From patchwork Wed Oct 11 12:08:50 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Chuyi Zhou X-Patchwork-Id: 13417274 X-Patchwork-Delegate: bpf@iogearbox.net 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 1E9331EA98 for ; Wed, 11 Oct 2023 12:09:21 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=bytedance.com header.i=@bytedance.com header.b="Mmo0Lnn+" Received: from mail-pf1-x42a.google.com (mail-pf1-x42a.google.com [IPv6:2607:f8b0:4864:20::42a]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 33DEAE4 for ; Wed, 11 Oct 2023 05:09:18 -0700 (PDT) Received: by mail-pf1-x42a.google.com with SMTP id d2e1a72fcca58-694ed847889so5203221b3a.2 for ; Wed, 11 Oct 2023 05:09:18 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=bytedance.com; s=google; t=1697026158; x=1697630958; darn=vger.kernel.org; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:from:to:cc:subject:date :message-id:reply-to; bh=FNW2oYGtelVvgczyk2A13Ij/ocoUNYFTCyV6b+P6gh8=; b=Mmo0Lnn+6H8KnO/eFtAmfbbl3hOGYqf/dJPe2Gl7jKVZA6i5IUgfYQmNNLIddHocA+ khn0amvjF094s7IG8TQIcf0740yn5BdlfLgsg+7Jdf0Y6u5Ch/xYr7wdfLd4UULrtYJO VGwe4GAU0n8qKA9iiqRGZFi8Dk5yEFpg54ZAU6s1HJ8y8dRg8yRWhrvk1SpyOfy++Z51 WCNs6OJGScGEa/qwzJJZiEjsbGHVgXOBtzqGjqumoSwQcaJA0hZ/vD/Pl9XSNl9Ke/pS 3YyynfVVqBpQ9rWrZuyp5KdApZQbZNHCU4c0FspeyoSMJ2o7kaJfsVx4c2s8RRDKB/kw YERw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1697026158; x=1697630958; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:x-gm-message-state:from:to:cc :subject:date:message-id:reply-to; bh=FNW2oYGtelVvgczyk2A13Ij/ocoUNYFTCyV6b+P6gh8=; b=laVOZ/74TthBWCYHk0/9Hl538ILTgrhlsHMRk8yqKmNWlDTshqGanbxd6JOxK0NpIN um9M3J3hqYp1yLegDnczjFex+QXA0ZZ3ZbkynpBZbJgMWdwUlNoUmjh1PNAN7VfQWBlu hodGPpLwUacPOcdLXv+L5WHXFaY0298dRNmqnGXGG3iXj3zzWQC1fjAICbcXgiu2l3Ls l4Re+gMY9C0F1VWbxf48zU3IJDPVt26NoMBuQGiE1ibsbkjYi/3EadyqBYDgf3arLOoo F/c7UNnnvF5nV+C8syUmx9i5z2z7P0dvgZrW7DgsuczOqaPs+cc3M+wGGNpGF+hoEQvG vjoA== X-Gm-Message-State: AOJu0Yy4qJQOM4HjHcH4eod6oRqAg2mTybSycBcb3dY0rO0VG0bgigHv Riuz4Hv8XibpN6T1DrIGXDcZCrwPRGPEa/LQ7zs= X-Google-Smtp-Source: AGHT+IESYxnB1J1sRdVkJQH+ZE6Y19Leh4aJwAI7/dVl9OQScpOyuiqMRtRlItHAn1x1rBydnQwedg== X-Received: by 2002:a05:6a00:4217:b0:697:4901:3d4d with SMTP id cd23-20020a056a00421700b0069749013d4dmr17449212pfb.5.1697026157840; Wed, 11 Oct 2023 05:09:17 -0700 (PDT) Received: from n37-019-243.byted.org ([180.184.51.142]) by smtp.gmail.com with ESMTPSA id u13-20020a62ed0d000000b006930db1e6cfsm9962769pfh.62.2023.10.11.05.09.15 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 11 Oct 2023 05:09:17 -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 v5 1/8] cgroup: Prepare for using css_task_iter_*() in BPF Date: Wed, 11 Oct 2023 20:08:50 +0800 Message-Id: <20231011120857.251943-2-zhouchuyi@bytedance.com> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20231011120857.251943-1-zhouchuyi@bytedance.com> References: <20231011120857.251943-1-zhouchuyi@bytedance.com> 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,URIBL_BLOCKED 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 This patch makes some preparations for using css_task_iter_*() in BPF Program. 