powerpc: Increase NR_IRQS Kconfig maximum to 32768
With dynamic irq descriptors the overhead of a large NR_IRQS is much lower
than it used to be. With more MSI-X capable adapters and drivers exploiting
multiple vectors we may as well allow the user to increase it beyond the
current maximum of 512.
32768 seems large enough that we'd never have to bump it again (although I bet
my prediction is horribly wrong). It boot tests OK and the vmlinux footprint
increase is only around 500kB due to:
struct irq_map_entry irq_map[NR_IRQS];
We format /proc/interrupts correctly with the previous changes:
CPU0 CPU1 CPU2 CPU3 CPU4 CPU5
286: 0 0 0 0 0 0
516: 0 0 0 0 0 0
16689: 1833 0 0 0 0 0
17157: 0 0 0 0 0 0
17158: 319 0 0 0 0 0
25092: 0 0 0 0 0 0
Signed-off-by: Anton Blanchard <anton@samba.org>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
diff --git a/arch/powerpc/Kconfig b/arch/powerpc/Kconfig
index ba3948c..bf15e7b 100644
--- a/arch/powerpc/Kconfig
+++ b/arch/powerpc/Kconfig
@@ -58,7 +58,7 @@
config NR_IRQS
int "Number of virtual interrupt numbers"
- range 32 512
+ range 32 32768
default "512"
help
This defines the number of virtual interrupt numbers the kernel