1// SPDX-License-Identifier: GPL-2.0
 2/*
 3 * Free some vmemmap pages of HugeTLB
 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#ifdef CONFIG_HUGETLB_PAGE_FREE_VMEMMAP
14int alloc_huge_page_vmemmap(struct hstate *h, struct page *head);
15void free_huge_page_vmemmap(struct hstate *h, struct page *head);
16void hugetlb_vmemmap_init(struct hstate *h);
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
17
18/*
19 * How many vmemmap pages associated with a HugeTLB page that can be freed
20 * to the buddy allocator.
21 */
22static inline unsigned int free_vmemmap_pages_per_hpage(struct hstate *h)
23{
24	return h->nr_free_vmemmap_pages;
 
 
 
 
25}
26#else
27static inline int alloc_huge_page_vmemmap(struct hstate *h, struct page *head)
28{
29	return 0;
30}
31
32static inline void free_huge_page_vmemmap(struct hstate *h, struct page *head)
 
 
 
 
 
 
 
 
33{
34}
35
36static inline void hugetlb_vmemmap_init(struct hstate *h)
37{
38}
39
40static inline unsigned int free_vmemmap_pages_per_hpage(struct hstate *h)
41{
42	return 0;
43}
44#endif /* CONFIG_HUGETLB_PAGE_FREE_VMEMMAP */
 
 
 
 
 
45#endif /* _LINUX_HUGETLB_VMEMMAP_H */

 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
21int hugetlb_vmemmap_restore_folio(const struct hstate *h, struct folio *folio);
22long hugetlb_vmemmap_restore_folios(const struct hstate *h,
23					struct list_head *folio_list,
24					struct list_head *non_hvo_folios);
25void hugetlb_vmemmap_optimize_folio(const struct hstate *h, struct folio *folio);
26void hugetlb_vmemmap_optimize_folios(struct hstate *h, struct list_head *folio_list);
27
28static 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 */
37static 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(sizeof(struct page)))
42		return 0;
43	return size > 0 ? size : 0;
44}
45#else
46static inline int hugetlb_vmemmap_restore_folio(const struct hstate *h, struct folio *folio)
47{
48	return 0;
49}
50
51static 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
59static inline void hugetlb_vmemmap_optimize_folio(const struct hstate *h, struct folio *folio)
60{
61}
62
63static inline void hugetlb_vmemmap_optimize_folios(struct hstate *h, struct list_head *folio_list)
64{
65}
66
67static inline unsigned int hugetlb_vmemmap_optimizable_size(const struct hstate *h)
68{
69	return 0;
70}
71#endif /* CONFIG_HUGETLB_PAGE_OPTIMIZE_VMEMMAP */
72
73static 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 */