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=-2.3 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_PASS,USER_AGENT_MUTT 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 C4614C32788 for ; Thu, 11 Oct 2018 13:37:34 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 8634020652 for ; Thu, 11 Oct 2018 13:37:34 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 8634020652 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=lst.de 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 S1728157AbeJKVEq (ORCPT ); Thu, 11 Oct 2018 17:04:46 -0400 Received: from verein.lst.de ([213.95.11.211]:42926 "EHLO newverein.lst.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727056AbeJKVEq (ORCPT ); Thu, 11 Oct 2018 17:04:46 -0400 Received: by newverein.lst.de (Postfix, from userid 2407) id CB5BA68BFE; Thu, 11 Oct 2018 15:37:30 +0200 (CEST) Date: Thu, 11 Oct 2018 15:37:30 +0200 From: Christoph Hellwig To: Logan Gunthorpe Cc: linux-kernel@vger.kernel.org, linux-mm@kvack.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 , Andrew Waterman , Olof Johansson , Michael Clark , Rob Herring , Zong Li Subject: Re: [PATCH 5/5] RISC-V: Implement sparsemem Message-ID: <20181011133730.GB7276@lst.de> References: <20181005161642.2462-1-logang@deltatee.com> <20181005161642.2462-6-logang@deltatee.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20181005161642.2462-6-logang@deltatee.com> User-Agent: Mutt/1.5.17 (2007-11-01) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org > +/* > + * 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 I know this is copied from arm64, but wouldn't this be a good time to move this next to the struct page defintion? Also this: arch/arm64/mm/init.c: BUILD_BUG_ON(sizeof(struct page) > (1 << STRUCT_PAGE_MAX_SHIFT)); should move to comment code (or would have to be duplicated for riscv) > +#define VMEMMAP_SIZE (UL(1) << (CONFIG_VA_BITS - PAGE_SHIFT - 1 + \ > + STRUCT_PAGE_MAX_SHIFT)) Might be more readable with a another define, and without abuse of the horrible UL macro: #define VMEMMAP_SHIFT \ (CONFIG_VA_BITS - PAGE_SHIFT - 1 + STRUCT_PAGE_MAX_SHIFT) #define VMEMMAP_SIZE (1UL << VMEMMAP_SHIFT) > +#define VMEMMAP_END (VMALLOC_START - 1) > +#define VMEMMAP_START (VMALLOC_START - VMEMMAP_SIZE) > + > +#define vmemmap ((struct page *)VMEMMAP_START) This could also use some comments.. > @@ -0,0 +1,11 @@ > +/* SPDX-License-Identifier: GPL-2.0 */ > + > +#ifndef __ASM_SPARSEMEM_H > +#define __ASM_SPARSEMEM_H > + > +#ifdef CONFIG_SPARSEMEM > +#define MAX_PHYSMEM_BITS CONFIG_PA_BITS > +#define SECTION_SIZE_BITS 30 > +#endif > + > +#endif For potentially wide-spanning ifdefs like inclusion headers it always is nice to have a comment with the symbol on the endif line.