From patchwork Tue Jun 29 02:42:43 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Andrew Morton X-Patchwork-Id: 12349237 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=-15.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER, INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS autolearn=unavailable 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 114A1C11F66 for ; Tue, 29 Jun 2021 02:42:46 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id BB47361D0E for ; Tue, 29 Jun 2021 02:42:45 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org BB47361D0E Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=linux-foundation.org Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id 201698D012A; Mon, 28 Jun 2021 22:42:45 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 18B868D00F0; Mon, 28 Jun 2021 22:42:45 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id F1EEF8D012A; Mon, 28 Jun 2021 22:42:44 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0225.hostedemail.com [216.40.44.225]) by kanga.kvack.org (Postfix) with ESMTP id C77528D00F0 for ; Mon, 28 Jun 2021 22:42:44 -0400 (EDT) Received: from smtpin31.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay01.hostedemail.com (Postfix) with ESMTP id C6636180361B1 for ; Tue, 29 Jun 2021 02:42:44 +0000 (UTC) X-FDA: 78305213448.31.01ED5FE Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by imf07.hostedemail.com (Postfix) with ESMTP id 86137A0010C1 for ; Tue, 29 Jun 2021 02:42:44 +0000 (UTC) Received: by mail.kernel.org (Postfix) with ESMTPSA id 63FA561D0D; Tue, 29 Jun 2021 02:42:43 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linux-foundation.org; s=korg; t=1624934563; bh=+sJEQvdy8tMc7SUQRQq5PCyPADHavqZiWFWsrH4M2k8=; h=Date:From:To:Subject:In-Reply-To:From; b=AIYURMKSc9gksiVgk+s1QUvoek4mKIbpQhJfZIGrjugsfI48bJsUTWf1BvFbxVqmi u5seLhiqrcnKzNQ1KNrKyE+tPG8Mb+a97MPUJYWk9jcCy5u3ZDAeiBB7KPrms6IaIW cxcmCwyN20WFvaXwCWcz7Ab+wAvmrNyezk/PW/Xs= Date: Mon, 28 Jun 2021 19:42:43 -0700 From: Andrew Morton To: akpm@linux-foundation.org, arnd@arndb.de, corbet@lwn.net, david@redhat.com, geert@linux-m68k.org, ink@jurassic.park.msu.ru, linux-mm@kvack.org, mattst88@gmail.com, mm-commits@vger.kernel.org, rppt@linux.ibm.com, rth@twiddle.net, torvalds@linux-foundation.org, vgupta@synopsys.com Subject: [patch 181/192] arc: update comment about HIGHMEM implementation Message-ID: <20210629024243.VERGuG22C%akpm@linux-foundation.org> In-Reply-To: <20210628193256.008961950a714730751c1423@linux-foundation.org> User-Agent: s-nail v14.8.16 Authentication-Results: imf07.hostedemail.com; dkim=pass header.d=linux-foundation.org header.s=korg header.b=AIYURMKS; spf=pass (imf07.hostedemail.com: domain of akpm@linux-foundation.org designates 198.145.29.99 as permitted sender) smtp.mailfrom=akpm@linux-foundation.org; dmarc=none X-Stat-Signature: 9xfjtaqou3diyp8zz9ajd7y8imkhtpn9 X-Rspamd-Queue-Id: 86137A0010C1 X-Rspamd-Server: rspam06 X-HE-Tag: 1624934564-250416 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: From: Mike Rapoport Subject: arc: update comment about HIGHMEM implementation Arc does not use DISCONTIGMEM to implement high memory, update the comment describing how high memory works to reflect this. Link: https://lkml.kernel.org/r/20210608091316.3622-3-rppt@kernel.org Signed-off-by: Mike Rapoport Acked-by: Vineet Gupta Acked-by: Arnd Bergmann Reviewed-by: David Hildenbrand Cc: Geert Uytterhoeven Cc: Ivan Kokshaysky Cc: Jonathan Corbet Cc: Matt Turner Cc: Richard Henderson Signed-off-by: Andrew Morton --- arch/arc/mm/init.c | 13 +++++-------- 1 file changed, 5 insertions(+), 8 deletions(-) --- a/arch/arc/mm/init.c~arc-update-comment-about-highmem-implementation +++ a/arch/arc/mm/init.c @@ -139,16 +139,13 @@ void __init setup_arch_memory(void) #ifdef CONFIG_HIGHMEM /* - * Populate a new node with highmem - * * On ARC (w/o PAE) HIGHMEM addresses are actually smaller (0 based) - * than addresses in normal ala low memory (0x8000_0000 based). + * than addresses in normal aka low memory (0x8000_0000 based). * Even with PAE, the huge peripheral space hole would waste a lot of - * mem with single mem_map[]. This warrants a mem_map per region design. - * Thus HIGHMEM on ARC is imlemented with DISCONTIGMEM. - * - * DISCONTIGMEM in turns requires multiple nodes. node 0 above is - * populated with normal memory zone while node 1 only has highmem + * mem with single contiguous mem_map[]. + * Thus when HIGHMEM on ARC is enabled the memory map corresponding + * to the hole is freed and ARC specific version of pfn_valid() + * handles the hole in the memory map. */ #ifdef CONFIG_DISCONTIGMEM node_set_online(1);