From a619e59c075c66e530a88e57b45bb0417e2f4fff Mon Sep 17 00:00:00 2001 From: Benjamin Herrenschmidt Date: Mon, 24 Jul 2017 14:28:02 +1000 Subject: powerpc/mm: Optimize detection of thread local mm's Instead of comparing the whole CPU mask every time, let's keep a counter of how many bits are set in the mask. Thus testing for a local mm only requires testing if that counter is 1 and the current CPU bit is set in the mask. Signed-off-by: Benjamin Herrenschmidt Signed-off-by: Michael Ellerman --- arch/powerpc/include/asm/mmu_context.h | 9 +++++++++ 1 file changed, 9 insertions(+) (limited to 'arch/powerpc/include/asm/mmu_context.h') diff --git a/arch/powerpc/include/asm/mmu_context.h b/arch/powerpc/include/asm/mmu_context.h index fb99c27bbf5e..2338abf6101a 100644 --- a/arch/powerpc/include/asm/mmu_context.h +++ b/arch/powerpc/include/asm/mmu_context.h @@ -96,6 +96,14 @@ static inline void switch_mm_pgdir(struct task_struct *tsk, struct mm_struct *mm) { } #endif +#ifdef CONFIG_PPC_BOOK3S_64 +static inline void inc_mm_active_cpus(struct mm_struct *mm) +{ + atomic_inc(&mm->context.active_cpus); +} +#else +static inline void inc_mm_active_cpus(struct mm_struct *mm) { } +#endif /* * switch_mm is the entry point called from the architecture independent @@ -110,6 +118,7 @@ static inline void switch_mm_irqs_off(struct mm_struct *prev, /* Mark this context has been used on the new CPU */ if (!cpumask_test_cpu(smp_processor_id(), mm_cpumask(next))) { cpumask_set_cpu(smp_processor_id(), mm_cpumask(next)); + inc_mm_active_cpus(next); /* * This full barrier orders the store to the cpumask above vs -- cgit