From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1764661AbZDJKYV (ORCPT ); Fri, 10 Apr 2009 06:24:21 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1760701AbZDJKX7 (ORCPT ); Fri, 10 Apr 2009 06:23:59 -0400 Received: from mail.gmx.net ([213.165.64.20]:33543 "HELO mail.gmx.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with SMTP id S1764007AbZDJKX6 (ORCPT ); Fri, 10 Apr 2009 06:23:58 -0400 Cc: akpm@linux-foundation.org, peterz@infradead.org, lowdanie@gmail.com Content-Type: text/plain; charset="iso-8859-1" Date: Fri, 10 Apr 2009 12:23:56 +0200 From: "Wolfram Strepp" Message-ID: <20090410102356.283330@gmx.net> MIME-Version: 1.0 Subject: [PATCH 2/3] Further optimization of function rb_erase() in lib/rbtree.c To: linux-kernel@vger.kernel.org X-Authenticated: #14768304 X-Flags: 0001 X-Mailer: WWW-Mail 6100 (Global Message Exchange) X-Priority: 3 X-Provags-ID: V01U2FsdGVkX19EH+pZS5hEf7TZYQeRQIua2s4sZBAdV4CeystAOm AqMnKxAdtpubUvDSzLNt2zMrNHp57XHsRZ6Q== Content-Transfer-Encoding: 8bit X-GMX-UID: WHe6CMMafW47UIoClmVoL61udmllckWT X-FuHaFi: 0.59 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org There are two cases when a node, having 2 childs, is erased: 'normal case': the successor is not the right-hand-child of the node to be erased 'special case': the successor is the right-hand child of the node to be erased Here some ascii-art, with following symbols (referring to the code): O: node to be deleted N: the successor of O P: parent of N C: child of N L: some other node normal case: O N / \ / \ / \ / \ L \ L \ / \ P ----> / \ P / \ / \ / / N C \ / \ \ C / \ special case: O|P N / \ / \ / \ / \ L \ L \ / \ N ----> / C \ / \ \ C / \ Notice that for the special case we don't have to reconnect C to N. Signed-off-by: Wolfram Strepp Signed-off-by: Peter Zijlstra --- lib/rbtree.c | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-) Index: linux-2.6/lib/rbtree.c =================================================================== --- linux-2.6.orig/lib/rbtree.c +++ linux-2.6/lib/rbtree.c @@ -251,13 +251,13 @@ void rb_erase(struct rb_node *node, stru parent = rb_parent(node); color = rb_color(node); - if (child) - rb_set_parent(child, parent); if (parent == old) { - parent->rb_right = child; parent = node; - } else + } else { + if (child) + rb_set_parent(child, parent); parent->rb_left = child; + } node->rb_parent_color = old->rb_parent_color; node->rb_right = old->rb_right; -- Psssst! Schon vom neuen GMX MultiMessenger gehört? Der kann`s mit allen: http://www.gmx.net/de/go/multimessenger01