From bf2d4334f72e4e033166c5a3bf1331a7238eab9d Mon Sep 17 00:00:00 2001 From: "Vishal Moola (Oracle)" Date: Mon, 7 Aug 2023 16:04:45 -0700 Subject: [PATCH] mm: add utility functions for ptdesc Introduce utility functions setting the foundation for ptdescs. These will also assist in the splitting out of ptdesc from struct page. Functions that focus on the descriptor are prefixed with ptdesc_* while functions that focus on the pagetable are prefixed with pagetable_*. pagetable_alloc() is defined to allocate new ptdesc pages as compound pages. This is to standardize ptdescs by allowing for one allocation and one free function, in contrast to 2 allocation and 2 free functions. Link: https://lkml.kernel.org/r/20230807230513.102486-4-vishal.moola@gmail.com Signed-off-by: Vishal Moola (Oracle) Cc: Arnd Bergmann Cc: Catalin Marinas Cc: Christophe Leroy Cc: Claudio Imbrenda Cc: Dave Hansen Cc: David Hildenbrand Cc: "David S. Miller" Cc: Dinh Nguyen Cc: Geert Uytterhoeven Cc: Geert Uytterhoeven Cc: Guo Ren Cc: Huacai Chen Cc: Hugh Dickins Cc: John Paul Adrian Glaubitz Cc: Jonas Bonn Cc: Matthew Wilcox Cc: Mike Rapoport (IBM) Cc: Palmer Dabbelt Cc: Paul Walmsley Cc: Richard Weinberger Cc: Thomas Bogendoerfer Cc: Yoshinori Sato Signed-off-by: Andrew Morton --- include/asm-generic/tlb.h | 11 +++++++ include/linux/mm.h | 61 +++++++++++++++++++++++++++++++++++++++ include/linux/mm_types.h | 12 ++++++++ 3 files changed, 84 insertions(+) diff --git a/include/asm-generic/tlb.h b/include/asm-generic/tlb.h index bc32a2284c56..129a3a759976 100644 --- a/include/asm-generic/tlb.h +++ b/include/asm-generic/tlb.h @@ -480,6 +480,17 @@ static inline void tlb_remove_page(struct mmu_gather *tlb, struct page *page) return tlb_remove_page_size(tlb, page, PAGE_SIZE); } +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) { diff --git a/include/linux/mm.h b/include/linux/mm.h index c63ec57a54dc..f75058783359 100644 --- a/include/linux/mm.h +++ b/include/linux/mm.h @@ -2772,6 +2772,57 @@ static inline pmd_t *pmd_alloc(struct mm_struct *mm, pud_t *pud, unsigned long a } #endif /* CONFIG_MMU */ +static inline struct ptdesc *virt_to_ptdesc(const void *x) +{ + return page_ptdesc(virt_to_page(x)); +} + +static inline void *ptdesc_to_virt(const struct ptdesc *pt) +{ + return page_to_virt(ptdesc_page(pt)); +} + +static inline void *ptdesc_address(const struct ptdesc *pt) +{ + return folio_address(ptdesc_folio(pt)); +} + +static inline bool pagetable_is_reserved(struct ptdesc *pt) +{ + return folio_test_reserved(ptdesc_folio(pt)); +} + +/** + * pagetable_alloc - Allocate pagetables + * @gfp: GFP flags + * @order: desired pagetable order + * + * pagetable_alloc allocates memory for page tables as well as a page table + * descriptor to describe that memory. + * + * Return: The ptdesc describing the allocated page tables. + */ +static inline struct ptdesc *pagetable_alloc(gfp_t gfp, unsigned int order) +{ + struct page *page = alloc_pages(gfp | __GFP_COMP, order); + + return page_ptdesc(page); +} + +/** + * pagetable_free - Free pagetables + * @pt: The page table descriptor + * + * pagetable_free frees the memory of all page tables described by a page + * table descriptor and the memory for the descriptor itself. + */ +static inline void pagetable_free(struct ptdesc *pt) +{ + struct page *page = ptdesc_page(pt); + + __free_pages(page, compound_order(page)); +} + #if USE_SPLIT_PTE_PTLOCKS #if ALLOC_SPLIT_PTLOCKS void __init ptlock_cache_init(void); @@ -2898,6 +2949,11 @@ static inline struct page *pmd_pgtable_page(pmd_t *pmd) return virt_to_page((void *)((unsigned long) pmd & mask)); } +static inline struct ptdesc *pmd_ptdesc(pmd_t *pmd) +{ + return page_ptdesc(pmd_pgtable_page(pmd)); +} + static inline spinlock_t *pmd_lockptr(struct mm_struct *mm, pmd_t *pmd) { return ptlock_ptr(pmd_pgtable_page(pmd)); @@ -3010,6 +3066,11 @@ static inline void mark_page_reserved(struct page *page) adjust_managed_page_count(page, -1); } +static inline void free_reserved_ptdesc(struct ptdesc *pt) +{ + free_reserved_page(ptdesc_page(pt)); +} + /* * Default method to free all the __init memory into the buddy system. * The freed pages will be poisoned with pattern "poison" if it's within diff --git a/include/linux/mm_types.h b/include/linux/mm_types.h index d4ebcefe482e..c57e940e60d0 100644 --- a/include/linux/mm_types.h +++ b/include/linux/mm_types.h @@ -467,6 +467,18 @@ TABLE_MATCH(memcg_data, pt_memcg_data); #undef TABLE_MATCH static_assert(sizeof(struct ptdesc) <= sizeof(struct page)); +#define ptdesc_page(pt) (_Generic((pt), \ + const struct ptdesc *: (const struct page *)(pt), \ + struct ptdesc *: (struct page *)(pt))) + +#define ptdesc_folio(pt) (_Generic((pt), \ + const struct ptdesc *: (const struct folio *)(pt), \ + struct ptdesc *: (struct folio *)(pt))) + +#define page_ptdesc(p) (_Generic((p), \ + const struct page *: (const struct ptdesc *)(p), \ + struct page *: (struct ptdesc *)(p))) + /* * Used for sizing the vmemmap region on some architectures */