From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752736Ab2G0UEg (ORCPT ); Fri, 27 Jul 2012 16:04:36 -0400 Received: from casper.infradead.org ([85.118.1.10]:56603 "EHLO casper.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752440Ab2G0UEf convert rfc822-to-8bit (ORCPT ); Fri, 27 Jul 2012 16:04:35 -0400 Message-ID: <1343419466.32120.50.camel@twins> Subject: Re: [PATCH 4/6] rbtree: faster augmented insert From: Peter Zijlstra To: Michel Lespinasse Cc: riel@redhat.com, daniel.santos@pobox.com, aarcange@redhat.com, dwmw2@infradead.org, akpm@linux-foundation.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org Date: Fri, 27 Jul 2012 22:04:26 +0200 In-Reply-To: <1342787467-5493-5-git-send-email-walken@google.com> References: <1342787467-5493-1-git-send-email-walken@google.com> <1342787467-5493-5-git-send-email-walken@google.com> Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7BIT X-Mailer: Evolution 3.2.2- Mime-Version: 1.0 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, 2012-07-20 at 05:31 -0700, Michel Lespinasse wrote: > +static void augment_rotate(struct rb_node *rb_old, struct rb_node *rb_new) > +{ > + struct test_node *old = rb_entry(rb_old, struct test_node, rb); > + struct test_node *new = rb_entry(rb_new, struct test_node, rb); > + > + /* Rotation doesn't change subtree's augmented value */ > + new->augmented = old->augmented; > + old->augmented = augment_recompute(old); > +} > +static inline void augment_propagate(struct rb_node *rb) > +{ > + while (rb) { > + struct test_node *node = rb_entry(rb, struct test_node, rb); > + node->augmented = augment_recompute(node); > + rb = rb_parent(&node->rb); > + } > +} So why do we have to introduce these two new function pointers to pass along when they can both be trivially expressed in the old single augment function?