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=-2.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, PDS_BAD_THREAD_QP_64,SPF_HELO_NONE,SPF_PASS,UNPARSEABLE_RELAY,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 6D732C433C1 for ; Mon, 22 Mar 2021 08:46:17 +0000 (UTC) Received: from lists.xenproject.org (lists.xenproject.org [192.237.175.120]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id DCA8461584 for ; Mon, 22 Mar 2021 08:46:16 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org DCA8461584 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=arm.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=xen-devel-bounces@lists.xenproject.org Received: from list by lists.xenproject.org with outflank-mailman.100041.190477 (Exim 4.92) (envelope-from ) id 1lOGCH-0006nC-IZ; Mon, 22 Mar 2021 08:46:01 +0000 X-Outflank-Mailman: Message body and most headers restored to incoming version Received: by outflank-mailman (output) from mailman id 100041.190477; Mon, 22 Mar 2021 08:46:01 +0000 Received: from localhost ([127.0.0.1] helo=lists.xenproject.org) by lists.xenproject.org with esmtp (Exim 4.92) (envelope-from ) id 1lOGCH-0006n5-FT; Mon, 22 Mar 2021 08:46:01 +0000 Received: by outflank-mailman (input) for mailman id 100041; Mon, 22 Mar 2021 08:46:00 +0000 Received: from us1-rack-iad1.inumbo.com ([172.99.69.81]) by lists.xenproject.org with esmtp (Exim 4.92) (envelope-from ) id 1lOGCG-0006n0-H5 for xen-devel@lists.xenproject.org; Mon, 22 Mar 2021 08:46:00 +0000 Received: from EUR01-HE1-obe.outbound.protection.outlook.com (unknown [2a01:111:f400:fe1e::61b]) by us1-rack-iad1.inumbo.com (Halon) with ESMTPS id 88ff52de-bf2f-4ab0-9fcf-915ae4d7a72d; Mon, 22 Mar 2021 08:45:58 +0000 (UTC) Received: from AS8PR04CA0047.eurprd04.prod.outlook.com (2603:10a6:20b:312::22) by AM6PR08MB4167.eurprd08.prod.outlook.com (2603:10a6:20b:ad::15) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.20.3955.18; Mon, 22 Mar 2021 08:45:53 +0000 Received: from VE1EUR03FT005.eop-EUR03.prod.protection.outlook.com (2603:10a6:20b:312:cafe::7a) by AS8PR04CA0047.outlook.office365.com (2603:10a6:20b:312::22) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.20.3955.18 via Frontend Transport; Mon, 22 Mar 2021 08:45:53 +0000 Received: from 64aa7808-outbound-1.mta.getcheckrecipient.com (63.35.35.123) by VE1EUR03FT005.mail.protection.outlook.com (10.152.18.172) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.20.3955.18 via Frontend Transport; Mon, 22 Mar 2021 08:45:52 +0000 Received: ("Tessian outbound eae0c21066a4:v87"); Mon, 22 Mar 2021 08:45:52 +0000 Received: from 3c02ffebfa19.1 by 64aa7808-outbound-1.mta.getcheckrecipient.com id E5AACAEC-A6BD-44BE-B5E4-C4D60C82E6ED.1; Mon, 22 Mar 2021 08:45:46 +0000 Received: