From patchwork Sat Oct 7 12:45:14 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: Chuyi Zhou X-Patchwork-Id: 13412325 Received: from lindbergh.monkeyblade.net (lindbergh.monkeyblade.net [23.128.96.19]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 909501C699 for ; Sat, 7 Oct 2023 12:45:34 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=bytedance.com header.i=@bytedance.com header.b="c8QW3k3q" Received: from mail-oi1-x22b.google.com (mail-oi1-x22b.google.com [IPv6:2607:f8b0:4864:20::22b]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 2FDC0BF for ; Sat, 7 Oct 2023 05:45:32 -0700 (PDT) Received: by mail-oi1-x22b.google.com with SMTP id 5614622812f47-3ae55c2e12bso2105256b6e.0 for ; Sat, 07 Oct 2023 05:45:32 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=bytedance.com; s=google; t=1696682731; x=1697287531; darn=vger.kernel.org; h=content-transfer-encoding:mime-version:message-id:date:subject:cc :to:from:from:to:cc:subject:date:message-id:reply-to; bh=CDaXcRhA+gdgCae4/53Q2d2Fl2r3AoTXrjF9zbGRXmI=; b=c8QW3k3qprf1xr2RjY22Q9LQYZfSNQXcWpqcCJ4lJ8OO7YbzFffXNQHu3Ux2qYapsN l8KBIoaUvk0MrZj6kO1bDNuqOFtHiHaCySIbL6W4LJxsp5vAiZ2wg84BptFsG43AZU3l Nfp9ynZZ07h8pRPNbN1ggjs1TsE5t6X8wJ7P6u+NDFd1jO/MHJAYKsF+ITGkL19ScUZ/ 44W8esSm1x3xjXMTPfeJ8q7/7wFQOu+BdDEaQKQgeZgZQfoUIHR0GDyGUSCooj86vDBC 19ng3EJGj23oxMfzppK6YL/u7eLmlzfkiFFHLwVq0lQPYIV8xos2/SCMiEVcEghTanG0 i6pQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1696682731; x=1697287531; h=content-transfer-encoding:mime-version:message-id:date:subject:cc :to:from:x-gm-message-state:from:to:cc:subject:date:message-id :reply-to; bh=CDaXcRhA+gdgCae4/53Q2d2Fl2r3AoTXrjF9zbGRXmI=; b=FHK5EKtlkoUgmXh5rqkhe/r+E5O3ZH0iHK3iJ0wv8dEu7NS662aFF76m8vkn+fq842 fgP43En5AIGw/UBS1A9QdKb7igxZxRHU7IbB28tz0LGnI4adm1bGZjies4qCcvXQk8mD 7R4ukPpR8WWVNquLhnm/B9x0yBARWuNvp1wNqpa0oJE8yMaU+Hjck++fyCWrdxpHCzKR FWhqsC9+UYeiurl8+PUqAh3Bhtf61yRJ5z8yLVYc/HJpSx2XHt6RZQ8l7YBgvqjF+DPm Js9264QEUYv+57Om8Hop8RaBgb/D960Fh/mYLm1ea704j+NgmwfwqD/xuIRsHZ6vEfWj XucA== X-Gm-Message-State: AOJu0YwqgHQUmJZNB+1/r3nX1KEPsw9g2izW7XXlVAOVGyrM+Wrd6+gP zZHXBDpPNOgu7XKmJxFFlBDhnbNkpJYvTDUGz54= X-Google-Smtp-Source: AGHT+IHUFRMpSu4SNkxxwn/WeGfgd14NUXUXzLV8+sjU8s2yXjHWZvKzt3fnYH7rVqCOP40xgfcJrA== X-Received: by 2002:a05:6358:7245:b0:134:ec9d:ef18 with SMTP id i5-20020a056358724500b00134ec9def18mr12997443rwa.28.1696682730919; Sat, 07 Oct 2023 05:45:30 -0700 (PDT) Received: from n37-019-243.byted.org ([180.184.51.134]) by smtp.gmail.com with ESMTPSA id d6-20020a17090ad3c600b00256799877ffsm5095388pjw.47.2023.10.07.05.45.28 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Sat, 07 Oct 2023 05:45:30 -0700 (PDT) From: Chuyi Zhou To: bpf@vger.kernel.org Cc: ast@kernel.org, daniel@iogearbox.net, andrii@kernel.org, martin.lau@kernel.org, tj@kernel.org, linux-kernel@vger.kernel.org, Chuyi Zhou Subject: [PATCH bpf-next v4 0/8] Add Open-coded task, css_task and css iters Date: Sat, 7 Oct 2023 20:45:14 +0800 Message-Id: <20231007124522.34834-1-zhouchuyi@bytedance.com> X-Mailer: git-send-email 2.20.1 Precedence: bulk X-Mailing-List: bpf@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Spam-Status: No, score=-2.1 required=5.