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 */