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=-11.6 required=3.0 tests=BAYES_00,DKIM_INVALID, DKIM_SIGNED,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, MSGID_FROM_MTA_HEADER,SPF_HELO_NONE,SPF_PASS,TVD_PH_BODY_ACCOUNTS_PRE, USER_AGENT_GIT 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 D77ACC6377A for ; Wed, 21 Jul 2021 23:05:33 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 6B3AA61029 for ; Wed, 21 Jul 2021 23:05:33 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 6B3AA61029 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=oracle.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id DB9F06B0072; Wed, 21 Jul 2021 19:05:32 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id D51726B0073; Wed, 21 Jul 2021 19:05:32 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id BBD806B0072; Wed, 21 Jul 2021 19:05:32 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0062.hostedemail.com [216.40.44.62]) by kanga.kvack.org (Postfix) with ESMTP id A1D646B006C for ; Wed, 21 Jul 2021 19:05:32 -0400 (EDT) Received: from smtpin22.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay03.hostedemail.com (Postfix) with ESMTP id 51E398248047 for ; Wed, 21 Jul 2021 23:05:32 +0000 (UTC) X-FDA: 78388128504.22.993C7F1 Received: from mx0a-00069f02.pphosted.com (mx0a-00069f02.pphosted.com [205.220.165.32]) by imf30.hostedemail.com (Postfix) with ESMTP id B6807E008BFE for ; Wed, 21 Jul 2021 23:05:31 +0000 (UTC) Received: from pps.filterd (m0246617.ppops.net [127.0.0.1]) by mx0b-00069f02.pphosted.com (8.16.0.43/8.16.0.43) with SMTP id 16LMvG6r009329; Wed, 21 Jul 2021 23:05:26 GMT DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=oracle.com; h=from : to : cc : subject : date : message-id : content-transfer-encoding : content-type : mime-version; s=corp-2021-07-09; bh=OEk2me/tuxVjQrtAfxnZ0WsH6lXIBG8II8327vcDUO4=; b=M2vy+PNbHaVv5gAGiKdJvxi2DUSViuLSFuPyGJ5IBZ4Rnrv7THgRYCt5TBcyQQtA1JTq VVCkKxTOs2GxBQ48w09oRLUPaZSq6AV/s5Mfj6lyZ5gqZjb34er1pm7FxcbZE3uVCS9b BmNLPn0OblTh8iLZvZnJ9UcN0tKvpW1y5BYIpg3mOiMtPq7eWkRuGcA/i5qsFATWkCW+ nA5534i6FE46D0V3cyEPodNm60YX6r1t/CHrBD3pOr7yGwbWSWQ6XFM4EqjjhltiWxZE BS1gMAqlESv22d2TYdcHNrmRwxr1Rn+lRpU7N1izC6SStSHUrjPSUd4f1a/UKBm9+dPE vQ== DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=oracle.com; h=from : to : cc : subject : date : message-id : content-transfer-encoding : content-type : mime-version; s=corp-2020-01-29; bh=OEk2me/tuxVjQrtAfxnZ0WsH6lXIBG8II8327vcDUO4=; b=raESjYOrSYg4LPzUZW5yvmrcFBplGnJjPQfFXVIDmKStR/kUc/8Kw/04mnsvdVzzoY2o x2t2Zot0IJtukl/YC0p7IuamB2J80pqTcM8jf1uz1yZjhdOf0V9mVIf1PabLXPHwjhc4 WMnv/smd3iWn3B8R23SWr3wMj7hwSbb0IcRcKmneY7e38XBf8pIEzpWY13Ac4fYsGu7g dpa/lnKJIVcyT/BlvgQZIj9PxB2GSb4Ap3YjHAnKtoLN3t3UEv2LbftWylpzICp9dVps vOyQirh9QXcQTgOJBBo1zbtbTcIFUsoxsR2onMQm/KSaYhvIB1sRJkTC7pSaM5Ksyd7n ig== Received: from aserp3030.oracle.com (aserp3030.oracle.com [141.146.126.71]) by mx0b-00069f02.pphosted.com with ESMTP id 39xu2fr5wa-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Wed, 21 Jul 2021 23:05:26 +0000 Received: from pps.filterd (aserp3030.oracle.com [127.0.0.1]) by aserp3030.oracle.com (8.16.0.42/8.16.0.42) with SMTP id 16LN5NPm103248; Wed, 21 Jul 2021 23:05:25 GMT Received: from nam04-dm6-obe.outbound.protection.outlook.com (mail-dm6nam08lp2042.outbound.protection.outlook.com [104.47.73.42]) by aserp3030.oracle.com with ESMTP id 39wunmv2ae-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Wed, 21 Jul 2021 23:05:24 +0000 ARC-Seal: i=1; a=rsa-sha256; s=arcselector9901; d=microsoft.com; cv=none; b=gKuC3oTfg7rKh08C4YpTt56KrVxjjTuD782qyuIB5JtraFelquSVbnQyJZ7ciwHZ1/kXLbC6VDCyhK/wJDeZ8RRbhIczSciC6D7CLrU5Vc7ap4PFRtcet2rjoE5LSxZgrdXZDnZ0kWMVyoKPkjq8aZ6ax6zOPi2K0HR6zF76DxXD6Y/6GEBeVQ1DwRODC+ReKF97pydoasWCp3Pi8M+b//qunaOmxnvrISeq56RGtEyH1kkhCxozuB6UQNLAtiVBTix2NNqmMHHatpJw1JcUdq938ptsxuO1KCR4BGQpr5rbpO0twUSHdP5VQ5Z5Mg7CkgBt0MktHbSHT2Zn2ZS+FQ== 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=OEk2me/tuxVjQrtAfxnZ0WsH6lXIBG8II8327vcDUO4=; b=D4YLEjMWGC0ImEe2edvt6OTxh38R0evk2mYeIfS7hGhquTIJ0woKegu/0CYudc3ITrydnE6TvClLJXBuCORcuR8VmEpJV//wWg5NLBu3+sr6MIFXnpKhSeriZ+kkjUoRXtfRHG1cwQiAfvQmhby6mjn6WQuUR2+YD146tpZPzkpgFLY9h2x/C/DFQE8VnBUj88IunFodHFrNnK+/W049mJHNWBPoO8FFPLa3JDYnGVFubCDOJ9qUw1YkEZVSFjxbo89S58PBZzSyOVBWVJ8kpU38Ih9p1jTGZscZCFaBmQMIhn0XnxD04e+sn0b/3KbgV6UhJeq5mGsOzAxiKC5z5w== ARC-Authentication-Results: i=1; mx.microsoft.com 1; spf=pass smtp.mailfrom=oracle.com; dmarc=pass action=none header.from=oracle.com; dkim=pass header.d=oracle.com; arc=none DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=oracle.onmicrosoft.com; s=selector2-oracle-onmicrosoft-com; h=From:Date:Subject:Message-ID:Content-Type:MIME-Version:X-MS-Exchange-SenderADCheck; bh=OEk2me/tuxVjQrtAfxnZ0WsH6lXIBG8II8327vcDUO4=; b=J6YmGsb42KjluhfbKFXwqXrEeHpJPLMPdVT3orsOqCZfDy02UGB1YesP1/sNXfcihNAtqnWVT2J6NqjgPBJ827UEVOSPGlrjhQxgiUNjUGZZ35EW4hVmwNa4e7yoVVBaMcmKcudx8oq+Eod2XktA6aKwxSIIipQ0TUtTaQlfvGI= Received: from BY5PR10MB4196.namprd10.prod.outlook.com (2603:10b6:a03:20d::23) by BYAPR10MB3735.namprd10.prod.outlook.com (2603:10b6:a03:11e::17) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.20.4331.26; Wed, 21 Jul 2021 23:05:21 +0000 Received: from BY5PR10MB4196.namprd10.prod.outlook.com ([fe80::8d2a:558d:ab4a:9c2a]) by BY5PR10MB4196.namprd10.prod.outlook.com ([fe80::8d2a:558d:ab4a:9c2a%5]) with mapi id 15.20.4331.034; Wed, 21 Jul 2021 23:05:21 +0000 From: Mike Kravetz To: linux-mm@kvack.org, linux-kernel@vger.kernel.org Cc: David Hildenbrand , Michal Hocko , Oscar Salvador , Zi Yan , Muchun Song , Naoya Horiguchi , David Rientjes , Andrew Morton , Mike Kravetz Subject: [PATCH 0/8] hugetlb: add demote/split page functionality Date: Wed, 21 Jul 2021 16:05:03 -0700 Message-Id: <20210721230511.201823-1-mike.kravetz@oracle.com> X-Mailer: git-send-email 2.31.1 Content-Type: text/plain X-ClientProxiedBy: MWHPR1201CA0021.namprd12.prod.outlook.com (2603:10b6:301:4a::31) To BY5PR10MB4196.namprd10.prod.outlook.com (2603:10b6:a03:20d::23) MIME-Version: 1.0 X-MS-Exchange-MessageSentRepresentingType: 1 Received: from monkey.oracle.com (50.38.35.18) by MWHPR1201CA0021.namprd12.prod.outlook.com (2603:10b6:301:4a::31) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.20.4331.22 