softirq: allocate less vectors

We don't need whole 32 of them, only NR_SOFTIRQS.
Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

include/linux/interrupt.h

@@ -252,6 +252,8 @@ enum
 	HRTIMER_SOFTIRQ,
 #endif
 	RCU_SOFTIRQ, 	/* Preferable RCU should always be the last softirq */
+
+	NR_SOFTIRQS
 };
 
 /* softirq mask and active fields moved to irq_cpustat_t in

kernel/softirq.c

@@ -46,7 +46,7 @@ irq_cpustat_t irq_stat[NR_CPUS] ____cacheline_aligned;
 EXPORT_SYMBOL(irq_stat);
 #endif
 
-static struct softirq_action softirq_vec[32] __cacheline_aligned_in_smp;
+static struct softirq_action softirq_vec[NR_SOFTIRQS] __cacheline_aligned_in_smp;
 
 static DEFINE_PER_CPU(struct task_struct *, ksoftirqd);