* John David Anglin <dave.anglin@xxxxxxxx>:
> We only need to switch contexts when prev != next, and we don't need to disable interrupts
> to do the check.
>
> Signed-off-by: John David Anglin <dave.anglin@xxxxxxxx>
>
>
> diff --git a/arch/parisc/include/asm/mmu_context.h b/arch/parisc/include/asm/mmu_context.h
> index a81226257878..b1dc6e3f0dd0 100644
> --- a/arch/parisc/include/asm/mmu_context.h
> +++ b/arch/parisc/include/asm/mmu_context.h
> @@ -49,26 +49,19 @@ static inline void load_context(mm_context_t context)
> mtctl(__space_to_prot(context), 8);
> }
>
> -static inline void switch_mm_irqs_off(struct mm_struct *prev,
> +static inline void switch_mm(struct mm_struct *prev,
> struct mm_struct *next, struct task_struct *tsk)
> {
> + unsigned long flags;
> +
> if (prev != next) {
> + local_irq_save(flags);
> mtctl(__pa(next->pgd), 25);
> load_context(next->context);
> + local_irq_restore(flags);
> }
> }
>
> -static inline void switch_mm(struct mm_struct *prev,
> - struct mm_struct *next, struct task_struct *tsk)
> -{
> - unsigned long flags;
> -
> - local_irq_save(flags);
> - switch_mm_irqs_off(prev, next, tsk);
> - local_irq_restore(flags);
> -}
> -#define switch_mm_irqs_off switch_mm_irqs_off
> -
> #define deactivate_mm(tsk,mm) do { } while (0)
>
> static inline void activate_mm(struct mm_struct *prev, struct mm_struct *next)
Instead I'd then suggest the patch below.
The if-clause in switch_mm_irqs_off() will then probably be optimized
away by the compiler.
diff --git a/arch/parisc/include/asm/mmu_context.h b/arch/parisc/include/asm/mmu_context.h
index a812262..e4a6570 100644
--- a/arch/parisc/include/asm/mmu_context.h
+++ b/arch/parisc/include/asm/mmu_context.h
@@ -63,6 +63,9 @@ static inline void switch_mm(struct mm_struct *prev,
{
unsigned long flags;
+ if (prev == next)
+ return;
+
local_irq_save(flags);
switch_mm_irqs_off(prev, next, tsk);
local_irq_restore(flags);
--
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