From nobody Wed Apr 29 13:38:26 2026 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 8F9B9C433EF for ; Fri, 10 Jun 2022 19:44:54 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1349163AbiFJTov (ORCPT ); Fri, 10 Jun 2022 15:44:51 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:45008 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1349545AbiFJToo (ORCPT ); Fri, 10 Jun 2022 15:44:44 -0400 Received: from mail-pj1-x104a.google.com (mail-pj1-x104a.google.com [IPv6:2607:f8b0:4864:20::104a]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 8A0E53631E for ; Fri, 10 Jun 2022 12:44:43 -0700 (PDT) Received: by mail-pj1-x104a.google.com with SMTP id w36-20020a17090a6ba700b001e876698a01so1895307pjj.5 for ; Fri, 10 Jun 2022 12:44:43 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20210112; h=date:in-reply-to:message-id:mime-version:references:subject:from:to :cc; bh=M8/ooGDXsUIPk2mNJ2l2OjGkicZ3p1bfFAHZWM/Ly3A=; b=GsYyQ0tB9bXQvXH2rfH1JcR8TEHmOvJ6SarwER+CY1co37p00ocODWPY6ALAvi7cC/ BhRL3SNdxxNtunT13h/LwWckSxL/x3PAnQlMiII3OjHHuxFjm/UiaqGQxGXDWeFua/FG Y41TkbjTNQZBdWmKWYSTYgE2O7pEhXg8S5aHcheB5zWS3P42tcPr1sfBsttz0m6u2hUS k57s9rBU2kRz1kN/xSirNBOIuFSqSk7cJ2Iomhw1Sciw7oQjyaJUK3RsSElxoEdJENaN Lak88pvz9+Eaj9JoaT6P2JaZC4ShxM85fhVOaqcNPgOPT2GVKO2t8qNWcDUt1V4NiF6D Kovg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:date:in-reply-to:message-id:mime-version :references:subject:from:to:cc; bh=M8/ooGDXsUIPk2mNJ2l2OjGkicZ3p1bfFAHZWM/Ly3A=; b=iY6FQ0XjyQiKphRHgX/UNcaUQS8E5qMLRHFeJVg6/xpinELsLdzphTrpEZjKKhvlpJ BFRebQeP/M5qawIV0J99KP+UUYrs2CPp/2JXNPb8PGVZmjjqrJ2KFHnP3J5jeG6sP9NJ caNZA5VbmUY8yK9FdvLVyrDuAlvrHE4XbgC0K9NPf4/jgTEORw/2lvfbNJ3fc25iLrod d6mBNmWxkeMmh5h7imCFyvieM2Pz5of8TM0PqSJWcBktWrDxHpplblCIme1VyjHJpXGF 8ErwiwjpIueEyCWcyR0sXO+Osrbm20ySEtFlaav0p3k2t+VpeqIeZTwez97hKAW0dQEH DzKw== X-Gm-Message-State: AOAM532qpV/z1c2FHy1OZB703avEQmoC2b5TJ5X00bH5yqQmC9sBgjJz zoah3NHuayNXCg7q+5yKjqjf9rNbogan5H+q X-Google-Smtp-Source: ABdhPJwzzXdJSQLS1yhXNkW4jZlIb5MwaItH0qGZ/ykK+7cJuSSeS2jc+LxoBuNLneYOkn5pxgmTPqyeft1R+UIp X-Received: from yosry.c.googlers.com ([fda3:e722:ac3:cc00:7f:e700:c0a8:2327]) (user=yosryahmed job=sendgmr) by 2002:a05:6a00:b81:b0:51c:3bfe:7d89 with SMTP id g1-20020a056a000b8100b0051c3bfe7d89mr21514984pfj.31.1654890283002; Fri, 10 Jun 2022 12:44:43 -0700 (PDT) Date: Fri, 10 Jun 2022 19:44:28 +0000 In-Reply-To: <20220610194435.2268290-1-yosryahmed@google.com> Message-Id: <20220610194435.2268290-2-yosryahmed@google.com> Mime-Version: 1.0 References: <20220610194435.2268290-1-yosryahmed@google.com> X-Mailer: git-send-email 2.36.1.476.g0c4daa206d-goog Subject: [PATCH bpf-next v2 1/8] cgroup: enable cgroup_get_from_file() on cgroup1 From: Yosry Ahmed To: Alexei Starovoitov , Daniel Borkmann , Andrii Nakryiko , Martin KaFai Lau , Song Liu , Yonghong Song , John Fastabend , KP Singh , Hao Luo , Tejun Heo , Zefan Li , Johannes Weiner , Shuah Khan , Michal Hocko Cc: Roman Gushchin , David Rientjes , Stanislav Fomichev , Greg Thelen , Shakeel Butt , linux-kernel@vger.kernel.org, netdev@vger.kernel.org, bpf@vger.kernel.org, cgroups@vger.kernel.org, Yosry Ahmed Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" cgroup_get_from_file() currently fails with -EBADF if called on cgroup v1. However, the current implementation works on cgroup v1 as well, so the restriction is unnecessary. This enabled cgroup_get_from_fd() to work on cgroup v1, which would be the only thing stopping bpf cgroup_iter from supporting cgroup v1. Signed-off-by: Yosry Ahmed --- kernel/cgroup/cgroup.c | 5 ----- 1 file changed, 5 deletions(-) diff --git a/kernel/cgroup/cgroup.c b/kernel/cgroup/cgroup.c index 1779ccddb734d..9943fcb1e574d 100644 --- a/kernel/cgroup/cgroup.c +++ b/kernel/cgroup/cgroup.c @@ -6090,11 +6090,6 @@ static struct cgroup *cgroup_get_from_file(struct fi= le *f) return ERR_CAST(css); =20 cgrp =3D css->cgroup; - if (!cgroup_on_dfl(cgrp)) { - cgroup_put(cgrp); - return ERR_PTR(-EBADF); - } - return cgrp; } =20 --=20 2.36.1.476.g0c4daa206d-goog From nobody Wed Apr 29 13:38:26 2026 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id A5355C433EF for ; Fri, 10 Jun 2022 19:44:59 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1349758AbiFJTo6 (ORCPT ); Fri, 10 Jun 2022 15:44:58 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:45118 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1347086AbiFJToq (ORCPT ); Fri, 10 Jun 2022 15:44:46 -0400 Received: from mail-pf1-x449.google.com (mail-pf1-x449.google.com [IPv6:2607:f8b0:4864:20::449]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 6451539141 for ; Fri, 10 Jun 2022 12:44:45 -0700 (PDT) Received: by mail-pf1-x449.google.com with SMTP id z67-20020a626546000000b0051bbb66c1bdso142831pfb.0 for ; Fri, 10 Jun 2022 12:44:45 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20210112; h=date:in-reply-to:message-id:mime-version:references:subject:from:to :cc; bh=BoKrpJKf0NJs+gRVFUxqhFbhSmPUCp4fm3z5hnvOZp8=; b=AwMbVnbr5q4cAXvZEcfd1LqfchA948H9iCk6EgWRZCrU9JhEVm5ktf2o6ZcthFHxtp fJR2NLnd0CP1ZVB3DUwvjogVI2lGFx+c1jhyCuYfDxaBpbmiyoNPt/4toEyzPoI8aG2L l7EJEOOgOdJokfnVs39pZpvlN/bMYVF8zi3c8INe95INBFA4jl4lIxoLgkCtuPsoV8/a 1XXWK4i4F34ceL4ZDMye01r9T5dL4OyM1vSa6CjC9wbd/gsB2aegqtszm1WaBXpeIDBW OkwEXnjpF+TFyYLJeSn6Le2Zl5Qm8eGCj8UZgJcfVmdvtpSuHd21o5lvW7PAjhTT2Zlu rkqw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:date:in-reply-to:message-id:mime-version :references:subject:from:to:cc; bh=BoKrpJKf0NJs+gRVFUxqhFbhSmPUCp4fm3z5hnvOZp8=; b=xOq3mkGEzSKrtstgdSfUPwTOHhpjO4FAOFaSBo/nU8JtDYgr+M4H9fXKHsO28ZlnHc cuo+WTmhgLxdeZ0HBXQEVz80cMDk4z56z2wcsbKWKvtVlIIIERRp4JJsaN0MV37Dreij C5/Ha7bcnP4OQC/bCuXGrFvsdWTVfWHYbi6jimmnDPps//caQ1aRk0l5KR43TgMPjCDw 8ee7jkLDGKphp+u1qHEeBFofW3gVVnWt+rrkT0ZXntgX84hM8frliOmhTp2gOjNfdv3r HewqLBRp+7CsMs/P2lz0KN7YfMGDpFNvlE5SS6Vm6gbZSmwn301ee5+YeptFyR5sYMmr GVGA== X-Gm-Message-State: AOAM533X1u2aDTijhfFBqaBHNBM/GTzdyMRl7qHLaRs+Rew0DiU2GYe6 yCQro2ND6xZ7SlCBhLNuqtB5je89KI8Mfjr0 X-Google-Smtp-Source: ABdhPJwQ9/O3cLtL091G/r5wtBr7xRRylG/pClmo9oRqteMdlU54kund+SWaTzWoyJFSyaMFBAR9HfurzCkT4g19 X-Received: from yosry.c.googlers.com ([fda3:e722:ac3:cc00:7f:e700:c0a8:2327]) (user=yosryahmed job=sendgmr) by 2002:a17:902:e0c2:b0:167:6128:e63d with SMTP id e2-20020a170902e0c200b001676128e63dmr35223277pla.16.1654890284796; Fri, 10 Jun 2022 12:44:44 -0700 (PDT) Date: Fri, 10 Jun 2022 19:44:29 +0000 In-Reply-To: <20220610194435.2268290-1-yosryahmed@google.com> Message-Id: <20220610194435.2268290-3-yosryahmed@google.com> Mime-Version: 1.0 References: <20220610194435.2268290-1-yosryahmed@google.com> X-Mailer: git-send-email 2.36.1.476.g0c4daa206d-goog Subject: [PATCH bpf-next v2 2/8] cgroup: Add cgroup_put() in !CONFIG_CGROUPS case From: Yosry Ahmed To: Alexei Starovoitov , Daniel Borkmann , Andrii Nakryiko , Martin KaFai Lau , Song Liu , Yonghong Song , John Fastabend , KP Singh , Hao Luo , Tejun Heo , Zefan Li , Johannes Weiner , Shuah Khan , Michal Hocko Cc: Roman Gushchin , David Rientjes , Stanislav Fomichev , Greg Thelen , Shakeel Butt , linux-kernel@vger.kernel.org, netdev@vger.kernel.org, bpf@vger.kernel.org, cgroups@vger.kernel.org, Yosry Ahmed Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" From: Hao Luo There is already a cgroup_get_from_id() in the !CONFIG_CGROUPS case, let's have a matching cgroup_put() in !CONFIG_CGROUPS too. Signed-off-by: Hao Luo Signed-off-by: Yosry Ahmed --- include/linux/cgroup.h | 3 +++ 1 file changed, 3 insertions(+) diff --git a/include/linux/cgroup.h b/include/linux/cgroup.h index 0d1ada8968d75..7485a2f939119 100644 --- a/include/linux/cgroup.h +++ b/include/linux/cgroup.h @@ -757,6 +757,9 @@ static inline struct cgroup *cgroup_get_from_id(u64 id) { return NULL; } + +static inline void cgroup_put(struct cgroup *cgrp) +{} #endif /* !CONFIG_CGROUPS */ =20 #ifdef CONFIG_CGROUPS --=20 2.36.1.476.g0c4daa206d-goog From nobody Wed Apr 29 13:38:26 2026 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 7D9C7C433EF for ; Fri, 10 Jun 2022 19:45:11 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1350524AbiFJTpJ (ORCPT ); Fri, 10 Jun 2022 15:45:09 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:45654 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1350261AbiFJTo4 (ORCPT ); Fri, 10 Jun 2022 15:44:56 -0400 Received: from mail-pg1-x549.google.com (mail-pg1-x549.google.com [IPv6:2607:f8b0:4864:20::549]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 9AF5B3DA42 for ; Fri, 10 Jun 2022 12:44:47 -0700 (PDT) Received: by mail-pg1-x549.google.com with SMTP id 78-20020a630051000000b003fe25580679so30899pga.9 for ; Fri, 10 Jun 2022 12:44:47 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20210112; h=date:in-reply-to:message-id:mime-version:references:subject:from:to :cc; bh=oRH9s66i/tSGRatQjV8lrlYVzRqMhVkli+0iViEEm3E=; b=EWvIhNpLP4xn7/AaqRD2ry5tJ0od8mdvtIo1l8Mu+AVSg+pAqesAczV/0Lr9wi2kiz Fy1MQLHaGvnHVaKfEvTTAGxuQ35arwQTMzrK2HRvce7BKsnt7sTyah4aPc8tPwHAGwCP alnn29BH+uZT8ISPg2q0Aplzk57S3UfzlWezvPJ4bm6+UjnhYvJElPhjilELUc3eMS3i biAZPX2dSat+7EcVOoZvb8GhkN6J+dYfXoCwKW+EU9nHCjcLl83cMunu9bKv9Kdj8e3T TmfhQM5pKilrhRQQjzkRZ7h9oFsr0mAh0K0WVdTgcxvqo9ykb8W3YB6HehNxkS1wukLn Pf+g== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:date:in-reply-to:message-id:mime-version :references:subject:from:to:cc; bh=oRH9s66i/tSGRatQjV8lrlYVzRqMhVkli+0iViEEm3E=; b=zQPyJ/0BmsTXDWW2v9w5M3k79jTgQda3od643wEke08tWi1nxcu4pc11nSmbPLfpB/ 