From: Daniel Wagner <dwagner@suse.de>
To: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Cc: Aaron Tomlin <atomlin@atomlin.com>,
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, longman@redhat.com,
chenridong@huawei.com, hare@suse.de, kch@nvidia.com,
ming.lei@redhat.com, tom.leiming@gmail.com, steve@abita.co,
sean@ashe.io, chjohnst@gmail.com, neelx@suse.com,
mproche@gmail.com, nick.lange@gmail.com,
marco.crivellari@suse.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
Subject: Re: [PATCH v12 05/13] blk-mq: add blk_mq_{online|possible}_queue_affinity
Date: Tue, 28 Apr 2026 14:53:43 +0200 [thread overview]
Message-ID: <c4927a2b-c18d-42ce-8a60-d6d388155671@flourine.local> (raw)
In-Reply-To: <20260427153416.MeVS8yxF@linutronix.de>
On Mon, Apr 27, 2026 at 05:34:16PM +0200, Sebastian Andrzej Siewior wrote:
> Which driver uses cpu_possible_mask? This mask is assigned at boot time
> once the kernel figured how many CPUs are possible based on ACPI or
> whatever the system uses. This mask does not change.
>
> I only see drivers/scsi/lpfc/lpfc_init.c using it. Looking at
> cpu_possible_mask might not be the right thing. It is usually the same
> thing as "online" except on system where ACPI thinks that something
> could be added via hotplug _or_ if the admin shuts down a CPU via
> cpuhotplug _or_ boots with less (there a command line option for
> that).
These HBAs are used on PowerPC which supports lpar (CPUs can be added
during runtime) I am told it's properly the only driver which is caring
about this type configuration, thus a bit of an odd ball.
> In case cpu_possible_mask != cpu_online_mask the intention is to
> allocate memory and setup irqs for the offline CPUs?
I can't answer this. The lpfc driver has several strategies implemented
how it spreads its resources.
next prev parent reply other threads:[~2026-04-28 12:53 UTC|newest]
Thread overview: 29+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-04-22 18:52 [PATCH v12 00/13] blk: honor isolcpus configuration Aaron Tomlin
2026-04-22 18:52 ` [PATCH v12 01/13] scsi: aacraid: use block layer helpers to calculate num of queues Aaron Tomlin
2026-05-05 18:42 ` Aaron Tomlin
2026-04-22 18:52 ` [PATCH v12 02/13] lib/group_cpus: remove dead !SMP code Aaron Tomlin
2026-04-27 15:21 ` Sebastian Andrzej Siewior
2026-04-29 23:32 ` Aaron Tomlin
2026-04-22 18:52 ` [PATCH v12 03/13] lib/group_cpus: Add group_mask_cpus_evenly() Aaron Tomlin
2026-04-22 18:52 ` [PATCH v12 04/13] genirq/affinity: Add cpumask to struct irq_affinity Aaron Tomlin
2026-05-05 20:40 ` Aaron Tomlin
2026-04-22 18:52 ` [PATCH v12 05/13] blk-mq: add blk_mq_{online|possible}_queue_affinity Aaron Tomlin
2026-04-27 15:34 ` Sebastian Andrzej Siewior
2026-04-28 12:53 ` Daniel Wagner [this message]
2026-04-29 7:15 ` Hannes Reinecke
2026-05-05 20:55 ` Aaron Tomlin
2026-04-22 18:52 ` [PATCH v12 06/13] nvme-pci: use block layer helpers to constrain queue affinity Aaron Tomlin
2026-05-05 19:47 ` Aaron Tomlin
2026-04-22 18:52 ` [PATCH v12 07/13] scsi: Use " Aaron Tomlin
2026-04-22 18:52 ` [PATCH v12 08/13] virtio: blk/scsi: use " Aaron Tomlin
2026-04-22 18:52 ` [PATCH v12 09/13] isolation: Introduce io_queue isolcpus type Aaron Tomlin
2026-04-22 18:52 ` [PATCH v12 10/13] blk-mq: use hk cpus only when isolcpus=io_queue is enabled Aaron Tomlin
2026-05-02 21:25 ` Aaron Tomlin
2026-04-22 18:52 ` [PATCH v12 11/13] blk-mq: prevent offlining hk CPUs with associated online isolated CPUs Aaron Tomlin
2026-04-22 18:52 ` [PATCH v12 12/13] genirq/affinity: Restrict managed IRQ affinity to housekeeping CPUs Aaron Tomlin
2026-04-22 18:52 ` [PATCH v12 13/13] docs: add io_queue flag to isolcpus Aaron Tomlin
2026-04-27 10:55 ` [PATCH v12 00/13] blk: honor isolcpus configuration Florian Bezdeka
2026-04-28 13:08 ` Daniel Wagner
2026-04-29 21:01 ` Florian Bezdeka
2026-04-30 12:09 ` Daniel Wagner
2026-04-30 15:45 ` Jan Kiszka
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