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=1793830880; b=NpNEnBGWbLtMVMtBVSFEc5T0H3bicsEvpeTcYjwe5+bt59mTV7idnR/HpC4OHKMk1cX7 smjtyQvEeH6ZxxYZA4JkCjEf3HNJ7eRWIM7YXT/8GQI3M+SGhusyOb07deu8b9ur31U33 TExjOmNroWq09UO5tGbCnenoF1nEvNAa7BUKczF5qg43h2ot0hOJo+t7TftI2pK0H1j+N dHNifoWivQCxjCtID2PcAAnugn8C6PK2NwwlxDnOwc3uWlbuD64vwwV1o0g3ve1nijsEM jnHgKjUepChNCtIYuisxEpg4Rcp3AEf14utrsUX/Fdh03Jf9wCOIUNbdiWiMQA60bGg== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1793830880; 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=dSi/FoBQG2Yxjit5Hvvi2xk0G+My+ZHMQ2+AM6bURMw=; b=NGsNq53RgQF7+5y4CynP2S7TEQ6ymT9iwRuqyAa0xbJn9DEshDCkcjaluvx8JL5RGYA5 mWMC9kaSazBV+eJhWVU+PQeK3SzYxxHLCiHA1Kcqh9PWJ31Yvgu6KyJoGKxedkc455cn9 vrVPGc7YB7lF922m6lHILXPBXDpTEB1phnc57+zziGTCoYUVffGkK/SLqupJZelmAR/+F jjqUXD4zov6dF8grrG36mfFWYOOCctQYipkme24mNEVob8cIrgTWfm1g33hj1RS9v9tBz +SzI3Qm3y9jiia/wQXCWh5aDdNGwlinzNdev1YoIVBEBmehMW8P925eeg187Jai0mIA== 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="lQh/7jyI"; 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 A8460606E82B; Wed, 4 Nov 2026 22:21:19 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key, unprotected) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.a=rsa-sha256 header.s=korg header.b=lQh/7jyI Received: by smtp.kernel.org (Postfix) with ESMTPSA id 40DFE1F0093A; Wed, 4 Nov 2026 22:21:19 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1793830879; bh=dSi/FoBQG2Yxjit5Hvvi2xk0G+My+ZHMQ2+AM6bURMw=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=lQh/7jyIwxBVVqby7fDBkbidBOmeBXuKSxKMaBXaSsCP7mLUk/YeIzxXL/CcZuvSx RaD3QMrNyH30LukYPUMmPlRky6ICfpWX414rRolRLCW+TO8G886vaEvxjevUE5D8EV VCsojGItz9DPzgXmQV7KLY363p6YBNS4a151Z6Pk= 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 6.18 0376/1005] docs: cgroup-v2: fix stale "io" controller introduction Date: Wed, 4 Nov 2026 16:01:49 -0500 Message-ID: <20261104211054.623730360@linuxfoundation.org> X-Mailer: git-send-email 2.56.0 In-Reply-To: <20261104211043.516122098@linuxfoundation.org> References: <20261104211043.516122098@linuxfoundation.org> User-Agent: quilt/0.69 X-stable: review X-Patchwork-Hint: ignore X-Mailing-List: patches@lists.linux.dev List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 6.18-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 edcd125d6992f..a62505e55dd07 100644 --- a/Documentation/admin-guide/cgroup-v2.rst +++ b/Documentation/admin-guide/cgroup-v2.rst @@ -1959,9 +1959,13 @@ 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