2ffsTeft9F+7+EPuhmO2fcIuXT6v25H4NqlXJQMJKK+u5r6lLoywGHpuPbqaFE6XvAIO 6FVS0BYj1ES3DX4Opci7e6ICLV1z8Y8iM3KTZeVVlPe8P2yZXJ9QbCrX99dgjlyh6RUF xqaa721WVoFy+MkxFZTgQQbQ4rcFK/t2fp3boArCnJ0SpHPoaLyM6ols770aHfb0Vofo j3qxEESZ6h6WsNJb5AC5jxxZc8/r/nxHBV8Z9yUpfD2vQD01K6BdLnDgG4/mqZPMWJdF yN/A== X-Gm-Message-State: AOAM532V0FDYLzjn39/ZInUenUuwf+e+GCZwA1XXB24lS9Jm4WFCep4X PeY2RzGTkrKGT9NfwoBgMtnrQmfo/LIRkugj X-Google-Smtp-Source: ABdhPJxLzCg7BT12DYURFJcz5iuhljjyz60dSOKo1LAt2zz0VKFLfw3YaQHFlASgYFV2U5cX9TzLETp7QJyh9R1w X-Received: from yosry.c.googlers.com ([fda3:e722:ac3:cc00:7f:e700:c0a8:2327]) (user=yosryahmed job=sendgmr) by 2002:a17:90a:249:b0:1e0:a8a3:3c6c with SMTP id t9-20020a17090a024900b001e0a8a33c6cmr2523pje.0.1654890286518; Fri, 10 Jun 2022 12:44:46 -0700 (PDT) Date: Fri, 10 Jun 2022 19:44:30 +0000 In-Reply-To: <20220610194435.2268290-1-yosryahmed@google.com> Message-Id: <20220610194435.2268290-4-yosryahmed@google.com> Mime-Version: 1.0 References: <20220610194435.2268290-1-yosryahmed@google.com> X-Mailer: git-send-email 2.36.1.476.g0c4daa206d-goog Subject: [PATCH bpf-next v2 3/8] bpf, iter: Fix the condition on p when calling stop. From: Yosry Ahmed To: Alexei Starovoitov , Daniel Borkmann , Andrii Nakryiko , Martin KaFai Lau , Song Liu , Yonghong Song , John Fastabend , KP Singh , Hao Luo , Tejun Heo , Zefan Li , Johannes Weiner , Shuah Khan , Michal Hocko Cc: Roman Gushchin , David Rientjes , Stanislav Fomichev , Greg Thelen , Shakeel Butt , linux-kernel@vger.kernel.org, netdev@vger.kernel.org, bpf@vger.kernel.org, cgroups@vger.kernel.org, Yosry Ahmed Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" From: Hao Luo In bpf_seq_read, seq->op->next() could return an ERR and jump to the label stop. However, the existing code in stop does not handle the case when p (returned from next()) is an ERR. Adds the handling of ERR of p by converting p into an error and jumping to done. Because all the current implementations do not have a case that returns ERR from next(), so this patch doesn't have behavior changes right now. Signed-off-by: Hao Luo Signed-off-by: Yosry Ahmed Acked-by: Yonghong Song --- kernel/bpf/bpf_iter.c | 5 +++++ 1 file changed, 5 insertions(+) diff --git a/kernel/bpf/bpf_iter.c b/kernel/bpf/bpf_iter.c index d5d96ceca1058..1585caf7c7200 100644 --- a/kernel/bpf/bpf_iter.c +++ b/kernel/bpf/bpf_iter.c @@ -198,6 +198,11 @@ static ssize_t bpf_seq_read(struct file *file, char __= user *buf, size_t size, } stop: offs =3D seq->count; + if (IS_ERR(p)) { + seq->op->stop(seq, NULL); + err =3D PTR_ERR(p); + goto done; + } /* bpf program called if !p */ seq->op->stop(seq, p); if (!p) { --=20 2.36.1.476.g0c4daa206d-goog From nobody Wed Apr 29 13:38:26 2026 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 5D161C433EF for ; Fri, 10 Jun 2022 19:45:17 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1347177AbiFJTpN (ORCPT ); Fri, 10 Jun 2022 15:45:13 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:45650 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1350289AbiFJTo4 (ORCPT ); Fri, 10 Jun 2022 15:44:56 -0400 Received: from mail-pj1-x104a.google.com (mail-pj1-x104a.google.com [IPv6:2607:f8b0:4864:20::104a]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 5CA013630E for ; Fri, 10 Jun 2022 12:44:49 -0700 (PDT) Received: by mail-pj1-x104a.google.com with SMTP id g14-20020a17090a128e00b001e882d66615so60743pja.9 for ; Fri, 10 Jun 2022 12:44:49 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20210112; h=date:in-reply-to:message-id:mime-version:references:subject:from:to :cc; bh=iWUTf7azRHWYJBbO/rjQ6tyhfLt2WZz4WFnWnc551p4=; b=mumc3P+TNgOg4ihd2eRqWKQ35uOgPIScsvj7x+G/6wWVvbFH+I2nbtRULXXs4VdOE/ 0wmkkZvtRp9Tyez18LlzzTPU28M3NdonOs1NYlc1qEQPUHE1eIdVV8VripIVkjGRyvRJ yTGO2QEqI7f8EhCTJNrKIG2qzXeMWkynvPmrqGzl0QqET3N8/4hhEUQ053+G9QROdIPc MTrcCLsylIYfP6OL3QbHodVKwb9mEGqt4NeJpdWPtoGLOQAuXhdAu0sB4oaC9W/umy9R vOdAGRljQ9EOKDYXkVQoYum8bstPA9ROySi8z57/mloHxoMTYfkEtuXdpu+c4s7vxwuw FGXA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:date:in-reply-to:message-id:mime-version :references:subject:from:to:cc; bh=iWUTf7azRHWYJBbO/rjQ6tyhfLt2WZz4WFnWnc551p4=; b=WLaNs6YYKcPNDFS2SLcCbeKW0eLOx1niFn54DojCilbwLbr2Q/oA0uotwpOsGxrCRi RZbjj8TzmjiLz7HgL7V1jWxOf3ESZnCtbhwGPePtjoEZKv4VBu2LNSK1SkZhFtni52iS aGRRa9aMy2SX7EhIb08612olUb1OUTv7BDJDPzbdAvLSA136oJuZtqUykluPzBoRQPb1 4OYz+VTehPI3aHTF6bR2L1sRMN+fd9rckf1w7wUTLgtpyi2EnlwA64DVpK79bBZi5GhA Z4Igic7zEMUNl+4CgeLfx+tpNicQXMf9HgxtZiAUXNkyp+C5Nk5zyG9uqf1iK0hC1iAl COfw== X-Gm-Message-State: AOAM5306xuTuhfADRFT/fOOgrNsQvVkQx1oped1khy3HX1/Fpjipti91 Mjr35KPLv8DkLhoAxes+Mw5vRmMnaaiIOYki X-Google-Smtp-Source: ABdhPJz+tTfQY7j+BSjA3MBoczrx1JLMSyr6jJy2Jyvg/mxQWhyQvGCi3dT/8Kh1ZO47fTk6jRS2jSEDYu1z1wAs X-Received: from yosry.c.googlers.com ([fda3:e722:ac3:cc00:7f:e700:c0a8:2327]) (user=yosryahmed job=sendgmr) by 2002:a05:6a00:2286:b0:51c:48b7:a445 with SMTP id f6-20020a056a00228600b0051c48b7a445mr18711373pfe.62.1654890288366; Fri, 10 Jun 2022 12:44:48 -0700 (PDT) Date: Fri, 10 Jun 2022 19:44:31 +0000 In-Reply-To: <20220610194435.2268290-1-yosryahmed@google.com> Message-Id: <20220610194435.2268290-5-yosryahmed@google.com> Mime-Version: 1.0 References: <20220610194435.2268290-1-yosryahmed@google.com> X-Mailer: git-send-email 2.36.1.476.g0c4daa206d-goog Subject: [PATCH bpf-next v2 4/8] bpf: Introduce cgroup iter From: Yosry Ahmed To: Alexei Starovoitov , Daniel Borkmann , Andrii Nakryiko , Martin KaFai Lau , Song Liu , Yonghong Song , John Fastabend , KP Singh , Hao Luo , Tejun Heo , Zefan Li , Johannes Weiner , Shuah Khan , Michal Hocko Cc: Roman Gushchin , David Rientjes , Stanislav Fomichev , Greg Thelen , Shakeel Butt , linux-kernel@vger.kernel.org, netdev@vger.kernel.org, bpf@vger.kernel.org, cgroups@vger.kernel.org, Yosry Ahmed Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" From: Hao Luo Cgroup_iter is a type of bpf_iter. It walks over cgroups in two modes: - walking a cgroup's descendants. - walking a cgroup's ancestors. When attaching cgroup_iter, one can set a cgroup to the iter_link created from attaching. This cgroup is passed as a file descriptor and serves as the starting point of the walk. If no cgroup is specified, the starting point will be the root cgroup. For walking descendants, one can specify the order: either pre-order or post-order. For walking ancestors, the walk starts at the specified cgroup and ends at the root. One can also terminate the walk early by returning 1 from the iter program. Note that because walking cgroup hierarchy holds cgroup_mutex, the iter program is called with cgroup_mutex held. Signed-off-by: Hao Luo Signed-off-by: Yosry Ahmed Acked-by: Yonghong Song Reported-by: kernel test robot --- include/linux/bpf.h | 8 ++ include/uapi/linux/bpf.h | 21 +++ kernel/bpf/Makefile | 2 +- kernel/bpf/cgroup_iter.c | 235 +++++++++++++++++++++++++++++++++ tools/include/uapi/linux/bpf.h | 21 +++ 5 files changed, 286 insertions(+), 1 deletion(-) create mode 100644 kernel/bpf/cgroup_iter.c diff --git a/include/linux/bpf.h b/include/linux/bpf.h index 8e6092d0ea956..48d8e836b9748 100644 --- a/include/linux/bpf.h +++ b/include/linux/bpf.h @@ -44,6 +44,7 @@ struct kobject; struct mem_cgroup; struct module; struct bpf_func_state; +struct cgroup; =20 extern struct idr btf_idr; extern spinlock_t btf_idr_lock; @@ -1590,7 +1591,14 @@ int bpf_obj_get_user(const char __user *pathname, in= t flags); int __init bpf_iter_ ## target(args) { return 0; } =20 struct bpf_iter_aux_info { + /* for map_elem iter */ struct bpf_map *map; + + /* for cgroup iter */ + struct { + struct cgroup *start; /* starting cgroup */ + int order; + } cgroup; }; =20 typedef int (*bpf_iter_attach_target_t)(struct bpf_prog *prog, diff --git a/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h index f4009dbdf62da..4fd05cde19116 100644 --- a/include/uapi/linux/bpf.h +++ b/include/uapi/linux/bpf.h @@ -87,10 +87,27 @@ struct bpf_cgroup_storage_key { __u32 attach_type; /* program attach type (enum bpf_attach_type) */ }; =20 +enum bpf_iter_cgroup_traversal_order { + BPF_ITER_CGROUP_PRE =3D 0, /* pre-order traversal */ + BPF_ITER_CGROUP_POST, /* post-order traversal */ + BPF_ITER_CGROUP_PARENT_UP, /* traversal of ancestors up to the root */ +}; + union bpf_iter_link_info { struct { __u32 map_fd; } map; + + /* cgroup_iter walks either the live descendants of a cgroup subtree, or = the ancestors + * of a given cgroup. + */ + struct { + /* Cgroup file descriptor. This is root of the subtree if for walking the + * descendants; this is the starting cgroup if for walking the ancestors. + */ + __u32 cgroup_fd; + __u32 traversal_order; + } cgroup; }; =20 /* BPF syscall commands, see bpf(2) man-page for more details. */ @@ -6050,6 +6067,10 @@ struct bpf_link_info { struct { __u32 map_id; } map; + struct { + __u32 traversal_order; + __aligned_u64 cgroup_id; + } cgroup; }; } iter; struct { diff --git a/kernel/bpf/Makefile b/kernel/bpf/Makefile index 057ba8e01e70f..9741b9314fb46 100644 --- a/kernel/bpf/Makefile +++ b/kernel/bpf/Makefile @@ -8,7 +8,7 @@ CFLAGS_core.o +=3D $(call cc-disable-warning, override-init= ) $(cflags-nogcse-yy) =20 obj-$(CONFIG_BPF_SYSCALL) +=3D syscall.o verifier.o inode.o helpers.o tnum= .o bpf_iter.o map_iter.o task_iter.o prog_iter.o link_iter.o obj-$(CONFIG_BPF_SYSCALL) +=3D hashtab.o arraymap.o percpu_freelist.o bpf_= lru_list.o lpm_trie.o map_in_map.o bloom_filter.o -obj-$(CONFIG_BPF_SYSCALL) +=3D local_storage.o queue_stack_maps.o ringbuf.o +obj-$(CONFIG_BPF_SYSCALL) +=3D local_storage.o queue_stack_maps.o ringbuf.