Re: [PATCH v3 15/17] mm: pgtable: remove tlb_remove_page_ptdesc()

Mike Rapoport
2024-12-28T09:26:44Z

On Mon, Dec 23, 2024 at 05:41:01PM +0800, Qi Zheng wrote:
> Here we are explicitly dealing with struct page, and the following logic
> semms strange:
>
> tlb_remove_page_ptdesc((tlb), (page_ptdesc(pte)));
>
> tlb_remove_page_ptdesc
> --> tlb_remove_page(tlb, ptdesc_page(pt));
>
> So remove tlb_remove_page_ptdesc() and make callers call tlb_remove_page()
> directly.

Please don't. The ptdesc wrappers are there as a part of reducing the size
of struct page project [1].

For now struct ptdesc overlaps struct page, but the goal is to have them
separate and always operate on struct ptdesc when working with page tables.

[1] https://kernelnewbies.org/MatthewWilcox/Memdescs

> Signed-off-by: Qi Zheng <zhengqi.arch@bytedance.com>
> Originally-by: Peter Zijlstra (Intel) <peterz@infradead.org>
> ---
> arch/csky/include/asm/pgalloc.h | 2 +-
> arch/hexagon/include/asm/pgalloc.h | 2 +-
> arch/loongarch/include/asm/pgalloc.h | 2 +-
> arch/m68k/include/asm/sun3_pgalloc.h | 2 +-
> arch/mips/include/asm/pgalloc.h | 2 +-
> arch/nios2/include/asm/pgalloc.h | 2 +-
> arch/openrisc/include/asm/pgalloc.h | 2 +-
> arch/riscv/include/asm/pgalloc.h | 2 +-
> arch/sh/include/asm/pgalloc.h | 2 +-
> arch/um/include/asm/pgalloc.h | 8 ++++----
> include/asm-generic/tlb.h | 6 ------
> 11 files changed, 13 insertions(+), 19 deletions(-)
>
> diff --git a/arch/csky/include/asm/pgalloc.h b/arch/csky/include/asm/pgalloc.h
> index f1ce5b7b28f22..936a43a49e704 100644
> --- a/arch/csky/include/asm/pgalloc.h
> +++ b/arch/csky/include/asm/pgalloc.h
> @@ -64,7 +64,7 @@ static inline pgd_t *pgd_alloc(struct mm_struct *mm)
> #define __pte_free_tlb(tlb, pte, address) \
> do { \
> pagetable_dtor(page_ptdesc(pte)); \
> - tlb_remove_page_ptdesc(tlb, page_ptdesc(pte)); \
> + tlb_remove_page(tlb, (pte)); \
> } while (0)
>
> extern void pagetable_init(void);
> diff --git a/arch/hexagon/include/asm/pgalloc.h b/arch/hexagon/include/asm/pgalloc.h
> index 40e42a0e71673..8b1550498f1bf 100644
> --- a/arch/hexagon/include/asm/pgalloc.h
> +++ b/arch/hexagon/include/asm/pgalloc.h
> @@ -90,7 +90,7 @@ static inline void pmd_populate_kernel(struct mm_struct *mm, pmd_t *pmd,
> #define __pte_free_tlb(tlb, pte, addr) \
> do { \
> pagetable_dtor((page_ptdesc(pte))); \
> - tlb_remove_page_ptdesc((tlb), (page_ptdesc(pte))); \
> + tlb_remove_page((tlb), (pte)); \
> } while (0)
>
> #endif
> diff --git a/arch/loongarch/include/asm/pgalloc.h b/arch/loongarch/include/asm/pgalloc.h
> index 7211dff8c969e..5a4f22aeb6189 100644
> --- a/arch/loongarch/include/asm/pgalloc.h
> +++ b/arch/loongarch/include/asm/pgalloc.h
> @@ -58,7 +58,7 @@ static inline pte_t *pte_alloc_one_kernel(struct mm_struct *mm)
> #define __pte_free_tlb(tlb, pte, address) \
> do { \
> pagetable_dtor(page_ptdesc(pte)); \
> - tlb_remove_page_ptdesc((tlb), page_ptdesc(pte)); \
> + tlb_remove_page((tlb), (pte)); \
> } while (0)
>
> #ifndef __PAGETABLE_PMD_FOLDED
> diff --git a/arch/m68k/include/asm/sun3_pgalloc.h b/arch/m68k/include/asm/sun3_pgalloc.h
> index 2b626cb3ad0ae..63d9f95f5e3dd 100644
> --- a/arch/m68k/include/asm/sun3_pgalloc.h
> +++ b/arch/m68k/include/asm/sun3_pgalloc.h
> @@ -20,7 +20,7 @@ extern const char bad_pmd_string[];
> #define __pte_free_tlb(tlb, pte, addr) \
> do { \
> pagetable_dtor(page_ptdesc(pte)); \
> - tlb_remove_page_ptdesc((tlb), page_ptdesc(pte)); \
> + tlb_remove_page((tlb), (pte)); \
> } while (0)
>
> static inline void pmd_populate_kernel(struct mm_struct *mm, pmd_t *pmd, pte_t *pte)
> diff --git a/arch/mips/include/asm/pgalloc.h b/arch/mips/include/asm/pgalloc.h
> index 36d9805033c4b..bbee21345154b 100644
> --- a/arch/mips/include/asm/pgalloc.h
> +++ b/arch/mips/include/asm/pgalloc.h
> @@ -57,7 +57,7 @@ static inline void pgd_free(struct mm_struct *mm, pgd_t *pgd)
> #define __pte_free_tlb(tlb, pte, address) \
> do { \
