lkml.org 
[lkml]   [2015]   [Oct]   [1]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: CPU hotplug and chained interrupts on x86
On Thu, 1 Oct 2015, Thomas Gleixner wrote:
> On Thu, 1 Oct 2015, Mika Westerberg wrote:
> > Now if I plug/unplug the card I may get few interrupts to CPU0 but rest
> > of the interrupts never happen. Probably because IO-APIC forwards them
> > to the lowest priority CPU which is offline at this point.
> >
> > There is following check in fixup_irqs():
> >
> > if (!irq_has_action(irq) || irqd_is_per_cpu(data) ||
> > cpumask_subset(affinity, cpu_online_mask)) {
> > raw_spin_unlock(&desc->lock);
> > continue;
> > }
> >
> > If an interrupt is requested by a driver it will force new affinity and
> > everything works fine. However if the interrupt is chained (it does not
> > have ->action) this is skipped and the current affinity remains.
> >
> > We could detect here if the interrupt is chained but there seems to be
> > no easy way to determine it currently so we would need to add a new flag
> > to desc->status_use_accessors that gets set in __irq_do_set_handler()
> > when is_chained is 1.
>
> Either there or in irq_data. Need to look at it in detail.

desc->status_use_accessors is the place where this wants to go.

Thanks,

tglx


\
 
 \ /
  Last update: 2015-10-02 00:21    [W:0.045 / U:0.028 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site