() Praveen Kumar
2017-06-12 16:19 ` Dario Faggioli
2017-05-31 21:20 ` [Resend][PATCH 15/17] rbtree: handle 1-child recoloring in rb_erase() instead of rb_erase_color() Praveen Kumar
2017-05-31 21:20 ` [Resend][PATCH 16/17] rbtree: low level optimizations in rb_erase() Praveen Kumar
2017-05-31 21:20 ` [Resend][PATCH 17/17] rbtree: add postorder iteration functions Praveen Kumar
2017-05-31 22:34 ` [Xen-devel[PATCH Resend v2] xen: common: rbtree: ported updates from linux tree Dario Faggioli
2017-06-01 7:26 ` Jan Beulich
2017-06-01 7:43 ` Dario Faggioli
2017-06-02 16:35 ` Praveen Kumar
2017-06-02 16:31 ` Praveen Kumar
2017-06-12 16:44 ` Dario Faggioli
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