Commit 23d0b8b0 authored Oct 04, 2006 by Eric W. Biederman Committed by Linus Torvalds Oct 04, 2006

[PATCH] genirq: irq: generalize the check for HARDIRQ_BITS



This patch adds support for systems that cannot receive every interrupt on a
single cpu simultaneously, in the check to see if we have enough HARDIRQ_BITS.

MAX_HARDIRQS_PER_CPU becomes the count of the maximum number of hardare
generated interrupts per cpu.

On architectures that support per cpu interrupt delivery this can be a
significant space savings and scalability bonus.

This patch adds support for systems that cannot receive every interrupt on

Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Rajesh Shah <rajesh.shah@intel.com>
Cc: Andi Kleen <ak@muc.de>
Cc: "Protasevich, Natalie" <Natalie.Protasevich@UNISYS.com>
Cc: "Luck, Tony" <tony.luck@intel.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

parent 323a01c5

include/asm-x86_64/hardirq.h

+3 −0

Original line number	Diff line number	Diff line
		@@ -6,6 +6,9 @@
		#include <asm/pda.h>
		#include <asm/apic.h>

		/* We can have at most NR_VECTORS irqs routed to a cpu at a time */
		#define MAX_HARDIRQS_PER_CPU NR_VECTORS

		#define __ARCH_IRQ_STAT 1

		#define local_softirq_pending() read_pda(__softirq_pending)

include/linux/hardirq.h

+6 −1

Original line number	Diff line number	Diff line
		@@ -28,11 +28,16 @@

		#ifndef HARDIRQ_BITS
		#define HARDIRQ_BITS 12

		#ifndef MAX_HARDIRQS_PER_CPU
		#define MAX_HARDIRQS_PER_CPU NR_IRQS
		#endif

		/*
		* The hardirq mask has to be large enough to have space for potentially
		* all IRQ sources in the system nesting on a single CPU.
		*/
		#if (1 << HARDIRQ_BITS) < NR_IRQS
		#if (1 << HARDIRQ_BITS) < MAX_HARDIRQS_PER_CPU
		# error HARDIRQ_BITS is too low!
		#endif
		#endif