from EUR05-DB8-obe.outbound.protection.outlook.com by 64aa7808-outbound-1.mta.getcheckrecipient.com with ESMTPS id 3c02ffebfa19.1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384); Mon, 22 Mar 2021 08:45:46 +0000 Received: from DB7PR08MB3500.eurprd08.prod.outlook.com (2603:10a6:10:49::10) by DB9PR08MB6442.eurprd08.prod.outlook.com (2603:10a6:10:259::9) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.20.3955.18; Mon, 22 Mar 2021 08:45:45 +0000 Received: from DB7PR08MB3500.eurprd08.prod.outlook.com ([fe80::5959:35df:3647:b78d]) by DB7PR08MB3500.eurprd08.prod.outlook.com ([fe80::5959:35df:3647:b78d%7]) with mapi id 15.20.3955.025; Mon, 22 Mar 2021 08:45:45 +0000 X-BeenThere: xen-devel@lists.xenproject.org List-Id: Xen developer discussion List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Errors-To: xen-devel-bounces@lists.xenproject.org Precedence: list Sender: "Xen-devel" X-Inumbo-ID: 88ff52de-bf2f-4ab0-9fcf-915ae4d7a72d DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=armh.onmicrosoft.com; s=selector2-armh-onmicrosoft-com; h=From:Date:Subject:Message-ID:Content-Type:MIME-Version:X-MS-Exchange-SenderADCheck; bh=NT0AObk4Ev3tKcCe1mU2Cya2/nyvJkUnm7haIPLQ4dA=; b=NeBgjK00G6AHaHCt7Hgo5+rmQDSw5ZUce8cJXuBj++pMOzwbPLd7atVE4Ht2doRKYwpvEETgL9YrZPWEpMbx3w2IruIpBUFBLN5zZV8nmX92XpUrGNtwRQurYehinl8mk7IUKLOtIdmjpmS3aiYS36djnqd5mPrNYttnqWhIjZk= X-MS-Exchange-Authentication-Results: spf=pass (sender IP is 63.35.35.123) smtp.mailfrom=arm.com; lists.xenproject.org; dkim=pass (signature was verified) header.d=armh.onmicrosoft.com;lists.xenproject.org; dmarc=pass action=none header.from=arm.com; Received-SPF: Pass (protection.outlook.com: domain of arm.com designates 63.35.35.123 as permitted sender) receiver=protection.outlook.com; client-ip=63.35.35.123; helo=64aa7808-outbound-1.mta.getcheckrecipient.com; X-CheckRecipientChecked: true X-CR-MTA-CID: fa8cae128acfbca1 X-CR-MTA-TID: 64aa7808 ARC-Seal: i=1; a=rsa-sha256; s=arcselector9901; d=microsoft.com; cv=none; b=NPH327ymgBCPwZhXs4OcfwHcLLgRfN9cKIJmQa3juBAM43uRXJG+rnY3+/WN1ki8eBSrO67g3RT/6y2uckz7KBrIj5o2+beJDFXRRDjFOnc8+EgDzke0G9koEKopZ/UGo6y/PtBWdJy/Z6jLKKLXl4Fr7tv/Aab77VFz0qOTSLEwqTYaN7zfbuCl//s7SdYiVp6jTVtniwYImJLeXQEQzGk2yX46HKUyjdrZzslBrSUrPSMDM4J15bXHznFPrUF5Xn0iDm92Z4nlH7YLK8m6lIzNwnX+pMa8rQgoxl90EI4QQGGd5wM2x/uSyhKFORiE5Tcy9u9vpnsZNDeLAw1dGw== 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=NT0AObk4Ev3tKcCe1mU2Cya2/nyvJkUnm7haIPLQ4dA=; b=TBBDS6Vy7QzVsFa+3ZyL1uIIG+4ICxT9Ic855dSswJjK4qySLFLfWoUpcuC4+0xYQjp/A/GsC70fY8LeMaXkqFsPw4E7JrOCSlkM/XuIcN6sV14coAR4ioVC8pyMdf9wy01JvB5rivZliePEPX05Cg8torZCbVKmidkdQ1KYoKXERIu3PbABRTbcejo9yiNzut3MctmtjX63hhGGV4XSlsXrtpsIUqsXdnYJBfRWZnGEmbwhhksSQpwcRuQNIupuoPRLZ4F4AIVOU83lB8CF4pwp33Ja6lRewDbyQOmSdktoL5hz/qVusB/oVXFe+KvYeRNyKQp5q6JCPEV4mfL81w== ARC-Authentication-Results: