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=-8.2 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, MSGID_FROM_MTA_HEADER,NICE_REPLY_A,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 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 B254DC433DF for ; Tue, 18 Aug 2020 22:28:52 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 89BA020738 for ; Tue, 18 Aug 2020 22:28:52 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=fb.com header.i=@fb.com header.b="N3gJccXD"; dkim=pass (1024-bit key) header.d=fb.onmicrosoft.com header.i=@fb.onmicrosoft.com header.b="MYD5HIw1" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726971AbgHRW2w (ORCPT ); Tue, 18 Aug 2020 18:28:52 -0400 Received: from mx0a-00082601.pphosted.com ([67.231.145.42]:59106 "EHLO mx0a-00082601.pphosted.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726539AbgHRW2p (ORCPT ); Tue, 18 Aug 2020 18:28:45 -0400 Received: from pps.filterd (m0148461.ppops.net [127.0.0.1]) by mx0a-00082601.pphosted.com (8.16.0.42/8.16.0.42) with SMTP id 07IMDP0p006433; Tue, 18 Aug 2020 15:28:33 -0700 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=fb.com; h=subject : from : to : cc : references : message-id : date : in-reply-to : content-type : content-transfer-encoding : mime-version; s=facebook; bh=A99tmk0+7C3bCsJPeqjZp0hm6to33V9YMyY7aGNhlJI=; b=N3gJccXDUnqXeHqhpPkky8J2GX2dSPnk774gLbv0TgWj9OPonb1CY2Kjn8bT+o8Iek/Q M4vBISm4VmSdxxuDRwWhRjzVVfxe0B5x88M1bQGmlUOIM5DvHCFJa5tDH0GuLXqVxEDn bPWzMmHvuqpaoXC8GQSYabtnA3OAMBvNQPk= Received: from mail.thefacebook.com ([163.114.132.120]) by mx0a-00082601.pphosted.com with ESMTP id 3304m2wevy-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128 verify=NOT); Tue, 18 Aug 2020 15:28:32 -0700 Received: from NAM10-BN7-obe.outbound.protection.outlook.com (100.104.98.9) by o365-in.thefacebook.com (100.104.94.199) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.1979.3; Tue, 18 Aug 2020 15:28:32 -0700 ARC-Seal: i=1; a=rsa-sha256; s=arcselector9901; d=microsoft.com; cv=none; b=BUDjY2jDG8RgBcRKOpAScS5tNrCRvdi6Yax5gPKOJCTWHXlXSz99LLmIn4rR8Al08BBeHrLIPVCe55nadhqRuo49SACkcNhPAQqcisEx+YbpvYWIdf1880mNw6Nffr7r7YdFKY+/7JvxkpupisjRo6IwHmJy+FsR9U9W+FDJ8D6SEefid8MwSi0Ke0DMVekoGjIIRitATNAnSJ2//sWDzlJctj8XHr+yc/mZaNiQApQDZEKBx7kHtI79EZuY8ud5ET40uR1F4hmAx0kL4Q1ue60etiLN34dpe3tDTHNbhNownaJtwx6wMbWBrY1VXfToPMKeMGM4QJMGFr78z3srng== 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=A99tmk0+7C3bCsJPeqjZp0hm6to33V9YMyY7aGNhlJI=; b=lz4alZD8M0lX6rqjc4KSsCwdtTXQIf/l66W5V9ERVRVvw05gYefmQ9JrMUPX+qLz/Kx/4SASOHDXkcXNavfuHWIKeGvLZCb2TLGiK+43J1pxVYJ9eYT73BpVvEYdCbviGwVdVxx6/t1zt8IoPvq9dlLXUG2gRv7Jfn8kAUaR0Orp2pfcT5o8O7MKkyxrwwPZivNtqoAFerUliHtmyi6nhKKISxbuj01QazO8yEGecpc0k3RaMmOYh0xutoaxEh3iDt+zO3p7zV/kl6PAW0UFss4KGyeoK+j2P5amh7yrVzmGtxBbw+kW/ikaCA0PmuhqMGo13TmRKPhoLgrFZpqXog== 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 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=fb.onmicrosoft.com; s=selector2-fb-onmicrosoft-com; h=From:Date:Subject:Message-ID:Content-Type:MIME-Version:X-MS-Exchange-SenderADCheck; bh=A99tmk0+7C3bCsJPeqjZp0hm6to33V9YMyY7aGNhlJI=; b=MYD5HIw1pdNCqehspZ1guaA12OU9DXi/tDa5u8fLK7BKnDtUKssjhm9FXvnCdsQRI8PtVtB0+zXSfbmv0j8uLem+IG62kpUkV5JtxMOOdKUflVfQcTb1GO5I6BR7+mgx9F4PgReQcVf0a1XV44XgVb1Vog0F121pUtwkNwWJ+qY= Received: from BYAPR15MB4088.namprd15.prod.outlook.com (2603:10b6:a02:c3::18) by BYAPR15MB2453.namprd15.prod.outlook.com (2603:10b6:a02:8d::30) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.20.3283.15; Tue, 18 Aug 2020 22:28:29 +0000 Received: from BYAPR15MB4088.namprd15.prod.outlook.com ([fe80::56b:2925:8762:2d80]) by BYAPR15MB4088.namprd15.prod.outlook.com ([fe80::56b:2925:8762:2d80%7]) with mapi id 15.20.3283.028; Tue, 18 Aug 2020 22:28:29 +0000 Subject: Re: [PATCH bpf v2 0/3] bpf: two fixes for bpf iterators From: Yonghong Song To: , CC: Alexei Starovoitov , Daniel Borkmann , References: <20200818222309.2181236-1-yhs@fb.com> Message-ID: Date: Tue, 18 Aug 2020 15:28:25 -0700 User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.15; rv:68.0) Gecko/20100101 Thunderbird/68.11.0 In-Reply-To: <20200818222309.2181236-1-yhs@fb.com> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit X-ClientProxiedBy: MN2PR07CA0025.namprd07.prod.outlook.com (2603:10b6:208:1a0::35) To BYAPR15MB4088.namprd15.prod.outlook.com (2603:10b6:a02:c3::18) MIME-Version: 1.0 X-MS-Exchange-MessageSentRepresentingType: 1 Received: from [IPv6:2620:10d:c0a8:11e8::10d3] (2620:10d:c091:480::1:a06c) by MN2PR07CA0025.namprd07.prod.outlook.com (2603:10b6:208:1a0::35) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.20.3283.16 via Frontend Transport; Tue, 18 Aug 2020 22:28:28 +0000 X-Originating-IP: [2620:10d:c091:480::1:a06c] X-MS-PublicTrafficType: Email X-MS-Office365-Filtering-Correlation-Id: ce392fec-bada-4a5d-3d79-08d843c60850 X-MS-TrafficTypeDiagnostic: BYAPR15MB2453: X-MS-Exchange-Transport-Forked: True X-Microsoft-Antispam-PRVS: X-FB-Source: Internal X-MS-Oob-TLC-OOBClassifiers: OLM:7691; X-MS-Exchange-SenderADCheck: 1 X-Microsoft-Antispam: BCL:0; X-Microsoft-Antispam-Message-Info: 4BYfVwUEX6FEc3WTG4BI6ON9WA0/8LRBre8aD652hGHymckkhVMf6rCWx40vNWFdSFuBzN/hboHt4EJhqPnhjKujO0RUEWv904w0wMU9XjCF32eUJV+TizgPHMJmKkxEoXEZrRTOkhiYjB6r2d5ufulWpdlHqN8E44iZehYGcQUfcKT658P4SOOYd/ahfT24LzF7L3eenjCvfzJjGPBeob8HBapKMGbVnrgfIQQfUQ8yV87oLzJ9hFUp4VHcMYmmgSa79hc0PvnTwDjbG49HtLoAJ1NviJ05PO3MpLBrkIDDDjQarNMx07QD1Lf32vojmhoAiCI2Hae3SkyYix6XdgYq2w/ZWiP1EXlDjmSd/13O253oILcAAK+BBDWM8fds X-Forefront-Antispam-Report: CIP:255.255.255.255;CTRY:;LANG:en;SCL:1;SRV:;IPV:NLI;SFV:NSPM;H:BYAPR15MB4088.namprd15.prod.outlook.com;PTR:;CAT:NONE;SFS:(346002)(396003)(136003)(376002)(366004)(39860400002)(31696002)(186003)(8936002)(66946007)(478600001)(66556008)(66476007)(316002)(54906003)(83380400001)(4326008)(53546011)(16526019)(6666004)(2616005)(6486002)(86362001)(36756003)(8676002)(31686004)(5660300002)(2906002)(52116002)(43740500002);DIR:OUT;SFP:1102; X-MS-Exchange-AntiSpam-MessageData: 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 X-MS-Exchange-CrossTenant-Network-Message-Id: ce392fec-bada-4a5d-3d79-08d843c60850 X-MS-Exchange-CrossTenant-AuthSource: BYAPR15MB4088.namprd15.prod.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Internal X-MS-Exchange-CrossTenant-OriginalArrivalTime: 18 Aug 2020 22:28:29.7355 (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: DhvZUn71J14wszzI2J8BJ6Adghl3qN5ncn4j2CwYu6eOocKbAgZEYNm+et0ePTp+ X-MS-Exchange-Transport-CrossTenantHeadersStamped: BYAPR15MB2453 X-OriginatorOrg: fb.com X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:6.0.235,18.0.687 definitions=2020-08-18_16:2020-08-18,2020-08-18 signatures=0 X-Proofpoint-Spam-Details: rule=fb_default_notspam policy=fb_default score=0 mlxlogscore=901 impostorscore=0 mlxscore=0 bulkscore=0 suspectscore=8 spamscore=0 phishscore=0 lowpriorityscore=0 malwarescore=0 clxscore=1015 adultscore=0 priorityscore=1501 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2006250000 definitions=main-2008180160 X-FB-Internal: deliver Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org On 8/18/20 3:23 PM, Yonghong Song wrote: > Patch #1 fixed a rcu stall warning when traversing large number > of tasks/files without overflowing seq_file buffer. The method > is to control the number of visited objects in bpf_seq_read() > so all bpf iterators will benefit. > > Patch #2 calculated tid properly in a namespace in order to avoid > visiting the name task multiple times. > > Patch #3 handled read() error code EAGAIN properly in bpftool > bpf_iter userspace code to collect pids. The change is needed > due to Patch #1. Sorry. Missed the changelog below. Changelogs: - v1 -> v2: . do ratelimiting in bpf_seq_read() with a counter. cond_resched() doesn't work as some iterators (e.g., tcp, netlink, etc.) has rcu read critical section across consecutive seq_ops->next() functions. > > Yonghong Song (3): > bpf: fix a rcu_sched stall issue with bpf task/task_file iterator > bpf: avoid visit same object multiple times > bpftool: handle EAGAIN error code properly in pids collection > > kernel/bpf/bpf_iter.c | 15 ++++++++++++++- > kernel/bpf/task_iter.c | 3 ++- > tools/bpf/bpftool/pids.c | 2 ++ > 3 files changed, 18 insertions(+), 2 deletions(-) >