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=-3.9 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS 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 28B73C433E7 for ; Sun, 18 Oct 2020 23:07:32 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 9D56621D6C for ; Sun, 18 Oct 2020 23:07:31 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=nxp.com header.i=@nxp.com header.b="pXOfj/xC" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729502AbgJRW61 (ORCPT ); Sun, 18 Oct 2020 18:58:27 -0400 Received: from mail-eopbgr40080.outbound.protection.outlook.com ([40.107.4.80]:38574 "EHLO EUR03-DB5-obe.outbound.protection.outlook.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1726681AbgJRW60 (ORCPT ); Sun, 18 Oct 2020 18:58:26 -0400 ARC-Seal: i=1; a=rsa-sha256; s=arcselector9901; d=microsoft.com; cv=none; b=UnScr4CG1GR6ux917CVY20Cpr4qMC1rN0jzKT2lHEQDixhcrikQOzCVHQUMA/gMCZsaWyPkrpgJesW1IPeCKQqEIH4AR/AJJxQPlPbEatYTXXU72KZnAjVHSjYdk/dOecQlzfitdXPUduddkQ4WNX4TBe4rRwwqJoo3rP5RBjYEIfPmkrniwkSBdAybE9FohgjJCuE8qyEPVgtslOK3YKyvCanKbaSv06E26oGiDnQHptMFPjuflbdn1Kz5o5IySC5VK8iBUBRmDp0hkLdKE3FtLPnCMyb3BKP8HkVjigbuA8dJ5vpBlR6OpcxfyGOwb2gaPn3gGYVU5zf4r49SBDQ== 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=Ul4Ax21WeiZ8LuMSI2qUrBDj7iyh9OsqZsoVp34NxLw=; b=Sxh4xdqV4IpnuHqYzaGzY9eKhozjNyw+gmJwf8/YfVyLEnSXt7CfTqGYi4t3owVVFnuWkhKbJ4Rnp8JrLkV3OyKplHS2731eB7Xqrv4txkypOpIgGCjsFKZLF5e6na9nCzzjsp3QvMzWgVnL6xefhiuYLlk5kNXJCHst8LUl7ZcMd7CuzYn8ul/hbTjWFpI+LrF9rER/YuqrTVYMmJZ2V0K1wvs7iYK8RY+zvlsUzzMhnip0t9P5ka6/oxix8JJo/JYY5JSYd6MI1UWRGdR/LUzsKMYOeDgYeS+xxjcasf+klA01DYerwhPs20UepOpwARBCjL6pM1SX2acDSp8a+g== ARC-Authentication-Results: i=1; mx.microsoft.com 1; spf=pass smtp.mailfrom=nxp.com; dmarc=pass action=none header.from=nxp.com; dkim=pass header.d=nxp.com; arc=none DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=nxp.com; s=selector2; h=From:Date:Subject:Message-ID:Content-Type:MIME-Version:X-MS-Exchange-SenderADCheck; bh=Ul4Ax21WeiZ8LuMSI2qUrBDj7iyh9OsqZsoVp34NxLw=; b=pXOfj/xCiiBTI4LMd0JfNKGGzMAII8vNKKC+STj6OkTqw1TRvrQvkqRu/jJ3P/MiqcO6/Ss3ARGG3/IeG3hgrPilGS/qrn1s755rbCbH/2QAR09PlfIPXavfvkA1KqDztAMNuo63xLxJFRSjX95Jbtta+Dg/OGeHAKb6871xaj0= Received: from VI1PR04MB5696.eurprd04.prod.outlook.com (2603:10a6:803:e7::13) by VI1PR0401MB2688.eurprd04.prod.outlook.com (2603:10a6:800:59::7) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.20.3477.25; Sun, 18 Oct 2020 22:58:21 +0000 Received: from VI1PR04MB5696.eurprd04.prod.outlook.com ([fe80::983b:73a7:cc93:e63d]) by VI1PR04MB5696.eurprd04.prod.outlook.com ([fe80::983b:73a7:cc93:e63d%3]) with mapi id 15.20.3477.028; Sun, 18 Oct 2020 22:58:21 +0000 From: Vladimir Oltean To: Heiner Kallweit CC: "netdev@vger.kernel.org" , "andrew@lunn.ch" , "f.fainelli@gmail.com" , "vivien.didelot@gmail.com" , "kuba@kernel.org" , Christian Eggers , Kurt Kanzenbach Subject: Re: [RFC PATCH 01/13] net: dsa: add plumbing for custom netdev statistics Thread-Topic: [RFC PATCH 01/13] net: dsa: add plumbing for custom netdev statistics Thread-Index: AQHWpM2VvXEF3YqeV0mNLAH0H5Z1UKmdQ5MAgAAD4gCAAA7GAIAACvKAgAAG6gCAAJKmAA== Date: Sun, 18 Oct 2020 22:58:21 +0000 Message-ID: <20201018225820.b2vhgzyzwk7vy62j@skbuf> References: <20201017213611.2557565-1-vladimir.oltean@nxp.com> <20201017213611.2557565-2-vladimir.oltean@nxp.com> <06538edb-65a9-c27f-2335-9213322bed3a@gmail.com> <20201018121640.jwzj6ivpis4gh4ki@skbuf> <19f10bf4-4154-2207-6554-e44ba05eed8a@gmail.com> <20201018134843.emustnvgyby32cm4@skbuf> <2ae30988-5918-3d02-87f1-e65942acc543@gmail.com> In-Reply-To: <2ae30988-5918-3d02-87f1-e65942acc543@gmail.com> Accept-Language: en-US Content-Language: en-US X-MS-Has-Attach: X-MS-TNEF-Correlator: authentication-results: gmail.com; dkim=none (message not signed) header.d=none;gmail.com; dmarc=none action=none header.from=nxp.com; x-originating-ip: [188.26.174.215] x-ms-publictraffictype: Email x-ms-office365-filtering-ht: Tenant x-ms-office365-filtering-correlation-id: 8aa47dfe-bd26-4a3e-7e83-08d873b94fb1 x-ms-traffictypediagnostic: VI1PR0401MB2688: x-microsoft-antispam-prvs: x-ms-oob-tlc-oobclassifiers: OLM:9508; x-ms-exchange-senderadcheck: 1 x-microsoft-antispam: BCL:0; x-microsoft-antispam-message-info: EpdrjcpbJ0yLfg5Hy7PVGAawXOByqP55OAZK7ugwR1MzgqM1m0/zY12xWx6crrOxG5Bq1ZOlxPwIEGiWVUlHH3rRRxP6+t5HOkEbKyBsWvO4XTppPFm5cPV0gwqDRYl675I7kGmjZFg+Sgx9w2FyqcWtsHuKq+FD2HU6xe+u9DJCdLs5myiJJfxJPIhSRQmC3G/ymuOgPCadHmtAOADkoKiLIEv199EAqKKmBaa8udeTj0XFaVEgfn91dJmjiFGwU5zrhdCeryHBqIwSmRj+He9D8G2hEFxu0vCD+fOLDJ9A8DZQCD2mquXlDrujicHmLqqQT6FpV/NvHefer7hp1A== x-forefront-antispam-report: CIP:255.255.255.255;CTRY:;LANG:en;SCL:1;SRV:;IPV:NLI;SFV:NSPM;H:VI1PR04MB5696.eurprd04.prod.outlook.com;PTR:;CAT:NONE;SFS:(7916004)(4636009)(136003)(396003)(366004)(376002)(346002)(39860400002)(9686003)(86362001)(6512007)(6486002)(83380400001)(71200400001)(4744005)(6916009)(2906002)(5660300002)(1076003)(6506007)(186003)(66446008)(66556008)(54906003)(4326008)(33716001)(26005)(44832011)(478600001)(8676002)(316002)(66476007)(8936002)(66946007)(64756008)(76116006)(91956017);DIR:OUT;SFP:1101; x-ms-exchange-antispam-messagedata: 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 x-ms-exchange-transport-forked: True Content-Type: text/plain; charset="us-ascii" Content-ID: <3764E619B320B1428A216573132820C2@eurprd04.prod.outlook.com> Content-Transfer-Encoding: quoted-printable MIME-Version: 1.0 X-OriginatorOrg: nxp.com X-MS-Exchange-CrossTenant-AuthAs: Internal X-MS-Exchange-CrossTenant-AuthSource: VI1PR04MB5696.eurprd04.prod.outlook.com X-MS-Exchange-CrossTenant-Network-Message-Id: 8aa47dfe-bd26-4a3e-7e83-08d873b94fb1 X-MS-Exchange-CrossTenant-originalarrivaltime: 18 Oct 2020 22:58:21.5112 (UTC) X-MS-Exchange-CrossTenant-fromentityheader: Hosted X-MS-Exchange-CrossTenant-id: 686ea1d3-bc2b-4c6f-a92c-d99c5c301635 X-MS-Exchange-CrossTenant-mailboxtype: HOSTED X-MS-Exchange-CrossTenant-userprincipalname: 3FozT+xZeZ91W2Mi0GHfOCjjsoINnHm0F5a5HkWCPY/LT+WR2RIgFN496vAWsQRhmJmWR7Gk1yRIJWmkQKYbjA== X-MS-Exchange-Transport-CrossTenantHeadersStamped: VI1PR0401MB2688 Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org On Sun, Oct 18, 2020 at 04:13:28PM +0200, Heiner Kallweit wrote: > On a side note, because I'm also just dealing with it: this_cpu_ptr() > is safe only if preemption is disabled. Is this the case here? Else > there's get_cpu_ptr/put_cpu_ptr. lockdep would shout about using smp_processor_id() in preemptible context? Because it doesn't do that, and never did, but I don't really understand why, coming to think of it. > Also, if irq's aren't disabled there might be a need to use > u64_stats_update_begin_irqsave() et al. See: 2695578b896a ("net: > usbnet: fix potential deadlock on 32bit hosts") But I don't know dsa > good enough to say whether this is applicable here. DSA xmit and receive path do not run from hardirq context, just softirq, so I believe the issue reported to Eric there does not apply here.=