linux-kernel - RE: [PATCH] genirq: Increase the number of interrupters

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Date:   Mon, 27 Jun 2022 04:53:45 +0000
From:   George Cherian <gcherian@...vell.com>
To:     David Laight <David.Laight@...LAB.COM>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
CC:     Sunil Kovvuri Goutham <sgoutham@...vell.com>,
        "tglx@...utronix.de" <tglx@...utronix.de>
Subject: RE: [PATCH] genirq: Increase the number of interrupters



> -----Original Message-----
> From: David Laight <David.Laight@...LAB.COM>
> Sent: Thursday, June 23, 2022 4:48 PM
> To: George Cherian <gcherian@...vell.com>; linux-kernel@...r.kernel.org
> Cc: Sunil Kovvuri Goutham <sgoutham@...vell.com>; tglx@...utronix.de
> Subject: RE: [PATCH] genirq: Increase the number of interrupters
> From: George Cherian
> > Sent: 23 June 2022 04:16
> >
> > Currently the maximum number of interrupters is capped at 8260 (64 +
> > 8196) in most of the architectures were CONFIG_SPARSE_IRQ is selected.
> > This upper limit is not sufficient for couple of existing SoC's from
> > Marvell.
> > For eg: Octeon TX2 series of processors support a maximum of 32K
> > interrupters.
> >
> > Bump up the upper limit from 8196 to 65536.
> 
> This seems to add 7kB of static data to the kernel just on the off chance that
> some sparse interrupt numbers are large.
> 
> 	David
> 
How about adding another CONFIG_SPARSE_IRQ_EXTENDED to increase the count?

-George
> >
> > Signed-off-by: George Cherian <george.cherian@...vell.com>
> > ---
> >  kernel/irq/internals.h | 2 +-
> >  1 file changed, 1 insertion(+), 1 deletion(-)
> >
> > diff --git a/kernel/irq/internals.h b/kernel/irq/internals.h index
> > f09c60393e559..9bb42757d4afc 100644
> > --- a/kernel/irq/internals.h
> > +++ b/kernel/irq/internals.h
> > @@ -12,7 +12,7 @@
> >  #include <linux/sched/clock.h>
> >
> >  #ifdef CONFIG_SPARSE_IRQ
> > -# define IRQ_BITMAP_BITS	(NR_IRQS + 8196)
> > +# define IRQ_BITMAP_BITS	(NR_IRQS + 65536)
> >  #else
> >  # define IRQ_BITMAP_BITS	NR_IRQS
> >  #endif
> > --
> > 2.25.1
> 
> -
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