From patchwork Mon Sep 25 10:55:45 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: Chuyi Zhou X-Patchwork-Id: 13397641 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 6FDF510A3D for ; Mon, 25 Sep 2023 10:56:01 +0000 (UTC) Received: from mail-pj1-x102c.google.com (mail-pj1-x102c.google.com [IPv6:2607:f8b0:4864:20::102c]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 54E99BE for ; Mon, 25 Sep 2023 03:55:59 -0700 (PDT) Received: by mail-pj1-x102c.google.com with SMTP id 98e67ed59e1d1-2769920fa24so4618411a91.1 for ; Mon, 25 Sep 2023 03:55:59 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=bytedance.com; s=google; t=1695639358; x=1696244158; 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=wkXNriz46VJXEH+3D4V7WJ8wWmj95WsD4ruF33VFe6Y=; b=dYoGhQZnQTjtT3XNrUjEyMr1KDyxfvm5mJz/dl1SiJkU4kc7dcgCqFwWhhiZzoNQhF wGHDGIxgplAzVXDDfO9XD97BeeCHXtQUgwUbJNef0KNmmlPD9qJ4YPi1p8MaV8hnlMSC Kf0MXsmGVmruOoM9MvnTPECPOYD32C/sjR2NjcJAkW1OQk1FCXK3D9Nv7TC4VuY5hLtI dPGng8a8uVdaXizvLonZEPYZkAED7osb6UNp6zsAAEKOLBVIIlcc/bscAxq+Mb85omyF jHt47t1t/gfrCIGBhUf5hsf8VBOOoZVYnwJytLVAc26sRzc1pewYITeNlpYNjDA9wbK8 93YQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1695639358; x=1696244158; 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=wkXNriz46VJXEH+3D4V7WJ8wWmj95WsD4ruF33VFe6Y=; b=ad9qdtm9gzpKdHklbMcnMkmq3olhKxPN1/UQiNGn9XgYpkSeKPZE/BWvbyOuEpnyFu vU5Xi1niwlnMatXdYrJRc3QDmEOocUNHcQMPVGOPObLADSou4bMLepqJQYMZdkQIxLlR Gwjh6PWfvDK6tY+Zcif+NicmZQ5vSL1mJgmkqzubwDu6X2uSR+hVirU6TUuHNq8asYQq nHni1f4/qo6NG/UcukT8fksakzBzQ5mKy3+VA/45roh1MxDsRpVCXoSDnLl/3Vy7LA6B e+X2i0yd2lWowYjdIjGurI6bPKAJ3WME4pnI/EzAWvFkXOkFB1AQI4+/+iuWJxBDfpb4 dy7A== X-Gm-Message-State: AOJu0YwPeZ1mlopzuPJwQpaS8G90gjox1+X8Z/7DJs1ELulxPdDyqYgD xgUqlJF17zeZVptqMvzriPkjdAe3rT3BsyneUXw= X-Google-Smtp-Source: AGHT+IFDBRmBp/V2qDkqnjBuMhMfYRGigwRGdWxy3LdHi+DIiXY8Ukq1z1VBhOcwG83sEcIb9X+nEg== X-Received: by 2002:a17:90a:a095:b0:26b:e27:8bc2 with SMTP id r21-20020a17090aa09500b0026b0e278bc2mr5663296pjp.45.1695639358348; Mon, 25 Sep 2023 03:55:58 -0700 (PDT) Received: from n37-019-243.byted.org ([180.184.51.134]) by smtp.gmail.com with ESMTPSA id y9-20020a17090a16c900b002772faee740sm2297842pje.5.2023.09.25.03.55.56 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 25 Sep 2023 03:55:58 -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 v3 0/7] Add Open-coded task, css_task and css iters Date: Mon, 25 Sep 2023 18:55:45 +0800 Message-Id: <20230925105552.817513-1-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_PASS autolearn=unavailable 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 3 of task, css_task and css iters support. Thanks for your review! --- Changelog --- 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_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 (7): 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: Add tests for open-coded task and css iter include/linux/bpf.h | 8 +- include/linux/bpf_verifier.h | 19 ++- include/linux/btf.h | 1 + include/linux/cgroup.h | 12 +- kernel/bpf/cgroup_iter.c | 57 +++++++ kernel/bpf/helpers.c | 9 + kernel/bpf/task_iter.c | 152 +++++++++++++++-- kernel/bpf/verifier.c | 84 +++++++-- kernel/cgroup/cgroup.c | 18 +- .../testing/selftests/bpf/bpf_experimental.h | 18 ++ .../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 .../testing/selftests/bpf/progs/iters_task.c | 132 ++++++++++++++ .../selftests/bpf/progs/iters_task_failure.c | 103 +++++++++++ 15 files changed, 734 insertions(+), 58 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_task.c create mode 100644 tools/testing/selftests/bpf/progs/iters_task_failure.c Acked-by: Tejun Heo