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=-2.5 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 DB3ABC43387 for ; Fri, 4 Jan 2019 15:09:47 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id AFB042087F for ; Fri, 4 Jan 2019 15:09:47 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727094AbfADPJq (ORCPT ); Fri, 4 Jan 2019 10:09:46 -0500 Received: from mx0b-001b2d01.pphosted.com ([148.163.158.5]:46664 "EHLO mx0a-001b2d01.pphosted.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1726117AbfADPJq (ORCPT ); Fri, 4 Jan 2019 10:09:46 -0500 Received: from pps.filterd (m0098413.ppops.net [127.0.0.1]) by mx0b-001b2d01.pphosted.com (8.16.0.22/8.16.0.22) with SMTP id x04F99Wa087439 for ; Fri, 4 Jan 2019 10:09:44 -0500 Received: from e06smtp05.uk.ibm.com (e06smtp05.uk.ibm.com [195.75.94.101]) by mx0b-001b2d01.pphosted.com with ESMTP id 2pt93jtfuh-1 (version=TLSv1.2 cipher=AES256-GCM-SHA384 bits=256 verify=NOT) for ; Fri, 04 Jan 2019 10:09:44 -0500 Received: from localhost by e06smtp05.uk.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! 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Violators will be prosecuted; (version=TLSv1/SSLv3 cipher=AES256-GCM-SHA384 bits=256/256) Fri, 4 Jan 2019 15:09:35 -0000 Received: from d06av22.portsmouth.uk.ibm.com (d06av22.portsmouth.uk.ibm.com [9.149.105.58]) by b06cxnps4074.portsmouth.uk.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id x04F9Yrr62062808 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=FAIL); Fri, 4 Jan 2019 15:09:34 GMT Received: from d06av22.portsmouth.uk.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id ED4F94C04E; Fri, 4 Jan 2019 15:09:33 +0000 (GMT) Received: from d06av22.portsmouth.uk.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id DED674C059; Fri, 4 Jan 2019 15:09:31 +0000 (GMT) Received: from rapoport-lnx (unknown [9.148.205.69]) by d06av22.portsmouth.uk.ibm.com (Postfix) with ESMTPS; Fri, 4 Jan 2019 15:09:31 +0000 (GMT) Date: Fri, 4 Jan 2019 17:09:29 +0200 From: Mike Rapoport To: Tejun Heo Cc: Baoquan He , Pingfan Liu , linux-acpi@vger.kernel.org, linux-mm@kvack.org, kexec@lists.infradead.org, Tang Chen , "Rafael J. Wysocki" , Len Brown , Andrew Morton , Mike Rapoport , Michal Hocko , Jonathan Corbet , Yaowei Bai , Pavel Tatashin , Nicholas Piggin , Naoya Horiguchi , Daniel Vacek , Mathieu Malaterre , Stefan Agner , Dave Young , yinghai@kernel.org, vgoyal@redhat.com, linux-kernel@vger.kernel.org Subject: Re: [PATCHv3 1/2] mm/memblock: extend the limit inferior of bottom-up after parsing hotplug attr References: <1545966002-3075-1-git-send-email-kernelfans@gmail.com> <1545966002-3075-2-git-send-email-kernelfans@gmail.com> <20181231084018.GA28478@rapoport-lnx> <20190102092749.GA22664@rapoport-lnx> <20190102101804.GD1990@MiWiFi-R3L-srv> <20190102170537.GA3591@rapoport-lnx> <20190103184706.GU2509588@devbig004.ftw2.facebook.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20190103184706.GU2509588@devbig004.ftw2.facebook.com> User-Agent: Mutt/1.5.24 (2015-08-30) X-TM-AS-GCONF: 00 x-cbid: 19010415-0020-0000-0000-00000300F2DE X-IBM-AV-DETECTION: SAVI=unused REMOTE=unused XFE=unused x-cbparentid: 19010415-0021-0000-0000-00002151F7D2 Message-Id: <20190104150929.GA32252@rapoport-lnx> X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:,, definitions=2019-01-04_06:,, signatures=0 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 priorityscore=1501 malwarescore=0 suspectscore=0 phishscore=0 bulkscore=0 spamscore=0 clxscore=1015 lowpriorityscore=0 mlxscore=0 impostorscore=0 mlxlogscore=710 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1810050000 definitions=main-1901040133 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Jan 03, 2019 at 10:47:06AM -0800, Tejun Heo wrote: > Hello, > > On Wed, Jan 02, 2019 at 07:05:38PM +0200, Mike Rapoport wrote: > > I agree that currently the bottom-up allocation after the kernel text has > > issues with KASLR. But this issues are not necessarily related to the > > memory hotplug. Even with a single memory node, a bottom-up allocation will > > fail if KASLR would put the kernel near the end of node0. > > > > What I am trying to understand is whether there is a fundamental reason to > > prevent allocations from [0, kernel_start)? > > > > Maybe Tejun can recall why he suggested to start bottom-up allocations from > > kernel_end. > > That's from 79442ed189ac ("mm/memblock.c: introduce bottom-up > allocation mode"). I wasn't involved in that patch, so no idea why > the restrictions were added, but FWIW it doesn't seem necessary to me. I should have added the reference [1] at the first place :) Thanks! [1] https://lore.kernel.org/lkml/20130904192215.GG26609@mtj.dyndns.org/ > Thanks. > > -- > tejun > -- Sincerely yours, Mike.