i=1; mx.microsoft.com 1; spf=pass smtp.mailfrom=arm.com; dmarc=pass action=none header.from=arm.com; dkim=pass header.d=arm.com; arc=none DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=armh.onmicrosoft.com; s=selector2-armh-onmicrosoft-com; h=From:Date:Subject:Message-ID:Content-Type:MIME-Version:X-MS-Exchange-SenderADCheck; bh=NT0AObk4Ev3tKcCe1mU2Cya2/nyvJkUnm7haIPLQ4dA=; b=NeBgjK00G6AHaHCt7Hgo5+rmQDSw5ZUce8cJXuBj++pMOzwbPLd7atVE4Ht2doRKYwpvEETgL9YrZPWEpMbx3w2IruIpBUFBLN5zZV8nmX92XpUrGNtwRQurYehinl8mk7IUKLOtIdmjpmS3aiYS36djnqd5mPrNYttnqWhIjZk= From: Rahul Singh To: Julien Grall CC: xen-devel , Bertrand Marquis , Stefano Stabellini , Volodymyr Babchuk Subject: Re: [PATCH 5/5] xen/arm: smmuv1: Intelligent SMR allocation Thread-Topic: [PATCH 5/5] xen/arm: smmuv1: Intelligent SMR allocation Thread-Index: AQHXFRE3FfFdAlAZ8Eu9+88zMBZ+gqqGwk6AgAAuSQCABea+AIAC7gYA Date: Mon, 22 Mar 2021 08:45:44 +0000 Message-ID: <17645655-7580-4E22-913E-4D7D919CB7AD@arm.com> References: <789abfb57568dcbaba122ea9b68c627e6c9707c4.1615312254.git.rahul.singh@arm.com> <299c8294-5f76-2fd6-85ec-d20c0b99368b@xen.org> <1C808D23-E8F3-4888-86AD-C37FCBAAD0D1@arm.com> In-Reply-To: Accept-Language: en-US Content-Language: en-US X-MS-Has-Attach: X-MS-TNEF-Correlator: Authentication-Results-Original: xen.org; dkim=none (message not signed) header.d=none;xen.org; dmarc=none action=none header.from=arm.com; x-originating-ip: [217.140.99.251] x-ms-publictraffictype: Email X-MS-Office365-Filtering-HT: Tenant X-MS-Office365-Filtering-Correlation-Id: 7cd4d50e-3f1f-49b5-d950-08d8ed0ee6c2 x-ms-traffictypediagnostic: DB9PR08MB6442:|AM6PR08MB4167: x-ms-exchange-transport-forked: True X-Microsoft-Antispam-PRVS: x-checkrecipientrouted: true nodisclaimer: true x-ms-oob-tlc-oobclassifiers: OLM:3383;OLM:3383; X-MS-Exchange-SenderADCheck: 1 X-Microsoft-Antispam-Untrusted: BCL:0; X-Microsoft-Antispam-Message-Info-Original: 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 X-Forefront-Antispam-Report-Untrusted: CIP:255.255.255.255;CTRY:;LANG:en;SCL:1;SRV:;IPV:NLI;SFV:NSPM;H:DB7PR08MB3500.eurprd08.prod.outlook.com;PTR:;CAT:NONE;SFS:(4636009)(376002)(39860400002)(396003)(346002)(136003)(366004)(71200400001)(316002)(8676002)(478600001)(26005)(38100700001)(33656002)(2616005)(5660300002)(6916009)(186003)(4326008)(54906003)(8936002)(6486002)(86362001)(2906002)(36756003)(76116006)(91956017)(6512007)(66476007)(66556008)(66946007)(66446008)(64756008)(53546011)(6506007)(83380400001)(3714002)(45980500001);DIR:OUT;SFP:1101; x-ms-exchange-antispam-messagedata: =?us-ascii?Q?qpXZ6Y1u+i+u9EIECMWVG2hzkkYeGJkcyC3d2VL3IfqfWwsunMQqO8Tq4mVL?= =?us-ascii?Q?UYp1V5MGSwWnod4PrHBKf+al8DJbbcX7orurTB5X1atBFDqT/KD3NUDRzDov?