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=-0.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,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 6BDA0C3279B for ; Fri, 6 Jul 2018 08:58:53 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 1CBE420871 for ; Fri, 6 Jul 2018 08:58:53 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 1CBE420871 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=arm.com 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 S932352AbeGFI6t (ORCPT ); Fri, 6 Jul 2018 04:58:49 -0400 Received: from foss.arm.com ([217.140.101.70]:32858 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753864AbeGFI6n (ORCPT ); Fri, 6 Jul 2018 04:58:43 -0400 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.72.51.249]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 3AC30ED1; Fri, 6 Jul 2018 01:58:43 -0700 (PDT) Received: from [10.1.206.34] (melchizedek.cambridge.arm.com [10.1.206.34]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 1CCA93F2EA; Fri, 6 Jul 2018 01:58:41 -0700 (PDT) Subject: Re: [PATCH v3 4/5] arm64/mm: Make swapper_pg_dir smaller To: Jun Yao , linux-arm-kernel@lists.infradead.org Cc: catalin.marinas@arm.com, will.deacon@arm.com, suzuki.poulose@arm.com, linux-kernel@vger.kernel.org References: <20180702111659.25570-1-yaojun8558363@gmail.com> <20180702111659.25570-5-yaojun8558363@gmail.com> From: James Morse Message-ID: <00553a1b-f354-ea74-c0c2-e68f9c6a16a5@arm.com> Date: Fri, 6 Jul 2018 09:58:40 +0100 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.8.0 MIME-Version: 1.0 In-Reply-To: <20180702111659.25570-5-yaojun8558363@gmail.com> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Jun, On 02/07/18 12:16, Jun Yao wrote: > Make swapper_pg_dir smaller so we don't need to memblock_free() it. Patch looks good, but could the commit message explain why its now safe to do this? Thanks, James > diff --git a/arch/arm64/kernel/vmlinux.lds.S b/arch/arm64/kernel/vmlinux.lds.S > index d4fc68286a49..d69e11ad92e3 100644 > --- a/arch/arm64/kernel/vmlinux.lds.S > +++ b/arch/arm64/kernel/vmlinux.lds.S > @@ -236,7 +236,7 @@ SECTIONS > . += RESERVED_TTBR0_SIZE; > #endif > swapper_pg_dir = .; > - . += SWAPPER_DIR_SIZE; > + . += PAGE_SIZE; > swapper_pg_end = .; > > __pecoff_data_size = ABSOLUTE(. - __initdata_begin); > diff --git a/arch/arm64/mm/mmu.c b/arch/arm64/mm/mmu.c > index a7ab0010ff80..a1e8fc624324 100644 > --- a/arch/arm64/mm/mmu.c > +++ b/arch/arm64/mm/mmu.c > @@ -632,14 +632,6 @@ void __init paging_init(void) > map_mem(swapper_pg_dir); > cpu_replace_ttbr1(swapper_pg_dir); > init_mm.pgd = swapper_pg_dir; > - > - /* > - * We only reuse the PGD from the swapper_pg_dir, not the pud + pmd > - * allocated with it. > - */ > - memblock_free(__pa_symbol(swapper_pg_dir) + PAGE_SIZE, > - __pa_symbol(swapper_pg_end) - __pa_symbol(swapper_pg_dir) > - - PAGE_SIZE); > } > > /* >