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,DKIM_VALID_EF,RCVD_IN_DNSWL_BLOCKED, SPF_HELO_NONE,SPF_NONE autolearn=ham autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on lindbergh.monkeyblade.net X-Patchwork-Delegate: bpf@iogearbox.net Hi, This is version 4 of task, css_task and css iters support. Thanks for your review! --- Changelog --- v3 -> v4:https://lore.kernel.org/all/20230925105552.817513-1-zhouchuyi@bytedance.com/ * Address all the comments from Andrii in patch-3 ~ patch-6 * Collect Tejun's ack * Add a extra patch to rename bpf_iter_task.c to bpf_iter_tasks.c * Seperate three BPF program files for selftests (iters_task.c iters_css_task.c iters_css.c) v2 -> v3:https://lore.kernel.org/lkml/20230912070149.969939-1-zhouchuyi@bytedance.com/ Patch 1 (cgroup: Prepare for using css_task_iter_*() in BPF) * Add tj's ack and Alexei's suggest-by. Patch 2 (bpf: Introduce css_task open-coded iterator kfuncs) * Use bpf_mem_alloc/bpf_mem_free rather than kzalloc() * Add KF_TRUSTED_ARGS for bpf_iter_css_task_new (Alexei) * Move bpf_iter_css_task's definition from uapi/linux/bpf.h to kernel/bpf/task_iter.c and we can use it from vmlinux.h * Move bpf_iter_css_task_XXX's declaration from bpf_helpers.h to bpf_experimental.h Patch 3 (Introduce task open coded iterator kfuncs) * Change th API design keep consistent with SEC("iter/task"), support iterating all threads(BPF_TASK_ITERATE_ALL) and threads of a specific task (BPF_TASK_ITERATE_THREAD).（Andrii) * Move bpf_iter_task's definition from uapi/linux/bpf.h to kernel/bpf/task_iter.c and we can use it from vmlinux.h * Move bpf_iter_task_XXX's declaration from bpf_helpers.h to bpf_experimental.h Patch 4 (Introduce css open-coded iterator kfuncs) * Change th API design keep consistent with cgroup_iters, reuse BPF_CGROUP_ITER_DESCENDANTS_PRE/BPF_CGROUP_ITER_DESCENDANTS_POST /BPF_CGROUP_ITER_ANCESTORS_UP(Andrii) * Add KF_TRUSTED_ARGS for bpf_iter_css_new * Move bpf_iter_css's definition from uapi/linux/bpf.h to kernel/bpf/task_iter.c and we can use it from vmlinux.h * Move bpf_iter_task_XXX's declaration from bpf_helpers.h to bpf_experimental.h Patch 4 (Introduce css open-coded iterator kfuncs) * Change th API design keep consistent with cgroup_iters, reuse BPF_CGROUP_ITER_DESCENDANTS_PRE/BPF_CGROUP_ITER_DESCENDANTS_POST /BPF_CGROUP_ITER_ANCESTORS_UP(Andrii) * Add KF_TRUSTED_ARGS for bpf_iter_css_new * Move bpf_iter_css's definition from uapi/linux/bpf.h to kernel/bpf/task_iter.c and we can use it from vmlinux.h * Move bpf_iter_css_XXX's declaration from bpf_helpers.h to bpf_experimental.h Patch 5 (teach the verifier to enforce css_iter and task_iter in RCU CS) * Add KF flag KF_RCU_PROTECTED to maintain kfuncs which need RCU CS.