= =?us-ascii?Q?Ruhex+gtufgwBpUfAS56zu5YGyNLifpAhon0RtZZeIKZF3awQSr92e1jwBGA?= =?us-ascii?Q?IOS0LQIIf8S6wDDH2cvaLKlpP37xHT+U2fplEljLAJ1k54MBOJ0e15zthM1z?= =?us-ascii?Q?nx2Yc1Dc0vYbc0fIGyj7vrOvB/r8w32egkJdHxChKqvyEW3mq6IrbfLsq0lm?= =?us-ascii?Q?pppoRxqYt5gJ/ArVA0h9k6jChwglsOZOpEYFA+XxuDUoEJy7fZYiU/cTpUAd?= =?us-ascii?Q?Y8hlG3XgNd1BXEBDpJyjGdvdHALhyyCr5+6dFb7EwvZjFGzOYYNeuystz3sN?= =?us-ascii?Q?ciqB1bsugHRonSsGRe0s8pNLpMcuGLTbEBXYpsSYeqeWMoEU7WO05+p4Zz95?= =?us-ascii?Q?ueMXr8idTt+6JwT2MR487s8mG3KucPiDwW71mfs1dltQmIJfoN7836zW0Rsa?= =?us-ascii?Q?B2BLCPQi8DC2+KA8GII8+Tbb/gJ86aHUgRdOSkmcjO8iCgcHRsVA0bGDzlxw?= =?us-ascii?Q?aBCId+D8N08WOqmpi8iM0c5ZG8N0MaSkCQL11+dyNrX/1mFPQz9jMAX4DhR5?= =?us-ascii?Q?HcWDsFtXsYb4IBBjr6sDlZAUQatXxHyz1k3tPOEPuL9bwdt3/JxGhCcNenR3?= =?us-ascii?Q?lsJp6fKclXv8AFKOPr1Y9sOOHxX3OKHiDenWN59mRvaut6em7iyARlbSSsj5?= =?us-ascii?Q?ctbCfO9nwZvQNlnP59qrbYLB29mXwdgSfW3SyuSoz+nB/hRxYrsxPRy/k3mN?= =?us-ascii?Q?XYUpXsVFe6dAqRr+K8kVanUhQ0aMaEahwieo0R+FRegv31CEoyXSL4DgjTgY?= =?us-ascii?Q?nKvxOHzAyzPpX4CjByLtlhpZ60iqUHSV4LgM7EoA/R0ECiQ2AnxU+YnaOp2+?= =?us-ascii?Q?TOBPAXTn6hVouETChJzrgrl3nROYrmKd1UIccFU7bmErm1p54MuYCv2RpQjE?= =?us-ascii?Q?4y4zUFnYKgfYD2W6va52q7NK4e9yX3Ui1x9k/37vHuZrpz0i6Pdrdzm4fGDP?= =?us-ascii?Q?bB7TRg9PsA1hm75UTHCP58dBJXYXmbAc7s2TkgA45ltcLOROME5WfND5T2O+?= =?us-ascii?Q?UzepGvYqQQvMCg2jD3MLv2HQSzKBFlxgVdDSnn5R4wM45VCyRUo89/VGRVMx?= =?us-ascii?Q?jYn8Bk+ew36IWmmIs1xWfVXEAaoz750U8SL73RaRyNtJkLmzP/2iaoWWDKAx?= =?us-ascii?Q?aIjxT8RrvqepzW9P4w+jhaYfWGKy1TAwnb6T8a/2iEthtfVrzcTK4HPsvsGj?= =?us-ascii?Q?LWAX6HCGlJcZRbmAWv++9+tZ?= Content-Type: text/plain; charset="us-ascii" Content-ID: <3EAD3F7D50C03642A3DCDDFF48042476@eurprd08.prod.outlook.com> Content-Transfer-Encoding: quoted-printable MIME-Version: 1.0 X-MS-Exchange-Transport-CrossTenantHeadersStamped: DB9PR08MB6442 Original-Authentication-Results: xen.org; dkim=none (message not signed) header.d=none;xen.org; dmarc=none action=none header.from=arm.com; X-EOPAttributedMessage: 0 X-MS-Exchange-Transport-CrossTenantHeadersStripped: VE1EUR03FT005.eop-EUR03.prod.protection.outlook.com X-MS-Office365-Filtering-Correlation-Id-Prvs: c5810349-0265-4f68-078f-08d8ed0ee204 X-Microsoft-Antispam: BCL:0; X-Microsoft-Antispam-Message-Info: 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 X-Forefront-Antispam-Report: CIP:63.35.35.123;CTRY:IE;LANG:en;SCL:1;SRV:;IPV:CAL;SFV:NSPM;H:64aa7808-outbound-1.mta.getcheckrecipient.com;PTR:ec2-63-35-35-123.eu-west-1.compute.amazonaws.com;CAT:NONE;SFS:(4636009)(376002)(396003)(136003)(346002)(39860400002)(36840700001)(46966006)(316002)(478600001)(26005)(8676002)(6862004)(36860700001)(336012)(82740400003)(33656002)(5660300002)(2616005)(47076005)(54906003)(4326008)(186003)(8936002)(86362001)(2906002)(82310400003)(36756003)(70586007)(356005)(6512007)(107886003)(83380400001)(53546011)(6506007)(6486002)(81166007)(70206006)(3714002);DIR:OUT;SFP:1101; X-OriginatorOrg: