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=-5.1 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, NICE_REPLY_A,SPF_HELO_NONE,SPF_PASS autolearn=no 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 A8F86C433E1 for ; Wed, 19 Aug 2020 17:22:17 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 677A520885 for ; Wed, 19 Aug 2020 17:22:17 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=kernel.org header.i=@kernel.org header.b="biwztO1i" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 677A520885 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 E9D8D8D001D; Wed, 19 Aug 2020 13:22:16 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id E4E138D0002; Wed, 19 Aug 2020 13:22:16 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id D64D78D001D; Wed, 19 Aug 2020 13:22:16 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0032.hostedemail.com [216.40.44.32]) by kanga.kvack.org (Postfix) with ESMTP id BF4208D0002 for ; Wed, 19 Aug 2020 13:22:16 -0400 (EDT) Received: from smtpin06.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay05.hostedemail.com (Postfix) with ESMTP id 7FFB7181AEF15 for ; Wed, 19 Aug 2020 17:22:16 +0000 (UTC) X-FDA: 77167986672.06.ball74_3a091bd27029 Received: from filter.hostedemail.com (10.5.16.251.rfc1918.com [10.5.16.251]) by smtpin06.hostedemail.com (Postfix) with ESMTP id 32FA810053C1A for ; Wed, 19 Aug 2020 17:22:16 +0000 (UTC) X-HE-Tag: ball74_3a091bd27029 X-Filterd-Recvd-Size: 2829 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by imf13.hostedemail.com (Postfix) with ESMTP for ; Wed, 19 Aug 2020 17:22:15 +0000 (UTC) Received: from localhost.localdomain (c-73-231-172-41.hsd1.ca.comcast.net [73.231.172.41]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 757FC206FA; Wed, 19 Aug 2020 17:22:14 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1597857734; bh=ns3QqN1GE86TyATblzqVP/NCI85PrE0w52RqoEnvbBg=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=biwztO1ihUXf4Euv72Qr3Rri8ht6NKWGwsqFXckg/nbkuURUNgmIs3mw3wg/xmvKp w9LlJlTBn2g0nRd+NYSiFy0nwZv5mnv3/883shiNjSOxvRLMBKParaJI2R4PnvHTDc /AmICpbuSNWIxMgrOgeuPRS+J1+c+LrZZxUiSOoE= Date: Wed, 19 Aug 2020 10:22:14 -0700 From: Andrew Morton To: Florian Fainelli Cc: Doug Berger , Jason Baron , David Rientjes , "Kirill A. Shutemov" , linux-mm@kvack.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH v2] mm: include CMA pages in lowmem_reserve at boot Message-Id: <20200819102214.32238093b116ab6f1c5c7b73@linux-foundation.org> In-Reply-To: References: <1597423766-27849-1-git-send-email-opendmb@gmail.com> <20200818201817.351499e75cba2a84e8bf33e6@linux-foundation.org> X-Mailer: Sylpheed 3.5.1 (GTK+ 2.24.31; x86_64-pc-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit X-Rspamd-Queue-Id: 32FA810053C1A X-Spamd-Result: default: False [0.00 / 100.00] X-Rspamd-Server: rspam01 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: On Wed, 19 Aug 2020 10:15:53 -0700 Florian Fainelli wrote: > >> In many cases the difference is not significant, but for example > >> an ARM platform with 1GB of memory and the following memory layout > >> [ 0.000000] cma: Reserved 256 MiB at 0x0000000030000000 > >> [ 0.000000] Zone ranges: > >> [ 0.000000] DMA [mem 0x0000000000000000-0x000000002fffffff] > >> [ 0.000000] Normal empty > >> [ 0.000000] HighMem [mem 0x0000000030000000-0x000000003fffffff] > >> > >> would result in 0 lowmem_reserve for the DMA zone. This would allow > >> userspace to deplete the DMA zone easily. > > > > Sounds fairly serious for thos machines. Was a cc:stable considered? > > Since there is a Fixes: tag, it may have been assumed that the patch > would be picked up and as soon as it reaches Linus' tree it would be > picked up by the stable selection. It doesn't work that way - sometimes a fix isn't considered important enough to backport. It could just fix a typo in a comment!