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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 8550FC46CA3 for ; Wed, 29 Nov 2023 19:47:23 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233699AbjK2TrP (ORCPT ); Wed, 29 Nov 2023 14:47:15 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:55672 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233713AbjK2TrN (ORCPT ); Wed, 29 Nov 2023 14:47:13 -0500 Received: from NAM11-CO1-obe.outbound.protection.outlook.com (mail-co1nam11on2044.outbound.protection.outlook.com [40.107.220.44]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 3981710C8 for ; Wed, 29 Nov 2023 11:47:18 -0800 (PST) ARC-Seal: i=1; a=rsa-sha256; s=arcselector9901; d=microsoft.com; cv=none; b=S+htZ5ops9A3nM7BIHgq4L8rEqGGtUpPeUnU17qNQoB6ZfQyoeHG2L12O/4ypCc7pCEevKM1cwUIVMYf0WTFZLJqccucWOUxRwT6GTf9Bqy3HTG70y202dKiKdjEuPMZ/hnmC4ncrgvvB7YhCOO1AVpywaPu23BYIIF/TtY3P9MvPB6exdnjRTKfaeRinJaGQDTkRt6R1Qz2ckrUsbmPVNc5qGqyVALnGma9UyoqjQE35aq+3BTeC5W+34qrwmVK+IB4YouMDqW9mc4S2srNFUjbkzkassPwzV92dJOsCEoWZOeVC61CVbojV0K1Fl6wVGuniuuYQ825hGHtB5Zy3w== 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-AntiSpam-MessageData-ChunkCount:X-MS-Exchange-AntiSpam-MessageData-0:X-MS-Exchange-AntiSpam-MessageData-1; bh=EambDCrw/rWaHC+JKGcsbw1er7EEuN1uxEzbpgwnSyA=; b=EjCIGfxufeDkBIbQP83rO34dOMzlFULH9JI9//4SYsrC5jp01nNUWA/o53YhtdAkjwjHGXYTMVp9fbLvhiHLq1L5nMy1kxiwjRMm8csSiDsahv+5Fqx9Rstv3IgUziTxq6Uj28RcqCWL5o/Z/IovBzJdwtOVu4bOlukET4+tddEFq+bPKrYmLhcu69QCmFCx2gI9HqBJMlZ6x6EgBZ7WcOG2bUTPsYXDQZWfJWIJ++CElRXuL2f6Kx9asLm8miYf8mtJZfYLNidHyoYCYpSYny9U67s+yGq9zNvpXJ3Wpp9NuQjdtOx1Dqaf4QXZkZqJQL4epQNm3iQ0pJUZkSQ1yA== 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=EambDCrw/rWaHC+JKGcsbw1er7EEuN1uxEzbpgwnSyA=; b=aP+PCCa9FQSDmiqhJOSnwL077Hp4Fx6EUqQRN4rgY9hQJaPjuODuw90VM0lC5GXq3sR7uqGnv05if8emi1FiJYBOc5o8NXsVQYL9pxa72NAJGD31cY74cjmO9z21siRyy5Z0iAiGlXExaFpWjZZtMNPj+5fqDIFUBgEoGVY6thQRgnVJd/aSy0IZ1MX/o6S82xuhISNcafZyCjbMjxgFZIiLTe35oVuR7yfPiO8rzfhMGcTJpHDeW3ls6lWXiqdrDsosf6VwF+eXOfjMk4Qcv6dHvKNUKhKk/hsNi4kvqOZDduX9IqJJaILJDiN4G15tDyp+M225kosznDrijCu7+w== Authentication-Results: dkim=none (message not signed) header.d=none;dmarc=none action=none header.from=nvidia.com; Received: from BY5PR12MB4130.namprd12.prod.outlook.com (2603:10b6:a03:20b::16) by SA1PR12MB8967.namprd12.prod.outlook.com (2603:10b6:806:38b::11) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.20.7046.22; Wed, 29 Nov 2023 19:47:15 +0000 Received: from BY5PR12MB4130.namprd12.prod.outlook.com ([fe80::6b9f:df87:1ee2:88ca]) by BY5PR12MB4130.namprd12.prod.outlook.com ([fe80::6b9f:df87:1ee2:88ca%6]) with mapi id 15.20.7046.015; Wed, 29 Nov 2023 19:47:15 +0000 Message-ID: <84636e85-8b94-4b68-8b3b-6f09d26aefbe@nvidia.com> Date: Wed, 29 Nov 2023 11:46:53 -0800 User-Agent: Mozilla Thunderbird Subject: Re: [RESEND PATCH v7 00/10] Small-sized THP for anonymous memory Content-Language: en-US To: Ryan Roberts , David Hildenbrand , Alistair Popple Cc: Matthew Wilcox , Andrew Morton , Yin Fengwei , Yu Zhao , Catalin Marinas , Anshuman Khandual , Yang Shi , "Huang, Ying" , Zi Yan , Luis Chamberlain , Itaru Kitayama , "Kirill A. Shutemov" , David Rientjes , Vlastimil Babka , Hugh Dickins , Kefeng Wang , linux-mm@kvack.org, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org References: <20231122162950.3854897-1-ryan.roberts@arm.com> <9c8f6d2a-7ed8-45d2-9684-d77489bd99b8@redhat.com> <26c361bc-6d87-4a57-9fae-ef635c9039c7@redhat.com> <87sf4rppuc.fsf@nvdebian.thelocal> <51e6c9f1-e863-464b-b5f3-d7f60a7ebed6@arm.com> <58af512c-3d7d-4774-88f7-6336c9384b61@arm.com> <137902b6-24dc-4d51-9be2-6f94aa9dbc3a@redhat.com> <47d27539-6cf1-4375-9bbb-2ebb9a2acfb3@nvidia.com> <832a486c-7f22-49cd-a3f5-3709dc6c6d09@arm.com> From: John Hubbard In-Reply-To: <832a486c-7f22-49cd-a3f5-3709dc6c6d09@arm.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit X-ClientProxiedBy: BYAPR04CA0028.namprd04.prod.outlook.com (2603:10b6:a03:40::41) To BY5PR12MB4130.namprd12.prod.outlook.com (2603:10b6:a03:20b::16) MIME-Version: 1.0 X-MS-PublicTrafficType: Email X-MS-TrafficTypeDiagnostic: BY5PR12MB4130:EE_|SA1PR12MB8967:EE_ X-MS-Office365-Filtering-Correlation-Id: 315f278e-1878-4a06-8d25-08dbf113fce6 X-MS-Exchange-SenderADCheck: 1 X-MS-Exchange-AntiSpam-Relay: 0 X-Microsoft-Antispam: BCL:0; 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As discussed, extending the existing single-large-file statistics might >>>> not be possible and we'd have to come up with a new interface, that maybe >>>> completely lacks "AnonHugePages" and directly goes for the individual sizes. >>> >>> Yes, but I think we are agreed this is future work. >>> >> >> We do want to have at least some way to verify that mTHP is active from >> day 0, though. > > Could you clarify what you mean by "active"? I was thinking of the *pte* counters that we had in v6, in /proc/vmstat and /proc/meminfo. I missed those, they were helpful in confirming that the test was actually using the new feature. It's easy to misconfigure these tests because there are so many settings (in addition to kernel settings), and people were having some difficulty. > > Current plan is that there will be a per-size > transparent_hugepage/hugepages-kB/enabled sysfs file that can be querried > to see if the size is enabled (available for the kernel to use). > > But for this initial submission, we previously agreed (well, at least David and > I) that not having a full set of stats is not a problem - they can come later. > So the only way to verify that the kernel is allocating and mapping a particular > THP size is to parse /proc/pagemap and look at the PFNs for now. Is that > sufficient? > ugh, that's a little rough for just a command line sysadmin or QA person, isn't it? Still, I expect we can survive without it for an initial release. thanks, -- John Hubbard NVIDIA