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Thu, 02 Apr 2026 21:55:11 -0400 X-MC-Unique: NvGV8eYKMJmendw6hIzqCQ-1 X-Mimecast-MFC-AGG-ID: NvGV8eYKMJmendw6hIzqCQ_1775181307 Received: from mx-prod-int-08.mail-002.prod.us-west-2.aws.redhat.com (mx-prod-int-08.mail-002.prod.us-west-2.aws.redhat.com [10.30.177.111]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by mx-prod-mc-01.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id 270C4195608F; Fri, 3 Apr 2026 01:55:05 +0000 (UTC) Received: from [10.22.88.243] (unknown [10.22.88.243]) by mx-prod-int-08.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTP id 0EAEF1800361; Fri, 3 Apr 2026 01:54:55 +0000 (UTC) Message-ID: <57ccc69b-2f4b-40ae-b7a5-feb99e34789a@redhat.com> Date: Thu, 2 Apr 2026 21:54:55 -0400 Precedence: bulk X-Mailing-List: virtualization@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v9 09/13] isolation: Introduce io_queue isolcpus type To: Sebastian Andrzej Siewior Cc: Aaron Tomlin , axboe@kernel.dk, kbusch@kernel.org, hch@lst.de, sagi@grimberg.me, mst@redhat.com, aacraid@microsemi.com, James.Bottomley@hansenpartnership.com, martin.petersen@oracle.com, liyihang9@h-partners.com, kashyap.desai@broadcom.com, sumit.saxena@broadcom.com, shivasharan.srikanteshwara@broadcom.com, chandrakanth.patil@broadcom.com, sathya.prakash@broadcom.com, sreekanth.reddy@broadcom.com, suganath-prabu.subramani@broadcom.com, ranjan.kumar@broadcom.com, jinpu.wang@cloud.ionos.com, tglx@kernel.org, mingo@redhat.com, peterz@infradead.org, juri.lelli@redhat.com, vincent.guittot@linaro.org, akpm@linux-foundation.org, maz@kernel.org, ruanjinjie@huawei.com, yphbchou0911@gmail.com, wagi@kernel.org, frederic@kernel.org, chenridong@huawei.com, hare@suse.de, kch@nvidia.com, ming.lei@redhat.com, steve@abita.co, sean@ashe.io, chjohnst@gmail.com, neelx@suse.com, mproche@gmail.com, linux-block@vger.kernel.org, linux-kernel@vger.kernel.org, virtualization@lists.linux.dev, linux-nvme@lists.infradead.org, linux-scsi@vger.kernel.org, megaraidlinux.pdl@broadcom.com, mpi3mr-linuxdrv.pdl@broadcom.com, MPT-FusionLinux.pdl@broadcom.com References: <20260330221047.630206-1-atomlin@atomlin.com> <20260330221047.630206-10-atomlin@atomlin.com> <20260401124947.-d4D5Cr-@linutronix.de> <5e6aa61e-0ad0-4027-bba9-cd906ab0d7e8@redhat.com> <20260402075810.w0GVbX0Z@linutronix.de> From: Waiman Long In-Reply-To: <20260402075810.w0GVbX0Z@linutronix.de> X-Scanned-By: MIMEDefang 3.4.1 on 10.30.177.111 X-Mimecast-MFC-PROC-ID: RLZ-xMyD19JmokCgWQWz0CFPuf_rnYS8wuIYfdjVrZc_1775181307 X-Mimecast-Originator: redhat.com Content-Language: en-US Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit On 4/2/26 3:58 AM, Sebastian Andrzej Siewior wrote: > On 2026-04-01 15:05:21 [-0400], Waiman Long wrote: >>> Could we please clarify whether we want to keep it and this >>> additionally or if managed_irq could be used instead. This adds another >>> bit. If networking folks jump in on managed_irqs, would they need to >>> duplicate this with their net sub flag? >> Yes, I will very much prefer to reuse an existing HK cpumask like >> managed_irqs for this purpose, if possible, rather than adding another >> cpumask that we need to manage. Note that we are in the process of making >> these housekeeping cpumasks modifiable at run time in the near future. > Now if you want to change it at run time, it would mean to reconfigure > the interrupts, device and so on. Not sure if this useful _or_ if it > would be "easier" to just the tell upper layer (block in case of I/O) > not to perform any request on this CPU. Then we would have an interrupt > on that CPU but it wouldn't do anything. > It would only become a problem if you would have less queues than CPUs > and you would like to migrate things. I know that it will not be easy. Anyway, I will let this patch reaching a good compromise and get merged first before thinking about that. Cheers, Longman