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 52EBBC43334 for ; Thu, 16 Jun 2022 08:53:55 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1376460AbiFPIxx (ORCPT ); Thu, 16 Jun 2022 04:53:53 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:47062 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1376926AbiFPIxh (ORCPT ); Thu, 16 Jun 2022 04:53:37 -0400 X-Greylist: delayed 115 seconds by postgrey-1.37 at lindbergh.monkeyblade.net; Thu, 16 Jun 2022 01:51:37 PDT Received: from esa5.hc3370-68.iphmx.com (esa5.hc3370-68.iphmx.com [216.71.155.168]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 147605EBF7 for ; Thu, 16 Jun 2022 01:51:37 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=simple/simple; d=citrix.com; s=securemail; t=1655369498; h=date:from:to:cc:subject:message-id:references: in-reply-to:mime-version; bh=fLJ/1BCNMT7a26LAEsyfKBEGOYqfOjKVa9uNnWC3Az4=; b=KN/D1JsaGSDWjPfmA28D2u5la9/TK7AIuF9OaprxocAnaLCCsfQ2iyND jsKplslRr8AVTtSBmXkMOY6aGgKMgQox9HLfaerp2GNvz/sksc3dj0qOY QUrvTbvwcmFQCtdJjdkeM87UjCNrJ9s/FYoC+gQQQAgYTF9MIrw0YpalJ w=; X-IronPort-RemoteIP: 104.47.58.172 X-IronPort-MID: 73082122 X-IronPort-Reputation: None X-IronPort-Listener: OutboundMail X-IronPort-SenderGroup: RELAY_O365 X-IronPort-MailFlowPolicy: $RELAYED IronPort-Data: A9a23:ehFWMqzwpH3nKrQMqVd6t+fLxyrEfRIJ4+MujC+fZmUNrF6WrkUFy WFLX2HTPvmDYjb2co9/at/lo0xQ78TcydFkSAFqqyAxQypGp/SeCIXCJC8cHc8zwu4v7q5Dx 59DAjUVBJlsFhcwnj/0bv656yMUOZigHtIQMsadUsxKbVIiGX5JZS5LwbZj2NY22IbhWmthh PupyyHhEA79s9JLGjp8B5Kr8HuDa9yr5Vv0FnRnDRx6lAe2e0s9VfrzFonoR5fMeaFGH/bSe gr25OrRElU1XfsaIojNfr7TKiXmS1NJVOSEoiI+t6OK2nCuqsGuu0qS2TV1hUp/0l20c95NJ Npl7Jy7ED4oE6P3qc9HYxoAPQ5MBasd9+qSSZS/mZT7I0zuVVLJmqwrJmdmeIoS96BwHH1E8 uEeJHYVdBefiumqwbW9DO5xmsAkK8qtN4Qa0p1i5WiBUbB6HtaeE+OTuoUwMDQY36iiGd7EY MUUc3x3ZQnoaBxTIFYHTpk5mY9Eg1GgKGUI8gvP/8Lb5UD3xktP/KbsP+DvXfu6a51rsRiW/ kP/qjGR7hYycYb3JSC+2mm3mubFkCf/WYQTPL617PhnhBuU3GN7IBoSWFigveiiimaxXtteL wof/S9Ghbg/8gmnQ8fwWzW8oWWYpVgMVtxICeo45QqRjK3O7G6xAmkCUy4Ea9E8ssIybSIl2 0XPnN7zAzFr9rqPRhq18bOZrii7PyQPGnMTfi8PTQYD4N7LrZk6i1TESdMLOKSylNzuXzbr3 yqNsjM9lp0Ul8cA06j99lfC6xquqYLOVRUd/RjMUySu6QYRTIy4Y42l73DL4PAGK5yWJmRtp 1ABksmaqeoIXZeEkXXURP1XRe7zofGYLDfbnFhjWYE78Cig8GKieoYW5yxiIEBuMYAPfjqBj