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x86: Increase NR_IRQS and nr_irqs 

I have a system with lots of igb and ixgbe, when iov/vf are
enabled for them, we hit the limit of 3064.

when system has 20 pcie installed, and one card has 2
functions, and one function needs 64 msi-x,
 may need 20 * 2 * 64 = 2560 for msi-x

but if iov and vf are enabled
 may need 20 * 2 * 64 * 3 = 7680 for msi-x
assume system with 5 ioapic, nr_irqs_gsi will be 120.

NR_CPUS = 512, and nr_cpu_ids = 128
will have NR_IRQS = 256 + 512 * 64 = 33024
will have nr_irqs = 120 + 8 * 128 + 120 * 64 = 8824

When SPARSE_IRQ is not set, there is no increase with kernel data
size.

when NR_CPUS=128, and SPARSE_IRQ is set:
   text		   data	    bss		   dec		 hex	filename
21837444	4216564	12480736	38534744	24bfe58	vmlinux.before
21837442	4216580	12480736	38534758	24bfe66	vmlinux.after
when NR_CPUS=4096, and SPARSE_IRQ is set
   text		   data	    bss		   dec		 hex	filename
21878619	5610244	13415392	40904255	270263f	vmlinux.before
21878617	5610244	13415392	40904253	270263d	vmlinux.after

Signed-off-by: Yinghai Lu <yinghai@kernel.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
LKML-Reference: <4B398ECD.1080506@kernel.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
This commit is contained in:
Yinghai Lu 2009-12-28 21:08:29 -08:00 committed by Ingo Molnar
parent 6b7b284958
commit 9959c888a3
2 changed files with 7 additions and 7 deletions
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12
arch/x86/include/asm/irq_vectors.h
View File

@ -154,21 +154,21 @@ static inline int invalid_vm86_irq(int irq)
#define NR_IRQS_LEGACY 16
#define CPU_VECTOR_LIMIT ( 8 * NR_CPUS )
#define IO_APIC_VECTOR_LIMIT ( 32 * MAX_IO_APICS )
#ifdef CONFIG_X86_IO_APIC
# ifdef CONFIG_SPARSE_IRQ
# define CPU_VECTOR_LIMIT (64 * NR_CPUS)
# define NR_IRQS \
(CPU_VECTOR_LIMIT > IO_APIC_VECTOR_LIMIT ? \
(NR_VECTORS + CPU_VECTOR_LIMIT) : \
(NR_VECTORS + IO_APIC_VECTOR_LIMIT))
# else
# if NR_CPUS < MAX_IO_APICS
# define NR_IRQS (NR_VECTORS + 4*CPU_VECTOR_LIMIT)
# else
# define NR_IRQS (NR_VECTORS + IO_APIC_VECTOR_LIMIT)
# endif
# define CPU_VECTOR_LIMIT (32 * NR_CPUS)
# define NR_IRQS \
(CPU_VECTOR_LIMIT < IO_APIC_VECTOR_LIMIT ? \
(NR_VECTORS + CPU_VECTOR_LIMIT) : \
(NR_VECTORS + IO_APIC_VECTOR_LIMIT))
# endif
#else /* !CONFIG_X86_IO_APIC: */
# define NR_IRQS NR_IRQS_LEGACY

2
arch/x86/kernel/apic/io_apic.c
View File

@ -3840,7 +3840,7 @@ int __init arch_probe_nr_irqs(void)
/*
* for MSI and HT dyn irq
*/
nr += nr_irqs_gsi * 16;
nr += nr_irqs_gsi * 64;
#endif
if (nr < nr_irqs)
nr_irqs = nr;