Re: [PATCH v2 01/34] mm: Add PAGE_TYPE_OP folio functions

From: Mike Rapoport <rppt@kernel.org>
To: "Vishal Moola (Oracle)" <vishal.moola@gmail.com>
Cc: Andrew Morton <akpm@linux-foundation.org>,
	Matthew Wilcox <willy@infradead.org>,
	linux-mm@kvack.org, linux-arch@vger.kernel.org,
	linux-arm-kernel@lists.infradead.org, linux-csky@vger.kernel.org,
	linux-hexagon@vger.kernel.org, loongarch@lists.linux.dev,
	linux-m68k@lists.linux-m68k.org, linux-mips@vger.kernel.org,
	linux-openrisc@vger.kernel.org, linuxppc-dev@lists.ozlabs.org,
	linux-riscv@lists.infradead.org, linux-s390@vger.kernel.org,
	linux-sh@vger.kernel.org, sparclinux@vger.kernel.org,
	linux-um@lists.infradead.org, xen-devel@lists.xenproject.org,
	kvm@vger.kernel.org
Subject: Re: [PATCH v2 01/34] mm: Add PAGE_TYPE_OP folio functions
Date: Thu, 25 May 2023 11:55:55 +0300	[thread overview]
Message-ID: <20230525085555.GV4967@kernel.org> (raw)
In-Reply-To: <20230501192829.17086-2-vishal.moola@gmail.com>

Hi,

On Mon, May 01, 2023 at 12:27:56PM -0700, Vishal Moola (Oracle) wrote:
> No folio equivalents for page type operations have been defined, so
> define them for later folio conversions.

Can you please elaborate why would we need folios for page table descriptors? 

> Also changes the Page##uname macros to take in const struct page* since
> we only read the memory here.
> 
> Signed-off-by: Vishal Moola (Oracle) <vishal.moola@gmail.com>
> ---
>  include/linux/page-flags.h | 20 ++++++++++++++++++--
>  1 file changed, 18 insertions(+), 2 deletions(-)
> 
> diff --git a/include/linux/page-flags.h b/include/linux/page-flags.h
> index 1c68d67b832f..607b495d1b57 100644
> --- a/include/linux/page-flags.h
> +++ b/include/linux/page-flags.h
> @@ -902,6 +902,8 @@ static inline bool is_page_hwpoison(struct page *page)
>  
>  #define PageType(page, flag)						\
>  	((page->page_type & (PAGE_TYPE_BASE | flag)) == PAGE_TYPE_BASE)
> +#define folio_test_type(folio, flag)					\
> +	((folio->page.page_type & (PAGE_TYPE_BASE | flag)) == PAGE_TYPE_BASE)
>  
>  static inline int page_type_has_type(unsigned int page_type)
>  {
> @@ -914,20 +916,34 @@ static inline int page_has_type(struct page *page)
>  }
>  
>  #define PAGE_TYPE_OPS(uname, lname)					\
> -static __always_inline int Page##uname(struct page *page)		\
> +static __always_inline int Page##uname(const struct page *page)		\
>  {									\
>  	return PageType(page, PG_##lname);				\
>  }									\
> +static __always_inline int folio_test_##lname(const struct folio *folio)\
> +{									\
> +	return folio_test_type(folio, PG_##lname);			\
> +}									\
>  static __always_inline void __SetPage##uname(struct page *page)		\
>  {									\
>  	VM_BUG_ON_PAGE(!PageType(page, 0), page);			\
>  	page->page_type &= ~PG_##lname;					\
>  }									\
> +static __always_inline void __folio_set_##lname(struct folio *folio)	\
> +{									\
> +	VM_BUG_ON_FOLIO(!folio_test_type(folio, 0), folio);		\
> +	folio->page.page_type &= ~PG_##lname;				\
> +}									\
>  static __always_inline void __ClearPage##uname(struct page *page)	\
>  {									\
>  	VM_BUG_ON_PAGE(!Page##uname(page), page);			\
>  	page->page_type |= PG_##lname;					\
> -}
> +}									\
> +static __always_inline void __folio_clear_##lname(struct folio *folio)	\
> +{									\
> +	VM_BUG_ON_FOLIO(!folio_test_##lname(folio), folio);		\
> +	folio->page.page_type |= PG_##lname;				\
> +}									\
>  
>  /*
>   * PageBuddy() indicates that the page is free and in the buddy system
> -- 
> 2.39.2
> 
> 

-- 
Sincerely yours,
Mike.

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