= o cgroup_iter.o obj-$(CONFIG_BPF_SYSCALL) +=3D bpf_local_storage.o bpf_task_storage.o obj-${CONFIG_BPF_LSM} +=3D bpf_inode_storage.o obj-$(CONFIG_BPF_SYSCALL) +=3D disasm.o diff --git a/kernel/bpf/cgroup_iter.c b/kernel/bpf/cgroup_iter.c new file mode 100644 index 0000000000000..88deb655efa71 --- /dev/null +++ b/kernel/bpf/cgroup_iter.c @@ -0,0 +1,235 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* Copyright (c) 2022 Google */ +#include +#include +#include +#include +#include + +#include "../cgroup/cgroup-internal.h" /* cgroup_mutex and cgroup_is_dead= */ + +/* cgroup_iter provides two modes of traversal to the cgroup hierarchy. + * + * 1. Walk the descendants of a cgroup. + * 2. Walk the ancestors of a cgroup. + * + * For walking descendants, cgroup_iter can walk in either pre-order or + * post-order. For walking ancestors, the iter walks up from a cgroup to + * the root. + * + * The iter program can terminate the walk early by returning 1. Walk + * continues if prog returns 0. + * + * The prog can check (seq->num =3D=3D 0) to determine whether this is + * the first element. The prog may also be passed a NULL cgroup, + * which means the walk has completed and the prog has a chance to + * do post-processing, such as outputing an epilogue. + * + * Note: the iter_prog is called with cgroup_mutex held. + */ + +struct bpf_iter__cgroup { + __bpf_md_ptr(struct bpf_iter_meta *, meta); + __bpf_md_ptr(struct cgroup *, cgroup); +}; + +struct cgroup_iter_priv { + struct cgroup_subsys_state *start_css; + bool terminate; + int order; +}; + +static void *cgroup_iter_seq_start(struct seq_file *seq, loff_t *pos) +{ + struct cgroup_iter_priv *p =3D seq->private; + + mutex_lock(&cgroup_mutex); + + /* support only one session */ + if (*pos > 0) + return NULL; + + ++*pos; + p->terminate =3D false; + if (p->order =3D=3D BPF_ITER_CGROUP_PRE) + return css_next_descendant_pre(NULL, p->start_css); + else if (p->order =3D=3D BPF_ITER_CGROUP_POST) + return css_next_descendant_post(NULL, p->start_css); + else /* BPF_ITER_CGROUP_PARENT_UP */ + return p->start_css; +} + +static int __cgroup_iter_seq_show(struct seq_file *seq, + struct cgroup_subsys_state *css, int in_stop); + +static void cgroup_iter_seq_stop(struct seq_file *seq, void *v) +{ + /* pass NULL to the prog for post-processing */ + if (!v) + __cgroup_iter_seq_show(seq, NULL, true); + mutex_unlock(&cgroup_mutex); +} + +static void *cgroup_iter_seq_next(struct seq_file *seq, void *v, loff_t *p= os) +{ + struct cgroup_subsys_state *curr =3D (struct cgroup_subsys_state *)v; + struct cgroup_iter_priv *p =3D seq->private; + + ++*pos; + if (p->terminate) + return NULL; + + if (p->order =3D=3D BPF_ITER_CGROUP_PRE) + return css_next_descendant_pre(curr, p->start_css); + else if (p->order =3D=3D BPF_ITER_CGROUP_POST) + return css_next_descendant_post(curr, p->start_css); + else + return curr->parent; +} + +static int __cgroup_iter_seq_show(struct seq_file *seq, + struct cgroup_subsys_state *css, int in_stop) +{ + struct cgroup_iter_priv *p =3D seq->private; + struct bpf_iter__cgroup ctx; + struct bpf_iter_meta meta; + struct bpf_prog *prog; + int ret =3D 0; + + /* cgroup is dead, skip this element */ + if (css && cgroup_is_dead(css->cgroup)) + return 0; + + ctx.meta =3D &meta; + ctx.cgroup =3D css ? css->cgroup : NULL; + meta.seq =3D seq; + prog =3D bpf_iter_get_info(&meta, in_stop); + if (prog) + ret =3D bpf_iter_run_prog(prog, &ctx); + + /* if prog returns > 0, terminate after this element. */ + if (ret !=3D 0) + p->terminate =3D true; + + return 0; +} + +static int cgroup_iter_seq_show(struct seq_file *seq, void *v) +{ + return __cgroup_iter_seq_show(seq, (struct cgroup_subsys_state *)v, + false); +} + +static const struct seq_operations cgroup_iter_seq_ops =3D { + .start =3D cgroup_iter_seq_start, + .next =3D cgroup_iter_seq_next, + .stop =3D cgroup_iter_seq_stop, + .show =3D cgroup_iter_seq_show, +}; + +BTF_ID_LIST_SINGLE(bpf_cgroup_btf_id, struct, cgroup) + +static int cgroup_iter_seq_init(void *priv, struct bpf_iter_aux_info *aux) +{ + struct cgroup_iter_priv *p =3D (struct cgroup_iter_priv *)priv; + struct cgroup *cgrp =3D aux->cgroup.start; + + p->start_css =3D &cgrp->self; + p->terminate =3D false; + p->order =3D aux->cgroup.order; + return 0; +} + +static const struct bpf_iter_seq_info cgroup_iter_seq_info =3D { + .seq_ops =3D &cgroup_iter_seq_ops, + .init_seq_private =3D cgroup_iter_seq_init, + .seq_priv_size =3D sizeof(struct cgroup_iter_priv), +}; + +static int bpf_iter_attach_cgroup(struct bpf_prog *prog, + union bpf_iter_link_info *linfo, + struct bpf_iter_aux_info *aux) +{ + int fd =3D linfo->cgroup.cgroup_fd; + struct cgroup *cgrp; + + if (fd) + cgrp =3D cgroup_get_from_fd(fd); + else /* walk the entire hierarchy by default. */ + cgrp =3D cgroup_get_from_path("/"); + + if (IS_ERR(cgrp)) + return PTR_ERR(cgrp); + + aux->cgroup.start =3D cgrp; + aux->cgroup.order =3D linfo->cgroup.traversal_order; + return 0; +} + +static void bpf_iter_detach_cgroup(struct bpf_iter_aux_info *aux) +{ + cgroup_put(aux->cgroup.start); +} + +static void bpf_iter_cgroup_show_fdinfo(const struct bpf_iter_aux_info *au= x, + struct seq_file *seq) +{ + char *buf; + + buf =3D kzalloc(PATH_MAX, GFP_KERNEL); + if (!buf) { + seq_puts(seq, "cgroup_path:\n"); + goto show_order; + } + + /* If cgroup_path_ns() fails, buf will be an empty string, cgroup_path + * will print nothing. + * + * Path is in the calling process's cgroup namespace. + */ + cgroup_path_ns(aux->cgroup.start, buf, PATH_MAX, + current->nsproxy->cgroup_ns); + seq_printf(seq, "cgroup_path:\t%s\n", buf); + kfree(buf); + +show_order: + if (aux->cgroup.order =3D=3D BPF_ITER_CGROUP_PRE) + seq_puts(seq, "traversal_order: pre\n"); + else if (aux->cgroup.order =3D=3D BPF_ITER_CGROUP_POST) + seq_puts(seq, "traversal_order: post\n"); + else /* BPF_ITER_CGROUP_PARENT_UP */ + seq_puts(seq, "traversal_order: parent_up\n"); +} + +static int bpf_iter_cgroup_fill_link_info(const struct bpf_iter_aux_info *= aux, + struct bpf_link_info *info) +{ + info->iter.cgroup.traversal_order =3D aux->cgroup.order; + info->iter.cgroup.cgroup_id =3D cgroup_id(aux->cgroup.start); + return 0; +} + +DEFINE_BPF_ITER_FUNC(cgroup, struct bpf_iter_meta *meta, + struct cgroup *cgroup) + +static struct bpf_iter_reg bpf_cgroup_reg_info =3D { + .target =3D "cgroup", + .attach_target =3D bpf_iter_attach_cgroup, + .detach_target =3D bpf_iter_detach_cgroup, + .show_fdinfo =3D bpf_iter_cgroup_show_fdinfo, + .fill_link_info =3D bpf_iter_cgroup_fill_link_info, + .ctx_arg_info_size =3D 1, + .ctx_arg_info =3D { + { offsetof(struct bpf_iter__cgroup, cgroup), + PTR_TO_BTF_ID }, + }, + .seq_info =3D &cgroup_iter_seq_info, +}; + +static int __init bpf_cgroup_iter_init(void) +{ + bpf_cgroup_reg_info.ctx_arg_info[0].btf_id =3D bpf_cgroup_btf_id[0]; + return bpf_iter_reg_target(&bpf_cgroup_reg_info); +} + +late_initcall(bpf_cgroup_iter_init); diff --git a/tools/include/uapi/linux/bpf.h b/tools/include/uapi/linux/bpf.h index f4009dbdf62da..4fd05cde19116 100644 --- a/tools/include/uapi/linux/bpf.h +++ b/tools/include/uapi/linux/bpf.h @@ -87,10 +87,27 @@ struct bpf_cgroup_storage_key { __u32 attach_type; /* program attach type (enum bpf_attach_type) */ }; =20 +enum bpf_iter_cgroup_traversal_order { + BPF_ITER_CGROUP_PRE =3D 0, /* pre-order traversal */ + BPF_ITER_CGROUP_POST, /* post-order traversal */ + BPF_ITER_CGROUP_PARENT_UP, /* traversal of ancestors up to the root */ +}; + union bpf_iter_link_info { struct { __u32 map_fd; } map; + + /* cgroup_iter walks either the live descendants of a cgroup subtree, or = the ancestors + * of a given cgroup. + */ + struct { + /* Cgroup file descriptor. This is root of the subtree if for walking the + * descendants; this is the starting cgroup if for walking the ancestors. + */ + __u32 cgroup_fd; + __u32 traversal_order; + } cgroup; }; =20 /* BPF syscall commands, see bpf(2) man-page for more details. */ @@ -6050,6 +6067,10 @@ struct bpf_link_info { struct { __u32 map_id; } map; + struct { + __u32 traversal_order; + __aligned_u64 cgroup_id; + } cgroup; }; } iter; struct { --=20 2.36.1.476.g0c4daa206d-goog From nobody Wed Apr 29 13:38:26 2026 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 94C5AC433EF for ; Fri, 10 Jun 2022 19:45:46 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1349976AbiFJTpo (ORCPT ); Fri, 10 Jun 2022 15:45:44 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:46716 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1350227AbiFJTpF (ORCPT ); Fri, 10 Jun 2022 15:45:05 -0400 Received: from mail-pg1-x549.google.com (mail-pg1-x549.google.com [IPv6:2607:f8b0:4864:20::549]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 396E045052 for ; Fri, 10 Jun 2022 12:44:50 -0700 (PDT) Received: by mail-pg1-x549.google.com with SMTP id d125-20020a636883000000b003db5e24db27so25253pgc.13 for ; Fri, 10 Jun 2022 12:44:50 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20210112; h=date:in-reply-to:message-id:mime-version:references:subject:from:to :cc; bh=/IZsw4MqQOAPkM1DnTHDc/9ak1wPo9vb+Fz6mOsZXS8=; b=LXZ+dVdWZCP97THZSCbjmToihMSItPPGE+c21TWVjRfhCelTq0WXd7Mp8EP6ntgHQC