powerpc: Make NR_IRQS a CONFIG option (551b81f2) · Commits · 戴 / test

The irq_desc array consumes quite a lot of space, and for systems that don't need or can't have 512 irqs it's just wasted space. The first 16 are reserved for ISA, so the minimum of 32 is really 16 - and no one has asked for more than 512 so leave that as the maximum. Signed-off-by:

Michael Ellerman <michael@ellerman.id.au> Signed-off-by:

Benjamin Herrenschmidt <benh@kernel.crashing.org>

arch/powerpc/Kconfig

+10 −0

Original line number	Diff line number	Diff line
		@@ -56,6 +56,16 @@ config IRQ_PER_CPU
		bool
		default y

		config NR_IRQS
		int "Number of virtual interrupt numbers"
		range 32 512
		default "512"
		help
		This defines the number of virtual interrupt numbers the kernel
		can manage. Virtual interrupt numbers are what you see in
		/proc/interrupts. If you configure your system to have too few,
		drivers will fail to load or worse - handle with care.

		config STACKTRACE_SUPPORT
		bool
		default y

arch/powerpc/include/asm/irq.h

+2 −2

Original line number	Diff line number	Diff line
		@@ -34,8 +34,8 @@ extern atomic_t ppc_n_lost_interrupts;
		*/
		#define NO_IRQ_IGNORE ((unsigned int)-1)

		/* Total number of virq in the platform (make it a CONFIG_* option ? */
		#define NR_IRQS 512
		/* Total number of virq in the platform */
		#define NR_IRQS CONFIG_NR_IRQS

		/* Number of irqs reserved for the legacy controller */
		#define NUM_ISA_INTERRUPTS 16

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