linux-kernel - Re: [PATCH v3 3/4] mm/damon/ops-common: Refactor to use {pte|pmd}p_clear_young

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Message-Id: <20230602215449.107659-1-sj@kernel.org>
Date:   Fri,  2 Jun 2023 21:54:49 +0000
From:   SeongJae Park <sj@...nel.org>
To:     Ryan Roberts <ryan.roberts@....com>
Cc:     Andrew Morton <akpm@...ux-foundation.org>,
        SeongJae Park <sj@...nel.org>,
        Christoph Hellwig <hch@...radead.org>,
        "Matthew Wilcox (Oracle)" <willy@...radead.org>,
        "Kirill A. Shutemov" <kirill.shutemov@...ux.intel.com>,
        Lorenzo Stoakes <lstoakes@...il.com>,
        Uladzislau Rezki <urezki@...il.com>, Zi Yan <ziy@...dia.com>,
        Yu Zhao <yuzhao@...gle.com>, Mike Rapoport <rppt@...nel.org>,
        linux-kernel@...r.kernel.org, linux-mm@...ck.org,
        damon@...ts.linux.dev
Subject: Re: [PATCH v3 3/4] mm/damon/ops-common: Refactor to use {pte|pmd}p_clear_young_notify()

Hi Ryan,

On Fri, 2 Jun 2023 10:29:48 +0100 Ryan Roberts <ryan.roberts@....com> wrote:

> With the fix in place to atomically test and clear young on ptes and
> pmds, simplify the code to handle the clearing for both the primary mmu
> and the mmu notifier with a single API call.
> 
> Signed-off-by: Ryan Roberts <ryan.roberts@....com>

Reviewed-by: SeongJae Park <sj@...nel.org>


Thanks,
SJ

> ---
>  mm/damon/ops-common.c | 22 ++--------------------
>  1 file changed, 2 insertions(+), 20 deletions(-)
> 
> diff --git a/mm/damon/ops-common.c b/mm/damon/ops-common.c
> index acc264b97903..d4ab81229136 100644
> --- a/mm/damon/ops-common.c
> +++ b/mm/damon/ops-common.c
> @@ -39,21 +39,12 @@ struct folio *damon_get_folio(unsigned long pfn)
>  
>  void damon_ptep_mkold(pte_t *pte, struct vm_area_struct *vma, unsigned long addr)
>  {
> -	bool referenced = false;
>  	struct folio *folio = damon_get_folio(pte_pfn(*pte));
>  
>  	if (!folio)
>  		return;
>  
> -	if (ptep_test_and_clear_young(vma, addr, pte))
> -		referenced = true;
> -
> -#ifdef CONFIG_MMU_NOTIFIER
> -	if (mmu_notifier_clear_young(vma->vm_mm, addr, addr + PAGE_SIZE))
> -		referenced = true;
> -#endif /* CONFIG_MMU_NOTIFIER */
> -
> -	if (referenced)
> +	if (ptep_clear_young_notify(vma, addr, pte))
>  		folio_set_young(folio);
>  
>  	folio_set_idle(folio);
> @@ -63,21 +54,12 @@ void damon_ptep_mkold(pte_t *pte, struct vm_area_struct *vma, unsigned long addr
>  void damon_pmdp_mkold(pmd_t *pmd, struct vm_area_struct *vma, unsigned long addr)
>  {
>  #ifdef CONFIG_TRANSPARENT_HUGEPAGE
> -	bool referenced = false;
>  	struct folio *folio = damon_get_folio(pmd_pfn(*pmd));
>  
>  	if (!folio)
>  		return;
>  
> -	if (pmdp_test_and_clear_young(vma, addr, pmd))
> -		referenced = true;
> -
> -#ifdef CONFIG_MMU_NOTIFIER
> -	if (mmu_notifier_clear_young(vma->vm_mm, addr, addr + HPAGE_PMD_SIZE))
> -		referenced = true;
> -#endif /* CONFIG_MMU_NOTIFIER */
> -
> -	if (referenced)
> +	if (pmdp_clear_young_notify(vma, addr, pmd))
>  		folio_set_young(folio);
>  
>  	folio_set_idle(folio);
> -- 
> 2.25.1
> 
>