(Andrii) * Consider STACK_ITER when using bpf_for_each_spilled_reg. Patch 6 (Let bpf_iter_task_new accept null task ptr) * Add this extra patch to let bpf_iter_task_new accept a 'nullable' * task pointer(Andrii) Patch 7 (selftests/bpf: Add tests for open-coded task and css iter) * Add failure testcase(Alexei) Changes from v1(https://lore.kernel.org/lkml/20230827072057.1591929-1-zhouchuyi@bytedance.com/): - Add a pre-patch to make some preparations before supporting css_task iters.(Alexei) - Add an allowlist for css_task iters(Alexei) - Let bpf progs do explicit bpf_rcu_read_lock() when using process iters and css_descendant iters.(Alexei) --------------------- In some BPF usage scenarios, it will be useful to iterate the process and css directly in the BPF program. One of the expected scenarios is customizable OOM victim selection via BPF[1]. Inspired by Dave's task_vma iter[2], this patchset adds three types of open-coded iterator kfuncs: 1. bpf_task_iters. It can be used to 1) iterate all process in the system, like for_each_forcess() in kernel. 2) iterate all threads in the system. 3) iterate all threads of a specific task 2. bpf_css_iters. It works like css_task_iter_{start, next, end} and would be used to iterating tasks/threads under a css. 3. css_iters. It works like css_next_descendant_{pre, post} to iterating all descendant css. BPF programs can use these kfuncs directly or through bpf_for_each macro. link[1]: https://lore.kernel.org/lkml/20230810081319.65668-1-zhouchuyi@bytedance.com/ link[2]: https://lore.kernel.org/all/20230810183513.684836-1-davemarchevsky@fb.com/ Chuyi Zhou (8): cgroup: Prepare for using css_task_iter_*() in BPF bpf: Introduce css_task open-coded iterator kfuncs bpf: Introduce task open coded iterator kfuncs bpf: Introduce css open-coded iterator kfuncs bpf: teach the verifier to enforce css_iter and task_iter in RCU CS bpf: Let bpf_iter_task_new accept null task ptr selftests/bpf: rename bpf_iter_task.c to bpf_iter_tasks.c selftests/bpf: Add tests for open-coded task and css iter include/linux/bpf_verifier.h | 19 ++- include/linux/btf.h | 1 + include/linux/cgroup.h | 12 +- kernel/bpf/cgroup_iter.c | 59 +++++++ kernel/bpf/helpers.c | 9 + kernel/bpf/task_iter.c | 138 +++++++++++++++ kernel/bpf/verifier.c | 86 ++++++++-- kernel/cgroup/cgroup.c | 18 +- .../testing/selftests/bpf/bpf_experimental.h | 19 +++ .../selftests/bpf/prog_tests/bpf_iter.c | 18 +- .../testing/selftests/bpf/prog_tests/iters.c | 161 ++++++++++++++++++ .../{bpf_iter_task.c => bpf_iter_tasks.c} | 0 tools/testing/selftests/bpf/progs/iters_css.c | 74 ++++++++ .../selftests/bpf/progs/iters_css_task.c | 42 +++++ .../testing/selftests/bpf/progs/iters_task.c | 41 +++++ .../selftests/bpf/progs/iters_task_failure.c | 105 ++++++++++++ 16 files changed, 760 insertions(+), 42 deletions(-) rename tools/testing/selftests/bpf/progs/{bpf_iter_task.c => bpf_iter_tasks.c} (100%) create mode 100644 tools/testing/selftests/bpf/progs/iters_css.c create mode 100644 tools/testing/selftests/bpf/progs/iters_css_task.c create mode 100644 tools/testing/selftests/bpf/progs/iters_task.c create mode 100644 tools/testing/selftests/bpf/progs/iters_task_failure.c