From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-pl1-f180.google.com (mail-pl1-f180.google.com [209.85.214.180]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 42D9F3672B3 for ; Fri, 10 Jul 2026 03:29:57 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.214.180 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1783654198; cv=none; b=eyTHZE4uxH2rnzTmZovJ0TWn2/DG/MJGS0jnpW4+UNRR+MpZY4faGbWIXPW2qWvFnkeWqUaETqCTeUDIv08QhcTg9Z8PbMrLj6lG3xvRJeIi+SLGYYGZp1k6oBfGrWpsU5DEL8Kk50E+VQOD9Q3rcbw0Hwn3nSUUNJo+z+MGlPI= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1783654198; c=relaxed/simple; bh=MNtb2Qrr3nNt+ub4rjVucp13CHEPWughXQYJLAqNpy4=; h=From:Date:Subject:MIME-Version:Content-Type:Message-Id:References: In-Reply-To:To:Cc; b=a2HAQ44ba/ynskx+08HJY2HfFVOqM0/Y8EyA1Xn8ItGWlxiqJGML0sOPtbOp5g+BhgbtP4WrDqlKTCYblyxzCr/SdxwkwOqKAW3Z9YVTVoKUkh2HNgaEq64fIN1ymjC7QYU/3xljgg2rj86loAdMBhmKZ0juhqfO7Y8LcLAnfhk= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gmail.com; spf=pass smtp.mailfrom=gmail.com; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b=FOw3hfY3; arc=none smtp.client-ip=209.85.214.180 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gmail.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=gmail.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="FOw3hfY3" Received: by mail-pl1-f180.google.com with SMTP id d9443c01a7336-2ce7d2adef4so5794565ad.3 for ; Thu, 09 Jul 2026 20:29:57 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20251104; t=1783654197; x=1784258997; darn=vger.kernel.org; h=cc:to:in-reply-to:references:message-id:content-transfer-encoding :content-type:mime-version:subject:date:from:from:to:cc:subject:date :message-id:reply-to:content-type; bh=Cx1US55ZcQE2IXAHU74DmTXGa2F7H+sEKzQcFe01wfY=; b=FOw3hfY3Oj5i9E3RdC0nhn5AdEWFb5cLVgRgArGb4bb6kp/M6RdpixAkzx0OUPJDS/ OCzD2dxGCeiV1VB4CXInwLgPPekz+xhtXDl4y2+YmSa5pu0nmL8y3IIK72XOV5kZDmln Utgz1Mii77S2ODs5veYjNP1vVJpupanprFN5EE7ZUg4o85bOuNpcpiMghscP5Ijsz71E rXtG6SZTWDTNwYG77d3fQGou5JIQZ8OqqhKiRxQ/0WaXggRpIzvnSYDPbftCBkkPlogi 9Utiz4nYmMvhnv8wEbcHsy3/cBDSIf/YTUzVFSx/EMMjTv//mq/relr7ibH0sRUlLyJa bZmw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20251104; t=1783654197; x=1784258997; h=cc:to:in-reply-to:references:message-id:content-transfer-encoding :content-type:mime-version:subject:date:from:x-gm-gg :x-gm-message-state:from:to:cc:subject:date:message-id:reply-to :content-type; bh=Cx1US55ZcQE2IXAHU74DmTXGa2F7H+sEKzQcFe01wfY=; b=iwxvcFbMlw65q6sTlVnGdyqiDYz/zx0K0E6xaDTHx8LMvjwk0O+Q4zJxWgbvC0KGgd NtrHpGXHIs0nCiC+ZnUDeUv7ajP3xNEOreCr06M6LZByzhHnG3HOd282f+Gerncsgi8D om2Eq/U7Z415oehLIz8Ho/C20qqSv7qyROfP258QyDjpZv1T+d2HXdvFTdhjak1bbMR/ 66+3aAx4E+QRY4d5zPLuY60lHfhNvzVLiJliHBEvR6lWOv+pwdduwJYlxoEr0zmRnYHR Ti3W846r10IcV4vDwkmTxX1A9VRc+l/LyAOU+eUc6fdt0U6GNqXpuH4ei9kMZ13K11An Di9A== X-Forwarded-Encrypted: i=1; AHgh+RpEO7waC9S+rtcCnrE53LAC1o1lXetcvlHVZV5RfiKXaJw4HNz41C5NIzPbk5ubaUGYf6+UGIUzflQ=@vger.kernel.org X-Gm-Message-State: AOJu0YyKA0wVrHjqM7vQLm5Tb7tCjNQLu/jvJrRkm9kS5uL0bgnRx7DE o2vSiwXQHpaHsniXqDeP7y5tGa2iuzgJAmjD/Q4MDlxFszK6+S396Yyt X-Gm-Gg: AfdE7clmMBxrS317oSjQMpPMJNBShPGp4lYuNq9vu2D1A4ET0EcScoHCNFf2WWwmTJB LdbLSsbG0l1RrjkjlHdet+p7pjYqOz1k95Gg+7WMg4YzeaQGfIHy6f9dwrWAL8JqGPB5TAiWdZA DT8qa0Dj/moP7oX7rAUWxhwglStRf1xzaKsVlo5mr/81k6/x0htL5xhSDGKvEJn/H80/+mxT/NY l2p53KQzlGDE/eMffUhcG8SZa7WojXE+0rLY7bMMnaTdy1xt7IU4sTDI+RDPyUsByVRtWYmnCje D3s1bRsM3BxpQVTvYaaxJ4/ehFYf1QRmVVzl5suxYyBOaEU4b0UOdYYZ0Jg4cKHuWMxfTbXSqHH