via Frontend Transport; Wed, 21 Jul 2021 23:05:20 +0000 X-MS-PublicTrafficType: Email X-MS-Office365-Filtering-Correlation-Id: fed741b9-e4b4-4933-cbdf-08d94c9c0387 X-MS-TrafficTypeDiagnostic: BYAPR10MB3735: X-MS-Exchange-Transport-Forked: True X-Microsoft-Antispam-PRVS: X-MS-Oob-TLC-OOBClassifiers: OLM:9508; X-MS-Exchange-SenderADCheck: 1 X-MS-Exchange-AntiSpam-Relay: 0 X-Microsoft-Antispam: BCL:0; X-Microsoft-Antispam-Message-Info: 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 X-Forefront-Antispam-Report: CIP:255.255.255.255;CTRY:;LANG:en;SCL:1;SRV:;IPV:NLI;SFV:NSPM;H:BY5PR10MB4196.namprd10.prod.outlook.com;PTR:;CAT:NONE;SFS:(346002)(366004)(39860400002)(396003)(136003)(376002)(186003)(66556008)(478600001)(52116002)(86362001)(2616005)(107886003)(8936002)(5660300002)(1076003)(4326008)(6486002)(2906002)(66946007)(66476007)(956004)(6666004)(26005)(316002)(38350700002)(38100700002)(7416002)(36756003)(83380400001)(7696005)(54906003)(966005)(8676002)(44832011);DIR:OUT;SFP:1101; X-MS-Exchange-AntiSpam-MessageData-ChunkCount: 1 X-MS-Exchange-AntiSpam-MessageData-0: =?us-ascii?Q?gLUKqWfinaiUoUeI1S8HhCYsR//cCG/EK8Jw0ry+++m3utYIMb1ZAeOYd9+k?= =?us-ascii?Q?FipDg8BGP73LX9RBhats6J1kluVJ92OG+HQShTclyWEdeUr6/2gcTvbEtOmO?= =?us-ascii?Q?WOJhqJHldrw7r8IUouI8fwCF+Af22B1uU9F4OPEV7H9zfJIEK7Sgnkx68Qnc?= =?us-ascii?Q?QIVEYCBmQUd57zQ/GOG+74CRo+RSOZQDdhc/TsRL7OesWJ3C/skpUsr5wCwp?= =?us-ascii?Q?Nz9YMavl2dLjXAqwZ5+gRk0KJK2VwQnDJBLgcuoMFM1WVUx2MWwqRdpZsWMY?= =?us-ascii?Q?HwMIeuSzeWex2M5lAeenkY7+BHhMD1r0XRSkoNi6+h8dX9oLl7JLab1roJ8k?= =?us-ascii?Q?rE4+FRF9UOA3T+BBwMWfSDEx+Tl8LkoRvUZiIo5y+n2GiwOPQKROW4zOVk9E?= =?us-ascii?Q?l+v5pgSMU4l5ikxght7fo3nEhaiRUTRkhLJKyzsVjx+oDYTzr6SY/JLS/Gm0?= =?us-ascii?Q?lor1osWC2Ye8F01YLRL5X750t77qmPzNh1vBx87eFxhWAu2pusB+Zdk7FnSE?= =?us-ascii?Q?w2V6RdrPsNJ5oZmMPNJKjQ7VeuJV8WrvsgDvZZjUMQey96eYK0qapJ9jew5d?= =?us-ascii?Q?0rG8DdNbSaSN3tfyMgQDRvHkrLw/MeRkYtDhjJUQ7Mv10tCsVhi43gvlLIIm?= =?us-ascii?Q?yTSu0hdKms3v40a5Tkph71wMcsfOq5uPPYn7vbT6+fkUMKo4eQvu1zClpcMr?= =?us-ascii?Q?+Uta7mrO7xDL600oj2qOXt3WNnZvxA2wpFXkG3imVS1VkkC2KQq5fSyNnVSQ?= =?us-ascii?Q?LjnsXEh4xYAq+zrWcKgx4ZNGW0fbSwRbIa7MM1R2YdZWUrJkKTcqT0AvAILW?= =?us-ascii?Q?nOszO9+qWE97PIgRVN7ffb+DJb+nsigFOxpEf6cSlbj/takWHsDfl81wTd2z?= =?us-ascii?Q?p0OyCOMrf8csJszuArub3hLT389gSHv66cSTAHHc67TZbxWu5a9rjfoGaCY/?= =?us-ascii?Q?mqcgxYlUR1dOn9EDZeudROSHjvh87CUuz6IjyV1fWKLxeu6gcYlqIPko7cYi?= =?us-ascii?Q?1n2wZ87KgCOrpWvrkAiaB6GdtZyih5UCYxB1eDKSThp3s18/Wk9uk/GfXKZ7?= =?us-ascii?Q?edaWpMsYqlus+4SllIcFbVQXf9QGuneSbuzYeyfZ9j37JjgHeFNi0EVmebSs?= =?us-ascii?Q?L/Pz/QDaWItddy1CF1XeYDa0V/lC202pihRHPiEHNMo7LbHfbKExnUrjidUZ?= =?us-ascii?Q?Ni8OjiYNRr0KZX+hdJkrxdCjHFCA6wLrbhC8nvsPxyLWxh4VibThp6dBUMa6?= =?us-ascii?Q?NIpM57u6RxSmQBQp6022gOV2Cg1RSFuc9RaGzQLfF23J+HCMKEhi9JW1SiYg?= =?us-ascii?Q?Q2LztU9Z2pghamKHeNIPwOWO?= X-OriginatorOrg: oracle.com X-MS-Exchange-CrossTenant-Network-Message-Id: fed741b9-e4b4-4933-cbdf-08d94c9c0387 X-MS-Exchange-CrossTenant-AuthSource: BY5PR10MB4196.namprd10.prod.