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 BC9B7C433EF for ; Wed, 20 Apr 2022 14:42:44 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1379741AbiDTOp2 (ORCPT ); Wed, 20 Apr 2022 10:45:28 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:45640 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S235868AbiDTOp1 (ORCPT ); Wed, 20 Apr 2022 10:45:27 -0400 Received: from mx0a-00082601.pphosted.com (mx0a-00082601.pphosted.com [67.231.145.42]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 831D228E3D; Wed, 20 Apr 2022 07:42:41 -0700 (PDT) Received: from pps.filterd (m0044012.ppops.net [127.0.0.1]) by mx0a-00082601.pphosted.com (8.16.1.2/8.16.1.2) with ESMTP id 23KBfgPw024070; Wed, 20 Apr 2022 07:42:41 -0700 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=fb.com; h=from : to : cc : subject : date : message-id : references : in-reply-to : content-type : content-id : mime-version; s=facebook; bh=w01TNDoAw/F2P5Z2ICY1odiri405XzNHvrL9ousHJkY=; b=UpxVsuCszv0Tj/MOYmhBpV9K4DcDoTdtKgR3egofLeK/pX/+C67JYZlVyYANmbkTMy3/ SvJ5ebg5OKDCL5L88Wd7d0Oi4WYuA+4LKRRzGXvmW67XegilzEeh5eKs7ML/JZ1IZfpR 8BoJt7wro18bOez6JWxt810O2ar5mDe+FVM= Received: from nam10-bn7-obe.outbound.protection.outlook.com (mail-bn7nam10lp2109.outbound.protection.outlook.com [104.47.70.109]) by mx0a-00082601.pphosted.com (PPS) with ESMTPS id 3fjhgxry76-2 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Wed, 20 Apr 2022 07:42:41 -0700 ARC-Seal: i=1; a=rsa-sha256; s=arcselector9901; d=microsoft.com; cv=none; b=U9Ci3ciSAFXO130WUdvpLzwaWRwlv6kchqQrQknIal++ySiViyZUZ2caMRfSJc3ybvPt2Dxwqsx3LiB3EyIkdHkFauEVb562Tx3HXaNliolcY+U48NQsq36MqBe7ZGF1J3GxFLWqODMREktTB4u/3jzf+GOfKSiH/jjJzxnm2Cd7ZiFYFj4eN3OgfViN7io+atpzO4k1k2Xb/qqL4j9btRvhjjLrMfsEtaNN6b8ISzKJrBIZfcSYRzwuBYS3QkG9fybJeHmn9Le6UEZikLI8IV2mnA7oE/Q0cKWMOHodHqgZ9IbKAi2uZg7IkgqXOpWusW0WVHT3EfookhwkyrvDTw== 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=w01TNDoAw/F2P5Z2ICY1odiri405XzNHvrL9ousHJkY=; b=RcUwaathUrM9vfTA1NPd/vL8+1ewOT7LNCthS9UwevSji7FRi+Sectkbj4v0S+p5pEazUoVx2zShouvVcxXJllmwQ9MgSKDsUqgkQw9j3pQIp1alzPwztnTd5h0hLWEcMZGbbV4YSZsIULy4T4ULV1jj8Zw2M2d7Zuh90Qqba2Pq8lMW0Kve8ijX8GwFYEw+o5liwtpB8e7lcko7V8JAZslyy+EuC4tArCiLme9pURNzmTRLbI3OrJJoWq/y4NyQTSo/+RcwNtitN5ZcJM23VCB8wdEnxkh2Wmpii5y3DHtJ9Gzk58sKKpy/E/+A6F0bApT2B8iIBfI8DwZVRlh/VA== ARC-Authentication-Results: i=1; mx.microsoft.com 1; spf=pass smtp.mailfrom=fb.com; dmarc=pass action=none header.from=fb.com; dkim=pass header.d=fb.com; arc=none Received: from SA1PR15MB5109.namprd15.prod.outlook.com (2603:10b6:806:1dc::10) by DM6PR15MB2905.namprd15.prod.outlook.com (2603:10b6:5:139::33) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.20.5164.20; Wed, 20 Apr 2022 14:42:37 +0000 Received: from SA1PR15MB5109.namprd15.prod.outlook.com ([fe80::20d2:26a2:6cb1:3c4b]) by SA1PR15MB5109.namprd15.prod.outlook.com ([fe80::20d2:26a2:6cb1:3c4b%6]) with mapi id 15.20.5164.025; Wed, 20 Apr 2022 14:42:37 +0000 From: Song Liu To: Linus Torvalds CC: Alexei Starovoitov , Mike Rapoport , "Edgecombe, Rick