From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from dggsgout11.his.huawei.com (dggsgout11.his.huawei.com [45.249.212.51]) (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 852D8DDA9; Fri, 25 Jul 2025 01:54:37 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=45.249.212.51 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1753408480; cv=none; b=uXAKC2A6EUPSwiVotkM7W58b/wRdB6APRBiVHwDHw+PSdyl8frn3/xa9SOGXzkq1EA7FOmRQC6ySTpkOeXVtWwz+bceOkDtCue83Ox2VDbpZqQUbf1AEc+PR7n2d0Gp+RpDzeCRNTexRbRT98BUuO1J0LFrLFNUD+6AZl9gfxcU= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1753408480; c=relaxed/simple; bh=7QA2XhirCdErGq0E2Mu2eOtTEn5CbyuoLwtcxlC4eQs=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=QW9klAWJZqBDI3ZU3E+XUAoShOX+JNqmTqwBlLyfbVwjoG40EuAq8N71FqkjAIyu4Y1GQ6uoFa2EZv2jNleplTU2H14/yqvkVv4KWWkVLWHEaUyJbjqL4UUEmsFPipApu06FcDi8uZG9fdRPEhK3SAbOzAaoKtd9ao/wd6ey8XY= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=huaweicloud.com; spf=pass smtp.mailfrom=huaweicloud.com; arc=none smtp.client-ip=45.249.212.51 Authentication-Results: smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=huaweicloud.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=huaweicloud.com Received: from mail.maildlp.com (unknown [172.19.163.235]) by dggsgout11.his.huawei.com (SkyGuard) with ESMTPS id 4bp9sm6GMNzYQvJG; Fri, 25 Jul 2025 09:54:36 +0800 (CST) Received: from mail02.huawei.com (unknown [10.116.40.75]) by mail.maildlp.com (Postfix) with ESMTP id 922491A0B69; Fri, 25 Jul 2025 09:54:35 +0800 (CST) Received: from [10.67.109.79] (unknown [10.67.109.79]) by APP2 (Coremail) with SMTP id Syh0CgDH07Xa44JoabeCBQ--.41840S2; Fri, 25 Jul 2025 09:54:35 +0800 (CST) Message-ID: <7746e963-1c2d-402b-9a28-1554a34e096a@huaweicloud.com> Date: Fri, 25 Jul 2025 09:54:33 +0800 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: cpu.stat in core or cpu controller (was Re: [RFC PATCH v2] cgroup: Track time in cgroup v2 freezer) To: Tejun Heo Cc: =?UTF-8?Q?Michal_Koutn=C3=BD?= , Tiffany Yang , linux-kernel@vger.kernel.org, John Stultz , Thomas Gleixner , Stephen Boyd , Anna-Maria Behnsen , Frederic Weisbecker , Johannes Weiner , "Rafael J. Wysocki" , Pavel Machek , Roman Gushchin , Chen Ridong , kernel-team@android.com, Jonathan Corbet , cgroups@vger.kernel.org, linux-doc@vger.kernel.org References: <5rm53pnhpdeqljxqywh26gffh6vlyb5j5s6pzxhv52odhkl4fm@o6p7daoponsn> <180b4c3f-9ea2-4124-b014-226ff8a97877@huaweicloud.com> <2c723007-710f-4592-9fe2-7534eb47e74f@huaweicloud.com> <0064b782-2bed-4375-aba8-3745aa306a6d@huaweicloud.com> Content-Language: en-US From: Chen Ridong In-Reply-To: Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit X-CM-TRANSID:Syh0CgDH07Xa44JoabeCBQ--.41840S2 X-Coremail-Antispam: 1UD129KBjvdXoWrtw18GFy3KF15uF45JrWxtFb_yoWxtrc_ur 9F9F17WF18WF48Ar4avFyDCF95Gay0vF90q3yjqw47X3WxAFn2qrnrWrZIvw45KF92krnr GF1vvanIyw17ZjkaLaAFLSUrUUUUjb8apTn2vfkv8UJUUUU8Yxn0WfASr-VFAUDa7-sFnT 9fnUUIcSsGvfJTRUUUbxxYFVCjjxCrM7AC8VAFwI0_Xr0_Wr1l1xkIjI8I6I8E6xAIw20E Y4v20xvaj40_Wr0E3s1l1IIY67AEw4v_Jr0_Jr4l8cAvFVAK0II2c7xJM28CjxkF64kEwV A0rcxSw2x7M28EF7xvwVC0I7IYx2IY67AKxVWDJVCq3wA2z4x0Y4vE2Ix0cI8IcVCY1x02 67AKxVW8Jr0_Cr1UM28EF7xvwVC2z280aVAFwI0_GcCE3s1l84ACjcxK6I8E87Iv6xkF7I 0E14v26rxl6s0DM2AIxVAIcxkEcVAq07x20xvEncxIr21l5I8CrVACY4xI64kE6c02F40E x7xfMcIj6xIIjxv20xvE14v26r1Y6r17McIj6I8E87Iv67AKxVWUJVW8JwAm72CE4IkC6x 0Yz7v_Jr0_Gr1lF7xvr2IY64vIr41lFIxGxcIEc7CjxVA2Y2ka0xkIwI1lc7CjxVAaw2AF wI0_GFv_Wryl42xK82IYc2Ij64vIr41l4I8I3I0E4IkC6x0Yz7v_Jr0_Gr1lx2IqxVAqx4 xG67AKxVWUJVWUGwC20s026x8GjcxK67AKxVWUGVWUWwC2zVAF1VAY17CE14v26r4a6rW5 MIIYrxkI7VAKI48JMIIF0xvE2Ix0cI8IcVAFwI0_Jr0_JF4lIxAIcVC0I7IYx2IY6xkF7I 0E14v26r4j6F4UMIIF0xvE42xK8VAvwI8IcIk0rVWUJVWUCwCI42IY6I8E87Iv67AKxVWU JVW8JwCI42IY6I8E87Iv6xkF7I0E14v26r4j6r4UJbIYCTnIWIevJa73UjIFyTuYvjxUIb yZUUUUU X-CM-SenderInfo: hfkh02xlgr0w46kxt4xhlfz01xgou0bp/ On 2025/7/25 9:08, Tejun Heo wrote: > On Wed, Jul 23, 2025 at 09:28:02AM +0800, Chen Ridong wrote: >>> But beware that the possibility of having cpu.stat without enabling the >>> cpu controller on v2 is a user visible behavior and I'm quite sure some >>> userspace relies on it, so you'd need to preserve that. >> >> This is what I worry about. Thank you for your confirmation. > > Yeah, this was an intentional decision - sacrificing a bit of code org > cleanliness for everyday usefulness. Enabling CPU controller can have > substantial overhead and having cpu stats available by default doesn't cost > much while improving usefulness. > > Thanks. > Thank you Tj, This is clear now. Best regards, Ridong