[PATCH 1/2] arm64: tlbflush: Rename MAX_TLBI_OPS

[Will Deacon]

On Wed, Sep 20, 2023 at 08:01:32AM +0000, Oliver Upton wrote:
> Perhaps unsurprisingly, I-cache invalidations suffer from performance
> issues similar to TLB invalidations on certain systems. TLB and I-cache
> maintenance all result in DVM on the mesh, which is where the real
> bottleneck lies.
> 
> Rename the heuristic to point the finger at DVM, such that it may be
> reused for limiting I-cache invalidations.
> 
> Signed-off-by: Oliver Upton <oliver.upton at linux.dev>
> ---
>  arch/arm64/include/asm/tlbflush.h | 8 ++++----
>  1 file changed, 4 insertions(+), 4 deletions(-)
> 
> diff --git a/arch/arm64/include/asm/tlbflush.h b/arch/arm64/include/asm/tlbflush.h
> index b149cf9f91bc..3431d37e5054 100644
> --- a/arch/arm64/include/asm/tlbflush.h
> +++ b/arch/arm64/include/asm/tlbflush.h
> @@ -333,7 +333,7 @@ static inline void arch_tlbbatch_flush(struct arch_tlbflush_unmap_batch *batch)
>   * This is meant to avoid soft lock-ups on large TLB flushing ranges and not
>   * necessarily a performance improvement.
>   */
> -#define MAX_TLBI_OPS	PTRS_PER_PTE
> +#define MAX_DVM_OPS	PTRS_PER_PTE
>  
>  /*
>   * __flush_tlb_range_op - Perform TLBI operation upon a range
> @@ -413,12 +413,12 @@ static inline void __flush_tlb_range(struct vm_area_struct *vma,
>  
>  	/*
>  	 * When not uses TLB range ops, we can handle up to
> -	 * (MAX_TLBI_OPS - 1) pages;
> +	 * (MAX_DVM_OPS - 1) pages;
>  	 * When uses TLB range ops, we can handle up to
>  	 * (MAX_TLBI_RANGE_PAGES - 1) pages.
>  	 */
>  	if ((!system_supports_tlb_range() &&
> -	     (end - start) >= (MAX_TLBI_OPS * stride)) ||
> +	     (end - start) >= (MAX_DVM_OPS * stride)) ||
>  	    pages >= MAX_TLBI_RANGE_PAGES) {
>  		flush_tlb_mm(vma->vm_mm);
>  		return;
> @@ -451,7 +451,7 @@ static inline void flush_tlb_kernel_range(unsigned long start, unsigned long end
>  {
>  	unsigned long addr;
>  
> -	if ((end - start) > (MAX_TLBI_OPS * PAGE_SIZE)) {
> +	if ((end - start) > (MAX_DVM_OPS * PAGE_SIZE)) {
>  		flush_tlb_all();
>  		return;
>  	}
> -- 
> 2.42.0.459.ge4e396fd5e-goog

Acked-by: Will Deacon <will at kernel.org>

Will