Re: [PATCH v2 3/5] lazy tlb: shoot lazies, a non-refcounting lazy tlb option

On 12/13/20 10:53 PM, Nicholas Piggin wrote: > diff --git a/arch/Kconfig b/arch/Kconfig > index 84faaba66364..e69c974369cc 100644 > --- a/arch/Kconfig > +++ b/arch/Kconfig > @@ -443,9 +443,22 @@ config MMU_LAZY_TLB > config MMU_LAZY_TLB_REFCOUNT > def_bool y > depends on MMU_LAZY_TLB >

[PATCH v2 3/5] lazy tlb: shoot lazies, a non-refcounting lazy tlb option

On big systems, the mm refcount can become highly contented when doing a lot of context switching with threaded applications (particularly switching between the idle thread and an application thread). Abandoning lazy tlb slows switching down quite a bit in the important user->idle->user cases, so