Messages in this thread | | | Subject | Re: [PATCH 4/4] genirq: use irq's affinity for threaded irq with IRQF_RESCUE_THREAD | From | John Garry <> | Date | Fri, 6 Sep 2019 09:50:26 +0100 |
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On 27/08/2019 09:53, Ming Lei wrote: > In case of IRQF_RESCUE_THREAD, the threaded handler is only used to > handle interrupt when IRQ flood comes, use irq's affinity for this thread > so that scheduler may select other not too busy CPUs for handling the > interrupt. > > Cc: Long Li <longli@microsoft.com> > Cc: Ingo Molnar <mingo@redhat.com>, > Cc: Peter Zijlstra <peterz@infradead.org> > Cc: Keith Busch <keith.busch@intel.com> > Cc: Jens Axboe <axboe@fb.com> > Cc: Christoph Hellwig <hch@lst.de> > Cc: Sagi Grimberg <sagi@grimberg.me> > Cc: John Garry <john.garry@huawei.com> > Cc: Thomas Gleixner <tglx@linutronix.de> > Cc: Hannes Reinecke <hare@suse.com> > Cc: linux-nvme@lists.infradead.org > Cc: linux-scsi@vger.kernel.org > Signed-off-by: Ming Lei <ming.lei@redhat.com>
> --- > kernel/irq/manage.c | 13 ++++++++++++- > 1 file changed, 12 insertions(+), 1 deletion(-) > > diff --git a/kernel/irq/manage.c b/kernel/irq/manage.c > index 1566abbf50e8..03bc041348b7 100644 > --- a/kernel/irq/manage.c > +++ b/kernel/irq/manage.c > @@ -968,7 +968,18 @@ irq_thread_check_affinity(struct irq_desc *desc, struct irqaction *action) > if (cpumask_available(desc->irq_common_data.affinity)) { > const struct cpumask *m; > > - m = irq_data_get_effective_affinity_mask(&desc->irq_data); > + /* > + * Managed IRQ's affinity is setup gracefull on MUNA locality,
gracefully
> + * also if IRQF_RESCUE_THREAD is set, interrupt flood has been > + * triggered, so ask scheduler to run the thread on CPUs > + * specified by this interrupt's affinity. > + */
Hi Ming,
> + if ((action->flags & IRQF_RESCUE_THREAD) && > + irqd_affinity_is_managed(&desc->irq_data))
This doesn't look to solve the other issue I reported - that being that we handle the interrupt in a threaded handler natively, and the hard irq+threaded handler fully occupies the cpu, limiting throughput.
So can we expand the scope to cover that scenario also? I don't think that it’s right to solve that separately. So if we're continuing this approach, can we add separate judgment for spreading the cpumask for the threaded part?
Thanks, John
> + m = desc->irq_common_data.affinity; > + else > + m = irq_data_get_effective_affinity_mask( > + &desc->irq_data); > cpumask_copy(mask, m); > } else { > valid = false; >
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