1 // SPDX-License-Identifier: GPL-2.0 2 /* 3 * HugeTLB Vmemmap Optimization (HVO) 4 * 5 * Copyright (c) 2020, ByteDance. All rights reserved. 6 * 7 * Author: Muchun Song <songmuchun@bytedance.com> 8 */ 9 #ifndef _LINUX_HUGETLB_VMEMMAP_H 10 #define _LINUX_HUGETLB_VMEMMAP_H 11 #include <linux/hugetlb.h> 12 #include <linux/io.h> 13 #include <linux/memblock.h> 14 15 /* 16 * Reserve one vmemmap page, all vmemmap addresses are mapped to it. See 17 * Documentation/mm/vmemmap_dedup.rst. 18 */ 19 #define HUGETLB_VMEMMAP_RESERVE_SIZE PAGE_SIZE 20 #define HUGETLB_VMEMMAP_RESERVE_PAGES (HUGETLB_VMEMMAP_RESERVE_SIZE / sizeof(struct page)) 21 22 #ifdef CONFIG_HUGETLB_PAGE_OPTIMIZE_VMEMMAP 23 int hugetlb_vmemmap_restore_folio(const struct hstate *h, struct folio *folio); 24 long hugetlb_vmemmap_restore_folios(const struct hstate *h, 25 struct list_head *folio_list, 26 struct list_head *non_hvo_folios); 27 void hugetlb_vmemmap_optimize_folio(const struct hstate *h, struct folio *folio); 28 void hugetlb_vmemmap_optimize_folios(struct hstate *h, struct list_head *folio_list); 29 void hugetlb_vmemmap_optimize_bootmem_folios(struct hstate *h, struct list_head *folio_list); 30 #ifdef CONFIG_SPARSEMEM_VMEMMAP_PREINIT 31 void hugetlb_vmemmap_init_early(int nid); 32 void hugetlb_vmemmap_init_late(int nid); 33 #endif 34 35 36 static inline unsigned int hugetlb_vmemmap_size(const struct hstate *h) 37 { 38 return pages_per_huge_page(h) * sizeof(struct page); 39 } 40 41 /* 42 * Return how many vmemmap size associated with a HugeTLB page that can be 43 * optimized and can be freed to the buddy allocator. 44 */ 45 static inline unsigned int hugetlb_vmemmap_optimizable_size(const struct hstate *h) 46 { 47 int size = hugetlb_vmemmap_size(h) - HUGETLB_VMEMMAP_RESERVE_SIZE; 48 49 if (!is_power_of_2(sizeof(struct page))) 50 return 0; 51 return size > 0 ? size : 0; 52 } 53 #else 54 static inline int hugetlb_vmemmap_restore_folio(const struct hstate *h, struct folio *folio) 55 { 56 return 0; 57 } 58 59 static inline long hugetlb_vmemmap_restore_folios(const struct hstate *h, 60 struct list_head *folio_list, 61 struct list_head *non_hvo_folios) 62 { 63 list_splice_init(folio_list, non_hvo_folios); 64 return 0; 65 } 66 67 static inline void hugetlb_vmemmap_optimize_folio(const struct hstate *h, struct folio *folio) 68 { 69 } 70 71 static inline void hugetlb_vmemmap_optimize_folios(struct hstate *h, struct list_head *folio_list) 72 { 73 } 74 75 static inline void hugetlb_vmemmap_optimize_bootmem_folios(struct hstate *h, 76 struct list_head *folio_list) 77 { 78 } 79 80 static inline void hugetlb_vmemmap_init_early(int nid) 81 { 82 } 83 84 static inline void hugetlb_vmemmap_init_late(int nid) 85 { 86 } 87 88 static inline unsigned int hugetlb_vmemmap_optimizable_size(const struct hstate *h) 89 { 90 return 0; 91 } 92 #endif /* CONFIG_HUGETLB_PAGE_OPTIMIZE_VMEMMAP */ 93 94 static inline bool hugetlb_vmemmap_optimizable(const struct hstate *h) 95 { 96 return hugetlb_vmemmap_optimizable_size(h) != 0; 97 } 98 #endif /* _LINUX_HUGETLB_VMEMMAP_H */ 99