From mboxrd@z Thu Jan 1 00:00:00 1970 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 CEEBF168A2 for ; Mon, 11 Sep 2023 20:27:45 +0000 (UTC) Received: from mail-pl1-x630.google.com (mail-pl1-x630.google.com [IPv6:2607:f8b0:4864:20::630]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id B0D25185; Mon, 11 Sep 2023 13:27:44 -0700 (PDT) Received: by mail-pl1-x630.google.com with SMTP id d9443c01a7336-1bf7423ef3eso35417155ad.3; Mon, 11 Sep 2023 13:27:44 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20221208; t=1694464064; x=1695068864; darn=vger.kernel.org; h=in-reply-to:content-disposition:mime-version:references:message-id :subject:cc:to:from:date:sender:from:to:cc:subject:date:message-id :reply-to; bh=SNnl2EUxq2zaX99R7tX9+iE5LFUxTKUThPqOegYIa5s=; b=i/kVnY717xMDqCNn3WYnViiOjjcMpjRZ3YDH8aw7uIBl6563xM8YlJRH0UUKIkzMnh Oy+VVJSeiQF17nUJj0keyWSm0EKkS064TuM65gKaN7cKXk+eDxX/f/PE9Mq659URYrHe xEkgSLA+Tf51xJozMHikNt7u5vqNY0lfOICQhaWYHi88CvK60oWo1gb1ggG49IBsOrsr I97r7rWLJyrFw3VLiX6JAeIb06R0U6ZHAoeLgqgUXnnBKcVOSzk6a/eFE9JBnEkHhCIm Ag6sSmOSPB8eLx6IT2BYVgPBkXm6hcCKZiUdcyOdAfD8z8xzunnGYF+heAxUmZMeWs4d Xy1g== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1694464064; x=1695068864; h=in-reply-to:content-disposition:mime-version:references:message-id :subject:cc:to:from:date:sender:x-gm-message-state:from:to:cc :subject:date:message-id:reply-to; bh=SNnl2EUxq2zaX99R7tX9+iE5LFUxTKUThPqOegYIa5s=; b=GJr1bVNln4mEQkuKMtgrD9dpt5hvsd82mQEf2g7TtbTiiZStZYF1nQEU8L4Xg2AdNU 6uecaGWKNVWf8Um07G7tGEQQdr+4S3v5WYGJ3YfVaP+TxEUMJST4cw/0IwWRQ40wnXyX cd9Ro6h5UCZ/Q9s0iyMmluu1ARNM4CWD15ukaUGraFnT2UpNpnMkuW6L8Y2YneZxDYwT jiTXXyLp5GtFMkR76nd2LT1KCg1QRKfgqtLGHEYXYsz5OBN3PqU6z4Yg03fV6Ex0P+wS i0GJZEIYGS0IRYo5gjLI1lTXCl9P98UQsZ15/o5DqIXQeP0/KDTbmXJOZtGbossxSuJS TjSw== X-Gm-Message-State: AOJu0YymsTAogienNJIkhaQYwlx0FEjs5X0yIoNrLuTKjy45U7ib059O k+ptkZy1D7vIwPYpjyEWFapA8mWirVFdiA== X-Google-Smtp-Source: AGHT+IGngHVyRdmTKS2TRrqK78EOerqzQ008OJjN7s8aS/kznDTkl0Gc09j8mylpOFyQkkxZWS+CFA== X-Received: by 2002:a17:903:2302:b0:1bc:2c58:ad97 with SMTP id d2-20020a170903230200b001bc2c58ad97mr10290139plh.22.1694464064016; Mon, 11 Sep 2023 13:27:44 -0700 (PDT) Received: from localhost (dhcp-72-235-13-41.hawaiiantel.net. [72.235.13.41]) by smtp.gmail.com with ESMTPSA id l12-20020a170902eb0c00b001bf574dd1fesm6835997plb.141.2023.09.11.13.27.43 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 11 Sep 2023 13:27:43 -0700 (PDT) Sender: Tejun Heo Date: Mon, 11 Sep 2023 10:27:42 -1000 From: Tejun Heo To: Yafang Shao Cc: ast@kernel.org, daniel@iogearbox.net, john.fastabend@gmail.com, andrii@kernel.org, martin.lau@linux.dev, song@kernel.org, yonghong.song@linux.dev, kpsingh@kernel.org, sdf@google.com, haoluo@google.com, jolsa@kernel.org, lizefan.x@bytedance.com, hannes@cmpxchg.org, yosryahmed@google.com, cgroups@vger.kernel.org, bpf@vger.kernel.org Subject: Re: [RFC PATCH bpf-next 1/5] cgroup: Enable task_under_cgroup_hierarchy() on cgroup1 Message-ID: References: <20230903142800.3870-1-laoar.shao@gmail.com> <20230903142800.3870-2-laoar.shao@gmail.com> Precedence: bulk X-Mailing-List: bpf@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: X-Spam-Status: No, score=-1.5 required=5.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_EF,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,RCVD_IN_DNSWL_BLOCKED,SPF_HELO_NONE, SPF_PASS autolearn=no autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on lindbergh.monkeyblade.net On Thu, Sep 07, 2023 at 11:05:07AM +0800, Yafang Shao wrote: > The fd-based cgroup interface plays a crucial role in BPF programs, > particularly in components such as cgroup_iter, bpf_cgrp_storage, and > cgroup_array maps, as well as in the attachment and detachment of > cgroups. Yeah, I know they're used. It's just that they are inferior identifiers from cgroup's POV as they are ephemeral, can't easily be transferred across process boundaries or persisted beyond the lifetime of the fd-owing process or the cgroups which are being pointed to. Thanks. -- tejun