[PATCH] genirq: Increase the number of interrupters

[PATCH] genirq: Increase the number of interrupters

[George Cherian]

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.

Signed-off-by: George Cherian <george.cherian@marvell.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

RE: [PATCH] genirq: Increase the number of interrupters

[David Laight]

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

> 
> Signed-off-by: George Cherian <george.cherian@marvell.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

-
Registered Address Lakeside, Bramley Road, Mount Farm, Milton Keynes, MK1 1PT, UK
Registration No: 1397386 (Wales)

RE: [PATCH] genirq: Increase the number of interrupters

[George Cherian]

> -----Original Message-----
> From: David Laight <David.Laight@ACULAB.COM>
> Sent: Thursday, June 23, 2022 4:48 PM
> To: George Cherian <gcherian@marvell.com>; linux-kernel@vger.kernel.org
> Cc: Sunil Kovvuri Goutham <sgoutham@marvell.com>; tglx@linutronix.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@marvell.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
> 
> -
> Registered Address Lakeside, Bramley Road, Mount Farm, Milton Keynes,
> MK1 1PT, UK Registration No: 1397386 (Wales)