Re: [Xen-devel] [PATCH v2 08/10] xen/arm: Release timer interrupts when CPU is hot-unplugged

[Julien Grall <julien.grall@xxxxxxx>]

On 25/04/18 11:34, Mirela Simonovic wrote:
> Hi Julien,
>
> You may have missed this one. Should we try using notifiers here as well?
Yes, I assumed this was implied by my comments previously, so I skipped 
the patch. Sorry for that.
Cheers,

> Thanks,
> Mirela
>
> On Fri, Apr 20, 2018 at 2:25 PM, Mirela Simonovic
> <mirela.simonovic@xxxxxxxxxx> wrote:
> > When a CPU is hot-unplugged timer interrupts have to be released
> > in order to free the memory that was allocated when the interrupts
> > were requested (using request_irq()). The request_irq is called
> > for each timer interrupt when the CPU gets hotplugged
> > (start_secondary->init_timer_interrupt->request_irq).
> >
> > Signed-off-by: Mirela Simonovic <mirela.simonovic@xxxxxxxxxx>
> >
> > ---
> > CC: Stefano Stabellini <sstabellini@xxxxxxxxxx>
> > CC: Julien Grall <julien.grall@xxxxxxx>
> > ---
> >   xen/arch/arm/smpboot.c     | 1 +
> >   xen/arch/arm/time.c        | 7 +++++++
> >   xen/include/asm-arm/time.h | 6 ++++++
> >   3 files changed, 14 insertions(+)
> >
> > diff --git a/xen/arch/arm/smpboot.c b/xen/arch/arm/smpboot.c
> > index 449fefc77d..b4ed479dc6 100644
> > --- a/xen/arch/arm/smpboot.c
> > +++ b/xen/arch/arm/smpboot.c
> > @@ -386,6 +386,7 @@ void __cpu_disable(void)
> >        * in respective init interrupt functions called from start_secondary)
> >        */
> >       deinit_maintenance_interrupt();
> > +    deinit_timer_interrupt();
> >
> >       /* It's now safe to remove this processor from the online map */
> >       cpumask_clear_cpu(cpu, &cpu_online_map);
> > diff --git a/xen/arch/arm/time.c b/xen/arch/arm/time.c
> > index c11fcfeadd..1d9dc16f89 100644
> > --- a/xen/arch/arm/time.c
> > +++ b/xen/arch/arm/time.c
> > @@ -312,6 +312,13 @@ void init_timer_interrupt(void)
> >       check_timer_irq_cfg(timer_irq[TIMER_PHYS_NONSECURE_PPI], "NS-physical");
> >   }
> >
> > +void deinit_timer_interrupt(void)
> > +{
> > +    release_irq(timer_irq[TIMER_HYP_PPI], NULL);
> > +    release_irq(timer_irq[TIMER_VIRT_PPI], NULL);
> > +    release_irq(timer_irq[TIMER_PHYS_NONSECURE_PPI], NULL);
> > +}
> > +
> >   /* Wait a set number of microseconds */
> >   void udelay(unsigned long usecs)
> >   {
> > diff --git a/xen/include/asm-arm/time.h b/xen/include/asm-arm/time.h
> > index 5b9a31de91..6fa4c47532 100644
> > --- a/xen/include/asm-arm/time.h
> > +++ b/xen/include/asm-arm/time.h
> > @@ -34,6 +34,12 @@ unsigned int timer_get_irq(enum timer_ppi ppi);
> >   /* Set up the timer interrupt on this CPU */
> >   extern void init_timer_interrupt(void);
> >
> > +/*
> > + * Revert actions done in init_timer_interrupt that are required to properly
> > + * disable this CPU.
> > + */
> > +extern void deinit_timer_interrupt(void);
> > +
> >   /* Counter value at boot time */
> >   extern uint64_t boot_count;
> >
> > --
> > 2.13.0
--
Julien Grall

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