1. Flags CSS_TASK_ITER_* are #define-s and it's not easy for bpf prog to use them. Convert them to enum so bpf prog can take them from vmlinux.h. 2. In the next patch we will add css_task_iter_*() in common kfuncs which is not safe. Since css_task_iter_*() does spin_unlock_irq() which might screw up irq flags depending on the context where bpf prog is running. So we should use irqsave/irqrestore here and the switching is harmless. Suggested-by: Alexei Starovoitov Signed-off-by: Chuyi Zhou Acked-by: Tejun Heo --- include/linux/cgroup.h | 12 +++++------- kernel/cgroup/cgroup.c | 18 ++++++++++++------ 2 files changed, 17 insertions(+), 13 deletions(-) diff --git a/include/linux/cgroup.h b/include/linux/cgroup.h index b307013b9c6c..0ef0af66080e 100644 --- a/include/linux/cgroup.h +++ b/include/linux/cgroup.h @@ -40,13 +40,11 @@ struct kernel_clone_args; #define CGROUP_WEIGHT_DFL 100 #define CGROUP_WEIGHT_MAX 10000 -/* walk only threadgroup leaders */ -#define CSS_TASK_ITER_PROCS (1U << 0) -/* walk all threaded css_sets in the domain */ -#define CSS_TASK_ITER_THREADED (1U << 1) - -/* internal flags */ -#define CSS_TASK_ITER_SKIPPED (1U << 16) +enum { + CSS_TASK_ITER_PROCS = (1U << 0), /* walk only threadgroup leaders */ + CSS_TASK_ITER_THREADED = (1U << 1), /* walk all threaded css_sets in the domain */ + CSS_TASK_ITER_SKIPPED = (1U << 16), /* internal flags */ +}; /* a css_task_iter should be treated as an opaque object */ struct css_task_iter { diff --git a/kernel/cgroup/cgroup.c b/kernel/cgroup/cgroup.c index 1fb7f562289d..b6d64f3b8888 100644 --- a/kernel/cgroup/cgroup.c +++ b/kernel/cgroup/cgroup.c @@ -4917,9 +4917,11 @@ static void css_task_iter_advance(struct css_task_iter *it) void css_task_iter_start(struct cgroup_subsys_state *css, unsigned int flags, struct css_task_iter *it) { + unsigned long irqflags; + memset(it, 0, sizeof(*it)); - spin_lock_irq(&css_set_lock); + spin_lock_irqsave(&css_set_lock, irqflags); it->ss = css->ss; it->flags = flags; @@ -4933,7 +4935,7 @@ void css_task_iter_start(struct cgroup_subsys_state *css, unsigned int flags, css_task_iter_advance(it); - spin_unlock_irq(&css_set_lock); + spin_unlock_irqrestore(&css_set_lock, irqflags); } /** @@ -4946,12 +4948,14 @@ void css_task_iter_start(struct cgroup_subsys_state *css, unsigned int flags, */ struct task_struct *css_task_iter_next(struct css_task_iter *it) { + unsigned long irqflags; + if (it->cur_task) { put_task_struct(it->cur_task); it->cur_task = NULL; } - spin_lock_irq(&css_set_lock); + spin_lock_irqsave(&css_set_lock, irqflags); /* @it may be half-advanced by skips, finish advancing */ if (it->flags & CSS_TASK_ITER_SKIPPED) @@ -4964,7 +4968,7 @@ struct task_struct *css_task_iter_next(struct css_task_iter *it) css_task_iter_advance(it); } - spin_unlock_irq(&css_set_lock); + spin_unlock_irqrestore(&css_set_lock, irqflags); return it->cur_task; } @@ -4977,11 +4981,13 @@ struct task_struct *css_task_iter_next(struct css_task_iter *it) */ void css_task_iter_end(struct css_task_iter *it) { + unsigned long irqflags; + if (it->cur_cset) { - spin_lock_irq(&css_set_lock); + spin_lock_irqsave(&css_set_lock, irqflags); list_del(&it->iters_node); put_css_set_locked(it->cur_cset); - spin_unlock_irq(&css_set_lock); + spin_unlock_irqrestore(&css_set_lock, irqflags); } if (it->cur_dcset)