P" , "mcgrof@kernel.org" , "linux-kernel@vger.kernel.org" , "bpf@vger.kernel.org" , "hch@infradead.org" , "ast@kernel.org" , "daniel@iogearbox.net" , "linux-mm@kvack.org" , "song@kernel.org" , Kernel Team , "pmladek@suse.com" , "akpm@linux-foundation.org" , "hpa@zytor.com" , "dborkman@redhat.com" , "edumazet@google.com" , "bp@alien8.de" , "mbenes@suse.cz" , "imbrenda@linux.ibm.com" Subject: Re: [PATCH v4 bpf 0/4] vmalloc: bpf: introduce VM_ALLOW_HUGE_VMAP Thread-Topic: [PATCH v4 bpf 0/4] vmalloc: bpf: introduce VM_ALLOW_HUGE_VMAP Thread-Index: AQHYUOjRr/eYt5HVI0ucQZg4JV/u/6zxVckAgACoe4CAAPedAIAACgKAgAAgN4CAAlYOAIAA9TuAgAAUC4CAAD2oAIAA23uAgAAKuICAAHT81IAAz6kA Date: Wed, 20 Apr 2022 14:42:37 +0000 Message-ID: <3F75142B-3E87-4195-A026-3A7F1E595960@fb.com> References: <4AD023F9-FBCE-4C7C-A049-9292491408AA@fb.com> <88eafc9220d134d72db9eb381114432e71903022.camel@intel.com> <20220420020311.6ojfhcooumflnbbk@MacBook-Pro.local.dhcp.thefacebook.com> In-Reply-To: Accept-Language: en-US Content-Language: en-US X-MS-Has-Attach: X-MS-TNEF-Correlator: x-mailer: Apple Mail (2.3696.80.82.1.1) x-ms-publictraffictype: Email x-ms-office365-filtering-correlation-id: 873d8637-3be4-4f84-a6df-08da22dc03c9 x-ms-traffictypediagnostic: DM6PR15MB2905:EE_ x-microsoft-antispam-prvs: x-fb-source: Internal 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:SA1PR15MB5109.namprd15.prod.outlook.com;PTR:;CAT:NONE;SFS:(13230001)(366004)(6512007)(7416002)(91956017)(66476007)(71200400001)(5660300002)(64756008)(54906003)(36756003)(38070700005)(8676002)(316002)(86362001)(6916009)(122000001)(38100700002)(76116006)(2616005)(66946007)(508600001)(66446008)(8936002)(26005)(2906002)(6506007)(53546011)(33656002)(4326008)(6486002)(66556008)(186003)(14583001)(45980500001);DIR:OUT;SFP:1102; x-ms-exchange-antispam-messagedata-chunkcount: 1 x-ms-exchange-antispam-messagedata-0: =?us-ascii?Q?wTh5VkcLZysLZxxnUi5+f43O+QkWg8rObtHhHR1T5GSEPpBNgaYmVse3dXCj?= =?us-ascii?Q?LlV9Nh7wacUNP5ebcV+m2DcWmA0Ln5Hlp4884duKz0AZZ2dbQwp8kUd8j9mb?= =?us-ascii?Q?n1aNk76TBbnLo0InTW9LavK3OWbvJKiV+C4RKqsz2dWMsDIQgE2O52oaFL+L?= =?us-ascii?Q?D8u97qDK9RYNaoG6if0eHeTbM8FhMdnf1lz5mEKZZoj5EwEW76bZVI4e50RN?= =?us-ascii?Q?ouzRdqJS4bTL/HTAQp6LKvqZWC6JnP/3o4pZK+tQlF7M7HR20wNx4TxCyisy?= =?us-ascii?Q?dhVYc+Js7gmgZctsHiSNaUsxFZirrAJ2mxuD61oTN9SUoG4mSqgswgh5lu0o?= =?us-ascii?Q?sdanO3wuaiYET22KgJrv/eorkQVgMoo3XryaxmpbYQc07epM1+c1uJKL8atP?= =?us-ascii?Q?/5QAVFOfbWxLa65G3K2+x3iW96tnOqtvCx+FsRp1b2IIaU98PRDEK62b7e1F?= =?us-ascii?Q?xn7jLxpdOMD393Wv3MXL5N5F+HwNT3p18zdGYYmPftXlymsVwJHnBBff/hjm?= =?us-ascii?Q?bALv6Z3BNPdrBniAa5/ExwqZ1/V7Fp+iv8w2F0L1J0o+JL4Gc7XyRWg8Npii?= =?us-ascii?Q?GqjIiNVLTGwVvKa2QQdG/IpisOinAc7ErS6zDdsgkid5IccyAF13ZQ09eteT?= =?us-ascii?Q?0LXm/5Thi2ihRcQHa+eaWsShK87BshdEFuOdsHMwQGFNDYlhtdZDQbZo/Sdq?= =?us-ascii?Q?TyWs3Gwfp1PkgO4Fjf8DRxEMy+WvC4/vXT3Y5XRGX/d9D5DPSf6Jr8Qqf46P?= =?us-ascii?Q?MZjFYKkKZzhE+wwvAMDCRLdiIH51zkxx1h7gFChJuJK6Ih0rhLwO7QGAEizl?= =?us-ascii?Q?vP/jk6XdVfO2Q17yZUIJjGZ/XlaFYTSvl3407OFzHSedhybwDBuHA0M8p6Ik?= =?us-ascii?Q?MSkiZQg1MbSblWjBJJJz/HHVwMQpkp9Ww3Q/baLJA0+ks2c8HJV78gL4cFtu?= =?us-ascii?Q?yDbG+/uHKOr33wT6/BdoSJygz9nj9LgfcQhHHUrGmnaAw3NOi2u5OrQRzPDM?= =?us-ascii?Q?aDHBHzzuRHedXML2ScyJRBhr9m7201dBie8OEe9p0zhyHDA6ruVgnBbmDPKO?