From: Thomas Gleixner <tglx@linutronix.de>
To: Ming Lei <ming.lei@redhat.com>
Cc: Christoph Hellwig <hch@lst.de>,
Bjorn Helgaas <helgaas@kernel.org>, Jens Axboe <axboe@kernel.dk>,
linux-block@vger.kernel.org, Sagi Grimberg <sagi@grimberg.me>,
linux-nvme@lists.infradead.org, linux-kernel@vger.kernel.org,
linux-pci@vger.kernel.org
Subject: Re: [PATCH 2/5] genirq/affinity: allow driver to setup managed IRQ's affinity
Date: Sun, 10 Feb 2019 17:30:41 +0100 (CET) [thread overview]
Message-ID: <alpine.DEB.2.21.1902101723400.8784@nanos.tec.linutronix.de> (raw)
In-Reply-To: <20190125095347.17950-3-ming.lei@redhat.com>
Ming,
On Fri, 25 Jan 2019, Ming Lei wrote:
> This patch introduces callback of .setup_affinity into 'struct
> irq_affinity', so that:
Please see Documentation/process/submitting-patches.rst. Search for 'This
patch' ....
>
> 1) allow drivers to customize the affinity for managed IRQ, for
> example, now NVMe has special requirement for read queues & poll
> queues
That's nothing new and already handled today.
> 2) 6da4b3ab9a6e9 ("genirq/affinity: Add support for allocating interrupt sets")
> makes pci_alloc_irq_vectors_affinity() a bit difficult to use for
> allocating interrupt sets: 'max_vecs' is required to same with 'min_vecs'.
So it's a bit difficult, but you fail to explain why it's not sufficient.
> With this patch, driver can implement their own .setup_affinity to
> customize the affinity, then the above thing can be solved easily.
Well, I don't really understand what is solved easily and you are merily
describing the fact that the new callback allows drivers to customize
something. What's the rationale? If it's just the 'bit difficult' part,
then what is the reason for not making the core functionality easier to use
instead of moving stuff into driver space again?
NVME is not special and all this achieves is that all drivers writers will
claim that their device is special and needs its own affinity setter
routine. The whole point of having the generic code is to exactly avoid
that. If it has shortcomings, then they need to be addressed, but not
worked around with random driver callbacks.
Thanks,
tglx
next prev parent reply other threads:[~2019-02-10 16:30 UTC|newest]
Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-01-25 9:53 [PATCH 0/5] genirq/affinity: introduce .setup_affinity to support allocating interrupt sets Ming Lei
2019-01-25 9:53 ` [PATCH 1/5] genirq/affinity: move allocation of 'node_to_cpumask' to irq_build_affinity_masks Ming Lei
2019-02-07 22:02 ` Bjorn Helgaas
2019-01-25 9:53 ` [PATCH 2/5] genirq/affinity: allow driver to setup managed IRQ's affinity Ming Lei
2019-02-07 22:21 ` Bjorn Helgaas
2019-02-10 9:22 ` Ming Lei
2019-02-10 16:30 ` Thomas Gleixner [this message]
2019-02-11 3:54 ` Ming Lei
2019-02-11 14:39 ` Bjorn Helgaas
2019-02-11 22:38 ` Thomas Gleixner
2019-02-12 11:17 ` Ming Lei
2019-01-25 9:53 ` [PATCH 3/5] genirq/affinity: introduce irq_build_affinity() Ming Lei
2019-01-25 9:53 ` [PATCH 4/5] nvme-pci: simplify nvme_setup_irqs() via .setup_affinity callback Ming Lei
2019-02-10 16:39 ` Thomas Gleixner
2019-02-11 3:58 ` Ming Lei
2019-02-10 18:49 ` Thomas Gleixner
2019-02-11 4:09 ` Ming Lei
2019-01-25 9:53 ` [PATCH 5/5] genirq/affinity: remove support for allocating interrupt sets Ming Lei
2019-02-07 22:22 ` Bjorn Helgaas
2019-01-25 9:56 ` [PATCH 0/5] genirq/affinity: introduce .setup_affinity to support " Ming Lei
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