From patchwork Fri Feb 12 01:42:28 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Song Liu X-Patchwork-Id: 382751 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=-14.3 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH, MAILING_LIST_MULTI, SPF_HELO_NONE, SPF_PASS, USER_AGENT_GIT autolearn=unavailable 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 53636C433E0 for ; Fri, 12 Feb 2021 01:43:34 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 2DAB264E26 for ; Fri, 12 Feb 2021 01:43:34 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229730AbhBLBnc (ORCPT ); Thu, 11 Feb 2021 20:43:32 -0500 Received: from mx0b-00082601.pphosted.com ([67.231.153.30]:24410 "EHLO mx0b-00082601.pphosted.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229469AbhBLBn1 (ORCPT ); Thu, 11 Feb 2021 20:43:27 -0500 Received: from pps.filterd (m0109332.ppops.net [127.0.0.1]) by mx0a-00082601.pphosted.com (8.16.0.43/8.16.0.43) with SMTP id 11C1d9lU004454 for ; Thu, 11 Feb 2021 17:42:46 -0800 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=fb.com; h=from : to : cc : subject : date : message-id : mime-version : content-transfer-encoding : content-type; s=facebook; bh=UtuLx3WTMjSSGxzy7SrBCAV0KTEWZY8gpHt64S9m+YM=; b=VZUJCOaxPKWCUo8W3KC4YrrgiNdckmmtn+oSjzLqoUYtTH8FYmx3oak0t23eHQNfSqb0 OZOJ513IY7TZX5bb/YrMTQA3vjajV6RMf4tQbiZu6m+ds7GWcNnQChwjP7Taqd6x4Dm6 xUCQFV/2gdlToHEuVqHK9ZHBQFiNnuj03Tg= Received: from mail.thefacebook.com ([163.114.132.120]) by mx0a-00082601.pphosted.com with ESMTP id 36n91fjtce-2 (version=TLSv1.2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128 verify=NOT) for ; Thu, 11 Feb 2021 17:42:46 -0800 Received: from intmgw001.06.ash9.facebook.com (2620:10d:c085:208::11) by mail.thefacebook.com (2620:10d:c085:11d::7) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.1979.3; Thu, 11 Feb 2021 17:42:44 -0800 Received: by devbig006.ftw2.facebook.com (Postfix, from userid 4523) id 3420A62E0B5D; Thu, 11 Feb 2021 17:42:39 -0800 (PST) From: Song Liu To: , , CC: , , , , Song Liu Subject: [PATCH v6 bpf-next 0/4] introduce bpf_iter for task_vma Date: Thu, 11 Feb 2021 17:42:28 -0800 Message-ID: <20210212014232.414643-1-songliubraving@fb.com> X-Mailer: git-send-email 2.24.1 MIME-Version: 1.0 X-FB-Internal: Safe X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:6.0.369, 18.0.737 definitions=2021-02-11_07:2021-02-11,2021-02-11 signatures=0 X-Proofpoint-Spam-Details: rule=fb_default_notspam policy=fb_default score=0 bulkscore=0 spamscore=0 impostorscore=0 malwarescore=0 suspectscore=0 adultscore=0 mlxscore=0 clxscore=1015 phishscore=0 priorityscore=1501 mlxlogscore=870 lowpriorityscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2009150000 definitions=main-2102120008 X-FB-Internal: deliver Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org This set introduces bpf_iter for task_vma, which can be used to generate information similar to /proc/pid/maps. Patch 4/4 adds an example that mimics /proc/pid/maps. Current /proc//maps and /proc//smaps provide information of vma's of a process. However, these information are not flexible enough to cover all use cases. For example, if a vma cover mixed 2MB pages and 4kB pages (x86_64), there is no easy way to tell which address ranges are backed by 2MB pages. task_vma solves the problem by enabling the user to generate customize information based on the vma (and vma->vm_mm, vma->vm_file, etc.). Changes v5 => v6: 1. Add more comments for task_vma_seq_get_next() to explain the logic of find_vma() calls. (Alexei) 2. Skip vma found by find_vma() when both vm_start and vm_end matches prev_vm_[start|end]. Previous versions only compares vm_start. IOW, if vma of [4k, 8k] is replaced by [4k, 12k] after relocking mmap_lock, v5 will skip the new vma, while v6 will process it. Changes v4 => v5: 1. Fix a refcount leak on task_struct. (Yonghong) 2. Fix the selftest. (Yonghong) Changes v3 => v4: 1. Avoid skipping vma by assigning invalid prev_vm_start in task_vma_seq_stop(). (Yonghong) 2. Move "again" label in task_vma_seq_get_next() save a check. (Yonghong) Changes v2 => v3: 1. Rewrite 1/4 so that we hold mmap_lock while calling BPF program. This enables the BPF program to access the real vma with BTF. (Alexei) 2. Fix the logic when the control is returned to user space. (Yonghong) 3. Revise commit log and cover letter. (Yonghong) Changes v1 => v2: 1. Small fixes in task_iter.c and the selftests. (Yonghong) Song Liu (4): bpf: introduce task_vma bpf_iter bpf: allow bpf_d_path in sleepable bpf_iter program libbpf: introduce section "iter.s/" for sleepable bpf_iter program selftests/bpf: add test for bpf_iter_task_vma kernel/bpf/task_iter.c | 267 +++++++++++++++++- kernel/trace/bpf_trace.c | 5 + tools/lib/bpf/libbpf.c | 5 + .../selftests/bpf/prog_tests/bpf_iter.c | 118 +++++++- tools/testing/selftests/bpf/progs/bpf_iter.h | 8 + .../selftests/bpf/progs/bpf_iter_task_vma.c | 58 ++++ 6 files changed, 450 insertions(+), 11 deletions(-) create mode 100644 tools/testing/selftests/bpf/progs/bpf_iter_task_vma.c --- 2.24.1