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 BEFE6C433E1 for ; Tue, 25 Aug 2020 14:58:01 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id A0B162075F for ; Tue, 25 Aug 2020 14:58:01 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726783AbgHYO57 convert rfc822-to-8bit (ORCPT ); Tue, 25 Aug 2020 10:57:59 -0400 Received: from eu-smtp-delivery-151.mimecast.com ([185.58.86.151]:32048 "EHLO eu-smtp-delivery-151.mimecast.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726336AbgHYOwk (ORCPT ); Tue, 25 Aug 2020 10:52:40 -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-229-XTGr5FjFOiOuMkOxNdlKew-1; Tue, 25 Aug 2020 15:52:36 +0100 X-MC-Unique: XTGr5FjFOiOuMkOxNdlKew-1 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 15:52:35 +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 15:52:35 +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 07/13] lib/generic-radix-tree: Optimise __genradix_iter_peek() Thread-Topic: [PATCH 07/13] lib/generic-radix-tree: Optimise __genradix_iter_peek() Thread-Index: AdZ67z36LdYIWMqoTRCrizJoKBNmVA== Date: Tue, 25 Aug 2020 14:52:35 +0000 Message-ID: Accept-Language: en-GB, en-US Content-Language: 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: 0.002 X-Mimecast-Originator: aculab.com Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8BIT Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Use the the 'shift' rather than the 'level'. NB There are exactly zero users of this code. Signed-off-by: David Laight --- lib/generic-radix-tree.c | 24 ++++++++---------------- 1 file changed, 8 insertions(+), 16 deletions(-) diff --git a/lib/generic-radix-tree.c b/lib/generic-radix-tree.c index 219b43250a06..0df99ee428d8 100644 --- a/lib/generic-radix-tree.c +++ b/lib/generic-radix-tree.c @@ -22,14 +22,6 @@ static inline int genradix_depth_shift(unsigned depth) return PAGE_SHIFT + GENRADIX_ARY_SHIFT * depth; } -/* - * Returns size (of data, in bytes) that a tree of a given depth holds: - */ -static inline size_t genradix_depth_size(unsigned depth) -{ - return 1UL << genradix_depth_shift(depth); -} - /* * The 'depth' of the tree is held in the low bits of the 'root'. * Since all the buffers are allocated as pages lots of low bits are zero. @@ -209,7 +201,7 @@ void *__genradix_iter_peek(struct genradix_iter *iter, { struct genradix_root *r; struct genradix_node *n; - unsigned level, i; + unsigned int shift, level, i; restart: r = READ_ONCE(radix->root); if (!r) @@ -217,21 +209,21 @@ void *__genradix_iter_peek(struct genradix_iter *iter, n = genradix_root_to_node(r); level = genradix_root_to_depth(r); + shift = genradix_depth_shift(level); - if (iter->offset >> genradix_depth_shift(level)) + if (iter->offset >> shift) return NULL; - while (level) { - level--; + while (shift > GENRADIX_ARY_SHIFT) { + shift -= GENRADIX_ARY_SHIFT; - i = (iter->offset >> genradix_depth_shift(level)) & - (GENRADIX_ARY - 1); + i = (iter->offset >> shift) % GENRADIX_ARY; while (!n->children[i]) { i++; iter->offset = round_down(iter->offset + - genradix_depth_size(level), - genradix_depth_size(level)); + (1u << shift), + 1u << shift); iter->pos = (iter->offset >> PAGE_SHIFT) * objs_per_page; if (i == GENRADIX_ARY) -- 2.25.1 - Registered Address Lakeside, Bramley Road, Mount Farm, Milton Keynes, MK1 1PT, UK Registration No: 1397386 (Wales)