FLvhD69LaR7ZBOCBZKbqaroYyj25cAMzejYa80= IronPort-HdrOrdr: A9a23:DCM+EKpc/VPf7C22khEIzqUaV5u3L9V00zEX/kB9WHVpm5Oj+v xGzc5w6farsl0ssREb9uxo9pPwJE800aQFmbX5XI3SJTUO3VHFEGgM1+vfKlHbak7DH6tmpN xdmstFeaHN5DpB/KHHCWCDer5PoeVvsprY49s2p00dMD2CAJsQizuRZDzrcHGfE2J9dOAE/d enl7x6jgvlXU5SQtWwB3EDUeSGj9rXlKj+aRpDIxI88gGBgR6h9ba/SnGjr18jegIK5Y1n3X nOkgT/6Knmm/anyiXE32uWy5hNgtPuxvZKGcTJoMkILTfHjBquee1aKvS/lQFwhNvqxEchkd HKrRtlF8Nv60nJdmXwmhfp0xmI6kda11bSjXujxVfzq83wQzw3T+Bbg5hCTxff4008+Plhza NixQuixtZqJCKFuB64y8nDVhlsmEbxi2Eli/Qvg3tWVpZbQKNNrLYY4FheHP47bW/HAbgcYa dT5fznlbdrmQvwVQGYgoAv+q3nYp0LJGbIfqBY0fblkAS/nxhCvjklLYIk7zU9HakGOud5Dt T/Q9tVfY51P74rhIJGdZM8qJiMexvwqSylChPjHX3XUIc6Blnql7nbpJ0I2cDCQu168HJ1ou WLbG9l X-IronPort-AV: E=Sophos;i="5.91,304,1647316800"; d="scan'208";a="73082122" Received: from mail-bn8nam11lp2172.outbound.protection.outlook.com (HELO NAM11-BN8-obe.outbound.protection.outlook.com) ([104.47.58.172]) by ob1.hc3370-68.iphmx.com with ESMTP/TLS/ECDHE-RSA-AES128-GCM-SHA256; 16 Jun 2022 04:49:40 -0400 ARC-Seal: i=1; a=rsa-sha256; s=arcselector9901; d=microsoft.com; cv=none; b=d+y1kzb/rUnRZCpySi9IVUFsbeVZ3dbHcJRpBuEm74nbUhCSA211d98me6MZCjbZF/xxVKK44thVDysA8FHmtfihdyfzxFVrUJ+Ndedv5A9kQvqUS7NDYtXnMoQYwDwxtufnqo2aTkjAnab1vZWV3atVefS9AZgCWleEvdS7uRPoYesS+iW0rDlewQ8vr4HjdxpI1GTmPTA233tTMWkmy8G/mxVJOhWz9/wrcp0UaLKHI1jM8AD+Au9cazgzZtXK7w3Qgbslqog4LkwIGqhpBnL6Gx+yuGYwP7YaMq5lIVKl4GXrb+L6+bIUYZSSCuL0CqWmXNzlLV1btvoHT+v3Cg== 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=2cLom0y4HWD07Ic3sPVf5/TfOrMlkRnW1dnPd1g2lys=; b=IbLC9PRs3kranqis8T6IzYRG0a5xDAzFIKZOEIKbNzXRrhUSXicNDYsUgkVrgeFg/MvwGwCeK1e9GoUe+29aMJ5Cr+fg8l+T5u7VLJHGdaO7VFJMKeVbWPn6SZDaFedbIFcBt0YOHFdmJfewB/K1+10muJzrKsdRi0djpyMnRo5a8oX/DrScp3f0PkqG7xEtD88wUCoeYloPOCEsSrkBAkYoRk8EQdICDIrREGBlM5Ylc+Hk/tAgcIMPsVtmd4tBPnFuN5w/C+8vtj6C22tSugG7ABSDS0J+Y8B5kr7tDthh4DO11iv+uBa7nWT4zwvM2CS67/b1qANajEQmfy9rug== ARC-Authentication-Results: i=1; mx.microsoft.com 1; spf=pass smtp.mailfrom=citrix.com; dmarc=pass action=none header.from=citrix.com; dkim=pass header.d=citrix.com; arc=none DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=citrix.onmicrosoft.com; s=selector2-citrix-onmicrosoft-com; h=From:Date:Subject:Message-ID:Content-Type:MIME-Version:X-MS-Exchange-SenderADCheck; bh=2cLom0y4HWD07Ic3sPVf5/TfOrMlkRnW1dnPd1g2lys=; b=aoAfw5RKCIM8x9yB/pNxP+V68kasK6L1MfsrPa458yT73hq1qMb0tQvN32K2y1JTDIZECWWX7uVMMTTAGqJ7YIiQdqRzBSCJIl+iUgaelxMmw4Ldwh33zcFmNk6fuNMy3Ib1jbCpy9wpPG3S7Wb6sBxeb2zy5l07gRK8fE2EdlQ= Authentication-Results: dkim=none (message not signed) header.d=none;dmarc=none action=none header.from=citrix.com; Received: from DS7PR03MB5608.namprd03.prod.outlook.com (2603:10b6:5:2c9::18) by DS7PR03MB5525.namprd03.prod.outlook.com (2603:10b6:5:2d3::7) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.20.5332.14; Thu, 16 Jun 2022 08:49:38 +0000 Received: from DS7PR03MB5608.namprd03.prod.outlook.com ([fe80::40af:d5f4:95eb:d534]) by DS7PR03MB5608.namprd03.prod.outlook.com ([fe80::40af:d5f4:95eb:d534%7]) with mapi id 15.20.5353.015; Thu, 16 Jun 2022 08:49:38 +0000 Date: Thu, 16 Jun 2022 10:49:34 +0200 From: Roger Pau =?utf-8?B?TW9ubsOp?= To: Stefano Stabellini Cc: Oleksandr , xen-devel@lists.xenproject.org, linux-kernel@vger.kernel.org, Oleksandr Tyshchenko , Boris Ostrovsky , Juergen Gross , Julien Grall Subject: Re: [RFC PATCH 1/2] xen/unpopulated-alloc: Introduce helpers for DMA allocations Message-ID: References: <1652810658-27810-1-git-send-email-olekstysh@gmail.com> <1652810658-27810-2-git-send-email-olekstysh@gmail.com> <00c14b91-4cf2-179c-749d-593db853e42e@gmail.com> Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: X-ClientProxiedBy: LO2P265CA0120.GBRP265.PROD.OUTLOOK.COM (2603:10a6:600:c::36) To DS7PR03MB5608.namprd03.prod.outlook.com (2603:10b6:5:2c9::18) MIME-Version: 1.0 X-MS-PublicTrafficType: Email X-MS-Office365-Filtering-Correlation-Id: 5e77ae81-37b2-406b-37e4-08da4f75253d X-MS-TrafficTypeDiagnostic: DS7PR03MB5525:EE_ X-Microsoft-Antispam-PRVS: 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:DS7PR03MB5608.namprd03.prod.outlook.com;PTR:;CAT:NONE;SFS:(13230016)(4636009)(7916004)(366004)(6666004)(85182001)(8936002)(38100700002)(6506007)(33716001)(9686003)(6512007)(26005)(6486002)(54906003)(8676002)(4326008)(186003)(2906002)(5660300002)(508600001)(316002)(6916009)(83380400001)(82960400001)(4744005)(66556008)(66476007)(66946007)(86362001);DIR:OUT;SFP:1101; X-MS-Exchange-AntiSpam-MessageData-ChunkCount: 1 X-MS-Exchange-AntiSpam-MessageData-0: =?utf-8?B?MnUwbWJPa2Y5bEVrdVgrRkQwMXBDQ2hQNUM1YUovejF0RVY5UjNlZ2F3a1pC?