61 lines
1.6 KiB
C
61 lines
1.6 KiB
C
// SPDX-License-Identifier: GPL-2.0
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/*
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* HugeTLB Vmemmap Optimization (HVO)
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*
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* Copyright (c) 2020, ByteDance. All rights reserved.
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*
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* Author: Muchun Song <songmuchun@bytedance.com>
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*/
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#ifndef _LINUX_HUGETLB_VMEMMAP_H
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#define _LINUX_HUGETLB_VMEMMAP_H
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#include <linux/hugetlb.h>
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#ifdef CONFIG_HUGETLB_PAGE_OPTIMIZE_VMEMMAP
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int hugetlb_vmemmap_restore(const struct hstate *h, struct page *head);
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void hugetlb_vmemmap_optimize(const struct hstate *h, struct page *head);
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/*
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* Reserve one vmemmap page, all vmemmap addresses are mapped to it. See
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* Documentation/vm/vmemmap_dedup.rst.
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*/
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#define HUGETLB_VMEMMAP_RESERVE_SIZE PAGE_SIZE
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static inline unsigned int hugetlb_vmemmap_size(const struct hstate *h)
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{
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return pages_per_huge_page(h) * sizeof(struct page);
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}
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/*
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* Return how many vmemmap size associated with a HugeTLB page that can be
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* optimized and can be freed to the buddy allocator.
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*/
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static inline unsigned int hugetlb_vmemmap_optimizable_size(const struct hstate *h)
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{
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int size = hugetlb_vmemmap_size(h) - HUGETLB_VMEMMAP_RESERVE_SIZE;
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if (!is_power_of_2(sizeof(struct page)))
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return 0;
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return size > 0 ? size : 0;
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}
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#else
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static inline int hugetlb_vmemmap_restore(const struct hstate *h, struct page *head)
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{
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return 0;
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}
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static inline void hugetlb_vmemmap_optimize(const struct hstate *h, struct page *head)
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{
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}
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static inline unsigned int hugetlb_vmemmap_optimizable_size(const struct hstate *h)
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{
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return 0;
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}
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#endif /* CONFIG_HUGETLB_PAGE_OPTIMIZE_VMEMMAP */
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static inline bool hugetlb_vmemmap_optimizable(const struct hstate *h)
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{
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return hugetlb_vmemmap_optimizable_size(h) != 0;
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}
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#endif /* _LINUX_HUGETLB_VMEMMAP_H */
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