From: Anton Blanchard <anton@samba.org>
This appeared in the ia64 port and sounds like a good idea. Potentially
avoid an atomic operation in switch_mm.
---
include/asm-ppc64/mmu_context.h | 4 +++-
1 files changed, 3 insertions(+), 1 deletion(-)
diff -puN include/asm-ppc64/mmu_context.h~ppc64-flushfix include/asm-ppc64/mmu_context.h
--- 25/include/asm-ppc64/mmu_context.h~ppc64-flushfix 2004-02-21 20:58:14.000000000 -0800
+++ 25-akpm/include/asm-ppc64/mmu_context.h 2004-02-21 20:58:14.000000000 -0800
@@ -156,6 +156,9 @@ static inline void switch_mm(struct mm_s
: : );
#endif /* CONFIG_ALTIVEC */
+ if (!cpu_isset(smp_processor_id(), next->cpu_vm_mask))
+ cpu_set(smp_processor_id(), next->cpu_vm_mask);
+
/* No need to flush userspace segments if the mm doesnt change */
if (prev == next)
return;
@@ -164,7 +167,6 @@ static inline void switch_mm(struct mm_s
flush_slb(tsk, next);
else
flush_stab(tsk, next);
- cpu_set(smp_processor_id(), next->cpu_vm_mask);
}
#define deactivate_mm(tsk,mm) do { } while (0)
_