M5IJ2y5LWkIIA3KLdFGZzj9tCX+wiHf71D44GKqm7UOaO5aYcMMGQkZA6br7k0ESyVFfsc31kNl IgnDpHovywhT0= X-Received: by 2002:a17:903:244e:b0:2ca:d91d:d3a7 with SMTP id d9443c01a7336-2ccea2a5de9mr109420575ad.10.1783654196716; Thu, 09 Jul 2026 20:29:56 -0700 (PDT) Received: from [127.0.1.1] ([138.199.21.246]) by smtp.gmail.com with ESMTPSA id d9443c01a7336-2ccc9bdb56fsm53436465ad.15.2026.07.09.20.29.48 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 09 Jul 2026 20:29:56 -0700 (PDT) From: Jing Wu Date: Fri, 10 Jul 2026 11:28:21 +0800 Subject: [PATCH v4 10/11] docs: cgroup-v2: document kernel-noise isolation via isolated partitions Precedence: bulk X-Mailing-List: linux-doc@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Message-Id: <20260710-wujing-dhm-v4-10-2e912e5d9645@gmail.com> References: <20260710-wujing-dhm-v4-0-2e912e5d9645@gmail.com> In-Reply-To: <20260710-wujing-dhm-v4-0-2e912e5d9645@gmail.com> To: Ingo Molnar , Peter Zijlstra , Juri Lelli , Vincent Guittot , Dietmar Eggemann , Steven Rostedt , Ben Segall , Mel Gorman , Valentin Schneider , "Paul E. McKenney" , Frederic Weisbecker , Neeraj Upadhyay , Joel Fernandes , Josh Triplett , Boqun Feng , Uladzislau Rezki , Mathieu Desnoyers , Lai Jiangshan , Zqiang , Anna-Maria Behnsen , Tejun Heo , Jonathan Corbet , Shuah Khan , Shuah Khan , Thomas Gleixner Cc: Waiman Long , linux-kernel@vger.kernel.org, rcu@vger.kernel.org, cgroups@vger.kernel.org, linux-doc@vger.kernel.org, linux-kselftest@vger.kernel.org, Jing Wu , Qiliang Yuan X-Mailer: b4 0.13.0 Document that creating a cpuset isolated partition updates the kernel-noise housekeeping masks (HK_TYPE_KERNEL_NOISE and HK_TYPE_MANAGED_IRQ) in addition to the sched-domain mask, and that destroying it restores the boot configuration. No boot-time kernel parameters such as nohz_full= or rcu_nocbs= are required; writing "isolated" to cpuset.cpus.partition is the only mechanism needed. Co-developed-by: Qiliang Yuan Signed-off-by: Qiliang Yuan Signed-off-by: Jing Wu --- Documentation/admin-guide/cgroup-v2.rst | 17 +++++++++++++++++ 1 file changed, 17 insertions(+) diff --git a/Documentation/admin-guide/cgroup-v2.rst b/Documentation/admin-guide/cgroup-v2.rst index 6efd0095ed995..eaafe6d88c0e5 100644 --- a/Documentation/admin-guide/cgroup-v2.rst +++ b/Documentation/admin-guide/cgroup-v2.rst @@ -2721,6 +2721,23 @@ Cpuset Interface Files kernel boot command line option. If those CPUs are to be put into a partition, they have to be used in an isolated partition. + When an isolated partition is created or destroyed, the kernel + automatically drives runtime updates of the housekeeping masks + for kernel-noise types (nohz_full, RCU NOCB, managed IRQ + interrupts). This extends isolation beyond scheduler domains: + the tick is stopped on isolated CPUs, RCU callbacks are + offloaded to housekeeping cores, and managed interrupts are + migrated away. No boot-time kernel parameters such as + ``nohz_full=`` or ``rcu_nocbs=`` are required; writing + ``isolated`` to ``cpuset.cpus.partition`` is the only mechanism + needed. No additional cgroupfs files are required. + + CPUs with hotplug disabled (typically the boot CPU, CPU 0, on + x86-64) cannot be cycled offline for kernel-noise isolation. + The kernel emits a one-time warning and keeps those CPUs in + the tick and RCU-NOCB housekeeping set, even when they appear + in an isolated partition. + Device controller ----------------- -- 2.43.0