> pagetable_dtor(page_ptdesc(pte)); \
> - tlb_remove_page_ptdesc((tlb), page_ptdesc(pte)); \
> + tlb_remove_page((tlb), (pte)); \
> } while (0)
>
> #ifndef __PAGETABLE_PMD_FOLDED
> diff --git a/arch/nios2/include/asm/pgalloc.h b/arch/nios2/include/asm/pgalloc.h
> index 12a536b7bfbd4..641cec8fb2a22 100644
> --- a/arch/nios2/include/asm/pgalloc.h
> +++ b/arch/nios2/include/asm/pgalloc.h
> @@ -31,7 +31,7 @@ extern pgd_t *pgd_alloc(struct mm_struct *mm);
> #define __pte_free_tlb(tlb, pte, addr) \
> do { \
> pagetable_dtor(page_ptdesc(pte)); \
> - tlb_remove_page_ptdesc((tlb), (page_ptdesc(pte))); \
> + tlb_remove_page((tlb), (pte)); \
> } while (0)
>
> #endif /* _ASM_NIOS2_PGALLOC_H */
> diff --git a/arch/openrisc/include/asm/pgalloc.h b/arch/openrisc/include/asm/pgalloc.h
> index 596e2355824e3..e9b9bc53ece0b 100644
> --- a/arch/openrisc/include/asm/pgalloc.h
> +++ b/arch/openrisc/include/asm/pgalloc.h
> @@ -69,7 +69,7 @@ extern pte_t *pte_alloc_one_kernel(struct mm_struct *mm);
> #define __pte_free_tlb(tlb, pte, addr) \
> do { \
> pagetable_dtor(page_ptdesc(pte)); \
> - tlb_remove_page_ptdesc((tlb), (page_ptdesc(pte))); \
> + tlb_remove_page((tlb), (pte)); \
> } while (0)
>
> #endif
> diff --git a/arch/riscv/include/asm/pgalloc.h b/arch/riscv/include/asm/pgalloc.h
> index c8907b8317115..ab4f9b2cf9e11 100644
> --- a/arch/riscv/include/asm/pgalloc.h
> +++ b/arch/riscv/include/asm/pgalloc.h
> @@ -29,7 +29,7 @@ static inline void riscv_tlb_remove_ptdesc(struct mmu_gather *tlb, void *pt)
> tlb_remove_ptdesc(tlb, pt);
> } else {
> pagetable_dtor(pt);
> - tlb_remove_page_ptdesc(tlb, pt);
> + tlb_remove_page(tlb, ptdesc_page((struct ptdesc *)pt));
> }
> }
>
> diff --git a/arch/sh/include/asm/pgalloc.h b/arch/sh/include/asm/pgalloc.h
> index 96d938fdf2244..43812b2363efd 100644
> --- a/arch/sh/include/asm/pgalloc.h
> +++ b/arch/sh/include/asm/pgalloc.h
> @@ -35,7 +35,7 @@ static inline void pmd_populate(struct mm_struct *mm, pmd_t *pmd,
> #define __pte_free_tlb(tlb, pte, addr) \
> do { \
> pagetable_dtor(page_ptdesc(pte)); \
> - tlb_remove_page_ptdesc((tlb), (page_ptdesc(pte))); \
> + tlb_remove_page((tlb), (pte)); \
> } while (0)
>
> #endif /* __ASM_SH_PGALLOC_H */
> diff --git a/arch/um/include/asm/pgalloc.h b/arch/um/include/asm/pgalloc.h
> index f0af23c3aeb2b..98190c318a8e9 100644
> --- a/arch/um/include/asm/pgalloc.h
> +++ b/arch/um/include/asm/pgalloc.h
> @@ -28,7 +28,7 @@ extern pgd_t *pgd_alloc(struct mm_struct *);
> #define __pte_free_tlb(tlb, pte, address) \
> do { \
> pagetable_dtor(page_ptdesc(pte)); \
> - tlb_remove_page_ptdesc((tlb), (page_ptdesc(pte))); \
> + tlb_remove_page((tlb), (pte)); \
> } while (0)
>
> #if CONFIG_PGTABLE_LEVELS > 2
> @@ -36,15 +36,15 @@ do { \
> #define __pmd_free_tlb(tlb, pmd, address) \
> do { \
> pagetable_dtor(virt_to_ptdesc(pmd)); \
> - tlb_remove_page_ptdesc((tlb), virt_to_ptdesc(pmd)); \
> + tlb_remove_page((tlb), virt_to_page(pmd)); \
> } while (0)
>
> #if CONFIG_PGTABLE_LEVELS > 3
>
> #define __pud_free_tlb(tlb, pud, address) \
> do { \
> - pagetable_dtor(virt_to_ptdesc(pud)); \
> - tlb_remove_page_ptdesc((tlb), virt_to_ptdesc(pud)); \
> + pagetable_dtor(virt_to_ptdesc(pud)); \
> + tlb_remove_page((tlb), virt_to_page(pud)); \
> } while (0)
>
> #endif
> diff --git a/include/asm-generic/tlb.h b/include/asm-generic/tlb.h
> index 69de47c7ef3c5..8d6cfe5058543 100644
> --- a/include/asm-generic/tlb.h
> +++ b/include/asm-generic/tlb.h
> @@ -504,12 +504,6 @@ static inline void tlb_remove_ptdesc(struct mmu_gather *tlb, void *pt)
> tlb_remove_table(tlb, pt);
> }
>
> -/* Like tlb_remove_ptdesc, but for page-like page directories. */
> -static inline void tlb_remove_page_ptdesc(struct mmu_gather *tlb, struct ptdesc *pt)
> -{
> - tlb_remove_page(tlb, ptdesc_page(pt));
> -}
> -
> static inline void tlb_change_page_size(struct mmu_gather *tlb,
> unsigned int page_size)
> {
> --
> 2.20.1
>

--
Sincerely yours,
Mike.