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Internal X-MS-Exchange-CrossTenant-OriginalArrivalTime: 21 Jul 2021 23:05:20.9935 (UTC) X-MS-Exchange-CrossTenant-FromEntityHeader: Hosted X-MS-Exchange-CrossTenant-Id: 4e2c6054-71cb-48f1-bd6c-3a9705aca71b X-MS-Exchange-CrossTenant-MailboxType: HOSTED X-MS-Exchange-CrossTenant-UserPrincipalName: 4irN4HvLW6I9VCLGZTQqqjN9FDsbnOz9hD5p+y5fCSxn+KbG3Ymno1OsFqSQ+lr1VL69uTcypmoGMFb0ab7oNw== X-MS-Exchange-Transport-CrossTenantHeadersStamped: BYAPR10MB3735 X-Proofpoint-Virus-Version: vendor=nai engine=6200 definitions=10052 signatures=668682 X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 suspectscore=0 phishscore=0 spamscore=0 bulkscore=0 mlxlogscore=999 adultscore=0 malwarescore=0 mlxscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2104190000 definitions=main-2107210138 X-Proofpoint-ORIG-GUID: XZG7f0dbjawrbugYreERjOQ-NsaMNVbR X-Proofpoint-GUID: XZG7f0dbjawrbugYreERjOQ-NsaMNVbR X-Rspamd-Server: rspam06 X-Rspamd-Queue-Id: B6807E008BFE X-Stat-Signature: 7599o6k1scnucebdpra9sb1mxbgrjtb4 Authentication-Results: imf30.hostedemail.com; dkim=pass header.d=oracle.com header.s=corp-2021-07-09 header.b=M2vy+PNb; dkim=pass header.d=oracle.com header.s=corp-2020-01-29 header.b=raESjYOr; dkim=pass header.d=oracle.onmicrosoft.com header.s=selector2-oracle-onmicrosoft-com header.b=J6YmGsb4; spf=none (imf30.hostedemail.com: domain of mike.kravetz@oracle.com has no SPF policy when checking 205.220.165.32) smtp.mailfrom=mike.kravetz@oracle.com; dmarc=pass (policy=none) header.from=oracle.com X-HE-Tag: 1626908731-976108 Content-Transfer-Encoding: quoted-printable 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: The concurrent use of multiple hugetlb page sizes on a single system is becoming more common. One of the reasons is better TLB support for gigantic page sizes on x86 hardware. In addition, hugetlb pages are being used to back VMs in hosting environments. When using hugetlb pages to back VMs in such environments, it is sometimes desirable to preallocate hugetlb pools. This avoids the delay and uncertainty of allocating hugetlb pages at VM startup. In addition, preallocating huge pages minimizes the issue of memory fragmentation that increases the longer the system is up and running. In such environments, a combination of larger and smaller hugetlb pages are preallocated in anticipation of backing VMs of various sizes. Over time, the preallocated pool of smaller hugetlb pages may become depleted while larger hugetlb pages still remain. In such situations, it may be desirable to convert larger hugetlb pages to smaller hugetlb pages. Converting larger to smaller hugetlb pages can be accomplished today by first freeing the larger page to the buddy allocator and then allocating the smaller pages. However, there are two issues with this approach: 1) This process can take quite some time, especially if allocation of the smaller pages is not immediate and requires migration/compaction. 