xref: /linux/mm/sparse.h (revision 67f8bc848ee31831336bd478e57d2f993551902e)
1 /* SPDX-License-Identifier: GPL-2.0-or-later */
2 /*
3  * sparse.h:
4  *
5  * mm/ internal sparse and sparse-vmemmap declarations
6  */
7 
8 #ifndef __MM_SPARSE_H
9 #define __MM_SPARSE_H
10 
11 #include <linux/mmzone.h>
12 
13 /*
14  * mm/sparse.c
15  */
16 #ifdef CONFIG_SPARSEMEM
17 void sparse_init(void);
18 int sparse_index_init(unsigned long section_nr, int nid);
19 
20 static inline void sparse_init_one_section(struct mem_section *ms,
21 		unsigned long pnum, struct page *mem_map,
22 		struct mem_section_usage *usage, unsigned long flags)
23 {
24 	unsigned long coded_mem_map;
25 
26 	BUILD_BUG_ON(SECTION_MAP_LAST_BIT > PFN_SECTION_SHIFT);
27 
28 	/*
29 	 * We encode the start PFN of the section into the mem_map such that
30 	 * page_to_pfn() on !CONFIG_SPARSEMEM_VMEMMAP can simply subtract it
31 	 * from the page pointer to obtain the PFN.
32 	 */
33 	coded_mem_map = (unsigned long)(mem_map - section_nr_to_pfn(pnum));
34 	VM_WARN_ON_ONCE(coded_mem_map & ~SECTION_MAP_MASK);
35 
36 	ms->section_mem_map &= ~SECTION_MAP_MASK;
37 	ms->section_mem_map |= coded_mem_map;
38 	ms->section_mem_map |= flags | SECTION_HAS_MEM_MAP;
39 	ms->usage = usage;
40 }
41 
42 static inline void __section_mark_present(struct mem_section *ms,
43 		unsigned long section_nr)
44 {
45 	if (section_nr > __highest_present_section_nr)
46 		__highest_present_section_nr = section_nr;
47 
48 	ms->section_mem_map |= SECTION_MARKED_PRESENT;
49 }
50 
51 static inline size_t mem_section_usage_size(void)
52 {
53 	return struct_size_t(struct mem_section_usage, pageblock_flags,
54 			     BITS_TO_LONGS(SECTION_BLOCKFLAGS_BITS));
55 }
56 #else
57 static inline void sparse_init(void) {}
58 #endif /* CONFIG_SPARSEMEM */
59 
60 /*
61  * mm/sparse-vmemmap.c
62  */
63 #ifdef CONFIG_SPARSEMEM_VMEMMAP
64 void sparse_init_subsection_map(void);
65 #else
66 static inline void sparse_init_subsection_map(void) {}
67 #endif /* CONFIG_SPARSEMEM_VMEMMAP */
68 
69 #endif /* __MM_SPARSE_H */
70