1 | /* SPDX-License-Identifier: GPL-2.0 */ |
2 | #ifndef PAGE_FLAGS_LAYOUT_H |
3 | #define PAGE_FLAGS_LAYOUT_H |
4 | |
5 | #include <linux/numa.h> |
6 | #include <generated/bounds.h> |
7 | |
8 | /* |
9 | * When a memory allocation must conform to specific limitations (such |
10 | * as being suitable for DMA) the caller will pass in hints to the |
11 | * allocator in the gfp_mask, in the zone modifier bits. These bits |
12 | * are used to select a priority ordered list of memory zones which |
13 | * match the requested limits. See gfp_zone() in include/linux/gfp.h |
14 | */ |
15 | #if MAX_NR_ZONES < 2 |
16 | #define ZONES_SHIFT 0 |
17 | #elif MAX_NR_ZONES <= 2 |
18 | #define ZONES_SHIFT 1 |
19 | #elif MAX_NR_ZONES <= 4 |
20 | #define ZONES_SHIFT 2 |
21 | #elif MAX_NR_ZONES <= 8 |
22 | #define ZONES_SHIFT 3 |
23 | #else |
24 | #error ZONES_SHIFT "Too many zones configured" |
25 | #endif |
26 | |
27 | #define ZONES_WIDTH ZONES_SHIFT |
28 | |
29 | #ifdef CONFIG_SPARSEMEM |
30 | #include <asm/sparsemem.h> |
31 | #define SECTIONS_SHIFT (MAX_PHYSMEM_BITS - SECTION_SIZE_BITS) |
32 | #else |
33 | #define SECTIONS_SHIFT 0 |
34 | #endif |
35 | |
36 | #ifndef BUILD_VDSO32_64 |
37 | /* |
38 | * page->flags layout: |
39 | * |
40 | * There are five possibilities for how page->flags get laid out. The first |
41 | * pair is for the normal case without sparsemem. The second pair is for |
42 | * sparsemem when there is plenty of space for node and section information. |
43 | * The last is when there is insufficient space in page->flags and a separate |
44 | * lookup is necessary. |
45 | * |
46 | * No sparsemem or sparsemem vmemmap: | NODE | ZONE | ... | FLAGS | |
47 | * " plus space for last_cpupid: | NODE | ZONE | LAST_CPUPID ... | FLAGS | |
48 | * classic sparse with space for node:| SECTION | NODE | ZONE | ... | FLAGS | |
49 | * " plus space for last_cpupid: | SECTION | NODE | ZONE | LAST_CPUPID ... | FLAGS | |
50 | * classic sparse no space for node: | SECTION | ZONE | ... | FLAGS | |
51 | */ |
52 | #if defined(CONFIG_SPARSEMEM) && !defined(CONFIG_SPARSEMEM_VMEMMAP) |
53 | #define SECTIONS_WIDTH SECTIONS_SHIFT |
54 | #else |
55 | #define SECTIONS_WIDTH 0 |
56 | #endif |
57 | |
58 | #if ZONES_WIDTH + LRU_GEN_WIDTH + SECTIONS_WIDTH + NODES_SHIFT \ |
59 | <= BITS_PER_LONG - NR_PAGEFLAGS |
60 | #define NODES_WIDTH NODES_SHIFT |
61 | #elif defined(CONFIG_SPARSEMEM_VMEMMAP) |
62 | #error "Vmemmap: No space for nodes field in page flags" |
63 | #else |
64 | #define NODES_WIDTH 0 |
65 | #endif |
66 | |
67 | /* |
68 | * Note that this #define MUST have a value so that it can be tested with |
69 | * the IS_ENABLED() macro. |
70 | */ |
71 | #if NODES_SHIFT != 0 && NODES_WIDTH == 0 |
72 | #define NODE_NOT_IN_PAGE_FLAGS 1 |
73 | #endif |
74 | |
75 | #if defined(CONFIG_KASAN_SW_TAGS) || defined(CONFIG_KASAN_HW_TAGS) |
76 | #define KASAN_TAG_WIDTH 8 |
77 | #else |
78 | #define KASAN_TAG_WIDTH 0 |
79 | #endif |
80 | |
81 | #ifdef CONFIG_NUMA_BALANCING |
82 | #define LAST__PID_SHIFT 8 |
83 | #define LAST__PID_MASK ((1 << LAST__PID_SHIFT)-1) |
84 | |
85 | #define LAST__CPU_SHIFT NR_CPUS_BITS |
86 | #define LAST__CPU_MASK ((1 << LAST__CPU_SHIFT)-1) |
87 | |
88 | #define LAST_CPUPID_SHIFT (LAST__PID_SHIFT+LAST__CPU_SHIFT) |
89 | #else |
90 | #define LAST_CPUPID_SHIFT 0 |
91 | #endif |
92 | |
93 | #if ZONES_WIDTH + LRU_GEN_WIDTH + SECTIONS_WIDTH + NODES_WIDTH + \ |
94 | KASAN_TAG_WIDTH + LAST_CPUPID_SHIFT <= BITS_PER_LONG - NR_PAGEFLAGS |
95 | #define LAST_CPUPID_WIDTH LAST_CPUPID_SHIFT |
96 | #else |
97 | #define LAST_CPUPID_WIDTH 0 |
98 | #endif |
99 | |
100 | #if LAST_CPUPID_SHIFT != 0 && LAST_CPUPID_WIDTH == 0 |
101 | #define LAST_CPUPID_NOT_IN_PAGE_FLAGS |
102 | #endif |
103 | |
104 | #if ZONES_WIDTH + LRU_GEN_WIDTH + SECTIONS_WIDTH + NODES_WIDTH + \ |
105 | KASAN_TAG_WIDTH + LAST_CPUPID_WIDTH > BITS_PER_LONG - NR_PAGEFLAGS |
106 | #error "Not enough bits in page flags" |
107 | #endif |
108 | |
109 | /* see the comment on MAX_NR_TIERS */ |
110 | #define LRU_REFS_WIDTH min(__LRU_REFS_WIDTH, BITS_PER_LONG - NR_PAGEFLAGS - \ |
111 | ZONES_WIDTH - LRU_GEN_WIDTH - SECTIONS_WIDTH - \ |
112 | NODES_WIDTH - KASAN_TAG_WIDTH - LAST_CPUPID_WIDTH) |
113 | |
114 | #endif |
115 | #endif /* _LINUX_PAGE_FLAGS_LAYOUT */ |
116 | |