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From: "Kirill A. Shutemov" <kirill@shutemov.name>
To: Wei Yang <richardw.yang@linux.intel.com>
Cc: akpm@linux-foundation.org, kirill.shutemov@linux.intel.com,
	linux-mm@kvack.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH 1/2] mm/page_vma_mapped: use PMD_SIZE instead of calculating it
Date: Thu, 28 Nov 2019 11:32:55 +0300
Message-ID: <20191128083255.ab5rwj7gvktwunik@box.shutemov.name> (raw)
In-Reply-To: <20191128010321.21730-1-richardw.yang@linux.intel.com>

On Thu, Nov 28, 2019 at 09:03:20AM +0800, Wei Yang wrote:
> At this point, we are sure page is PageTransHuge, which means
> hpage_nr_pages is HPAGE_PMD_NR.
> 
> This is safe to use PMD_SIZE instead of calculating it.
> 
> Signed-off-by: Wei Yang <richardw.yang@linux.intel.com>
> ---
>  mm/page_vma_mapped.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/mm/page_vma_mapped.c b/mm/page_vma_mapped.c
> index eff4b4520c8d..76e03650a3ab 100644
> --- a/mm/page_vma_mapped.c
> +++ b/mm/page_vma_mapped.c
> @@ -223,7 +223,7 @@ bool page_vma_mapped_walk(struct page_vma_mapped_walk *pvmw)
>  			if (pvmw->address >= pvmw->vma->vm_end ||
>  			    pvmw->address >=
>  					__vma_address(pvmw->page, pvmw->vma) +
> -					hpage_nr_pages(pvmw->page) * PAGE_SIZE)
> +					PMD_SIZE)
>  				return not_found(pvmw);
>  			/* Did we cross page table boundary? */
>  			if (pvmw->address % PMD_SIZE == 0) {

It is dubious cleanup. Maybe page_size(pvmw->page) instead? It will not
break if we ever get PUD THP pages.

-- 
 Kirill A. Shutemov


  parent reply index

Thread overview: 15+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-11-28  1:03 Wei Yang
2019-11-28  1:03 ` [PATCH 2/2] mm/page_vma_mapped: page table boundary is already guaranteed Wei Yang
2019-11-28  8:31   ` Kirill A. Shutemov
2019-11-28 21:09     ` Wei Yang
2019-11-28 22:39       ` Matthew Wilcox
2019-11-29  8:30         ` Wei Yang
2019-11-29 11:18           ` Matthew Wilcox
2019-12-02  6:53             ` Wei Yang
2019-11-28  8:32 ` Kirill A. Shutemov [this message]
2019-11-28 21:22   ` [PATCH 1/2] mm/page_vma_mapped: use PMD_SIZE instead of calculating it Wei Yang
2019-12-02  8:03     ` Kirill A. Shutemov
2019-12-02  8:54       ` Wei Yang
2019-12-02 22:21       ` Wei Yang
2019-12-03  9:47         ` Kirill A. Shutemov
2019-12-03 15:14           ` Wei Yang

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