powerpc: Reduce footprint of irq_stat

PowerPC is currently using asm-generic/hardirq.h which statically allocates an
NR_CPUS irq_stat array. Switch to an arch specific implementation which uses
per cpu data:

On a kernel with NR_CPUS=1024, this saves quite a lot of memory:

   text    data     bss      dec         hex    filename
8767938 2944132 1636796 13348866         cbb002 vmlinux.baseline
8767779 2944260 1505724 13217763         c9afe3 vmlinux.irq_cpustat

A saving of around 128kB.

Signed-off-by: Anton Blanchard <anton@samba.org>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>

diff --git a/arch/powerpc/include/asm/hardirq.h b/arch/powerpc/include/asm/hardirq.h
index fb3c05a0cbbf11e48551550270d354b0e0eb7dc1..9bf3467581b1a0e6b14938aba8b080616d9bf962 100644 (file)
--- a/arch/powerpc/include/asm/hardirq.h
+++ b/arch/powerpc/include/asm/hardirq.h
@@ -1 +1,22 @@
-#include <asm-generic/hardirq.h>
+#ifndef _ASM_POWERPC_HARDIRQ_H
+#define _ASM_POWERPC_HARDIRQ_H
+
+#include <linux/threads.h>
+#include <linux/irq.h>
+
+typedef struct {
+       unsigned int __softirq_pending;
+} ____cacheline_aligned irq_cpustat_t;
+
+DECLARE_PER_CPU_SHARED_ALIGNED(irq_cpustat_t, irq_stat);
+
+#define __ARCH_IRQ_STAT
+
+#define local_softirq_pending()        __get_cpu_var(irq_stat).__softirq_pending
+
+static inline void ack_bad_irq(unsigned int irq)
+{
+       printk(KERN_CRIT "unexpected IRQ trap at vector %02x\n", irq);
+}
+
+#endif /* _ASM_POWERPC_HARDIRQ_H */

diff --git a/arch/powerpc/kernel/irq.c b/arch/powerpc/kernel/irq.c
index 9040330b0530f1dae82f75c4f5b5218495e7c4f1..c6ac5583672a7b73f3733cc5f389688ad4985296 100644 (file)
--- a/arch/powerpc/kernel/irq.c
+++ b/arch/powerpc/kernel/irq.c
@@ -73,6 +73,9 @@
 #define CREATE_TRACE_POINTS
 #include <asm/trace.h>
 
+DEFINE_PER_CPU_SHARED_ALIGNED(irq_cpustat_t, irq_stat);
+EXPORT_PER_CPU_SYMBOL(irq_stat);
+
 int __irq_offset_value;
 static int ppc_spurious_interrupts;