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
14 int alloc_huge_page_vmemmap(struct hstate *h, struct page *head);
15 void free_huge_page_vmemmap(struct hstate *h, struct page *head);
16 void 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  */
free_vmemmap_pages_per_hpage(struct hstate * h)22 static inline unsigned int free_vmemmap_pages_per_hpage(struct hstate *h)
23 {
24 	return h->nr_free_vmemmap_pages;
25 }
26 #else
alloc_huge_page_vmemmap(struct hstate * h,struct page * head)27 static inline int alloc_huge_page_vmemmap(struct hstate *h, struct page *head)
28 {
29 	return 0;
30 }
31 
free_huge_page_vmemmap(struct hstate * h,struct page * head)32 static inline void free_huge_page_vmemmap(struct hstate *h, struct page *head)
33 {
34 }
35 
hugetlb_vmemmap_init(struct hstate * h)36 static inline void hugetlb_vmemmap_init(struct hstate *h)
37 {
38 }
39 
free_vmemmap_pages_per_hpage(struct hstate * h)40 static 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 */
46