DqSnBIQv3750W3Gt7IIboxx9D+HZBbQpf94pibgmIIQ4TKoOz9phnlrUtvUcenmdcu+C lYyZLO/XQOaSTCboD+O3e/DNLzjoNYq4tIM7yUgbKay6D0mCZIRf4hKotHA0dLx07GhK AXbUkSdRtEVm3bmX3jIOh7+Kp1PTE0WNV47Nvbjr8598W8oHDpSd9gR6DwIKnkhjzKfx XuQEo/KKKpPWrFDYqf02XL0g4Y70gENomKvbVcYJI0kO4gzkJmgzmhQt3ZiIEYWY2hIY PAxg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:date:in-reply-to:message-id:mime-version :references:subject:from:to:cc; bh=/IZsw4MqQOAPkM1DnTHDc/9ak1wPo9vb+Fz6mOsZXS8=; b=w/9/abeZKI6LK4jdRaYhX41xxeOxGtZZC6TEe78RaT/nYqU4PRf9Fwx/KcHB6RrON7 3B2LUAusX8mI86nQfegng10j/g3L0sPz1faen+1aN2ZxxBWR26m05YYkGPSHFviyGK/K heczkxF1bb7n6/g1VpVo3tg2W/zSJuEDkedYCrIq8hZMYM3nPk9Vc8DFK+ESILzFwyo6 8KvrYhJMmXyA7pXFrSOBkZkBsYKSGxjJyJKSfYw3bdoY8WRTDsZWigmGaqoaWAzMFmhx yBNBfuRN14AzRY0jya4ZY3dPlSnYZc120xFcmDZL57wh7UoAFIbVRIMz+zBVDM8XObx/ G3TA== X-Gm-Message-State: AOAM5309OvSxm+T6m7EPvtAyywtE76qlI9cY8/aKTEgmS1NuH9tyDcLQ EXUjMqWdCQiyNhvoO+pkgxa+a7vKjYQZEg82 X-Google-Smtp-Source: ABdhPJy16TQrz4IjYTYmGgvn9Cp7jzO8tdL2Qm5UBy+SAqDg5b0KSSEb+fPcYmWU2svsxBE/BjN+yAfktOUcFy8U X-Received: from yosry.c.googlers.com ([fda3:e722:ac3:cc00:7f:e700:c0a8:2327]) (user=yosryahmed job=sendgmr) by 2002:aa7:8890:0:b0:51c:454f:c93f with SMTP id z16-20020aa78890000000b0051c454fc93fmr19390374pfe.35.1654890290101; Fri, 10 Jun 2022 12:44:50 -0700 (PDT) Date: Fri, 10 Jun 2022 19:44:32 +0000 In-Reply-To: <20220610194435.2268290-1-yosryahmed@google.com> Message-Id: <20220610194435.2268290-6-yosryahmed@google.com> Mime-Version: 1.0 References: <20220610194435.2268290-1-yosryahmed@google.com> X-Mailer: git-send-email 2.36.1.476.g0c4daa206d-goog Subject: [PATCH bpf-next v2 5/8] selftests/bpf: Test cgroup_iter. From: Yosry Ahmed To: Alexei Starovoitov , Daniel Borkmann , Andrii Nakryiko , Martin KaFai Lau , Song Liu , Yonghong Song , John Fastabend , KP Singh , Hao Luo , Tejun Heo , Zefan Li , Johannes Weiner , Shuah Khan , Michal Hocko Cc: Roman Gushchin , David Rientjes , Stanislav Fomichev , Greg Thelen , Shakeel Butt , linux-kernel@vger.kernel.org, netdev@vger.kernel.org, bpf@vger.kernel.org, cgroups@vger.kernel.org, Yosry Ahmed Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" From: Hao Luo Add a selftest for cgroup_iter. The selftest creates a mini cgroup tree of the following structure: ROOT (working cgroup) | PARENT / \ CHILD1 CHILD2 and tests the following scenarios: - invalid cgroup fd. - pre-order walk over descendants from PARENT. - post-order walk over descendants from PARENT. - walk of ancestors from PARENT. - early termination. Signed-off-by: Hao Luo Signed-off-by: Yosry Ahmed Acked-by: Yonghong Song --- .../selftests/bpf/prog_tests/cgroup_iter.c | 190 ++++++++++++++++++ tools/testing/selftests/bpf/progs/bpf_iter.h | 7 + .../testing/selftests/bpf/progs/cgroup_iter.c | 39 ++++ 3 files changed, 236 insertions(+) create mode 100644 tools/testing/selftests/bpf/prog_tests/cgroup_iter.c create mode 100644 tools/testing/selftests/bpf/progs/cgroup_iter.c diff --git a/tools/testing/selftests/bpf/prog_tests/cgroup_iter.c b/tools/t= esting/selftests/bpf/prog_tests/cgroup_iter.c new file mode 100644 index 0000000000000..4c8f11f784915 --- /dev/null +++ b/tools/testing/selftests/bpf/prog_tests/cgroup_iter.c @@ -0,0 +1,190 @@ +// SPDX-License-Identifier: GPL-2.0 +/* Copyright (c) 2022 Google */ + +#include +#include +#include +#include "cgroup_iter.skel.h" +#include "cgroup_helpers.h" + +#define ROOT 0 +#define PARENT 1 +#define CHILD1 2 +#define CHILD2 3 +#define NUM_CGROUPS 4 + +#define PROLOGUE "prologue\n" +#define EPILOGUE "epilogue\n" + +#define format_expected_output1(cg_id1) \ + snprintf(expected_output, sizeof(expected_output), \ + PROLOGUE "%8llu\n" EPILOGUE, (cg_id1)) + +#define format_expected_output2(cg_id1, cg_id2) \ + snprintf(expected_output, sizeof(expected_output), \ + PROLOGUE "%8llu\n%8llu\n" EPILOGUE, \ + (cg_id1), (cg_id2)) + +#define format_expected_output3(cg_id1, cg_id2, cg_id3) \ + snprintf(expected_output, sizeof(expected_output), \ + PROLOGUE "%8llu\n%8llu\n%8llu\n" EPILOGUE, \ + (cg_id1), (cg_id2), (cg_id3)) + +const char *cg_path[] =3D { + "/", "/parent", "/parent/child1", "/parent/child2" +}; + +static int cg_fd[] =3D {-1, -1, -1, -1}; +static unsigned long long cg_id[] =3D {0, 0, 0, 0}; +static char expected_output[64]; + +int setup_cgroups(void) +{ + int fd, i =3D 0; + + for (i =3D 0; i < NUM_CGROUPS; i++) { + fd =3D create_and_get_cgroup(cg_path[i]); + if (fd < 0) + return fd; + + cg_fd[i] =3D fd; + cg_id[i] =3D get_cgroup_id(cg_path[i]); + } + return 0; +} + +void cleanup_cgroups(void) +{ + int i; + + for (i =3D 0; i < NUM_CGROUPS; i++) + close(cg_fd[i]); +} + +static void read_from_cgroup_iter(struct bpf_program *prog, int cgroup_fd, + int order, const char *testname) +{ + DECLARE_LIBBPF_OPTS(bpf_iter_attach_opts, opts); + union bpf_iter_link_info linfo; + struct bpf_link *link; + int len, iter_fd; + static char buf[64]; + + memset(&linfo, 0, sizeof(linfo)); + linfo.cgroup.cgroup_fd =3D cgroup_fd; + linfo.cgroup.traversal_order =3D order; + opts.link_info =3D &linfo; + opts.link_info_len =3D sizeof(linfo); + + link =3D bpf_program__attach_iter(prog, &opts); + if (!ASSERT_OK_PTR(link, "attach_iter")) + return; + + iter_fd =3D bpf_iter_create(bpf_link__fd(link)); + if (iter_fd < 0) + goto free_link; + + memset(buf, 0, sizeof(buf)); + while ((len =3D read(iter_fd, buf, sizeof(buf))) > 0) + ; + + ASSERT_STREQ(buf, expected_output, testname); + + close(iter_fd); +free_link: + bpf_link__destroy(link); +} + +/* Invalid cgroup. */ +static void test_invalid_cgroup(struct cgroup_iter *skel) +{ + + DECLARE_LIBBPF_OPTS(bpf_iter_attach_opts, opts); + union bpf_iter_link_info linfo; + struct bpf_link *link; + + memset(&linfo, 0, sizeof(linfo)); + linfo.cgroup.cgroup_fd =3D (__u32)-1; + opts.link_info =3D &linfo; + opts.link_info_len =3D sizeof(linfo); + + link =3D bpf_program__attach_iter(skel->progs.cgroup_id_printer, &opts); + if (!ASSERT_ERR_PTR(link, "attach_iter")) + bpf_link__destroy(link); +} + +/* Preorder walk prints parent and child in order. */ +static void test_walk_preorder(struct cgroup_iter *skel) +{ + format_expected_output3(cg_id[PARENT], cg_id[CHILD1], cg_id[CHILD2]); + + read_from_cgroup_iter(skel->progs.cgroup_id_printer, cg_fd[PARENT], + BPF_ITER_CGROUP_PRE, "preorder"); +} + +/* Postorder walk prints child and parent in order. */ +static void test_walk_postorder(struct cgroup_iter *skel) +{ + format_expected_output3(cg_id[CHILD1], cg_id[CHILD2], cg_id[PARENT]); + + read_from_cgroup_iter(skel->progs.cgroup_id_printer, cg_fd[PARENT], + BPF_ITER_CGROUP_POST, "postorder"); +} + +/* Walking parents prints parent and then root. */ +static void test_walk_parent_up(struct cgroup_iter *skel) +{ + /* terminate the walk when ROOT is met. */ + skel->bss->terminal_cgroup =3D cg_id[ROOT]; + + format_expected_output2(cg_id[PARENT], cg_id[ROOT]); + + read_from_cgroup_iter(skel->progs.cgroup_id_printer, cg_fd[PARENT], + BPF_ITER_CGROUP_PARENT_UP, "parent_up"); + + skel->bss->terminal_cgroup =3D 0; +} + +/* Early termination prints parent only. */ +static void test_early_termination(struct cgroup_iter *skel) +{ + /* terminate the walk after the first element is processed. */ + skel->bss->terminate_early =3D 1; + + format_expected_output1(cg_id[PARENT]); + + read_from_cgroup_iter(skel->progs.cgroup_id_printer, cg_fd[PARENT], + BPF_ITER_CGROUP_PRE, "early_termination"); + + skel->bss->terminate_early =3D 0; +} + +void test_cgroup_iter(void) +{ + struct cgroup_iter *skel =3D NULL; + + if (setup_cgroup_environment() < 0) + return; + + if (setup_cgroups() < 0) + goto out; + + skel =3D cgroup_iter__open_and_load(); + if (!ASSERT_OK_PTR(skel, "cgroup_iter__open_and_load")) + goto out; + + if (test__start_subtest("cgroup_iter__invalid_cgroup")) + test_invalid_cgroup(skel); + if (test__start_subtest("cgroup_iter__preorder")) + test_walk_preorder(skel); + if (test__start_subtest("cgroup_iter__postorder")) + test_walk_postorder(skel); + if (test__start_subtest("cgroup_iter__parent_up_walk")) + test_walk_parent_up(skel); + if (test__start_subtest("cgroup_iter__early_termination")) + test_early_termination(skel); +out: + cgroup_iter__destroy(skel); + cleanup_cgroups(); + cleanup_cgroup_environment(); +} diff --git a/tools/testing/selftests/bpf/progs/bpf_iter.h b/tools/testing/s= elftests/bpf/progs/bpf_iter.h index 97ec8bc76ae62..df91f1daf74d3 100644 --- a/tools/testing/selftests/bpf/progs/bpf_iter.h +++ b/tools/testing/selftests/bpf/progs/bpf_iter.h @@ -17,6 +17,7 @@ #define bpf_iter__bpf_sk_storage_map bpf_iter__bpf_sk_storage_map___not_us= ed #define bpf_iter__sockmap bpf_iter__sockmap___not_used #define bpf_iter__bpf_link bpf_iter__bpf_link___not_used +#define bpf_iter__cgroup bpf_iter__cgroup__not_used #define btf_ptr btf_ptr___not_used #define BTF_F_COMPACT BTF_F_COMPACT___not_used #define BTF_F_NONAME BTF_F_NONAME___not_used @@ -39,6 +40,7 @@ #undef bpf_iter__bpf_sk_storage_map #undef bpf_iter__sockmap #undef bpf_iter__bpf_link +#undef bpf_iter__cgroup #undef btf_ptr #undef BTF_F_COMPACT #undef BTF_F_NONAME @@ -139,6 +141,11 @@ struct bpf_iter__bpf_link { struct bpf_link *link; }; =20 +struct bpf_iter__cgroup { + struct bpf_iter_meta *meta; + struct cgroup *cgroup; +} __attribute((preserve_access_index)); + struct btf_ptr { void *ptr; __u32 type_id; diff --git a/tools/testing/selftests/bpf/progs/cgroup_iter.c b/tools/testin= g/selftests/bpf/progs/cgroup_iter.c new file mode 100644 index 0000000000000..2a34d146d6df0 --- /dev/null +++ b/tools/testing/selftests/bpf/progs/cgroup_iter.c @@ -0,0 +1,39 @@ +// SPDX-License-Identifier: GPL-2.0 +/* Copyright (c) 2022 Google */ + +#include "bpf_iter.h" +#include +#include + +char _license[] SEC("license") =3D "GPL"; +volatile int terminate_early =3D 0; +volatile u64 terminal_cgroup =3D 0; + +static inline u64 cgroup_id(struct cgroup *cgrp) +{ + return cgrp->kn->id; +} + +SEC("iter/cgroup") +int cgroup_id_printer(struct bpf_iter__cgroup *ctx) +{ + struct seq_file *seq =3D ctx->meta->seq; + struct cgroup *cgrp =3D ctx->cgroup; + + /* epilogue */ + if (cgrp =3D=3D NULL) { + BPF_SEQ_PRINTF(seq, "epilogue\n"); + return 0; + } + + /* prologue */ + if (ctx->meta->seq_num =3D=3D 0) + BPF_SEQ_PRINTF(seq, "prologue\n"); + + BPF_SEQ_PRINTF(seq, "%8llu\n", cgroup_id(cgrp)); + + if (terminal_cgroup =3D=3D cgroup_id(cgrp)) + return 1; + + return terminate_early ? 