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, Keith Busch <keith.busch@intel.com>
Subject: Re: [PATCH V2 2/4] genirq/affinity: add new callback for caculating set vectors
Date: Tue, 12 Feb 2019 14:37:57 +0100 (CET) [thread overview]
Message-ID: <alpine.DEB.2.21.1902121435330.3710@nanos.tec.linutronix.de> (raw)
In-Reply-To: <20190212130439.14501-3-ming.lei@redhat.com>
On Tue, 12 Feb 2019, Ming Lei wrote:
> 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'.
Nice changelog!
> * Spread on present CPUs starting from affd->pre_vectors. If we
> * have multiple sets, build each sets affinity mask separately.
> */
> - nr_sets = affd->nr_sets;
> - if (!nr_sets) {
> + if (affd->calc_sets) {
> + affd->calc_sets(affd, nvecs);
> + nr_sets = affd->nr_sets;
> + } else if (!affd->nr_sets) {
> nr_sets = 1;
> affd->set_vectors[0] = affvecs;
> - }
> + } else
> + nr_sets = affd->nr_sets;
Lacks curly brackets.
Aside of that it might make sense to get rid of the local variable, but
that should be done in patch 1 if at all. No strong opinion though.
Thanks,
tglx
next prev parent reply other threads:[~2019-02-12 13:38 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-02-12 13:04 [PATCH V2 0/4] genirq/affinity: add .calc_sets for improving IRQ allocation & spread Ming Lei
2019-02-12 13:04 ` [PATCH V2 1/4] genirq/affinity: store irq set vectors in 'struct irq_affinity' Ming Lei
2019-02-12 13:35 ` Thomas Gleixner
2019-02-12 13:04 ` [PATCH V2 2/4] genirq/affinity: add new callback for caculating set vectors Ming Lei
2019-02-12 13:37 ` Thomas Gleixner [this message]
2019-02-12 13:04 ` [PATCH V2 3/4] nvme-pci: avoid irq allocation retrying via .calc_sets Ming Lei
2019-02-12 15:49 ` Keith Busch
2019-02-12 13:04 ` [PATCH V2 4/4] genirq/affinity: Document .calc_sets as required in case of multiple sets Ming Lei
2019-02-12 23:42 ` Bjorn Helgaas
2019-02-12 13:42 ` [PATCH V2 0/4] genirq/affinity: add .calc_sets for improving IRQ allocation & spread Thomas Gleixner
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