From 6004e1b7effcbb385a6b7c790e4b8008682cf679 Mon Sep 17 00:00:00 2001 From: James Cleverdon Date: Sat, 5 Nov 2005 17:25:53 +0100 Subject: [PATCH] i386/x86-64: Share interrupt vectors when there is a large number of interrupt sources Here's a patch that builds on Natalie Protasevich's IRQ compression patch and tries to work for MPS boots as well as ACPI. It is meant for a 4-node IBM x460 NUMA box, which was dying because it had interrupt pins with GSI numbers > NR_IRQS and thus overflowed irq_desc. The problem is that this system has 270 GSIs (which are 1:1 mapped with I/O APIC RTEs) and an 8-node box would have 540. This is much bigger than NR_IRQS (224 for both i386 and x86_64). Also, there aren't enough vectors to go around. There are about 190 usable vectors, not counting the reserved ones and the unused vectors at 0x20 to 0x2F. So, my patch attempts to compress the GSI range and share vectors by sharing IRQs. Cc: "Protasevich, Natalie" Signed-off-by: Andi Kleen Signed-off-by: Linus Torvalds --- include/asm-x86_64/desc.h | 3 +++ include/asm-x86_64/mpspec.h | 3 ++- 2 files changed, 5 insertions(+), 1 deletion(-) (limited to 'include/asm-x86_64') diff --git a/include/asm-x86_64/desc.h b/include/asm-x86_64/desc.h index 68ac3c62fe3..1a3d380f9d5 100644 --- a/include/asm-x86_64/desc.h +++ b/include/asm-x86_64/desc.h @@ -98,16 +98,19 @@ static inline void _set_gate(void *adr, unsigned type, unsigned long func, unsig static inline void set_intr_gate(int nr, void *func) { + BUG_ON((unsigned)nr > 0xFF); _set_gate(&idt_table[nr], GATE_INTERRUPT, (unsigned long) func, 0, 0); } static inline void set_intr_gate_ist(int nr, void *func, unsigned ist) { + BUG_ON((unsigned)nr > 0xFF); _set_gate(&idt_table[nr], GATE_INTERRUPT, (unsigned long) func, 0, ist); } static inline void set_system_gate(int nr, void *func) { + BUG_ON((unsigned)nr > 0xFF); _set_gate(&idt_table[nr], GATE_INTERRUPT, (unsigned long) func, 3, 0); } diff --git a/include/asm-x86_64/mpspec.h b/include/asm-x86_64/mpspec.h index f267e10c023..6b375384f5c 100644 --- a/include/asm-x86_64/mpspec.h +++ b/include/asm-x86_64/mpspec.h @@ -157,7 +157,8 @@ struct mpc_config_lintsrc */ #define MAX_MP_BUSSES 256 -#define MAX_IRQ_SOURCES 256 +/* Each PCI slot may be a combo card with its own bus. 4 IRQ pins per slot. */ +#define MAX_IRQ_SOURCES (MAX_MP_BUSSES * 4) enum mp_bustype { MP_BUS_ISA = 1, MP_BUS_EISA, -- cgit v1.2.3-70-g09d2