linux-kernel - Re: [PATCH v4 22/36] s390: Implement the new page table range API

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Date:   Wed, 15 Mar 2023 12:10:34 +0200
From:   Mike Rapoport <rppt@...nel.org>
To:     "Matthew Wilcox (Oracle)" <willy@...radead.org>
Cc:     linux-arch@...r.kernel.org, linux-mm@...ck.org,
        linux-kernel@...r.kernel.org,
        Gerald Schaefer <gerald.schaefer@...ux.ibm.com>,
        Heiko Carstens <hca@...ux.ibm.com>,
        Vasily Gorbik <gor@...ux.ibm.com>,
        Alexander Gordeev <agordeev@...ux.ibm.com>,
        Christian Borntraeger <borntraeger@...ux.ibm.com>,
        Sven Schnelle <svens@...ux.ibm.com>, linux-s390@...r.kernel.org
Subject: Re: [PATCH v4 22/36] s390: Implement the new page table range API

On Wed, Mar 15, 2023 at 05:14:30AM +0000, Matthew Wilcox (Oracle) wrote:
> Add set_ptes() and update_mmu_cache_range().
> 
> Signed-off-by: Matthew Wilcox (Oracle) <willy@...radead.org>
> Reviewed-by: Gerald Schaefer <gerald.schaefer@...ux.ibm.com>
> Cc: Heiko Carstens <hca@...ux.ibm.com>
> Cc: Vasily Gorbik <gor@...ux.ibm.com>
> Cc: Alexander Gordeev <agordeev@...ux.ibm.com>
> Cc: Christian Borntraeger <borntraeger@...ux.ibm.com>
> Cc: Sven Schnelle <svens@...ux.ibm.com>
> Cc: linux-s390@...r.kernel.org

Acked-by: Mike Rapoport (IBM) <rppt@...nel.org>

> ---
>  arch/s390/include/asm/pgtable.h | 33 ++++++++++++++++++++++++---------
>  1 file changed, 24 insertions(+), 9 deletions(-)
> 
> diff --git a/arch/s390/include/asm/pgtable.h b/arch/s390/include/asm/pgtable.h
> index c1f6b46ec555..fea678c67e51 100644
> --- a/arch/s390/include/asm/pgtable.h
> +++ b/arch/s390/include/asm/pgtable.h
> @@ -50,6 +50,7 @@ void arch_report_meminfo(struct seq_file *m);
>   * tables contain all the necessary information.
>   */
>  #define update_mmu_cache(vma, address, ptep)     do { } while (0)
> +#define update_mmu_cache_range(vma, addr, ptep, nr)	do { } while (0)
>  #define update_mmu_cache_pmd(vma, address, ptep) do { } while (0)
>  
>  /*
> @@ -1319,20 +1320,34 @@ pgprot_t pgprot_writecombine(pgprot_t prot);
>  pgprot_t pgprot_writethrough(pgprot_t prot);
>  
>  /*
> - * Certain architectures need to do special things when PTEs
> - * within a page table are directly modified.  Thus, the following
> - * hook is made available.
> + * Set multiple PTEs to consecutive pages with a single call.  All PTEs
> + * are within the same folio, PMD and VMA.
>   */
> -static inline void set_pte_at(struct mm_struct *mm, unsigned long addr,
> -			      pte_t *ptep, pte_t entry)
> +static inline void set_ptes(struct mm_struct *mm, unsigned long addr,
> +			      pte_t *ptep, pte_t entry, unsigned int nr)
>  {
>  	if (pte_present(entry))
>  		entry = clear_pte_bit(entry, __pgprot(_PAGE_UNUSED));
> -	if (mm_has_pgste(mm))
> -		ptep_set_pte_at(mm, addr, ptep, entry);
> -	else
> -		set_pte(ptep, entry);
> +	if (mm_has_pgste(mm)) {
> +		for (;;) {
> +			ptep_set_pte_at(mm, addr, ptep, entry);
> +			if (--nr == 0)
> +				break;
> +			ptep++;
> +			entry = __pte(pte_val(entry) + PAGE_SIZE);
> +			addr += PAGE_SIZE;
> +		}
> +	} else {
> +		for (;;) {
> +			set_pte(ptep, entry);
> +			if (--nr == 0)
> +				break;
> +			ptep++;
> +			entry = __pte(pte_val(entry) + PAGE_SIZE);
> +		}
> +	}
>  }
> +#define set_ptes set_ptes
>  
>  /*
>   * Conversion functions: convert a page and protection to a page entry,
> -- 
> 2.39.2
> 
> 

-- 
Sincerely yours,
Mike.