From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (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 A08F2315531; Wed, 2 Jul 2025 16:34:32 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1751474072; cv=none; b=AJOdWFqxSrQIKswThTtZTYBF+uAx5saV51e7RZTiuj2V8LTfT9oCzvzvHujo7AnM9nWoHCisvhF2N1P0pliteeTGZPhszvs/LSjI8iUZH+mP2sUCETedRyMhw4SsTQw5XK2Gfyk550logWJErNJb+6ZLmoAU1tjCZ3uqrD/qSNc= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1751474072; c=relaxed/simple; bh=vxQYCEdaJjhalXM2LWdmwU2NhYSit9L084ZrGvIAi1s=; h=From:Date:Subject:MIME-Version:Content-Type:Message-Id:References: In-Reply-To:To:Cc; b=fAf99RPBDC6rzt2ngvQ+HOZabbqPsWKB86LzH90j3GqxqBtCWRNU0tbGklCH2VGthYUUZVQ2Hc8noQJhfGJECbpZN+drq81c8cIha6y2PC5kj/sopHqiV/uR6nUO5Z7WG7k77SO8JD1xs7VI9JWACypZ3W6OP55RUigd1VISuk8= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=YlsqVWRq; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="YlsqVWRq" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 914E1C4CEE7; Wed, 2 Jul 2025 16:34:31 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1751474072; bh=vxQYCEdaJjhalXM2LWdmwU2NhYSit9L084ZrGvIAi1s=; h=From:Date:Subject:References:In-Reply-To:To:Cc:From; b=YlsqVWRqiOBec/ZJdDuUpTDrfzbfsA+bKi15TlITzblzeP22TZmGTvlkF19SPArgo H7D3EBxICYst9MAFD+hOcP7eRP96DiFZcLNoMb36JG0ZrR4jKNwuVsBMijfbId73xQ cgOvlGuiLyWnaiuZ4gxNpoN4TAdi1AlxKtPj6HMOHpgdQGUb1c+5CvFLLr5KRK7dhm Z7rj95qpCR6A9qix29WifwcQkjNrPp6Il1stkf/rSwvPTonaYg5RLy7H1wdMPp5+Gd YToOqMCLr5TOE0aB6RSl0rvQVZTFXd81MtLk8qfWSZojEpoEwqt6O+vyftQm9AuIk+ 95aQqtRPe2o/Q== From: Daniel Wagner Date: Wed, 02 Jul 2025 18:34:00 +0200 Subject: [PATCH v7 10/10] docs: add io_queue flag to isolcpus Precedence: bulk X-Mailing-List: linux-kernel@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: <20250702-isolcpus-io-queues-v7-10-557aa7eacce4@kernel.org> References: <20250702-isolcpus-io-queues-v7-0-557aa7eacce4@kernel.org> In-Reply-To: <20250702-isolcpus-io-queues-v7-0-557aa7eacce4@kernel.org> To: Jens Axboe , Keith Busch , Christoph Hellwig , Sagi Grimberg , "Michael S. Tsirkin" Cc: Aaron Tomlin , "Martin K. Petersen" , Thomas Gleixner , Costa Shulyupin , Juri Lelli , Valentin Schneider , Waiman Long , Ming Lei , Frederic Weisbecker , Mel Gorman , Hannes Reinecke , Mathieu Desnoyers , linux-kernel@vger.kernel.org, linux-block@vger.kernel.org, linux-nvme@lists.infradead.org, megaraidlinux.pdl@broadcom.com, linux-scsi@vger.kernel.org, storagedev@microchip.com, virtualization@lists.linux.dev, GR-QLogic-Storage-Upstream@marvell.com, Daniel Wagner X-Mailer: b4 0.14.2 The io_queue flag informs multiqueue device drivers where to place hardware queues. Document this new flag in the isolcpus command-line argument description. Signed-off-by: Daniel Wagner --- Documentation/admin-guide/kernel-parameters.txt | 19 ++++++++++++++++++- 1 file changed, 18 insertions(+), 1 deletion(-) diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt index f1f2c0874da9ddfc95058c464fdf5dabaf0de713..7594ac5448575cc895ebf7af0fe051d42dc5e0e9 100644 --- a/Documentation/admin-guide/kernel-parameters.txt +++ b/Documentation/admin-guide/kernel-parameters.txt @@ -2590,7 +2590,6 @@ "number of CPUs in system - 1". managed_irq - Isolate from being targeted by managed interrupts which have an interrupt mask containing isolated CPUs. The affinity of managed interrupts is @@ -2613,6 +2612,24 @@ housekeeping CPUs has no influence on those queues. + io_queue + Isolate from I/O queue work caused by multiqueue + device drivers. Restrict the placement of + queues to housekeeping CPUs only, ensuring that + all I/O work is processed by a housekeeping CPU. + + Housekeeping CPUs that serve isolated CPUs + cannot be offlined. + + The io_queue configuration takes precedence over + managed_irq; thus, when io_queue is used, + managed_irq has no effect. + + Note: When an isolated CPU issues an I/O request, + it is forwarded to a housekeeping CPU. This will + trigger a software interrupt on the completion + path. + The format of is described above. iucv= [HW,NET] -- 2.50.0