2) There is no guarantee that the total size of smaller pages allocated will match the size of the larger page which was freed. This is because the area freed by the larger page could quickly be fragmented. To address these issues, introduce the concept of hugetlb page demotion. Demotion provides a means of 'in place' splitting a hugetlb page to pages of a smaller size. For example, on x86 one 1G page can be demoted to 512 2M pages. Page demotion is controlled via sysfs files. - demote_size Read only target page size for demotion - demote Writable number of hugetlb pages to be demoted Only hugetlb pages which are free at the time of the request can be demot= ed. Demotion does not add to the complexity surplus pages. Demotion also hon= ors reserved huge pages. Therefore, when a value is written to the sysfs dem= ote file, that value is only the maximum number of pages which will be demote= d. It is possible fewer will actually be demoted. If demote_size is PAGESIZE, demote will simply free pages to the buddy allocator. Real world use cases -------------------- There are groups today using hugetlb pages to back VMs on x86. Their use case is as described above. They have experienced the issues with performance and not necessarily getting the excepted number smaller huge pages after free/allocate cycle. Note to reviewers ----------------- Patches 1-5 provide the basic demote functionality. They are built on next-20210721. Patch 3 deals with this issue of speculative page references as discussed in [1] and [2]. It builds on the ideas used in patches currently in mmotm. There have been few comments on those patches in mmotm, so I do not feel the approach has been well vetted. Patches 6-8 are an optimization to deal with vmemmap optimized pages. This was discussed in the RFC. IMO, the code may not be worth the benefit. They could be dropped with no loss of functionality. In addition, Muchun has recently sent patches to further optimize hugetlb vmemmap reduction by only requiring one vmemmap page per huge page [3]. These patches do not take Muchun's new patches into account. RFC -> v1 - Provides basic support for vmemmap optimized pages - Takes speculative page references into account - Updated Documentation file - Added optimizations for vmemmap optimized pages [1] https://lore.kernel.org/linux-mm/CAG48ez23q0Jy9cuVnwAe7t_fdhMk2S7N5Hd= i-GLcCeq5bsfLxw@mail.gmail.com/ [2] https://lore.kernel.org/linux-mm/20210710002441.167759-1-mike.kravetz= @oracle.com/ [3] https://lore.kernel.org/linux-mm/20210714091800.42645-1-songmuchun@by= tedance.com/ Mike Kravetz (8): hugetlb: add demote hugetlb page sysfs interfaces hugetlb: add HPageCma flag and code to free non-gigantic pages in CMA hugetlb: add demote bool to gigantic page routines hugetlb: add hugetlb demote page support hugetlb: document the demote sysfs interfaces hugetlb: vmemmap optimizations when demoting hugetlb pages hugetlb: prepare destroy and prep routines for vmemmap optimized pages hugetlb: Optimized demote vmemmap optimizatized pages Documentation/admin-guide/mm/hugetlbpage.rst | 29 +- include/linux/hugetlb.h | 8 + include/linux/mm.h | 4 + mm/hugetlb.c | 328 +++++++++++++++++-- mm/hugetlb_vmemmap.c | 72 +++- mm/hugetlb_vmemmap.h | 16 + mm/sparse-vmemmap.c | 123 ++++++- 7 files changed, 538 insertions(+), 42 deletions(-) --=20 2.31.1