1 : 0; +} --=20 2.36.1.476.g0c4daa206d-goog From nobody Wed Apr 29 13:38:26 2026 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 89792C43334 for ; Fri, 10 Jun 2022 19:45:39 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S244289AbiFJTph (ORCPT ); Fri, 10 Jun 2022 15:45:37 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:45656 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1350397AbiFJTpG (ORCPT ); Fri, 10 Jun 2022 15:45:06 -0400 Received: from mail-pg1-x549.google.com (mail-pg1-x549.google.com [IPv6:2607:f8b0:4864:20::549]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id C8343483B2 for ; 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Fri, 10 Jun 2022 12:44:52 -0700 (PDT) Date: Fri, 10 Jun 2022 19:44:33 +0000 In-Reply-To: <20220610194435.2268290-1-yosryahmed@google.com> Message-Id: <20220610194435.2268290-7-yosryahmed@google.com> Mime-Version: 1.0 References: <20220610194435.2268290-1-yosryahmed@google.com> X-Mailer: git-send-email 2.36.1.476.g0c4daa206d-goog Subject: [PATCH bpf-next v2 6/8] cgroup: bpf: enable bpf programs to integrate with rstat From: Yosry Ahmed To: Alexei Starovoitov , Daniel Borkmann , Andrii Nakryiko , Martin KaFai Lau , Song Liu , Yonghong Song , John Fastabend , KP Singh , Hao Luo , Tejun Heo , Zefan Li , Johannes Weiner , Shuah Khan , Michal Hocko Cc: Roman Gushchin , David Rientjes , Stanislav Fomichev , Greg Thelen , Shakeel Butt , linux-kernel@vger.kernel.org, netdev@vger.kernel.org, bpf@vger.kernel.org, cgroups@vger.kernel.org, Yosry Ahmed Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" Enable bpf programs to make use of rstat to collect cgroup hierarchical stats efficiently: - Add cgroup_rstat_updated() kfunc, for bpf progs that collect stats. - Add cgroup_rstat_flush() kfunc, for bpf progs that read stats. - Add an empty bpf_rstat_flush() hook that is called during rstat flushing, for bpf progs that flush stats to attach to. Attaching a bpf prog to this hook effectively registers it as a flush callback. Signed-off-by: Yosry Ahmed Acked-by: Yonghong Song Reported-by: kernel test robot --- kernel/cgroup/rstat.c | 46 +++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 46 insertions(+) diff --git a/kernel/cgroup/rstat.c b/kernel/cgroup/rstat.c index 24b5c2ab55983..94140bd0d02a4 100644 --- a/kernel/cgroup/rstat.c +++ b/kernel/cgroup/rstat.c @@ -3,6 +3,11 @@ =20 #include =20 +#include +#include +#include + + static DEFINE_SPINLOCK(cgroup_rstat_lock); static DEFINE_PER_CPU(raw_spinlock_t, cgroup_rstat_cpu_lock); =20 @@ -141,6 +146,23 @@ static struct cgroup *cgroup_rstat_cpu_pop_updated(str= uct cgroup *pos, return pos; } =20 +/* + * A hook for bpf stat collectors to attach to and flush their stats. + * Together with providing bpf kfuncs for cgroup_rstat_updated() and + * cgroup_rstat_flush(), this enables a complete workflow where bpf progs = that + * collect cgroup stats can integrate with rstat for efficient flushing. + * + * A static noinline declaration here could cause the compiler to optimize= away + * the function. A global noinline declaration will keep the definition, b= ut may + * optimize away the callsite. Therefore, __weak is needed to ensure that = the + * call is still emitted, by telling the compiler that we don't know what = the + * function might eventually be. + */ +__weak noinline void bpf_rstat_flush(struct cgroup *cgrp, + struct cgroup *parent, int cpu) +{ +} + /* see cgroup_rstat_flush() */ static void cgroup_rstat_flush_locked(struct cgroup *cgrp, bool may_sleep) __releases(&cgroup_rstat_lock) __acquires(&cgroup_rstat_lock) @@ -168,6 +190,7 @@ static void cgroup_rstat_flush_locked(struct cgroup *cg= rp, bool may_sleep) struct cgroup_subsys_state *css; =20 cgroup_base_stat_flush(pos, cpu); + bpf_rstat_flush(pos, cgroup_parent(pos), cpu); =20 rcu_read_lock(); list_for_each_entry_rcu(css, &pos->rstat_css_list, @@ -469,3 +492,26 @@ void cgroup_base_stat_cputime_show(struct seq_file *se= q) "system_usec %llu\n", usage, utime, stime); } + +/* Add bpf kfuncs for cgroup_rstat_updated() and cgroup_rstat_flush() */ +BTF_SET_START(bpf_rstat_check_kfunc_ids) +BTF_ID(func, cgroup_rstat_updated) +BTF_ID(func, cgroup_rstat_flush) +BTF_SET_END(bpf_rstat_check_kfunc_ids) + +BTF_SET_START(bpf_rstat_sleepable_kfunc_ids) +BTF_ID(func, cgroup_rstat_flush) +BTF_SET_END(bpf_rstat_sleepable_kfunc_ids) + +static const struct btf_kfunc_id_set bpf_rstat_kfunc_set =3D { + .owner =3D THIS_MODULE, + .check_set =3D &bpf_rstat_check_kfunc_ids, + .sleepable_set =3D &bpf_rstat_sleepable_kfunc_ids, +}; + +static int __init bpf_rstat_kfunc_init(void) +{ + return register_btf_kfunc_id_set(BPF_PROG_TYPE_TRACING, + &bpf_rstat_kfunc_set); +} +late_initcall(bpf_rstat_kfunc_init); --=20 2.36.1.476.g0c4daa206d-goog From nobody Wed Apr 29 13:38:26 2026 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 5CD8BC433EF for ; Fri, 10 Jun 2022 19:45:32 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1350290AbiFJTp1 (ORCPT ); Fri, 10 Jun 2022 15:45:27 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:45800 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1350461AbiFJTpH (ORCPT ); Fri, 10 Jun 2022 15:45:07 -0400 Received: from mail-pl1-x649.google.com (mail-pl1-x649.google.com [IPv6:2607:f8b0:4864:20::649]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 9A8BB4A3E8 for ; 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Fri, 10 Jun 2022 12:44:53 -0700 (PDT) Date: Fri, 10 Jun 2022 19:44:34 +0000 In-Reply-To: <20220610194435.2268290-1-yosryahmed@google.com> Message-Id: <20220610194435.2268290-8-yosryahmed@google.com> Mime-Version: 1.0 References: <20220610194435.2268290-1-yosryahmed@google.com> X-Mailer: git-send-email 2.36.1.476.g0c4daa206d-goog Subject: [PATCH bpf-next v2 7/8] selftests/bpf: extend cgroup helpers From: Yosry Ahmed To: Alexei Starovoitov , Daniel Borkmann , Andrii Nakryiko , Martin KaFai Lau , Song Liu , Yonghong Song , John Fastabend , KP Singh , Hao Luo , Tejun Heo , Zefan Li , Johannes Weiner , Shuah Khan , Michal Hocko Cc: Roman Gushchin , David Rientjes , Stanislav Fomichev , Greg Thelen , Shakeel Butt , linux-kernel@vger.kernel.org, netdev@vger.kernel.org, bpf@vger.kernel.org, cgroups@vger.kernel.org, Yosry Ahmed Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" This patch extends bpf selftests cgroup helpers in various ways: - Add enable_controllers() that allows tests to enable all or a subset of controllers for a specific cgroup. - Add write_cgroup_file(). - Add join_cgroup_parent(). The cgroup workdir is based on the pid, therefore a spawned child cannot join the same cgroup hierarchy of the test through join_cgroup(). join_cgroup_parent() is used in child processes to join a cgroup under the parent's workdir. - Distinguish relative and absolute cgroup paths in function arguments. Now relative paths are called relative_path, and absolute paths are called cgroup_path. Signed-off-by: Yosry Ahmed --- tools/testing/selftests/bpf/cgroup_helpers.c | 173 ++++++++++++++----- tools/testing/selftests/bpf/cgroup_helpers.h | 15 +- 2 files changed, 142 insertions(+), 46 deletions(-) diff --git a/tools/testing/selftests/bpf/cgroup_helpers.c b/tools/testing/s= elftests/bpf/cgroup_helpers.c index 9d59c3990ca8d..98c5f2f3d3c60 100644 --- a/tools/testing/selftests/bpf/cgroup_helpers.c +++ b/tools/testing/selftests/bpf/cgroup_helpers.c @@ -33,49 +33,51 @@ #define CGROUP_MOUNT_DFLT "/sys/fs/cgroup" #define NETCLS_MOUNT_PATH CGROUP_MOUNT_DFLT "/net_cls" #define CGROUP_WORK_DIR "/cgroup-test-work-dir" -#define format_cgroup_path(buf, path) \ + +#define format_cgroup_path_pid(buf, path, pid) \ snprintf(buf, sizeof(buf), "%s%s%d%s", CGROUP_MOUNT_PATH, \ - CGROUP_WORK_DIR, getpid(), path) + CGROUP_WORK_DIR, pid, path) + +#define format_cgroup_path(buf, path) \ + format_cgroup_path_pid(buf, path, getpid()) + +#define format_parent_cgroup_path(buf, path) \ + format_cgroup_path_pid(buf, path, getppid()) =20 #define format_classid_path(buf) \ snprintf(buf, sizeof(buf), "%s%s", NETCLS_MOUNT_PATH, \ CGROUP_WORK_DIR) =20 -/** - * enable_all_controllers() - Enable all available cgroup v2 controllers - * - * Enable all available cgroup v2 controllers in order to increase - * the code coverage. - * - * If successful, 0 is returned. - */ -static int enable_all_controllers(char *cgroup_path) + +static int __enable_controllers(const char *cgroup_path, const char *contr= ollers) { char path[PATH_MAX + 1]; - char buf[PATH_MAX]; + char enable[PATH_MAX + 1]; char *c, *c2; int fd, cfd; ssize_t len; =20 - snprintf(path, sizeof(path), "%s/cgroup.controllers", cgroup_path); - fd =3D open(path, O_RDONLY); - if (fd < 0) { - log_err("Opening cgroup.controllers: %s", path); - return 1; - } + /* If not controllers are passed, enable all available controllers */ + if (!controllers) { + snprintf(path, sizeof(path), "%s/cgroup.controllers", + cgroup_path); + fd =3D open(path, O_RDONLY); + if (fd < 0) { + log_err("Opening cgroup.controllers: %s", path); + return 1; + } =20 - len =3D read(fd, buf, sizeof(buf) - 1); - if (len < 0) { + len =3D read(fd, enable, sizeof(enable) - 1); + if (len < 0) { + close(fd); + log_err("Reading cgroup.controllers: %s", path); + return 1; + } else if (len =3D=3D 0) /* No controllers to enable */ + return 0; + enable[len] =3D 0; close(fd); - log_err("Reading cgroup.controllers: %s", path); - return 1; - } - buf[len] =3D 0; - close(fd); - - /* No controllers available? We're probably on cgroup v1. */ - if (len =3D=3D 0) - return 0; + } else + strncpy(enable, controllers, sizeof(enable)); =20 snprintf(path, sizeof(path), "%s/cgroup.subtree_control", cgroup_path); cfd =3D open(path, O_RDWR); @@ -84,7 +86,7 @@ static int enable_all_controllers(char *cgroup_path) return 1; } =20 - for (c =3D strtok_r(buf, " ", &c2); c; c =3D strtok_r(NULL, " ", &c2)) { + for (c =3D strtok_r(enable, " ", &c2); c; c =3D strtok_r(NULL, " ", &c2))= { if (dprintf(cfd, "+%s\n", c) <=3D 0) { log_err("Enabling controller %s: %s", c, path); close(cfd); @@ -95,6 +97,59 @@ static int enable_all_controllers(char *cgroup_path) return 0; } =20 +/** + * enable_controllers() - Enable cgroup v2 controllers + * @relative_path: The cgroup path, relative to the workdir + * @controllers: List of controllers to enable in cgroup.controllers format + * + * + * Enable given cgroup v2 controllers, if @controllers is NULL, enable all + * available controllers. + * + * If successful, 0 is returned. + */ +int enable_controllers(const char *relative_path, const char *controllers) +{ + char cgroup_path[PATH_MAX + 1]; + + format_cgroup_path(cgroup_path, relative_path); + return __enable_controllers(cgroup_path, controllers); +} + +/** + * write_cgroup_file() - Write to a cgroup file + * @relative_path: The cgroup path, relative to the workdir + * @buf: Buffer to write to the file + * + * Write to a file in the given cgroup's directory. + * + * If successful, 0 is returned. + */ +int write_cgroup_file(const char *relative_path, const char *file, + const char *buf) +{ + char cgroup_path[PATH_MAX - 24]; + char file_path[PATH_MAX + 1]; + int fd; + + format_cgroup_path(cgroup_path, relative_path); + + snprintf(file_path, sizeof(file_path), "%s/%s", cgroup_path, file); + fd =3D open(file_path, O_RDWR); + if (fd < 0) { + log_err("Opening cgroup.subtree_control: %s", file_path); + return 1; + } + + if (dprintf(fd, "%s", buf) <=3D 0) { + log_err("Writing to %s", file_path); + close(fd); + return 1; + } + close(fd); + return 0; +} + /** * setup_cgroup_environment() - Setup the cgroup environment * @@ -133,7 +188,9 @@ int setup_cgroup_environment(void) return 1; } =20 - if (enable_all_controllers(cgroup_workdir)) + /* Enable all available controllers to increase test coverage */ + if (__enable_controllers(CGROUP_MOUNT_PATH, NULL) || + __enable_controllers(cgroup_workdir, NULL)) return 1; =20 return 0; @@ -173,7 +230,7 @@ static int join_cgroup_from_top(const char *cgroup_path) =20 /** * join_cgroup() - Join a cgroup - * @path: The cgroup path, relative to the workdir, to join + * @relative_path: The cgroup path, relative to the workdir, to join * * This function expects a cgroup to already be created, relative to the c= group * work dir, and it joins it. For example, passing "/my-cgroup" as the path @@ -182,11 +239,27 @@ static int join_cgroup_from_top(const char *cgroup_pa= th) * * On success, it returns 0, otherwise on failure it returns 1. */ -int join_cgroup(const char *path) +int join_cgroup(const char *relative_path) +{ + char cgroup_path[PATH_MAX + 1]; + + format_cgroup_path(cgroup_path, relative_path); + return join_cgroup_from_top(cgroup_path); +} + +/** + * join_parent_cgroup() - Join a cgroup in the parent process workdir + * @relative_path: The cgroup path, relative to parent process workdir, to= join + * + * See join_cgroup(). + * + * On success, it returns 0, otherwise on failure it returns 1. + */ +int join_parent_cgroup(const char *relative_path) { char cgroup_path[PATH_MAX + 1]; =20 - format_cgroup_path(cgroup_path, path); + format_parent_cgroup_path(cgroup_path, relative_path); return join_cgroup_from_top(cgroup_path); } =20 @@ -212,9 +285,27 @@ void cleanup_cgroup_environment(void) nftw(cgroup_workdir, nftwfunc, WALK_FD_LIMIT, FTW_DEPTH | FTW_MOUNT); } =20 +/** + * get_root_cgroup() - Get the FD of the root cgroup + * + * On success, it returns the file descriptor. On failure, it returns -1. + * If there is a failure, it prints the error to stderr. + */ +int get_root_cgroup(void) +{ + int fd; + + fd =3D open(CGROUP_MOUNT_PATH, O_RDONLY); + if (fd < 0) { + log_err("Opening root cgroup"); + return -1; + } + return fd; +} + /** * create_and_get_cgroup() - Create a cgroup, relative to workdir, and get= the FD - * @path: The cgroup path, relative to the workdir, to join + * @relative_path: The cgroup path, relative to the workdir, to join * * This function creates a cgroup under the top level workdir and returns = the * file descriptor. It is idempotent. @@ -222,14 +313,14 @@ void cleanup_cgroup_environment(void) * On success, it returns the file descriptor. On failure it returns -1. * If there is a failure, it prints the error to stderr. */ -int create_and_get_cgroup(const char *path) +int create_and_get_cgroup(const char *relative_path) { char cgroup_path[PATH_MAX + 1]; int fd; =20 - format_cgroup_path(cgroup_path, path); + format_cgroup_path(cgroup_path, relative_path); if (mkdir(cgroup_path, 0777) && errno !=3D EEXIST) { - log_err("mkdiring cgroup %s .. %s", path, cgroup_path); + log_err("mkdiring cgroup %s .. %s", relative_path, cgroup_path); return -1; } =20 @@ -244,13 +335,13 @@ int create_and_get_cgroup(const char *path) =20 /** * get_cgroup_id() - Get cgroup id for a particular cgroup path - * @path: The cgroup path, relative to the workdir, to join + * @relative_path: The cgroup path, relative to the workdir, to join * * On success, it returns the cgroup id. On failure it returns 0, * which is an invalid cgroup id. * If there is a failure, it prints the error to stderr. */ -unsigned long long get_cgroup_id(const char *path) +unsigned long long get_cgroup_id(const char *relative_path) { int dirfd, err, flags, mount_id, fhsize; union { @@ -261,7 +352,7 @@ unsigned long long get_cgroup_id(const char *path) struct file_handle *fhp, *fhp2; unsigned long long ret =3D 0; =20 - format_cgroup_path(cgroup_workdir, path); + format_cgroup_path(cgroup_workdir, relative_path); =20 dirfd =3D AT_FDCWD; flags =3D 0; diff --git a/tools/testing/selftests/bpf/cgroup_helpers.h b/tools/testing/s= elftests/bpf/cgroup_helpers.h index fcc9cb91b2111..895e4de1174c9 100644 --- a/tools/testing/selftests/bpf/cgroup_helpers.h +++ b/tools/testing/selftests/bpf/cgroup_helpers.h @@ -10,11 +10,16 @@ __FILE__, __LINE__, clean_errno(), ##__VA_ARGS__) =20 /* cgroupv2 related */ -int cgroup_setup_and_join(const char *path); -int create_and_get_cgroup(const char *path); -unsigned long long get_cgroup_id(const char *path); +int enable_controllers(const char *relative_path, const char *controllers); +int write_cgroup_file(const char *relative_path, const char *file, + const char *buf); +int cgroup_setup_and_join(const char *relative_path); +int get_root_cgroup(void); +int create_and_get_cgroup(const char *relative_path); +unsigned long long get_cgroup_id(const char *relative_path); =20 -int join_cgroup(const char *path); +int join_cgroup(const char *relative_path); +int join_parent_cgroup(const char *relative_path); =20 int setup_cgroup_environment(void); void cleanup_cgroup_environment(void); @@ -26,4 +31,4 @@ int join_classid(void); int setup_classid_environment(void); void cleanup_classid_environment(void); =20 -#endif /* __CGROUP_HELPERS_H */ \ No newline at end of file +#endif /* __CGROUP_HELPERS_H */ --=20 2.36.1.476.g0c4daa206d-goog From nobody Wed Apr 29 13:38:26 2026 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 31DABC43334 for ; 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Fri, 10 Jun 2022 12:44:56 -0700 (PDT) Date: Fri, 10 Jun 2022 19:44:35 +0000 In-Reply-To: <20220610194435.2268290-1-yosryahmed@google.com> Message-Id: <20220610194435.2268290-9-yosryahmed@google.com> Mime-Version: 1.0 References: <20220610194435.2268290-1-yosryahmed@google.com> X-Mailer: git-send-email 2.36.1.476.g0c4daa206d-goog Subject: [PATCH bpf-next v2 8/8] bpf: add a selftest for cgroup hierarchical stats collection From: Yosry Ahmed To: Alexei Starovoitov , Daniel Borkmann , Andrii Nakryiko , Martin KaFai Lau , Song Liu , Yonghong Song , John Fastabend , KP Singh , Hao Luo , Tejun Heo , Zefan Li , Johannes Weiner , Shuah Khan , Michal Hocko Cc: Roman Gushchin , David Rientjes , Stanislav