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 Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by smtp.lore.kernel.org (Postfix) with ESMTP id E0419C4167B for ; Wed, 29 Nov 2023 16:18:39 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id E512D6B0122; Wed, 29 Nov 2023 11:18:38 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id E02236B012B; Wed, 29 Nov 2023 11:18:38 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id C79E46B012C; Wed, 29 Nov 2023 11:18:38 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0015.hostedemail.com [216.40.44.15]) by kanga.kvack.org (Postfix) with ESMTP id B3F006B0122 for ; Wed, 29 Nov 2023 11:18:38 -0500 (EST) Received: from smtpin12.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay07.hostedemail.com (Postfix) with ESMTP id 7CCBE160582 for ; Wed, 29 Nov 2023 16:18:38 +0000 (UTC) X-FDA: 81511499916.12.2DDDB44 Received: from mx0b-001b2d01.pphosted.com (mx0b-001b2d01.pphosted.com [148.163.158.5]) by imf12.hostedemail.com (Postfix) with ESMTP id 1755F40016 for ; Wed, 29 Nov 2023 16:18:35 +0000 (UTC) Authentication-Results: imf12.hostedemail.com; dkim=pass header.d=ibm.com header.s=pp1 header.b=D39fFs1j; spf=pass (imf12.hostedemail.com: domain of agordeev@linux.ibm.com designates 148.163.158.5 as permitted sender) smtp.mailfrom=agordeev@linux.ibm.com; dmarc=pass (policy=none) header.from=ibm.com ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1701274716; h=from:from:sender:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type:content-transfer-encoding: in-reply-to:in-reply-to:references:references:dkim-signature; bh=7Al7YW5EcJe38iOapGOTryhpkSoVdc5WNB+0kfMZscs=; b=hX67vDILd0u0oIc688U3LuPWP1iIiy4cd8YWDK5oF5L/U3rlcpO/PwSXydnmIDgDimn0Jf MJU8nhbk3/vkmte5bevVz7zGLZ3qTgF2OXKVgNev0l0saJ8eXJDwDYxfps2/h5pfB8NehR zSDRCYE6CTtj8g97l2/9cBknAfktG7k= ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1701274716; a=rsa-sha256; cv=none; b=M1wfiJQ/Z8AsJ14nsv8adg/4DzZ7i9Bs7Qvh+XRwGfhf1F2lEs5PZ4URzt4Uy9LCuGP678 6vrM75JiCt0bxCTryMa2BMT20BIDxu5JVaWHMjYA72HmH+I3upJx82J6ubOLkWr2BmTPF8 qAXVLCNZkGAx/6u3NDa6/ZwPMYNIah0= ARC-Authentication-Results: i=1; imf12.hostedemail.com; dkim=pass header.d=ibm.com header.s=pp1 header.b=D39fFs1j; spf=pass (imf12.hostedemail.com: domain of agordeev@linux.ibm.com designates 148.163.158.5 as permitted sender) smtp.mailfrom=agordeev@linux.ibm.com; dmarc=pass (policy=none) header.from=ibm.com Received: from pps.filterd (m0353725.ppops.net [127.0.0.1]) by mx0a-001b2d01.pphosted.com (8.17.1.19/8.17.1.19) with ESMTP id 3ATG3SlX002432; Wed, 29 Nov 2023 16:18:33 GMT DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=ibm.com; h=date : from : to : cc : subject : message-id : references : mime-version : content-type : in-reply-to; s=pp1; bh=7Al7YW5EcJe38iOapGOTryhpkSoVdc5WNB+0kfMZscs=; b=D39fFs1jfE9PV+ZUVYROUdIZNqpcTFHOCkdcthGOaQOgwvPQ8FkyzN4UwwPTIcSv3ktB WdR0ck/mo+954QbNd9Z23tOZ+AWk3zSGQBLjXrX47ssgMlI4TkcoDOkAH/dh1o8qzW5B E1FLhiu/Or8d6aBoA9BtsoPsEXDppLwqF7Vjs1QTTafkxP8ZAYasMJ6qYRUa5bLJhHE5 n7w9cP3bM4ZIlhR1qZx7bQqUkx21P4/knMZO8pvd9LOM3BaXd2njEV8T1hasQtLJ+5YN r0GfCNV/7i1Xm7bN5GGkEmIZrZxdLznCMl8cuao4hUdkRV2mqyASar+9N1MuK+04VCeY AQ== Received: from pps.reinject (localhost [127.0.0.1]) by mx0a-001b2d01.pphosted.com (PPS) with ESMTPS id 3up8g28sqq-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Wed, 29 Nov 2023 16:18:32 +0000 Received: from m0353725.ppops.net (m0353725.ppops.net [127.0.0.1]) by pps.reinject (8.17.1.5/8.17.1.5) with ESMTP id 3ATGHCkB032409; Wed, 29 Nov 2023 16:18:31 GMT Received: from ppma13.dal12v.mail.ibm.com (dd.9e.1632.ip4.static.sl-reverse.com [50.22.158.221]) by mx0a-001b2d01.pphosted.com (PPS) with ESMTPS id 3up8g28spd-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Wed, 29 Nov 2023 16:18:31 +0000 Received: from pps.filterd (ppma13.dal12v.mail.ibm.com [127.0.0.1]) by ppma13.dal12v.mail.ibm.com (8.17.1.19/8.17.1.19) with ESMTP id 3ATE7cAJ025719; Wed, 29 Nov 2023 16:18:30 GMT Received: from smtprelay07.fra02v.mail.ibm.com ([9.218.2.229]) by ppma13.dal12v.mail.ibm.com (PPS) with ESMTPS id 3ukwfk7xxw-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Wed, 29 Nov 2023 16:18:30 +0000 Received: from smtpav01.fra02v.mail.ibm.com (smtpav01.fra02v.mail.ibm.com [10.20.54.100]) by smtprelay07.fra02v.mail.