arm.com X-MS-Exchange-CrossTenant-OriginalArrivalTime: 22 Mar 2021 08:45:52.8430 (UTC) X-MS-Exchange-CrossTenant-Network-Message-Id: 7cd4d50e-3f1f-49b5-d950-08d8ed0ee6c2 X-MS-Exchange-CrossTenant-Id: f34e5979-57d9-4aaa-ad4d-b122a662184d X-MS-Exchange-CrossTenant-OriginalAttributedTenantConnectingIp: TenantId=f34e5979-57d9-4aaa-ad4d-b122a662184d;Ip=[63.35.35.123];Helo=[64aa7808-outbound-1.mta.getcheckrecipient.com] X-MS-Exchange-CrossTenant-AuthSource: VE1EUR03FT005.eop-EUR03.prod.protection.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Anonymous X-MS-Exchange-CrossTenant-FromEntityHeader: HybridOnPrem X-MS-Exchange-Transport-CrossTenantHeadersStamped: AM6PR08MB4167 Hello Julien, > On 20 Mar 2021, at 12:01 pm, Julien Grall wrote: >=20 >=20 >=20 > On 16/03/2021 17:54, Rahul Singh wrote: >> Hello Julien, >=20 > Hi Rahul, >=20 >>> On 16 Mar 2021, at 3:08 pm, Julien Grall wrote: >>>=20 >>> Hi Rahul, >>>=20 >>> On 09/03/2021 18:19, Rahul Singh wrote: >>>> Backport 588888a7399db352d2b1a41c9d5b3bf0fd482390 >>>> "iommu/arm-smmu: Intelligent SMR allocation" from the Linux kernel >>>> This patch fix the stream match conflict issue when two devices have t= he >>>> same stream-id. >>>> Only difference while applying this patch is to use spinlock in place = of >>>> mutex and move iommu_group_alloc(..) function call in >>>> arm_smmu_add_device(..) function from the start of the function >>>> to the end. >>>=20 >>> As you may remember the discussion on the SMMUv3 thread, replacing a sp= inlock by a mutex has consequences. Can you explain why this is fine? >> Yes, I remember the discussion on the SMMUv3 thread, replacing a spinloc= k with a mutex has consequences. >> I replaced the mutex with spinlock in the SMMUv1 code when we are config= uring the SMMUv1 hardware arm_smmu_master_alloc_smes(..). >> I think it is fine to use the spinlock in place of mutex in SMMUv1 where= we are configuring the hardware via registers as compared to SMMUv3 where = we are configuring the SMMUv3 hardware with Memory-based circular buffer qu= eues. Configuring the hardware via queues might take a long time that why m= utex is a good choice but if we are configuring the hardware via registers = it is very fast. >> Configuring the SMMUv1 with the register is very fast and there are no s= ide effects of this if we use spinlock. Let me know your view on this. >=20 > This looks fine. Can you explain it the commit message? Yes, I will add the explanation in the commit message and will send the v2. Regards, Rahul >=20 > Cheers, >=20 > --=20 > Julien Grall