From patchwork Wed Oct 18 06:17:39 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Chuyi Zhou X-Patchwork-Id: 13426420 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 B7D168F69 for ; Wed, 18 Oct 2023 06:18:11 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=bytedance.com header.i=@bytedance.com header.b="V4T7oq8V" Received: from mail-pl1-x636.google.com (mail-pl1-x636.google.com [IPv6:2607:f8b0:4864:20::636]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 20241D5A for ; Tue, 17 Oct 2023 23:17:59 -0700 (PDT) Received: by mail-pl1-x636.google.com with SMTP id d9443c01a7336-1ca74e77aecso23225715ad.1 for ; Tue, 17 Oct 2023 23:17:59 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=bytedance.com; s=google; t=1697609878; x=1698214678; 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=V4T7oq8VpxNt6t2w14WbFy1JCSIyBZZb/8p38RNc0BIImJ1ucXOw68wWgX+Ywv7Nsi Vl3hVKY43Dz1IqRE5jkxkR0Y53AhOnCikPS1y5BDRZmrjmEwklA8FQQlhJHxGFUfHNdT ZFFm0GY8hrHCG4KF3hui+1/gn1zx6Md8MjOi0sTcHcSCjz6ngvwF4DJyRLCSrJv2C3H5 Z/JEAkBoQiRbZL0hHDVlgh1xznXAas4wpOiwHh4pO+Dh23KuUMKBEuf5TL7+TK8JsRvk DMMB3CuGfSC0TgkFT8r++RvrZAHkD3MCJz7FS7TdmRf7cP35y5hKp4zzfs4JA5Xh5F+H qbCA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1697609878; x=1698214678; 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=Sf6in4sCzyw18g3P6MskB2XjU8aHbzKHAOP8Vc2SGOvhQhLg+CwA7LR0ZuiF+UOVYC s/XZpPP/4WiLdMptVAJ6ZJO7GB2LbhdsM4EGHbKZfZgaDQm/mXtw9ezv/CehTFgDAOV5 hnwWf8CU+w/r63VAFASgJsCKEcAdzFnQuleFUtj57KNLk3KktxQ3jzJTo0z0ZU4Rqz6S qV/OFL9wsiyn097Vd+ZYp217vSsk35rZrWak1OwvlyuSsVhrvIgFgxLMHzaO8gAZ3Te3 cgA9g1HNyz2Rzd7Wtdnzuq/fbFsgHXk6TLH66vz1RslFiE6iU6gqrU7oUxjFQVlct3xW tUoA== X-Gm-Message-State: AOJu0YyFce9DiqbY6sZux+CR2J7icBUCUWQFlXpMFAnMDIGpPOCEGEwz CPDz7oc3x/HnzFgOJ40igWmERFNRTe6JtSvmBgGIAw== X-Google-Smtp-Source: AGHT+IEW/SIo2swuWYnxf2PCWQq7o5dnjZYKadyrosONhQGYQvdQ8A9ZnePa6p8+5KKhLaMtOqCY0A== X-Received: by 2002:a17:903:41d1:b0:1c5:7d49:570e with SMTP id u17-20020a17090341d100b001c57d49570emr4978737ple.29.1697609877965; Tue, 17 Oct 2023 23:17:57 -0700 (PDT) Received: from n37-019-243.byted.org ([180.184.103.200]) by smtp.gmail.com with ESMTPSA id ix13-20020a170902f80d00b001c61acd5bd2sm2659116plb.112.2023.10.17.23.17.55 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 17 Oct 2023 23:17:57 -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: [RESEND PATCH bpf-next v6 1/8] cgroup: Prepare for using css_task_iter_*() in BPF Date: Wed, 18 Oct 2023 14:17:39 +0800 Message-Id: <20231018061746.111364-2-zhouchuyi@bytedance.com> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20231018061746.111364-1-zhouchuyi@bytedance.com> References: <20231018061746.111364-1-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_NONE 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)