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id 3ATGIRbt47907102 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Wed, 29 Nov 2023 16:18:27 GMT Received: from smtpav01.fra02v.mail.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 3BB6720043; Wed, 29 Nov 2023 16:18:27 +0000 (GMT) Received: from smtpav01.fra02v.mail.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id F2F9620040; Wed, 29 Nov 2023 16:18:26 +0000 (GMT) Received: from li-008a6a4c-3549-11b2-a85c-c5cc2836eea2.ibm.com (unknown [9.155.204.135]) by smtpav01.fra02v.mail.ibm.com (Postfix) with ESMTPS; Wed, 29 Nov 2023 16:18:26 +0000 (GMT) Date: Wed, 29 Nov 2023 17:18:25 +0100 From: Alexander Gordeev To: Andrew Morton Cc: Sumanth Korikkar , linux-mm , David Hildenbrand , Oscar Salvador , Michal Hocko , "Aneesh Kumar K.V" , Anshuman Khandual , Gerald Schaefer , Heiko Carstens , Vasily Gorbik , linux-s390 , LKML Subject: Re: [PATCH v5 0/5] implement "memmap on memory" feature on s390 Message-ID: References: <20231128155227.1315063-1-sumanthk@linux.ibm.com> <20231128155634.9c325682d2cf87d0a6d48728@linux-foundation.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20231128155634.9c325682d2cf87d0a6d48728@linux-foundation.org> X-TM-AS-GCONF: 00 X-Proofpoint-ORIG-GUID: qTrVLAn3wiWvCXazFliWEEALVKCXkl3I X-Proofpoint-GUID: WN159P1Dg67ethR_7bWb_C68SBNQbkzl X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.272,Aquarius:18.0.997,Hydra:6.0.619,FMLib:17.11.176.26 definitions=2023-11-29_14,2023-11-29_01,2023-05-22_02 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 clxscore=1011 malwarescore=0 suspectscore=0 bulkscore=0 adultscore=0 priorityscore=1501 phishscore=0 spamscore=0 mlxscore=0 lowpriorityscore=0 mlxlogscore=480 impostorscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2311060000 definitions=main-2311290124 X-Rspamd-Queue-Id: 1755F40016 X-Rspam-User: X-Rspamd-Server: rspam11 X-Stat-Signature: pur79y6mrzbysgsmrwdndohjm38zuush X-HE-Tag: 1701274715-952299 X-HE-Meta: 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 vtYNa+70 ozm5LAKtEfqkX9R0rrQvYC7HkvlTy8kCKSl6wWH33yBHykdExfwhN2ywAZSrAN6QI01ENnGcrQJ4iFPVJPeez2CQkx3EhZfR6xpyCo3hpwB62MTlsXDeCoB28ZVc+fs1X+/6O6wzj+Mrj51J/HyWMFREvJwIbQk0Xgio5maA+RWIizwTFA422Z5J/ZpycIVCGBPUJUUkXqVAF5jOu92XIxP6kKwLLfRKlJARR 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: List-Subscribe: List-Unsubscribe: On Tue, Nov 28, 2023 at 03:56:34PM -0800, Andrew Morton wrote: Hi Andrew, > The cover letter doesn't acutally have a description of what "memmap on > memory" *is*. A nice overview to help readers understand what they're > about to look at. A description of what value this feature brings to > our users. Use-cases. That sort of thing. > > I guess the [1/N] changelog covers it, but it's hard to tell. It isn't > exactly broad-sweep overview. > > Probably something short would suffice. There are plenty of examples > on the mailing list, please take a look and send us something? Sumanth is on vacation, I will try to answer. This series brings "memmap on memory" support to s390 platform. That is - allocate 'struct pages' array describing a memory block being onlined not from available system memory, but from the memory block itself. This improves the current situation on s390, where struct pages for all memory that potentially can be added to the system, is preallocated, so that memory online will always succeed but at the cost of significant memory consumption. Unlike other architectures, the challenge s390 faces is the memory block being onlined is not accessible at the time of hotplug event. To make it physically accessible two new MEM_PREPARE_ONLINE and MEM_FINISH_OFFLINE memory notifiers are added. That allows to succeed "memmap on memory" initialization. For the existing architectures the two new notifiers are unknown and they are not affected in any way. Thanks!