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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, Hugh Dickins <hughd@google.com>
Subject: Re: [PATCH v4 04/34] pgtable: Create struct ptdesc
Date: Wed, 14 Jun 2023 16:34:51 +0300	[thread overview]
Message-ID: <20230614133451.GC52412@kernel.org> (raw)
In-Reply-To: <20230612210423.18611-5-vishal.moola@gmail.com>

On Mon, Jun 12, 2023 at 02:03:53PM -0700, Vishal Moola (Oracle) wrote:
> Currently, page table information is stored within struct page. As part
> of simplifying struct page, create struct ptdesc for page table
> information.
> 
> Signed-off-by: Vishal Moola (Oracle) <vishal.moola@gmail.com>

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

> ---
>  include/linux/pgtable.h | 51 +++++++++++++++++++++++++++++++++++++++++
>  1 file changed, 51 insertions(+)
> 
> diff --git a/include/linux/pgtable.h b/include/linux/pgtable.h
> index c5a51481bbb9..330de96ebfd6 100644
> --- a/include/linux/pgtable.h
> +++ b/include/linux/pgtable.h
> @@ -975,6 +975,57 @@ static inline void ptep_modify_prot_commit(struct vm_area_struct *vma,
>  #endif /* __HAVE_ARCH_PTEP_MODIFY_PROT_TRANSACTION */
>  #endif /* CONFIG_MMU */
>  
> +
> +/**
> + * struct ptdesc - Memory descriptor for page tables.
> + * @__page_flags: Same as page flags. Unused for page tables.
> + * @pt_list: List of used page tables. Used for s390 and x86.
> + * @_pt_pad_1: Padding that aliases with page's compound head.
> + * @pmd_huge_pte: Protected by ptdesc->ptl, used for THPs.
> + * @_pt_s390_gaddr: Aliases with page's mapping. Used for s390 gmap only.
> + * @pt_mm: Used for x86 pgds.
> + * @pt_frag_refcount: For fragmented page table tracking. Powerpc and s390 only.
> + * @ptl: Lock for the page table.

Do you mind aligning the descriptions by @pt_frag_refcount? I think it'll
be more readable.

> + *
> + * This struct overlays struct page for now. Do not modify without a good
> + * understanding of the issues.
> + */
> +struct ptdesc {
> +	unsigned long __page_flags;
> +
> +	union {
> +		struct list_head pt_list;
> +		struct {
> +			unsigned long _pt_pad_1;
> +			pgtable_t pmd_huge_pte;
> +		};
> +	};
> +	unsigned long _pt_s390_gaddr;
> +
> +	union {
> +		struct mm_struct *pt_mm;
> +		atomic_t pt_frag_refcount;
> +	};
> +
> +#if ALLOC_SPLIT_PTLOCKS
> +	spinlock_t *ptl;
> +#else
> +	spinlock_t ptl;
> +#endif
> +};
> +
> +#define TABLE_MATCH(pg, pt)						\
> +	static_assert(offsetof(struct page, pg) == offsetof(struct ptdesc, pt))
> +TABLE_MATCH(flags, __page_flags);
> +TABLE_MATCH(compound_head, pt_list);
> +TABLE_MATCH(compound_head, _pt_pad_1);
> +TABLE_MATCH(pmd_huge_pte, pmd_huge_pte);
> +TABLE_MATCH(mapping, _pt_s390_gaddr);
> +TABLE_MATCH(pt_mm, pt_mm);
> +TABLE_MATCH(ptl, ptl);
> +#undef TABLE_MATCH
> +static_assert(sizeof(struct ptdesc) <= sizeof(struct page));
> +
>  /*
>   * No-op macros that just return the current protection value. Defined here
>   * because these macros can be used even if CONFIG_MMU is not defined.
> -- 
> 2.40.1
> 
> 

-- 
Sincerely yours,
Mike.

  reply	other threads:[~2023-06-14 13:35 UTC|newest]

