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=-6.4 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,MSGID_FROM_MTA_HEADER,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED 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 D650CC43460 for ; Thu, 6 May 2021 15:37:26 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 692C2610A1 for ; Thu, 6 May 2021 15:37:26 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 692C2610A1 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=nvidia.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id C766D6B006C; Thu, 6 May 2021 11:37:25 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id C27006B0071; Thu, 6 May 2021 11:37:25 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id A51ED6B0072; Thu, 6 May 2021 11:37:25 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0193.hostedemail.com [216.40.44.193]) by kanga.kvack.org (Postfix) with ESMTP id 8C22A6B006C for ; Thu, 6 May 2021 11:37:25 -0400 (EDT) Received: from smtpin22.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay02.hostedemail.com (Postfix) with ESMTP id 47C3C1DF5 for ; Thu, 6 May 2021 15:37:25 +0000 (UTC) X-FDA: 78111210450.22.EA6D2B0 Received: from NAM10-BN7-obe.outbound.protection.outlook.com (mail-bn7nam10on2041.outbound.protection.outlook.com [40.107.92.41]) by imf06.hostedemail.com (Postfix) with ESMTP id E1CA9C0007F7 for ; Thu, 6 May 2021 15:37:25 +0000 (UTC) ARC-Seal: i=1; a=rsa-sha256; s=arcselector9901; d=microsoft.com; cv=none; b=FPN3Vtq71/AIplxqLw1M7kkASYtj2ER1h6bC3BecQ3Y6UP+G0/OVaXIRMQcb/a1mE9+oACP/azbSOyLHi851hO9IE/qLVLgMcgf4YXY0zviwV6Tf86R2leYG8GqevEWmyW0hknv1S+SyadubAgp5BduywgNVF1PbfTsy1fwHUb+e+FSx5imuSzBqxagTEfHOc/OAWYEIHJh2n24c4OJPNDGzR0E3NCEuxTomOhpGjHNUdPamSiQHSpQcuh8I+UgqtFgy3E58DmGMpQn4xSse+cTV/+3GTerlofaXcb2cXLFKOYkvOqGJ76kIncCld81VPrp+8Wj78WAEQqaP69llxw== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=microsoft.com; s=arcselector9901; h=From:Date:Subject:Message-ID:Content-Type:MIME-Version:X-MS-Exchange-SenderADCheck; bh=CgtgXQrH0EO88ortFz8WULLNVVyBTVnkFegymJEXa3Q=; b=NqYCZAmNBr46NxV9zqePvCFwW2657BbqsAC0EZP5ohvrzUWwqwSCYA2czz6G/P4r9yzU8XIVurdq3/PxXLakucrTo0dRgw9uE76sj4QokAwJ9ykZCEKtI/ud5QA2jObbil+svlKLGc1KuPPIQVg9CwpPKps6JYbz9lqAnYqkxmQuDsIu3HKZ4ikuSxMPzERVNyX7tpgpOY4yxGhZDArDYs9qXY1iVVvRizqBFA1uE2mqbnVWFyZv/Dmlh+cfnoMi4ATpTFZvl/7R0pTCFDsUeE9bJDsg5y+TXUX/n/r3ZicPQkaBusxV4ouvoKPTNehVMP6JOZBxaWa8c3JfUncODg== ARC-Authentication-Results: i=1; mx.microsoft.com 1; spf=pass smtp.mailfrom=nvidia.com; dmarc=pass action=none header.from=nvidia.com; dkim=pass header.d=nvidia.com; arc=none DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=Nvidia.com; s=selector2; h=From:Date:Subject:Message-ID:Content-Type:MIME-Version:X-MS-Exchange-SenderADCheck; bh=CgtgXQrH0EO88ortFz8WULLNVVyBTVnkFegymJEXa3Q=; b=O/pSaiWa+POdtJGLv6NwkRVJdEbjuZ1cYIgqsjaKgGCvCGneSb+HlYLSly87+06ZTCoPn/RXw8wrv8bKqhELSmQsFUc+djtMv+4JEns9grGwvD6wOCIei54kAlGhOzs1/JyOZmn2L+tcxwyh+p7cZ5rtNt4XbOH29F8lsCyZkuOM2CYoHi4hwIIiuoWXwxzQaZmm3RSf+0Jj3a5zcS63byDRb7ulHKoLBzAlQtgEy4g+W3ofePiNLx8dk1eOcNh93pWaGq5Lj8wah4oMnH8/lCJ2ODnvOQUmTFnTQvutU95h8YrNBVdB7Y41vRYKzrCIPn9DzflgEjVJuugIPcZtmQ== Received: from MN2PR12MB3823.namprd12.prod.outlook.com (2603:10b6:208:168::26) by BL0PR12MB4994.namprd12.prod.outlook.com (2603:10b6:208:1ca::13) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.20.4108.26; Thu, 6 May 2021 15:37:23 +0000 Received: from MN2PR12MB3823.namprd12.prod.outlook.com ([fe80::ccd7:fb49:6f2d:acf2]) by MN2PR12MB3823.namprd12.prod.outlook.com ([fe80::ccd7:fb49:6f2d:acf2%7]) with mapi id 15.20.4108.026; Thu, 6 May 2021 15:37:23 +0000 From: "Zi Yan" To: "David Hildenbrand" Cc: "Oscar Salvador" , "Michael Ellerman" , "Benjamin Herrenschmidt" , "Thomas Gleixner" , x86@kernel.org, "Andy Lutomirski" , "Rafael J . Wysocki" , "Andrew Morton" , "Mike Rapoport" , "Anshuman Khandual" , "Michal Hocko" , "Dan Williams" , "Wei Yang" , linux-ia64@vger.kernel.org, linux-kernel@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, linux-mm@kvack.org Subject: Re: [RFC PATCH 0/7] Memory hotplug/hotremove at subsection size Date: Thu, 06 May 2021 11:37:15 -0400 X-Mailer: MailMate (1.14r5757) Message-ID: <9D7FD316-988E-4B11-AC1C-64FF790BA79E@nvidia.com> In-Reply-To: References: <20210506152623.178731-1-zi.yan@sent.com> Content-Type: multipart/signed; boundary="=_MailMate_20560B3D-9CB2-4483-BBC2-6D4DFD4AF167_="; micalg=pgp-sha512; protocol="application/pgp-signature" X-Originating-IP: [216.228.112.22] X-ClientProxiedBy: BL0PR02CA0023.namprd02.prod.outlook.com (2603:10b6:207:3c::36) To MN2PR12MB3823.namprd12.prod.outlook.com (2603:10b6:208:168::26) MIME-Version: 1.0 X-MS-Exchange-MessageSentRepresentingType: 1 Received: from [10.2.63.7] (216.228.112.22) by BL0PR02CA0023.namprd02.prod.outlook.com (2603:10b6:207:3c::36) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.20.4108.24 via Frontend Transport; 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dkim=pass header.d=Nvidia.com header.s=selector2 header.b="O/pSaiWa"; spf=none (imf06.hostedemail.com: domain of ziy@nvidia.com has no SPF policy when checking 40.107.92.41) smtp.mailfrom=ziy@nvidia.com; dmarc=pass (policy=none) header.from=nvidia.com X-Rspamd-Server: rspam01 X-Rspamd-Queue-Id: E1CA9C0007F7 X-Stat-Signature: oaxf4zd6fj9j5jnh5tnn914wy9dhz8ps Received-SPF: none (nvidia.com>: No applicable sender policy available) receiver=imf06; identity=mailfrom; envelope-from=""; helo=NAM10-BN7-obe.outbound.protection.outlook.com; client-ip=40.107.92.41 X-HE-DKIM-Result: pass/pass X-HE-Tag: 1620315445-636973 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: --=_MailMate_20560B3D-9CB2-4483-BBC2-6D4DFD4AF167_= Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable On 6 May 2021, at 11:31, David Hildenbrand wrote: > On 06.05.21 17:26, Zi Yan wrote: >> From: Zi Yan >> >> Hi all, >> >> This patchset tries to remove the restriction on memory hotplug/hotrem= ove >> granularity, which is always greater or equal to memory section size[1= ]. >> With the patchset, kernel is