From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-9.8 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id A5AFEC433DF for ; Tue, 25 Aug 2020 14:57:39 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 7795620786 for ; Tue, 25 Aug 2020 14:57:39 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726985AbgHYOzA convert rfc822-to-8bit (ORCPT ); Tue, 25 Aug 2020 10:55:00 -0400 Received: from eu-smtp-delivery-151.mimecast.com ([185.58.86.151]:58485 "EHLO eu-smtp-delivery-151.mimecast.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726804AbgHYOw4 (ORCPT ); Tue, 25 Aug 2020 10:52:56 -0400 Received: from AcuMS.aculab.com (156.67.243.126 [156.67.243.126]) (Using TLS) by relay.mimecast.com with ESMTP id uk-mta-7-_XvlfVdZOXe9OgmpDD8wmA-3; Tue, 25 Aug 2020 15:52:48 +0100 X-MC-Unique: _XvlfVdZOXe9OgmpDD8wmA-3 Received: from AcuMS.Aculab.com (fd9f:af1c:a25b:0:43c:695e:880f:8750) by AcuMS.aculab.com (fd9f:af1c:a25b:0:43c:695e:880f:8750) with Microsoft SMTP Server (TLS) id 15.0.1347.2; Tue, 25 Aug 2020 15:52:47 +0100 Received: from AcuMS.Aculab.com ([fe80::43c:695e:880f:8750]) by AcuMS.aculab.com ([fe80::43c:695e:880f:8750%12]) with mapi id 15.00.1347.000; Tue, 25 Aug 2020 15:52:47 +0100 From: David Laight To: "linux-kernel@vger.kernel.org" , "'linux-sctp@vger.kernel.org'" , Eric Biggers , 'Marcelo Ricardo Leitner' , 'Catalin Marinas' , "'kent.overstreet@gmail.com'" , Andrew Morton , "'Neil Horman'" Subject: [PATCH 10/13] lib/generic-radix-tree: Simplify offset calculation: Thread-Topic: [PATCH 10/13] lib/generic-radix-tree: Simplify offset calculation: Thread-Index: AdZ672R+peJB3QHpRkKEQyAm6F6LmA== Date: Tue, 25 Aug 2020 14:52:47 +0000 Message-ID: Accept-Language: en-GB, en-US X-MS-Has-Attach: X-MS-TNEF-Correlator: x-ms-exchange-transport-fromentityheader: Hosted x-originating-ip: [10.202.205.107] MIME-Version: 1.0 Authentication-Results: relay.mimecast.com; auth=pass smtp.auth=C51A453 smtp.mailfrom=david.laight@aculab.com X-Mimecast-Spam-Score: 0.001 X-Mimecast-Originator: aculab.com Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8BIT Content-Language: en-US Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Since these are equivalent: (idx / objs_per_page) * PAGE_SIZE + (idx % objs_per_page) * obj_size; idx * obj_size + (idx / objs_per_page) * (PAGE_SIZE % obj_size); Use the latter since it is slightly faster. It also deosn't need an extra check for obj_size being a power of 2. Signed-off-by: David Laight --- include/linux/generic-radix-tree.h | 9 ++------- 1 file changed, 2 insertions(+), 7 deletions(-) diff --git a/include/linux/generic-radix-tree.h b/include/linux/generic-radix-tree.h index 53149bc1b92a..5fe1c4c5588d 100644 --- a/include/linux/generic-radix-tree.h +++ b/include/linux/generic-radix-tree.h @@ -100,14 +100,9 @@ void __genradix_free(struct __genradix *); static inline size_t __idx_to_offset(size_t idx, size_t obj_size) { - if (!is_power_of_2(obj_size)) { - size_t objs_per_page = PAGE_SIZE / obj_size; + size_t objs_per_page = PAGE_SIZE / obj_size; - return (idx / objs_per_page) * PAGE_SIZE + - (idx % objs_per_page) * obj_size; - } else { - return idx * obj_size; - } + return idx * obj_size + (idx / objs_per_page) * (PAGE_SIZE % obj_size); } #define __genradix_cast(_radix) (typeof((_radix)->type[0]) *) -- 2.25.1 - Registered Address Lakeside, Bramley Road, Mount Farm, Milton Keynes, MK1 1PT, UK Registration No: 1397386 (Wales)