Re: [RFC PATCH v6 3/3] arm: fix a migrating irq bug when hotplug cpu

[Yang Yingliang]

On 2015/10/22 17:26, Russell King - ARM Linux wrote:
> On Wed, Oct 21, 2015 at 09:29:08PM +0100, Russell King - ARM Linux wrote:
> > On Wed, Oct 21, 2015 at 01:47:49PM +0200, Geert Uytterhoeven wrote:
> > > On Thu, Sep 24, 2015 at 11:32 AM, Yang Yingliang
> > > <yangyingliang@xxxxxxxxxx> wrote:
> > > > When cpu is disabled, all irqs will be migratged to another cpu.
> > > > In some cases, a new affinity is different, the old affinity need
> > > > to be updated and if irq_set_affinity's return value is IRQ_SET_MASK_OK_DONE,
> > > > the old affinity can not be updated. Fix it by using irq_do_set_affinity.
> > > >
> > > > And migrating interrupts is a core code matter, so use the generic
> > > > function irq_migrate_all_off_this_cpu() to migrate interrupts in
> > > > kernel/irq/migration.c.
> > > >
> > > > Cc: Jiang Liu <jiang.liu@xxxxxxxxxxxxxxx>
> > > > Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
> > > > Cc: Marc Zyngier <marc.zyngier@xxxxxxx>
> > > > Cc: Mark Rutland <mark.rutland@xxxxxxx>
> > > > Cc: Will Deacon <will.deacon@xxxxxxx>
> > > > Cc: Russell King - ARM Linux <linux@xxxxxxxxxxxxxxxx>
> > > > Cc: Hanjun Guo <hanjun.guo@xxxxxxxxxx>
> > > > Signed-off-by: Yang Yingliang <yangyingliang@xxxxxxxxxx>
> > > > ---
> > > >   arch/arm/Kconfig           |  1 +
> > > >   arch/arm/include/asm/irq.h |  1 -
> > > >   arch/arm/kernel/irq.c      | 62 ----------------------------------------------
> > > >   arch/arm/kernel/smp.c      |  2 +-
> > > >   4 files changed, 2 insertions(+), 64 deletions(-)
> > > >
> > > > diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig
> > > > index 72ad724..bffba78 100644
> > > > --- a/arch/arm/Kconfig
> > > > +++ b/arch/arm/Kconfig
> > > > @@ -1492,6 +1492,7 @@ config NR_CPUS
> > > >   config HOTPLUG_CPU
> > > >          bool "Support for hot-pluggable CPUs"
> > > >          depends on SMP
> > > > +       select GENERIC_IRQ_MIGRATION
> > >
> > > This causes the following warnings during s2ram on r8a7791/koelsch
> > > (dual-core CA15):
> >
> > Thanks for the report.  I'll see what tonight's boot run says for my
> > platforms.  Hopefully, the author of these changes can help debug
> > this.
>
> What's happened is that:
>
> -	c = irq_data_get_irq_chip(d);
> -	if (!c->irq_set_affinity)
> -		pr_debug("IRQ%u: unable to set affinity\n", d->irq);
>
> has become:
>
> +	c = irq_data_get_irq_chip(d);
> +	if (!c->irq_set_affinity) {
> +		pr_warn_ratelimited("IRQ%u: unable to set affinity\n", d->irq);
>
> which makes things more noisy.
>
> This is a change that was not described in the commit message for the
> patch Thomas merged.

I described it in v2 cover letter and kept the change history in v6
cover letter. There is no comment on the change when patch the was
reviewing in v2, so I thought it's ok and I kept the change in the
next versions.

Need I send a patch to the Thomas branch to revert the change ?

Thanks,
Yang


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