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 | |
13 | /* |
14 | * Reserve one vmemmap page, all vmemmap addresses are mapped to it. See |
15 | * Documentation/mm/vmemmap_dedup.rst. |
16 | */ |
17 | #define HUGETLB_VMEMMAP_RESERVE_SIZE PAGE_SIZE |
18 | #define HUGETLB_VMEMMAP_RESERVE_PAGES (HUGETLB_VMEMMAP_RESERVE_SIZE / sizeof(struct page)) |
19 | |
20 | #ifdef CONFIG_HUGETLB_PAGE_OPTIMIZE_VMEMMAP |
21 | int hugetlb_vmemmap_restore_folio(const struct hstate *h, struct folio *folio); |
22 | long hugetlb_vmemmap_restore_folios(const struct hstate *h, |
23 | struct list_head *folio_list, |
24 | struct list_head *non_hvo_folios); |
25 | void hugetlb_vmemmap_optimize_folio(const struct hstate *h, struct folio *folio); |
26 | void hugetlb_vmemmap_optimize_folios(struct hstate *h, struct list_head *folio_list); |
27 | |
28 | static inline unsigned int hugetlb_vmemmap_size(const struct hstate *h) |
29 | { |
30 | return pages_per_huge_page(h) * sizeof(struct page); |
31 | } |
32 | |
33 | /* |
34 | * Return how many vmemmap size associated with a HugeTLB page that can be |
35 | * optimized and can be freed to the buddy allocator. |
36 | */ |
37 | static inline unsigned int hugetlb_vmemmap_optimizable_size(const struct hstate *h) |
38 | { |
39 | int size = hugetlb_vmemmap_size(h) - HUGETLB_VMEMMAP_RESERVE_SIZE; |
40 | |
41 | if (!is_power_of_2(n: sizeof(struct page))) |
42 | return 0; |
43 | return size > 0 ? size : 0; |
44 | } |
45 | #else |
46 | static inline int hugetlb_vmemmap_restore_folio(const struct hstate *h, struct folio *folio) |
47 | { |
48 | return 0; |
49 | } |
50 | |
51 | static long hugetlb_vmemmap_restore_folios(const struct hstate *h, |
52 | struct list_head *folio_list, |
53 | struct list_head *non_hvo_folios) |
54 | { |
55 | list_splice_init(folio_list, non_hvo_folios); |
56 | return 0; |
57 | } |
58 | |
59 | static inline void hugetlb_vmemmap_optimize_folio(const struct hstate *h, struct folio *folio) |
60 | { |
61 | } |
62 | |
63 | static inline void hugetlb_vmemmap_optimize_folios(struct hstate *h, struct list_head *folio_list) |
64 | { |
65 | } |
66 | |
67 | static inline unsigned int hugetlb_vmemmap_optimizable_size(const struct hstate *h) |
68 | { |
69 | return 0; |
70 | } |
71 | #endif /* CONFIG_HUGETLB_PAGE_OPTIMIZE_VMEMMAP */ |
72 | |
73 | static inline bool hugetlb_vmemmap_optimizable(const struct hstate *h) |
74 | { |
75 | return hugetlb_vmemmap_optimizable_size(h) != 0; |
76 | } |
77 | #endif /* _LINUX_HUGETLB_VMEMMAP_H */ |
78 | |