able to online/offline memory at a size i= ndependent >> of memory section size, as small as 2MB (the subsection size). > > ... which doesn't make any sense as we can only online/offline whole me= mory block devices. Why limit the memory block size to section size? Patch 3 removes the rest= riction by using (start_pfn, nr_pages) to allow memory block size goes below sect= ion size. Also we have subsection bitmap available to tell us which subsection is o= nline, there is no reason to force memory block size to match section size. > >> >> The motivation is to increase MAX_ORDER of the buddy allocator and pag= eblock >> size without increasing memory hotplug/hotremove granularity at the sa= me time, > > Gah, no. Please no. No. > >> so that the kernel can allocator 1GB pages using buddy allocator and u= tilizes >> existing pageblock based anti-fragmentation, paving the road for 1GB T= HP >> support[2]. > > Not like this, please no. > >> >> The patchset utilizes the existing subsection support[3] and changes t= he >> section size alignment checks to subsection size alignment checks. The= re are >> also changes to pageblock code to support partial pageblocks, when pag= eblock >> size is increased along with MAX_ORDER. Increasing pageblock size can = enable >> kernel to utilize existing anti-fragmentation mechanism for gigantic p= age >> allocations. > > Please not like this. > >> >> The last patch increases SECTION_SIZE_BITS to demonstrate the use of m= emory >> hotplug/hotremove subsection, but is not intended to be merged as is. = It is >> there in case one wants to try this out and will be removed during the= final >> submission. >> >> Feel free to give suggestions and comments. I am looking forward to yo= ur >> feedback. > > Please not like this. Do you mind sharing more useful feedback instead of just saying a lot of = No? Thanks. =E2=80=94 Best Regards, Yan Zi --=_MailMate_20560B3D-9CB2-4483-BBC2-6D4DFD4AF167_= Content-Description: OpenPGP digital signature Content-Disposition: attachment; filename=signature.asc Content-Type: application/pgp-signature; name=signature.asc -----BEGIN PGP SIGNATURE----- iQJDBAEBCgAtFiEEh7yFAW3gwjwQ4C9anbJR82th+ooFAmCUDSsPHHppeUBudmlk aWEuY29tAAoJEJ2yUfNrYfqKuzEP/jmIOHHfzAPAXeBAyTyp5XWNQJbjDR7uTubU wbuJC5jOofGdiSKypbdGSB5ta/srQPxD8wEeXFfBDKgTeL438WTPlchWYTQE0rst hzSVWGQYddrh5V3BGXqRTRoUIIJicIVo053gqojjoDhxNWnCA+xThcoIpFoIADe3 PlG5o4CQjzfE+vjawuuiCRhSW8vlFg0Sxyg2TV1T47IMdvogvazYSJVuhuUp/5l2 iOfaartwDXifmb+88qMGXuulvThLlD5I7eXCqrs/Y1AtkW3O++cwmCOSwKrT/9r9 6vs3fRel0PSM66B2lLpWynmv0EjtQbSW2yq7RMBswI62WhjwSNaieTtLX+1VG+tT 19MlmlrAdg97LIkWRh97si6z1xTsh7C712gPLXfijBPebruYtVts3XDSDwTS982+ 1HIEYnnM7BUDxvoZ8F1zRTHIauSioFyV1IhJnYxhfamYBtZzAfbbT/hOsi28nVZ7 6PXf4oyJeLLcjlbQ+9MROFbbwZNhDoABW3iIfwalNL0IdErLP8Uh34AF2YOLdKOy Xv2hWs+1SNnhqZH1XfHRvFFxdte2P/rpXVh7qR48MfPw/58bWGgnLJvwNecighkm vLE6VBMxUjtTI9N5gu+KqCJwNIvhGGfUCffA+e9UQ5xPrB7NgkH4W2kDMpocCiUE hODKA/KB =h9b6 -----END PGP SIGNATURE----- --=_MailMate_20560B3D-9CB2-4483-BBC2-6D4DFD4AF167_=--