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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, kpraveen.lkml@gmail.com, jbeulich@suse.com
Subject: [PATCH v5 02/17] rbtree: remove redundant if()-condition in rb_erase()
Date: Fri, 14 Jul 2017 13:56:21 +0530	[thread overview]
Message-ID: <20170714082636.29511-3-kpraveen.lkml@gmail.com> (raw)
In-Reply-To: <20170714082636.29511-1-kpraveen.lkml@gmail.com>

From: Wolfram Strepp <wstrepp@gmx.de>

Furthermore, notice that the initial checks:

            if (!node->rb_left)
                    child = node->rb_right;
            else if (!node->rb_right)
                    child = node->rb_left;
            else
            {
                    ...
            }
guarantee that old->rb_right is set in the final else branch, therefore
we can omit checking that again.

Signed-off-by: Wolfram Strepp <wstrepp@gmx.de>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
[Linux commit 4b324126e0c6c3a5080ca3ec0981e8766ed6f1ee]

Ported to Xen.

Signed-off-by: Praveen Kumar <kpraveen.lkml@gmail.com>
---
 xen/common/rbtree.c | 7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/xen/common/rbtree.c b/xen/common/rbtree.c
index 167ebfdc4d..acfd34a62d 100644
--- a/xen/common/rbtree.c
+++ b/xen/common/rbtree.c
@@ -250,15 +250,16 @@ void rb_erase(struct rb_node *node, struct rb_root *root)
 			if (child)
 				rb_set_parent(child, parent);
 			parent->rb_left = child;
+
+			node->rb_right = old->rb_right;
+			rb_set_parent(old->rb_right, node);
 		}
 
 		node->rb_parent_color = old->rb_parent_color;
-		node->rb_right = old->rb_right;
 		node->rb_left = old->rb_left;
 
 		rb_set_parent(old->rb_left, node);
-		if (old->rb_right)
-			rb_set_parent(old->rb_right, node);
+
 		goto color;
 	}
 
-- 
2.12.0


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  parent reply	other threads:[~2017-07-14  8:26 UTC|newest]

Thread overview: 27+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2017-07-14  8:26 [PATCH v5 00/17] xen: common: rbtree: ported updates from Linux tree Praveen Kumar
2017-07-14  8:26 ` [PATCH v5 01/17] rbtree: changes to align the coding conventions with " Praveen Kumar
2017-07-14 12:28   ` Jan Beulich
2017-07-14 12:51     ` Praveen Kumar
2017-07-14 13:05       ` Jan Beulich
2017-08-03 10:37         ` Dario Faggioli
2017-08-04 16:59           ` Praveen Kumar
2017-08-04 17:04             ` Jan Beulich
2017-08-04 17:21               ` Praveen Kumar
2017-08-06  7:42                 ` Jan Beulich
2017-07-14  8:26 ` Praveen Kumar [this message]
2017-08-03 10:11   ` [PATCH v5 02/17] rbtree: remove redundant if()-condition in rb_erase() Jan Beulich
2017-07-14  8:26 ` [PATCH v5 03/17] rbtree: empty nodes have no color Praveen Kumar
2017-07-14  8:26 ` [PATCH v5 04/17] rbtree: move some implementation details from rbtree.h to rbtree.c Praveen Kumar
2017-07-14  8:26 ` [PATCH v5 05/17] rbtree: break out of rb_insert_color loop after tree rotation Praveen Kumar
2017-07-14  8:26 ` [PATCH v5 06/17] rbtree: adjust root color in rb_insert_color() only when necessary Praveen Kumar
2017-07-14  8:26 ` [PATCH v5 07/17] rbtree: low level optimizations in rb_insert_color() Praveen Kumar
2017-07-14  8:26 ` [PATCH v5 08/17] rbtree: adjust node color in __rb_erase_color() only when necessary Praveen Kumar
2017-07-14  8:26 ` [PATCH v5 09/17] rbtree: optimize case selection logic in __rb_erase_color() Praveen Kumar
2017-07-14  8:26 ` [PATCH v5 10/17] rbtree: low level optimizations " Praveen Kumar
2017-07-14  8:26 ` [PATCH v5 11/17] rbtree: coding style adjustments Praveen Kumar
2017-07-14  8:26 ` [PATCH v5 12/17] rbtree: optimize fetching of sibling node Praveen Kumar
2017-07-14  8:26 ` [PATCH v5 13/17] rbtree: add __rb_change_child() helper function Praveen Kumar
2017-07-14  8:26 ` [PATCH v5 14/17] rbtree: place easiest case first in rb_erase() Praveen Kumar
2017-07-14  8:26 ` [PATCH v5 15/17] rbtree: handle 1-child recoloring in rb_erase() instead of rb_erase_color() Praveen Kumar
2017-07-14  8:26 ` [PATCH v5 16/17] rbtree: low level optimizations in rb_erase() Praveen Kumar
2017-07-14  8:26 ` [PATCH v5 17/17] rbtree: fix typo in comment of rb_insert_color Praveen Kumar

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