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Date:   Tue, 12 Feb 2019 14:42:04 +0100 (CET)
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,
        LKML <linux-kernel@vger.kernel.org>, linux-pci@vger.kernel.org,
        Keith Busch <keith.busch@intel.com>
Subject: Re: [PATCH V2 0/4] genirq/affinity: add .calc_sets for improving
 IRQ allocation & spread
In-Reply-To: <20190212130439.14501-1-ming.lei@redhat.com>
Message-ID: <alpine.DEB.2.21.1902121438310.3710@nanos.tec.linutronix.de>
References: <20190212130439.14501-1-ming.lei@redhat.com>
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On Tue, 12 Feb 2019, Ming Lei wrote:

> Hi,
> 
> Currently pre-caculated set vectors are provided by driver for
> allocating & spread vectors. This way only works when drivers passes
> same 'max_vecs' and 'min_vecs' to pci_alloc_irq_vectors_affinity(),
> also requires driver to retry the allocating & spread.
> 
> As Bjorn and Keith mentioned, the current usage & interface for irq sets
> is a bit awkward because the retrying should have been avoided by providing
> one resonable 'min_vecs'. However, if 'min_vecs' isn't same with
> 'max_vecs', number of the allocated vectors is unknown before calling
> pci_alloc_irq_vectors_affinity(), then each set's vectors can't be
> pre-caculated.
> 
> Add a new callback of .calc_sets into 'struct irq_affinity' so that
> driver can caculate set vectors after IRQ vector is allocated and
> before spread IRQ vectors. Add 'priv' so that driver may retrieve
> its private data via the 'struct irq_affinity'.
> 
> 
> V2:
> 	- add .calc_sets instead of .setup_affinity() which is easy to
> 	be abused by drivers

This looks really well done. If you can address the minor nitpicks, then
this is good to go, unless someone has objections.

Thanks,

	tglx