From mboxrd@z Thu Jan 1 00:00:00 1970 Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.remote-ip=100.103.45.18 ARC-Seal: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; cv=none; t=1794060953; b=YKYpDaseoqeVoIzSEySKkKot+E2XNAGiGVGgFZfsubLeDbOJeSXlIACE5deD0rFPY7nY 5eHTDkVOYaxg+t0mDRJp8agsmf5+HmHeO0wLuBUDxIv63ggUzLYDI2q+PZ+DB/UW/BFrV GttReJH4aWkG3idQJTjkQHy1moFwT+SL9jD01o4utxYW/hls7/S8ZX0UK1zn16nsapHQ+ K7jDVcCb7IiW4YB4sYKv4vY1mDPzWPAHhk/Ubin/l8fPqEo11pnch2CBqA3Mm95dqO1n0 FqV9zp/qKZrgJObVJ/u5W4A4ZYr0B7gR7AbJMy759SjRH09VM1wlAlkEgtf6NPP73bg== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1794060953; h=Received:DKIM-Signature:From:To:Cc:Subject:Date:Message-ID:X-Mailer: In-Reply-To:References:User-Agent:X-stable:X-Patchwork-Hint: MIME-Version:Content-Transfer-Encoding; bh=NTdyMteTWCeSlpaE7q5Lixp8JTYTbzOp6S8yJAFYN+c=; b=jsjXox2kT7YgtcvuxMCR+8PdBJjhaUbA9HsCmkoi1dDNllfW49r3ZfCw+oNff/BpHEXe uKPLONb0QRFQ+GOMK23J4snSgUQHGs45Offh+IufNTNfdmXUVapYsX4RFSE5AArv8ut8L 0jlg2TTN3+O2n4LnwYcvTiKbX+YKtuW6CVeLjN8YPI/t3RDeV4Bu2S7QS+hqbg44RjjTH ngLXAkuMgW6fHxb6DImpg4lfy5+pK86yfYfOxY+SsCxpcBdRttypdJNILP6+i5Lu/FMli yMceTtAMyamAfQc9e3LDdEf8tTMknkQyUScZLgh3uMK1EbFFasVj/FTQBkxtx2mp5jA== ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass header.d=linuxfoundation.org header.i=@linuxfoundation.org header.a=rsa-sha256 header.s=korg header.b=QuzNAA7R; arc=none smtp.remote-ip=100.103.45.18 Received: from smtp.kernel.org (quasi.space.kernel.org [100.103.45.18]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (prime256v1)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id C36E9606A33B; Sat, 7 Nov 2026 14:15:52 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.a=rsa-sha256 header.s=korg header.b=QuzNAA7R Received: by smtp.kernel.org (Postfix) with ESMTPSA id 691F41F008A2; Sat, 7 Nov 2026 14:15:52 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1794060952; bh=NTdyMteTWCeSlpaE7q5Lixp8JTYTbzOp6S8yJAFYN+c=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=QuzNAA7RbN9PJ1WmMxG0yXYCBuHIT5gdirAA4lMlzZjhb1jZx+hWbDAPdopdMN4Rx eMsm7F8wdDwFluyvjwl9YMqVTvgq7k3lu9E8gmAOCb0kRhGu6ULV8bniJhXImWGxFP APToEaXXocdqaj+w+2ZilOynLFaNcHCPUXHiCFsQ= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Zhe Liu , Tao Cui , Tejun Heo , Sasha Levin Subject: [PATCH 6.12 0311/1536] docs: cgroup-v2: fix stale "io" controller introduction Date: Sat, 7 Nov 2026 08:38:47 -0500 Message-ID: <20261107135006.457170656@linuxfoundation.org> X-Mailer: git-send-email 2.56.0 In-Reply-To: <20261107134957.653319350@linuxfoundation.org> References: <20261107134957.653319350@linuxfoundation.org> User-Agent: quilt/0.69 X-stable: review X-Patchwork-Hint: ignore X-Mailing-List: stable@vger.kernel.org List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 6.12-stable review patch. If anyone has any objections, please let me know. ------------------ From: Zhe Liu [ Upstream commit 3345c7248a9e2a91cb9e2477c29af16881706f4f ] The introductory paragraph for the IO controller still states that weight based distribution is "available only if cfq-iosched is in use" and that "neither scheme is available for blk-mq devices". This text dates from when the cgroup v2 documentation was first written (2015) and was correct at the time, but is no longer accurate: * cfq-iosched was removed in v5.0; * blk-mq is now the only block I/O path, and both the absolute limit scheme (io.max via blk-throttle) and the weight based scheme (io.weight via iocost, or io.bfq.weight under BFQ) work on it; * latency based protection (iolatency) and I/O priority (ioprio) controllers have since been added. The rest of the section already documents io.weight, io.max, io.cost.{qos,model}, io.latency and io.prio.class correctly, so the introduction is the only part that contradicts them. Rewrite it to reflect the current state. Signed-off-by: Zhe Liu Reviewed-by: Tao Cui Signed-off-by: Tejun Heo Signed-off-by: Sasha Levin --- Documentation/admin-guide/cgroup-v2.rst | 10 +++++++--- 1 file changed, 7 insertions(+), 3 deletions(-) diff --git a/Documentation/admin-guide/cgroup-v2.rst b/Documentation/admin-guide/cgroup-v2.rst index 2cb58daf3089b..8aab1c3b48ea3 100644 --- a/Documentation/admin-guide/cgroup-v2.rst +++ b/Documentation/admin-guide/cgroup-v2.rst @@ -1833,9 +1833,13 @@ IO The "io" controller regulates the distribution of IO resources. This controller implements both weight based and absolute bandwidth or IOPS -limit distribution; however, weight based distribution is available -only if cfq-iosched is in use and neither scheme is available for -blk-mq devices. +limit distribution. Absolute BPS and IOPS limits are enforced by +blk-throttle and apply to all devices, while weight based proportional +distribution is provided by the iocost cost model controller +(CONFIG_BLK_CGROUP_IOCOST) and, when the BFQ I/O scheduler is in use +for a device, by BFQ's own cgroup support. Latency-based protection +(CONFIG_BLK_CGROUP_IOLATENCY) and I/O priority assignment +(CONFIG_BLK_CGROUP_IOPRIO) are also available. IO Interface Files -- 2.53.0