Thread overview: 81+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-06-12 21:03 [PATCH v4 00/34] Split ptdesc from struct page Vishal Moola (Oracle)
2023-06-12 21:03 ` [PATCH v4 01/34] mm: Add PAGE_TYPE_OP folio functions Vishal Moola (Oracle)
2023-06-14 13:02   ` Mike Rapoport
2023-06-12 21:03 ` [PATCH v4 02/34] s390: Use _pt_s390_gaddr for gmap address tracking Vishal Moola (Oracle)
2023-06-14 13:14   ` Mike Rapoport
2023-06-12 21:03 ` [PATCH v4 03/34] s390: Use pt_frag_refcount for pagetables Vishal Moola (Oracle)
2023-06-14 13:21   ` Mike Rapoport
2023-06-12 21:03 ` [PATCH v4 04/34] pgtable: Create struct ptdesc Vishal Moola (Oracle)
2023-06-14 13:34   ` Mike Rapoport [this message]
2023-06-15  7:57   ` Hugh Dickins
2023-06-16 20:38     ` Matthew Wilcox
2023-06-16 21:28     ` Vishal Moola
2023-06-16 12:38   ` Jason Gunthorpe
2023-06-20 20:01     ` Vishal Moola
2023-06-20 23:05       ` Jason Gunthorpe
2023-06-20 23:10         ` Vishal Moola
2023-06-12 21:03 ` [PATCH v4 05/34] mm: add utility functions for ptdesc Vishal Moola (Oracle)
2023-06-14 13:48   ` Mike Rapoport
2023-06-12 21:03 ` [PATCH v4 06/34] mm: Convert pmd_pgtable_page() to pmd_ptdesc() Vishal Moola (Oracle)
2023-06-14 13:51   ` Mike Rapoport
2023-06-12 21:03 ` [PATCH v4 07/34] mm: Convert ptlock_alloc() to use ptdescs Vishal Moola (Oracle)
2023-06-14 13:51   ` Mike Rapoport
2023-06-12 21:03 ` [PATCH v4 08/34] mm: Convert ptlock_ptr() " Vishal Moola (Oracle)
2023-06-14 13:52   ` Mike Rapoport
2023-06-12 21:03 ` [PATCH v4 09/34] mm: Convert pmd_ptlock_init() " Vishal Moola (Oracle)
2023-06-14 13:52   ` Mike Rapoport
2023-06-12 21:03 ` [PATCH v4 10/34] mm: Convert ptlock_init() " Vishal Moola (Oracle)
2023-06-14 13:57   ` Mike Rapoport
2023-06-12 21:04 ` [PATCH v4 11/34] mm: Convert pmd_ptlock_free() " Vishal Moola (Oracle)
2023-06-14 13:59   ` Mike Rapoport
2023-06-12 21:04 ` [PATCH v4 12/34] mm: Convert ptlock_free() " Vishal Moola (Oracle)
2023-06-14 13:59   ` Mike Rapoport
2023-06-12 21:04 ` [PATCH v4 13/34] mm: Create ptdesc equivalents for pgtable_{pte,pmd}_page_{ctor,dtor} Vishal Moola (Oracle)
2023-06-14 14:10   ` Mike Rapoport
2023-06-12 21:04 ` [PATCH v4 14/34] powerpc: Convert various functions to use ptdescs Vishal Moola (Oracle)
2023-06-14 14:19   ` Mike Rapoport
2023-06-12 21:04 ` [PATCH v4 15/34] x86: " Vishal Moola (Oracle)
2023-06-14 14:27   ` Mike Rapoport
2023-06-12 21:04 ` [PATCH v4 16/34] s390: Convert various gmap " Vishal Moola (Oracle)
2023-06-14 14:28   ` Mike Rapoport
2023-06-12 21:04 ` [PATCH v4 17/34] s390: Convert various pgalloc " Vishal Moola (Oracle)
2023-06-14 14:46   ` Mike Rapoport
2023-06-12 21:04 ` [PATCH v4 18/34] mm: Remove page table members from struct page Vishal Moola (Oracle)
2023-06-14 14:53   ` Mike Rapoport
2023-06-12 21:04 ` [PATCH v4 19/34] pgalloc: Convert various functions to use ptdescs Vishal Moola (Oracle)
2023-06-14 14:59   ` Mike Rapoport
2023-06-12 21:04 ` [PATCH v4 20/34] arm: " Vishal Moola (Oracle)
2023-06-14 15:03   ` Mike Rapoport
2023-06-12 21:04 ` [PATCH v4 21/34] arm64: " Vishal Moola (Oracle)
2023-06-14 15:05   ` Mike Rapoport
2023-06-14 16:41   ` Catalin Marinas
2023-06-12 21:04 ` [PATCH v4 22/34] csky: Convert __pte_free_tlb() " Vishal Moola (Oracle)
2023-06-14 15:07   ` Mike Rapoport
2023-06-12 21:04 ` [PATCH v4 23/34] hexagon: " Vishal Moola (Oracle)
2023-06-14 15:07   ` Mike Rapoport
2023-06-12 21:04 ` [PATCH v4 24/34] loongarch: Convert various functions " Vishal Moola (Oracle)
2023-06-14 15:09   ` Mike Rapoport
2023-06-12 21:04 ` [PATCH v4 25/34] m68k: " Vishal Moola (Oracle)
2023-06-13  7:28   ` Geert Uytterhoeven
2023-06-14 15:12   ` Mike Rapoport
2023-06-12 21:04 ` [PATCH v4 26/34] mips: " Vishal Moola (Oracle)
2023-06-14 15:16   ` Mike Rapoport
2023-06-12 21:04 ` [PATCH v4 27/34] nios2: Convert __pte_free_tlb() " Vishal Moola (Oracle)
2023-06-13 22:16   ` Dinh Nguyen
2023-06-14  9:30     ` Geert Uytterhoeven
2023-06-14 21:23       ` Dinh Nguyen
2023-06-14 15:16   ` Mike Rapoport
2023-06-12 21:04 ` [PATCH v4 28/34] openrisc: " Vishal Moola (Oracle)
2023-06-14 15:17   ` Mike Rapoport
2023-06-12 21:04 ` [PATCH v4 29/34] riscv: Convert alloc_{pmd, pte}_late() " Vishal Moola (Oracle)
2023-06-14 15:18   ` Mike Rapoport
2023-06-12 21:04 ` [PATCH v4 30/34] sh: Convert pte_free_tlb() " Vishal Moola (Oracle)
2023-06-14 15:19   ` Mike Rapoport
2023-06-12 21:04 ` [PATCH v4 31/34] sparc64: Convert various functions " Vishal Moola (Oracle)
2023-06-14 15:20   ` Mike Rapoport
2023-06-12 21:04 ` [PATCH v4 32/34] sparc: Convert pgtable_pte_page_{ctor, dtor}() to ptdesc equivalents Vishal Moola (Oracle)
2023-06-14 15:20   ` Mike Rapoport
2023-06-12 21:04 ` [PATCH v4 33/34] um: Convert {pmd, pte}_free_tlb() to use ptdescs Vishal Moola (Oracle)
2023-06-14 15:21   ` Mike Rapoport
2023-06-12 21:04 ` [PATCH v4 34/34] mm: Remove pgtable_{pmd, pte}_page_{ctor, dtor}() wrappers Vishal Moola (Oracle)
2023-06-14 15:23   ` Mike Rapoport

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