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

[Gavin Shan]

On 9/20/23 18:01, 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(-)
> 

Reviewed-by: Gavin Shan <gshan at redhat.com>
Tested-by: Gavin Shan <gshan at redhat.com>

> 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;
>   	}