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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>
This commit is contained in:
Anton Blanchard 2010-01-31 20:30:23 +00:00 committed by Benjamin Herrenschmidt
parent 8d3d50bf19
commit 8c007bfdf1
2 changed files with 25 additions and 1 deletions
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23
arch/powerpc/include/asm/hardirq.h
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@ -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 */

3
arch/powerpc/kernel/irq.c
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@ -73,6 +73,9 @@
#define CREATE_TRACE_POINTS #define CREATE_TRACE_POINTS
#include <asm/trace.h> #include <asm/trace.h>
DEFINE_PER_CPU_SHARED_ALIGNED(irq_cpustat_t, irq_stat);
EXPORT_PER_CPU_SYMBOL(irq_stat);
int __irq_offset_value; int __irq_offset_value;
static int ppc_spurious_interrupts; static int ppc_spurious_interrupts;