= =?us-ascii?Q?+XfjbhF+wb1A7UR0/actohZv5dzqKLe2FLdSvh2XaQwmLK43h53/MlaT2alX?= =?us-ascii?Q?uCOpYJz0WBlceYdpPEmJJxoUlygVs1Uzp5MwMJCbkRcecegokuqN68GAQWCd?= =?us-ascii?Q?PEJptVow4qIcB9OWA4EXJYwIpuoOaRj+fxXnMA1b+aQjUNkdZSqcVyHvPVsx?= =?us-ascii?Q?6eAiWTi/SB2vg55Lg1pyvlStrev9wb7+NWHKKfwAx+1a6r+3klZaBjdutvQX?= =?us-ascii?Q?95g19Qt0m/TORRvc96OgbNlyRVQuPA9I7yYNDvQ4EBlU/qETTTQQW+yT2gvr?= =?us-ascii?Q?NoQ3J054fKOz8cjg4uwvUlVpVWx+ECaRT5MkiQ8NMPFwU5JncU6CupcmiNRV?= =?us-ascii?Q?qibUfQHJoh/oGuM1cur/osQ4cIsZEd5I6KL03l+4DF/MFyfJtcIt0xKONuXv?= =?us-ascii?Q?vNt1DcX0Sfo+jVkHF4FBauVyWQFiA8edJZdPdPtvx+zuqFv5rPvAgk83NAL2?= =?us-ascii?Q?5FpstDCHPFG9UMnERcyJiYmwbA4b5JeZU5pi8xmFaG06Cwme48vD8Ko+wbpm?= =?us-ascii?Q?h8wKUXGl2zI3re8TwLPkhmmz+T/Bi9UnM54Rypmu6V/tWlODczGslI2t61c3?= =?us-ascii?Q?XOqIdFQaWuHLrTodSNYGzWu6CMHKQmN+iKF0yceGr/aZ09Qk6+UcmvufKcZ7?= =?us-ascii?Q?uKUxzTTfO6jeGwILM9DrhTqlsk8qdbE=3D?= Content-Type: text/plain; charset="us-ascii" Content-ID: MIME-Version: 1.0 X-OriginatorOrg: fb.com X-MS-Exchange-CrossTenant-AuthAs: Internal X-MS-Exchange-CrossTenant-AuthSource: SA1PR15MB5109.namprd15.prod.outlook.com X-MS-Exchange-CrossTenant-Network-Message-Id: 873d8637-3be4-4f84-a6df-08da22dc03c9 X-MS-Exchange-CrossTenant-originalarrivaltime: 20 Apr 2022 14:42:37.7261 (UTC) X-MS-Exchange-CrossTenant-fromentityheader: Hosted X-MS-Exchange-CrossTenant-id: 8ae927fe-1255-47a7-a2af-5f3a069daaa2 X-MS-Exchange-CrossTenant-mailboxtype: HOSTED X-MS-Exchange-CrossTenant-userprincipalname: Ks+T/flHOxZYHPl8D5iJdAjw65uwzCWGIVgNIOAgmlKUHk88ABeo3i2bLYJcowLuDX6w8BhJ0YlYnvOi+Pw1QA== X-MS-Exchange-Transport-CrossTenantHeadersStamped: DM6PR15MB2905 X-Proofpoint-ORIG-GUID: uwA9Sc6SdeAW-kR36YZTo6ic6bgDB2HS X-Proofpoint-GUID: uwA9Sc6SdeAW-kR36YZTo6ic6bgDB2HS X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.205,Aquarius:18.0.858,Hydra:6.0.486,FMLib:17.11.64.514 definitions=2022-04-20_04,2022-04-20_01,2022-02-23_01 Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Linus, > On Apr 19, 2022, at 7:18 PM, Linus Torvalds wrote: > > On Tue, Apr 19, 2022 at 7:03 PM Alexei Starovoitov > wrote: >> >> Here is the quote from Song's cover letter for bpf_prog_pack series: > > I care about performance as much as the next person, but I care about > correctness too. > > That large-page code was a disaster, and was buggy and broken. > > And even with those four patches, it's still broken. > > End result: there's no way that thigh gets re-enabled without the > correctness being in place. > > At a minimum, to re-enable it, it needs (a) that zeroing and (b) > actual numbers on real loads. (not some artificial benchmark). > > Because without (a) there's no way in hell I'll enable it. > > And without (b), "performance" isn't actually an argument. I will send patch to do (a) later this week. For (b), we have seen direct map fragmentation causing visible performance drop for our major services. This is the shadow production benchmark, so it is not possible to run it out of our data centers. Tracing showed that BPF program was the top trigger of these direct map splits. Thanks, Song