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=-1.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_PASS,URIBL_BLOCKED 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 B3046C0044C for ; Wed, 7 Nov 2018 20:12:03 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 7938A2081D for ; Wed, 7 Nov 2018 20:12:03 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 7938A2081D Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=linux-foundation.org Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726659AbeKHFn5 (ORCPT ); Thu, 8 Nov 2018 00:43:57 -0500 Received: from mail.linuxfoundation.org ([140.211.169.12]:60562 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726352AbeKHFn5 (ORCPT ); Thu, 8 Nov 2018 00:43:57 -0500 Received: from akpm3.svl.corp.google.com (unknown [104.133.8.65]) by mail.linuxfoundation.org (Postfix) with ESMTPSA id E5BB0AB5; Wed, 7 Nov 2018 20:12:00 +0000 (UTC) Date: Wed, 7 Nov 2018 12:11:59 -0800 From: Andrew Morton To: Logan Gunthorpe Cc: linux-kernel@vger.kernel.org, linux-mm@kvack.org, linux-arch@vger.kernel.org, linux-riscv@lists.infradead.org, linux-arm-kernel@lists.infradead.org, linux-sh@vger.kernel.org, Stephen Bates , Palmer Dabbelt , Albert Ou , Christoph Hellwig , Arnd Bergmann , Catalin Marinas Subject: Re: [PATCH 1/2] mm: Introduce common STRUCT_PAGE_MAX_SHIFT define Message-Id: <20181107121159.b8c9add7c61fb97f48ddd7de@linux-foundation.org> In-Reply-To: <20181107173859.24096-2-logang@deltatee.com> References: <20181107173859.24096-1-logang@deltatee.com> <20181107173859.24096-2-logang@deltatee.com> X-Mailer: Sylpheed 3.6.0 (GTK+ 2.24.31; x86_64-pc-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, 7 Nov 2018 10:38:58 -0700 Logan Gunthorpe wrote: > This define is used by arm64 to calculate the size of the vmemmap > region. It is defined as the log2 of the upper bound on the size > of a struct page. > > We move it into mm_types.h so it can be defined properly instead of > set and checked with a build bug. This also allows us to use the same > define for riscv. > > --- a/arch/arm64/include/asm/memory.h > +++ b/arch/arm64/include/asm/memory.h > @@ -34,15 +34,6 @@ > */ > #define PCI_IO_SIZE SZ_16M > > -/* > - * Log2 of the upper bound of the size of a struct page. Used for sizing > - * the vmemmap region only, does not affect actual memory footprint. > - * We don't use sizeof(struct page) directly since taking its size here > - * requires its definition to be available at this point in the inclusion > - * chain, and it may not be a power of 2 in the first place. > - */ > -#define STRUCT_PAGE_MAX_SHIFT 6 Well that was lame. > --- a/include/linux/mm_types.h > +++ b/include/linux/mm_types.h > @@ -206,6 +206,11 @@ struct page { > #endif > } _struct_page_alignment; > > +/* > + * Used for sizing the vmemmap region on some architectures > + */ > +#define STRUCT_PAGE_MAX_SHIFT (order_base_2(sizeof(struct page))) Much better. Acked-by: Andrew Morton