= =?utf-8?B?Y2gyNjhUVkZNMjdSWVRrZURxQXRxbk9lVFlWc00zWHFPOGErUGhxZ0ZZTzBu?= =?utf-8?B?bFV5NFY5ZStOYnR5RlVOQmYyNjNacjJBYW9ZeVRVdHVVRER3dVR0NDAyV2d6?= =?utf-8?B?T0tjczNwWkswS2dtOW1DVnJVL3l2OVJVZmU5eEN4T1czRGNLSG5XYm1JTXNT?= =?utf-8?B?UldMS2ZZV1JlN096Z1F1OGdLZWdNblN0cmowS1dGRndMRUZwdC82K21KcENw?= =?utf-8?B?ZzRFcUZDWTRPWHFMR0JaQmdDMFk5RU1uVy9kdGdDd2xIY1U1bE5PWnFWOHBC?= =?utf-8?B?MmxUdGFYSmpJQUUyWXA2cS9tWVNrWHJESGFHd1l5dlBYVUhMVVVLZFNHa0Nl?= =?utf-8?B?elJKMjM3MS9rWXJhd1A2Wm42RUV0UWhIcC8zeTM3bE1JY2JXL21pNFBTdzc4?= =?utf-8?B?ZXQySnhFVVF4R1lJam9seEZKUE5uZlR6cDNvVGJFRk5yYW1oOVhKYzdVcHlX?= =?utf-8?B?ZE9VdnNVdFJlR0JPeXdTM3VVMVR2eFhORUFqQ0NaWm5NQVdRZEs4Z1JXQmdp?= =?utf-8?B?ejQ1S3YyaGdGbVBUcUhwYzRKWE5kS1VocGJteGkzamU4NUJiTXpuMHVGYlhB?= =?utf-8?B?bm5RaWRJS3FtNG51NzRmVnQxeCtSVzZIcDhrK0FBYlc4QVAvUU9GQUsydXZ6?= =?utf-8?B?QTNRWERkT2FkRFlWYzRNVTJVZVJSaXhGalZBckNFbFJrL3dVTnZVY0hjMGZw?= =?utf-8?B?bm1xeU5iWUttNzhPYTZ5eGJMYm9kaXF6cnJKTEZMZzR6VDJxS2tTV1hRaDU4?= =?utf-8?B?eFFNNkdiVGhKdGtSYWlXOE1GdEpRNkJ1Z2dtOWlvRTFoUTZQZDdwa0hNMFBj?= =?utf-8?B?T0U0b2FZS2pDN1l2WVRsVTB6QVVSeVBoSTdIMFdkV3d3SWRwTFRNdVpHdEtl?= =?utf-8?B?VytxYk9GRTNWZXhDVy8vTEk4c2RxQnZ0c2dtMzd0M3BQVk1VYVNmcUpyTmg1?= =?utf-8?B?SHBTeVB5UHY0K29paEo1cWw4QWVRNkJselpvZ01pV3NVaXdxZUp3aEtodG9a?= =?utf-8?B?NlloR1I3QUZhYlVXcjVSTUxEbXJ3dkZpSkhyencyeml3V0VrbUQ2TmRlMXoz?= =?utf-8?B?UVhUZkN2Sjd0alhia0tPQzFMejJST2RaUFlEblk1ZThJR3pUK3ZVbkQyMkJa?= =?utf-8?B?Qm9ZTzJwcCtpcmtOQlJKN21qWVh6SE5RLzF1c0V1cU9MZFVBTjZrUHJZMklX?= =?utf-8?B?RXZqRDZpcEpleDNqMVAxOENtZU9Udkl5QzRDZzdpbGt3dHQrcmk1eDUzb016?= =?utf-8?B?aDJLNUFpeGNwR2szT1dsbDA4ZUNVRDlZdGxuaHlDaVNSOS81QVhhR05oRzVo?= =?utf-8?B?Z2NMaCtZYzY3WDJTTjBReWkrbWVYNGZKOENBWjFaaUVIdis5WCswNElaVExn?= =?utf-8?B?U09EZUpQVHNJREF3c0ZIcjBwRTI1cjhOMWQ0OFJjc012VjdXejF2NXlZNVVM?= =?utf-8?B?MkJnVnM1VHRYa01lRVJ0eWw5bkNpSnhRUmduQkRCZVZ1QzFuZjNDVmpuUzRy?= =?utf-8?B?WVE3MlN0eGJDZHNEOTJ6MUFLekZRT3lsdDFnK2hRRWZHYkdpbUw3MFlQRHVm?= =?utf-8?B?V0xESDVXUjBHU01MMzE3ajJrdG9jUitYYWdMRVNTMlhYZWRkS0R5bjYxWUJS?= =?utf-8?B?Z0NSelhpTjFHZ2JSbHhvYlBoVU1MaUdSWWxCbGVwY1VnRG9pWGN4c0dCRVJ2?