Re: [RFC 11/20] mm/tlb: remove arch-specific tlb_start/end_vma()

Peter Zijlstra
2021-02-01T12:10:49Z

On Sat, Jan 30, 2021 at 04:11:23PM -0800, Nadav Amit wrote:

> diff --git a/include/asm-generic/tlb.h b/include/asm-generic/tlb.h
> index 427bfcc6cdec..b97136b7010b 100644
> --- a/include/asm-generic/tlb.h
> +++ b/include/asm-generic/tlb.h
> @@ -334,8 +334,8 @@ static inline void __tlb_reset_range(struct mmu_gather *tlb)
>
> #ifdef CONFIG_MMU_GATHER_NO_RANGE
>
> -#if defined(tlb_flush) || defined(tlb_start_vma) || defined(tlb_end_vma)
> -#error MMU_GATHER_NO_RANGE relies on default tlb_flush(), tlb_start_vma() and tlb_end_vma()
> +#if defined(tlb_flush)
> +#error MMU_GATHER_NO_RANGE relies on default tlb_flush()
> #endif
>
> /*
> @@ -362,10 +362,6 @@ static inline void tlb_end_vma(struct mmu_gather *tlb, struct vm_area_struct *vm
>
> #ifndef tlb_flush
>
> -#if defined(tlb_start_vma) || defined(tlb_end_vma)
> -#error Default tlb_flush() relies on default tlb_start_vma() and tlb_end_vma()
> -#endif

#ifdef CONFIG_ARCH_WANT_AGGRESSIVE_TLB_FLUSH_BATCHING
#error ....
#endif

goes here...

> static inline void tlb_end_vma(struct mmu_gather *tlb, struct vm_area_struct *vma)
> {
> if (tlb->fullmm)
> return;
>
> + if (IS_ENABLED(CONFIG_ARCH_WANT_AGGRESSIVE_TLB_FLUSH_BATCHING))
> + return;

Also, can you please stick to the CONFIG_MMU_GATHER_* namespace?

I also don't think AGRESSIVE_FLUSH_BATCHING quite captures what it does.
How about:

CONFIG_MMU_GATHER_NO_PER_VMA_FLUSH

?