From: Thomas Gleixner <tglx@linutronix.de>
To: Christoph Hellwig <hch@lst.de>
Cc: Jens Axboe <axboe@kernel.dk>, Keith Busch <keith.busch@intel.com>,
linux-nvme@lists.infradead.org, linux-block@vger.kernel.org,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH 3/8] genirq/affinity: factor out a irq_affinity_set helper
Date: Fri, 16 Jun 2017 14:00:28 +0200 (CEST) [thread overview]
Message-ID: <alpine.DEB.2.20.1706161357380.2254@nanos> (raw)
In-Reply-To: <alpine.DEB.2.20.1706161306070.2254@nanos>
On Fri, 16 Jun 2017, Thomas Gleixner wrote:
> On Sat, 3 Jun 2017, Christoph Hellwig wrote:
> > +bool irq_affinity_set(int irq, struct irq_desc *desc, const cpumask_t *mask)
> > +{
> > + struct irq_data *data = irq_desc_get_irq_data(desc);
> > + struct irq_chip *chip = irq_data_get_irq_chip(data);
> > + bool ret = false;
> > +
> > + if (!irq_can_move_pcntxt(data) && chip->irq_mask)
> > + chip->irq_mask(data);
> > +
> > + if (chip->irq_set_affinity) {
> > + if (chip->irq_set_affinity(data, mask, true) == -ENOSPC)
> > + pr_crit("IRQ %d set affinity failed because there are no available vectors. The device assigned to this IRQ is unstable.\n", irq);
> > + ret = true;
> > + }
> > +
> > + /*
> > + * We unmask if the irq was not marked masked by the core code.
> > + * That respects the lazy irq disable behaviour.
> > + */
> > + if (!irq_can_move_pcntxt(data) &&
> > + !irqd_irq_masked(data) && chip->irq_unmask)
> > + chip->irq_unmask(data);
>
> There is another issue with this. Nothing updates the affinity mask in
> irq_desc, when we just invoke the chip callback. Let me have a look.
Indeed. So that magic you do in the next patches (the hotplug callbacks)
only work proper for affinity masks with a single cpu set.
The problem is that we don't have a distinction between the 'possible'
(e.g. set by /proc/irq/affinity) and the effective affinity mask.
Needs more thought.
Thanks,
tglx
next prev parent reply other threads:[~2017-06-16 12:00 UTC|newest]
Thread overview: 30+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-06-03 14:03 spread MSI(-X) vectors to all possible CPUs V2 Christoph Hellwig
2017-06-03 14:03 ` [PATCH 1/8] genirq: allow assigning affinity to present but not online CPUs Christoph Hellwig
2017-06-04 15:14 ` Sagi Grimberg
2017-06-17 23:21 ` Thomas Gleixner
2017-06-03 14:03 ` [PATCH 2/8] genirq: move pending helpers to internal.h Christoph Hellwig
2017-06-04 15:15 ` Sagi Grimberg
2017-06-03 14:03 ` [PATCH 3/8] genirq/affinity: factor out a irq_affinity_set helper Christoph Hellwig
2017-06-04 15:15 ` Sagi Grimberg
2017-06-16 10:23 ` Thomas Gleixner
2017-06-16 11:08 ` Thomas Gleixner
2017-06-16 12:00 ` Thomas Gleixner [this message]
2017-06-17 23:14 ` Thomas Gleixner
2017-06-03 14:03 ` [PATCH 4/8] genirq/affinity: assign vectors to all present CPUs Christoph Hellwig
2017-06-04 15:17 ` Sagi Grimberg
2017-06-03 14:04 ` [PATCH 5/8] genirq/affinity: update CPU affinity for CPU hotplug events Christoph Hellwig
2017-06-16 10:26 ` Thomas Gleixner
2017-06-16 10:29 ` Thomas Gleixner
2017-06-03 14:04 ` [PATCH 6/8] blk-mq: include all present CPUs in the default queue mapping Christoph Hellwig
2017-06-04 15:11 ` Sagi Grimberg
2017-06-03 14:04 ` [PATCH 7/8] blk-mq: create hctx for each present CPU Christoph Hellwig
2017-06-04 15:11 ` Sagi Grimberg
2017-06-07 9:10 ` Ming Lei
2017-06-07 19:06 ` Christoph Hellwig
2017-06-08 2:28 ` Ming Lei
2017-06-07 22:04 ` Omar Sandoval
2017-06-08 6:58 ` Christoph Hellwig
2017-06-03 14:04 ` [PATCH 8/8] nvme: allocate queues for all possible CPUs Christoph Hellwig
2017-06-04 15:13 ` Sagi Grimberg
2017-06-16 6:48 ` spread MSI(-X) vectors to all possible CPUs V2 Christoph Hellwig
2017-06-16 7:28 ` Thomas Gleixner
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