= =?utf-8?B?a01hMjFVeWZFZGxXWHRKdmZuUjVTNzcvWGVLU2NRQmd2aklHWW1rMkJkR2h2?= =?utf-8?B?LzlzOWh6Tzc5R2UxS1hOekh6THYwbWZmUFlidy9GODVKVDlZaHkxeFhqems4?= =?utf-8?B?Q3Q3MEpseHlnYXRQcXJLa0hnSHgzaG9JVU5kRisxMjU1b2xiR2crMkhrc3Js?= =?utf-8?B?ZVZseUg1M2t4S29IcUhhU2E5OE9Gb0xkT3ZrOVd0N1VrRUpDOVozTm55OTJH?= =?utf-8?B?TW84ekNkU2V4Q1hrZ0NoalZUdjByTWFIM1pmc0g4ckpDNlRydy9QRGxFVTVI?= =?utf-8?B?YjhWOEhhNkUzRFl1aFZLaVZaV3hpTm5ibmU5aGdvamZBSHJFenBGRG9objla?= =?utf-8?B?dkI1MXFnTjdFTEw5M2pUK0tHNUlDcHA1UXZWMGIzMGE5bitaZWFTbG1qL2U5?= =?utf-8?B?WmcxbTA5cmN6aU55ZGE4RXlhamtsbWlHazJIbS9pT1hhcFBUVUpJTmtJdFpa?= =?utf-8?B?NWJOUXpPc1BPUkRyOGdzYWk2S0cybGl4ZTJXa2VrZ1ErVkx1bURTcTliaDBn?= =?utf-8?B?em01MWhuaVNUa2hxd2RwNlQ3UWZDRVpQSnpaeXMrZElpMk16b3pYSUQwcmZH?= =?utf-8?Q?2YboA+rg9jRMv0nk=3D?= X-OriginatorOrg: citrix.com X-MS-Exchange-CrossTenant-Network-Message-Id: 5e77ae81-37b2-406b-37e4-08da4f75253d X-MS-Exchange-CrossTenant-AuthSource: DS7PR03MB5608.namprd03.prod.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Internal X-MS-Exchange-CrossTenant-OriginalArrivalTime: 16 Jun 2022 08:49:38.3213 (UTC) X-MS-Exchange-CrossTenant-FromEntityHeader: Hosted X-MS-Exchange-CrossTenant-Id: 335836de-42ef-43a2-b145-348c2ee9ca5b X-MS-Exchange-CrossTenant-MailboxType: HOSTED X-MS-Exchange-CrossTenant-UserPrincipalName: +/uGnLNB6Ktf9E6jRUIHaibTVsrj58ddFnWVl28ewv5vov5wwa1/6YcToQ5T+wa2YBrZQczyZ82Kscvl1DuXWg== X-MS-Exchange-Transport-CrossTenantHeadersStamped: DS7PR03MB5525 Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Jun 14, 2022 at 05:45:53PM -0700, Stefano Stabellini wrote: > Basically, if we allocate (and free) page-by-page it leads to more > efficient resource utilization but it is slower. If we allocate larger > contiguous chunks it is faster but it leads to less efficient resource > utilization. > > Given that on both x86 and ARM the unpopulated memory resource is > arbitrarily large, I don't think we need to worry about resource > utilization. It is not backed by real memory. The only limitation is the > address space size which is very large. Well, unpopulated memory will consume memory to populate the related metadata (ie: struct page and realted tracking information) for the unpopulated region, so it's not completely free. Thanks, Roger.