Fomichev , Greg Thelen , Shakeel Butt , linux-kernel@vger.kernel.org, netdev@vger.kernel.org, bpf@vger.kernel.org, cgroups@vger.kernel.org, Yosry Ahmed Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" Add a selftest that tests the whole workflow for collecting, aggregating (flushing), and displaying cgroup hierarchical stats. TL;DR: - Whenever reclaim happens, vmscan_start and vmscan_end update per-cgroup percpu readings, and tell rstat which (cgroup, cpu) pairs have updates. - When userspace tries to read the stats, vmscan_dump calls rstat to flush the stats, and outputs the stats in text format to userspace (similar to cgroupfs stats). - rstat calls vmscan_flush once for every (cgroup, cpu) pair that has updates, vmscan_flush aggregates cpu readings and propagates updates to parents. Detailed explanation: - The test loads tracing bpf programs, vmscan_start and vmscan_end, to measure the latency of cgroup reclaim. Per-cgroup ratings are stored in percpu maps for efficiency. When a cgroup reading is updated on a cpu, cgroup_rstat_updated(cgroup, cpu) is called to add the cgroup to the rstat updated tree on that cpu. - A cgroup_iter program, vmscan_dump, is loaded and pinned to a file, for each cgroup. Reading this file invokes the program, which calls cgroup_rstat_flush(cgroup) to ask rstat to propagate the updates for all cpus and cgroups that have updates in this cgroup's subtree. Afterwards, the stats are exposed to the user. vmscan_dump returns 1 to terminate iteration early, so that we only expose stats for one cgroup per read. - An ftrace program, vmscan_flush, is also loaded and attached to bpf_rstat_flush. When rstat flushing is ongoing, vmscan_flush is invoked once for each (cgroup, cpu) pair that has updates. cgroups are popped from the rstat tree in a bottom-up fashion, so calls will always be made for cgroups that have updates before their parents. The program aggregates percpu readings to a total per-cgroup reading, and also propagates them to the parent cgroup. After rstat flushing is over, all cgroups will have correct updated hierarchical readings (including all cpus and all their descendants). Signed-off-by: Yosry Ahmed --- .../prog_tests/cgroup_hierarchical_stats.c | 351 ++++++++++++++++++ .../bpf/progs/cgroup_hierarchical_stats.c | 234 ++++++++++++ 2 files changed, 585 insertions(+) create mode 100644 tools/testing/selftests/bpf/prog_tests/cgroup_hierarchi= cal_stats.c create mode 100644 tools/testing/selftests/bpf/progs/cgroup_hierarchical_s= tats.c diff --git a/tools/testing/selftests/bpf/prog_tests/cgroup_hierarchical_sta= ts.c b/tools/testing/selftests/bpf/prog_tests/cgroup_hierarchical_stats.c new file mode 100644 index 0000000000000..b78a4043da49a --- /dev/null +++ b/tools/testing/selftests/bpf/prog_tests/cgroup_hierarchical_stats.c @@ -0,0 +1,351 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * Functions to manage eBPF programs attached to cgroup subsystems + * + * Copyright 2022 Google LLC. + */ +#include +#include +#include +#include +#include + +#include +#include +#include + +#include "cgroup_helpers.h" +#include "cgroup_hierarchical_stats.skel.h" + +#define PAGE_SIZE 4096 +#define MB(x) (x << 20) + +#define BPFFS_ROOT "/sys/fs/bpf/" +#define BPFFS_VMSCAN BPFFS_ROOT"vmscan/" + +#define CG_ROOT_NAME "root" +#define CG_ROOT_ID 1 + +#define CGROUP_PATH(p, n) {.path =3D #p"/"#n, .name =3D #n} + +static struct { + const char *path, *name; + unsigned long long id; + int fd; +} cgroups[] =3D { + CGROUP_PATH(/, test), + CGROUP_PATH(/test, child1), + CGROUP_PATH(/test, child2), + CGROUP_PATH(/test/child1, child1_1), + CGROUP_PATH(/test/child1, child1_2), + CGROUP_PATH(/test/child2, child2_1), + CGROUP_PATH(/test/child2, child2_2), +}; + +#define N_CGROUPS ARRAY_SIZE(cgroups) +#define N_NON_LEAF_CGROUPS 3 + +int root_cgroup_fd; +bool mounted_bpffs; + +static int read_from_file(const char *path, char *buf, size_t size) +{ + int fd, len; + + fd =3D open(path, O_RDONLY); + if (fd < 0) { + log_err("Open %s", path); + return -errno; + } + len =3D read(fd, buf, size); + if (len < 0) + log_err("Read %s", path); + else + buf[len] =3D 0; + close(fd); + return len < 0 ? -errno : 0; +} + +static int setup_bpffs(void) +{ + int err; + + /* Mount bpffs */ + err =3D mount("bpf", BPFFS_ROOT, "bpf", 0, NULL); + mounted_bpffs =3D !err; + if (!ASSERT_OK(err && errno !=3D EBUSY, "mount bpffs")) + return err; + + /* Create a directory to contain stat files in bpffs */ + err =3D mkdir(BPFFS_VMSCAN, 0755); + ASSERT_OK(err, "mkdir bpffs"); + return err; +} + +static void cleanup_bpffs(void) +{ + /* Remove created directory in bpffs */ + ASSERT_OK(rmdir(BPFFS_VMSCAN), "rmdir "BPFFS_VMSCAN); + + /* Unmount bpffs, if it wasn't already mounted when we started */ + if (mounted_bpffs) + return; + ASSERT_OK(umount(BPFFS_ROOT), "unmount bpffs"); +} + +static int setup_cgroups(void) +{ + int i, fd, err; + + err =3D setup_cgroup_environment(); + if (!ASSERT_OK(err, "setup_cgroup_environment")) + return err; + + root_cgroup_fd =3D get_root_cgroup(); + if (!ASSERT_GE(root_cgroup_fd, 0, "get_root_cgroup")) + return root_cgroup_fd; + + for (i =3D 0; i < N_CGROUPS; i++) { + fd =3D create_and_get_cgroup(cgroups[i].path); + if (!ASSERT_GE(fd, 0, "create_and_get_cgroup")) + return fd; + + cgroups[i].fd =3D fd; + cgroups[i].id =3D get_cgroup_id(cgroups[i].path); + + /* + * Enable memcg controller for the entire hierarchy. + * Note that stats are collected for all cgroups in a hierarchy + * with memcg enabled anyway, but are only exposed for cgroups + * that have memcg enabled. + */ + if (i < N_NON_LEAF_CGROUPS) { + err =3D enable_controllers(cgroups[i].path, "memory"); + if (!ASSERT_OK(err, "enable_controllers")) + return err; + } + } + return 0; +} + +static void cleanup_cgroups(void) +{ + close(root_cgroup_fd); + for (int i =3D 0; i < N_CGROUPS; i++) + close(cgroups[i].fd); + cleanup_cgroup_environment(); +} + + +static int setup_hierarchy(void) +{ + return setup_bpffs() || setup_cgroups(); +} + +static void destroy_hierarchy(void) +{ + cleanup_cgroups(); + cleanup_bpffs(); +} + +static void alloc_anon(size_t size) +{ + char *buf, *ptr; + + buf =3D malloc(size); + for (ptr =3D buf; ptr < buf + size; ptr +=3D PAGE_SIZE) + *ptr =3D 0; + free(buf); +} + +static int induce_vmscan(void) +{ + char size[128]; + int i, err; + + /* + * Set memory.high for test parent cgroup to 1 MB to throttle + * allocations and invoke reclaim in children. + */ + snprintf(size, 128, "%d", MB(1)); + err =3D write_cgroup_file(cgroups[0].path, "memory.high", size); + if (!ASSERT_OK(err, "write memory.high")) + return err; + /* + * In every leaf cgroup, run a memory hog for a few seconds to induce + * reclaim then kill it. + */ + for (i =3D N_NON_LEAF_CGROUPS; i < N_CGROUPS; i++) { + pid_t pid =3D fork(); + + if (pid =3D=3D 0) { + /* Join cgroup in the parent process workdir */ + join_parent_cgroup(cgroups[i].path); + + /* Allocate more memory than memory.high */ + alloc_anon(MB(2)); + exit(0); + } else { + /* Wait for child to cause reclaim then kill it */ + if (!ASSERT_GT(pid, 0, "fork")) + return pid; + sleep(2); + kill(pid, SIGKILL); + waitpid(pid, NULL, 0); + } + } + return 0; +} + +static unsigned long long get_cgroup_vmscan_delay(unsigned long long cgrou= p_id, + const char *file_name) +{ + char buf[128], path[128]; + unsigned long long vmscan =3D 0, id =3D 0; + int err; + + /* For every cgroup, read the file generated by cgroup_iter */ + snprintf(path, 128, "%s%s", BPFFS_VMSCAN, file_name); + err =3D read_from_file(path, buf, 128); + if (!ASSERT_OK(err, "read cgroup_iter")) + return 0; + + /* Check the output file formatting */ + ASSERT_EQ(sscanf(buf, "cg_id: %llu, total_vmscan_delay: %llu\n", + &id, &vmscan), 2, "output format"); + + /* Check that the cgroup_id is displayed correctly */ + ASSERT_EQ(id, cgroup_id, "cgroup_id"); + /* Check that the vmscan reading is non-zero */ + ASSERT_GT(vmscan, 0, "vmscan_reading"); + return vmscan; +} + +static void check_vmscan_stats(void) +{ + int i; + unsigned long long vmscan_readings[N_CGROUPS], vmscan_root; + + for (i =3D 0; i < N_CGROUPS; i++) + vmscan_readings[i] =3D get_cgroup_vmscan_delay(cgroups[i].id, + cgroups[i].name); + + /* Read stats for root too */ + vmscan_root =3D get_cgroup_vmscan_delay(CG_ROOT_ID, CG_ROOT_NAME); + + /* Check that child1 =3D=3D child1_1 + child1_2 */ + ASSERT_EQ(vmscan_readings[1], vmscan_readings[3] + vmscan_readings[4], + "child1_vmscan"); + /* Check that child2 =3D=3D child2_1 + child2_2 */ + ASSERT_EQ(vmscan_readings[2], vmscan_readings[5] + vmscan_readings[6], + "child2_vmscan"); + /* Check that test =3D=3D child1 + child2 */ + ASSERT_EQ(vmscan_readings[0], vmscan_readings[1] + vmscan_readings[2], + "test_vmscan"); + /* Check that root >=3D test */ + ASSERT_GE(vmscan_root, vmscan_readings[1], "root_vmscan"); +} + +static int setup_cgroup_iter(struct cgroup_hierarchical_stats *obj, int cg= roup_fd, + const char *file_name) +{ + DECLARE_LIBBPF_OPTS(bpf_iter_attach_opts, opts); + union bpf_iter_link_info linfo =3D {}; + struct bpf_link *link; + char path[128]; + int err; + + /* + * Create an iter link, parameterized by cgroup_fd. + * We only want to traverse one cgroup, so set the traversal order to + * "pre", and return 1 from dump_vmscan to stop iteration after the + * first cgroup. + */ + linfo.cgroup.cgroup_fd =3D cgroup_fd; + linfo.cgroup.traversal_order =3D BPF_ITER_CGROUP_PRE; + opts.link_info =3D &linfo; + opts.link_info_len =3D sizeof(linfo); + link =3D bpf_program__attach_iter(obj->progs.dump_vmscan, &opts); + if (!ASSERT_OK_PTR(link, "attach iter")) + return libbpf_get_error(link); + + /* Pin the link to a bpffs file */ + snprintf(path, 128, "%s%s", BPFFS_VMSCAN, file_name); + err =3D bpf_link__pin(link, path); + ASSERT_OK(err, "pin cgroup_iter"); + return err; +} + +static int setup_progs(struct cgroup_hierarchical_stats **skel) +{ + int i, err; + struct bpf_link *link; + struct cgroup_hierarchical_stats *obj; + + obj =3D cgroup_hierarchical_stats__open_and_load(); + if (!ASSERT_OK_PTR(obj, "open_and_load")) + return libbpf_get_error(obj); + + /* Attach cgroup_iter program that will dump the stats to cgroups */ + for (i =3D 0; i < N_CGROUPS; i++) { + err =3D setup_cgroup_iter(obj, cgroups[i].fd, cgroups[i].name); + if (!ASSERT_OK(err, "setup_cgroup_iter")) + return err; + } + /* Also dump stats for root */ + err =3D setup_cgroup_iter(obj, root_cgroup_fd, CG_ROOT_NAME); + if (!ASSERT_OK(err, "setup_cgroup_iter")) + return err; + + /* Attach rstat flusher */ + link =3D bpf_program__attach(obj->progs.vmscan_flush); + if (!ASSERT_OK_PTR(link, "attach rstat")) + return libbpf_get_error(link); + + /* Attach tracing programs that will calculate vmscan delays */ + link =3D bpf_program__attach(obj->progs.vmscan_start); + if (!ASSERT_OK_PTR(obj, "attach raw_tracepoint")) + return libbpf_get_error(obj); + + link =3D bpf_program__attach(obj->progs.vmscan_end); + if (!ASSERT_OK_PTR(obj, "attach raw_tracepoint")) + return libbpf_get_error(obj); + + *skel =3D obj; + return 0; +} + +void destroy_progs(struct cgroup_hierarchical_stats *skel) +{ + char path[128]; + int i; + + for (i =3D 0; i < N_CGROUPS; i++) { + /* Delete files in bpffs that cgroup_iters are pinned in */ + snprintf(path, 128, "%s%s", BPFFS_VMSCAN, + cgroups[i].name); + ASSERT_OK(remove(path), "remove cgroup_iter pin"); + } + + /* Delete root file in bpffs */ + snprintf(path, 128, "%s%s", BPFFS_VMSCAN, CG_ROOT_NAME); + ASSERT_OK(remove(path), "remove cgroup_iter root pin"); + cgroup_hierarchical_stats__destroy(skel); +} + +void test_cgroup_hierarchical_stats(void) +{ + struct cgroup_hierarchical_stats *skel =3D NULL; + + if (setup_hierarchy()) + goto hierarchy_cleanup; + if (setup_progs(&skel)) + goto cleanup; + if (induce_vmscan()) + goto cleanup; + check_vmscan_stats(); +cleanup: + destroy_progs(skel); +hierarchy_cleanup: + destroy_hierarchy(); +} diff --git a/tools/testing/selftests/bpf/progs/cgroup_hierarchical_stats.c = b/tools/testing/selftests/bpf/progs/cgroup_hierarchical_stats.c new file mode 100644 index 0000000000000..fd2028f1ed70b --- /dev/null +++ b/tools/testing/selftests/bpf/progs/cgroup_hierarchical_stats.c @@ -0,0 +1,234 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * Functions to manage eBPF programs attached to cgroup subsystems + * + * Copyright 2022 Google LLC. + */ +#include "vmlinux.h" +#include +#include + +char _license[] SEC("license") =3D "GPL"; + +/* + * Start times are stored per-task, not per-cgroup, as multiple tasks in o= ne + * cgroup can perform reclain concurrently. + */ +struct { + __uint(type, BPF_MAP_TYPE_TASK_STORAGE); + __uint(map_flags, BPF_F_NO_PREALLOC); + __type(key, int); + __type(value, __u64); +} vmscan_start_time SEC(".maps"); + +struct vmscan_percpu { + /* Previous percpu state, to figure out if we have new updates */ + __u64 prev; + /* Current percpu state */ + __u64 state; +}; + +struct vmscan { + /* State propagated through children, pending aggregation */ + __u64 pending; + /* Total state, including all cpus and all children */ + __u64 state; +}; + +struct { + __uint(type, BPF_MAP_TYPE_PERCPU_HASH); + __uint(max_entries, 10); + __type(key, __u64); + __type(value, struct vmscan_percpu); +} pcpu_cgroup_vmscan_elapsed SEC(".maps"); + +struct { + __uint(type, BPF_MAP_TYPE_HASH); + __uint(max_entries, 10); + __type(key, __u64); + __type(value, struct vmscan); +} cgroup_vmscan_elapsed SEC(".maps"); + +extern void cgroup_rstat_updated(struct cgroup *cgrp, int cpu) __ksym; +extern void cgroup_rstat_flush(struct cgroup *cgrp) __ksym; + +static inline struct cgroup *task_memcg(struct task_struct *task) +{ + return task->cgroups->subsys[memory_cgrp_id]->cgroup; +} + +static inline uint64_t cgroup_id(struct cgroup *cgrp) +{ + return cgrp->kn->id; +} + +static inline int create_vmscan_percpu_elem(__u64 cg_id, __u64 state) +{ + struct vmscan_percpu pcpu_init =3D {.state =3D state, .prev =3D 0}; + + if (bpf_map_update_elem(&pcpu_cgroup_vmscan_elapsed, &cg_id, + &pcpu_init, BPF_NOEXIST)) { + bpf_printk("failed to create pcpu entry for cgroup %llu\n" + , cg_id); + return 1; + } + return 0; +} + +static inline int create_vmscan_elem(__u64 cg_id, __u64 state, __u64 pendi= ng) +{ + struct vmscan init =3D {.state =3D state, .pending =3D pending}; + + if (bpf_map_update_elem(&cgroup_vmscan_elapsed, &cg_id, + &init, BPF_NOEXIST)) { + bpf_printk("failed to create entry for cgroup %llu\n" + , cg_id); + return 1; + } + return 0; +} + +SEC("tp_btf/mm_vmscan_memcg_reclaim_begin") +int BPF_PROG(vmscan_start, struct lruvec *lruvec, struct scan_control *sc) +{ + struct task_struct *task =3D bpf_get_current_task_btf(); + __u64 *start_time_ptr; + + start_time_ptr =3D bpf_task_storage_get(&vmscan_start_time, task, 0, + BPF_LOCAL_STORAGE_GET_F_CREATE); + if (!start_time_ptr) { + bpf_printk("error retrieving storage\n"); + return 0; + } + + *start_time_ptr =3D bpf_ktime_get_ns(); + return 0; +} + +SEC("tp_btf/mm_vmscan_memcg_reclaim_end") +int BPF_PROG(vmscan_end, struct lruvec *lruvec, struct scan_control *sc) +{ + struct vmscan_percpu *pcpu_stat; + struct task_struct *current =3D bpf_get_current_task_btf(); + struct cgroup *cgrp; + __u64 *start_time_ptr; + __u64 current_elapsed, cg_id; + __u64 end_time =3D bpf_ktime_get_ns(); + + /* + * cgrp is the first parent cgroup of current that has memcg enabled in + * its subtree_control, or NULL if memcg is disabled in the entire tree. + * In a cgroup hierarchy like this: + * a + * / \ + * b c + * If "a" has memcg enabled, while "b" doesn't, then processes in "b" + * will accumulate their stats directly to "a". This makes sure that no + * stats are lost from processes in leaf cgroups that don't have memcg + * enabled, but only exposes stats for cgroups that have memcg enabled. + */ + cgrp =3D task_memcg(current); + if (!cgrp) + return 0; + + cg_id =3D cgroup_id(cgrp); + start_time_ptr =3D bpf_task_storage_get(&vmscan_start_time, current, 0, + BPF_LOCAL_STORAGE_GET_F_CREATE); + if (!start_time_ptr) { + bpf_printk("error retrieving storage local storage\n"); + return 0; + } + + current_elapsed =3D end_time - *start_time_ptr; + pcpu_stat =3D bpf_map_lookup_elem(&pcpu_cgroup_vmscan_elapsed, + &cg_id); + if (pcpu_stat) + __sync_fetch_and_add(&pcpu_stat->state, current_elapsed); + else + create_vmscan_percpu_elem(cg_id, current_elapsed); + + cgroup_rstat_updated(cgrp, bpf_get_smp_processor_id()); + return 0; +} + +SEC("fentry/bpf_rstat_flush") +int BPF_PROG(vmscan_flush, struct cgroup *cgrp, struct cgroup *parent, int= cpu) +{ + struct vmscan_percpu *pcpu_stat; + struct vmscan *total_stat, *parent_stat; + __u64 cg_id =3D cgroup_id(cgrp); + __u64 parent_cg_id =3D parent ? cgroup_id(parent) : 0; + __u64 *pcpu_vmscan; + __u64 state; + __u64 delta =3D 0; + + /* Add CPU changes on this level since the last flush */ + pcpu_stat =3D bpf_map_lookup_percpu_elem(&pcpu_cgroup_vmscan_elapsed, + &cg_id, cpu); + if (pcpu_stat) { + state =3D pcpu_stat->state; + delta +=3D state - pcpu_stat->prev; + pcpu_stat->prev =3D state; + } + + total_stat =3D bpf_map_lookup_elem(&cgroup_vmscan_elapsed, &cg_id); + if (!total_stat) { + create_vmscan_elem(cg_id, delta, 0); + goto update_parent; + } + + /* Collect pending stats from subtree */ + if (total_stat->pending) { + delta +=3D total_stat->pending; + total_stat->pending =3D 0; + } + + /* Propagate changes to this cgroup's total */ + total_stat->state +=3D delta; + +update_parent: + /* Skip if there are no changes to propagate, or no parent */ + if (!delta || !parent_cg_id) + return 0; + + /* Propagate changes to cgroup's parent */ + parent_stat =3D bpf_map_lookup_elem(&cgroup_vmscan_elapsed, + &parent_cg_id); + if (parent_stat) + parent_stat->pending +=3D delta; + else + create_vmscan_elem(parent_cg_id, 0, delta); + + return 0; +} + +SEC("iter.s/cgroup") +int BPF_PROG(dump_vmscan, struct bpf_iter_meta *meta, struct cgroup *cgrp) +{ + struct seq_file *seq =3D meta->seq; + struct vmscan *total_stat; + __u64 cg_id =3D cgroup_id(cgrp); + + /* Do nothing for the terminal call */ + if (!cgrp) + return 1; + + /* Flush the stats to make sure we get the most updated numbers */ + cgroup_rstat_flush(cgrp); + + total_stat =3D bpf_map_lookup_elem(&cgroup_vmscan_elapsed, &cg_id); + if (!total_stat) { + bpf_printk("error finding stats for cgroup %llu\n", cg_id); + BPF_SEQ_PRINTF(seq, "cg_id: %llu, total_vmscan_delay: -1\n", + cg_id); + return 1; + } + BPF_SEQ_PRINTF(seq, "cg_id: %llu, total_vmscan_delay: %llu\n", + cg_id, total_stat->state); + + /* + * We only dump stats for one cgroup here, so return 1 to stop + * iteration after the first cgroup. + */ + return 1; +} --=20 2.36.1.476.g0c4daa206d-goog