From 0b8f1efad30bd58f89961b82dfe68b9edf8fd2ac Mon Sep 17 00:00:00 2001 From: Yinghai Lu Date: Fri, 5 Dec 2008 18:58:31 -0800 Subject: sparse irq_desc[] array: core kernel and x86 changes Impact: new feature Problem on distro kernels: irq_desc[NR_IRQS] takes megabytes of RAM with NR_CPUS set to large values. The goal is to be able to scale up to much larger NR_IRQS value without impacting the (important) common case. To solve this, we generalize irq_desc[NR_IRQS] to an (optional) array of irq_desc pointers. When CONFIG_SPARSE_IRQ=y is used, we use kzalloc_node to get irq_desc, this also makes the IRQ descriptors NUMA-local (to the site that calls request_irq()). This gets rid of the irq_cfg[] static array on x86 as well: irq_cfg now uses desc->chip_data for x86 to store irq_cfg. Signed-off-by: Yinghai Lu Signed-off-by: Ingo Molnar --- include/linux/kernel_stat.h | 14 +++++++++++++- 1 file changed, 13 insertions(+), 1 deletion(-) (limited to 'include/linux/kernel_stat.h') diff --git a/include/linux/kernel_stat.h b/include/linux/kernel_stat.h index 4a145caeee07..4ee4b3d2316f 100644 --- a/include/linux/kernel_stat.h +++ b/include/linux/kernel_stat.h @@ -28,7 +28,9 @@ struct cpu_usage_stat { struct kernel_stat { struct cpu_usage_stat cpustat; - unsigned int irqs[NR_IRQS]; +#ifndef CONFIG_SPARSE_IRQ + unsigned int irqs[NR_IRQS]; +#endif }; DECLARE_PER_CPU(struct kernel_stat, kstat); @@ -39,6 +41,10 @@ DECLARE_PER_CPU(struct kernel_stat, kstat); extern unsigned long long nr_context_switches(void); +#ifndef CONFIG_SPARSE_IRQ +#define kstat_irqs_this_cpu(irq) \ + (kstat_this_cpu.irqs[irq]) + struct irq_desc; static inline void kstat_incr_irqs_this_cpu(unsigned int irq, @@ -46,11 +52,17 @@ static inline void kstat_incr_irqs_this_cpu(unsigned int irq, { kstat_this_cpu.irqs[irq]++; } +#endif + +#ifndef CONFIG_SPARSE_IRQ static inline unsigned int kstat_irqs_cpu(unsigned int irq, int cpu) { return kstat_cpu(cpu).irqs[irq]; } +#else +extern unsigned int kstat_irqs_cpu(unsigned int irq, int cpu); +#endif /* * Number of interrupts per specific IRQ source, since bootup -- cgit v1.2.2