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bbeae5b0 PZ |
1 | #ifndef PAGE_FLAGS_LAYOUT_H |
2 | #define PAGE_FLAGS_LAYOUT_H | |
3 | ||
4 | #include <linux/numa.h> | |
5 | #include <generated/bounds.h> | |
6 | ||
7 | /* | |
8 | * When a memory allocation must conform to specific limitations (such | |
9 | * as being suitable for DMA) the caller will pass in hints to the | |
10 | * allocator in the gfp_mask, in the zone modifier bits. These bits | |
11 | * are used to select a priority ordered list of memory zones which | |
12 | * match the requested limits. See gfp_zone() in include/linux/gfp.h | |
13 | */ | |
14 | #if MAX_NR_ZONES < 2 | |
15 | #define ZONES_SHIFT 0 | |
16 | #elif MAX_NR_ZONES <= 2 | |
17 | #define ZONES_SHIFT 1 | |
18 | #elif MAX_NR_ZONES <= 4 | |
19 | #define ZONES_SHIFT 2 | |
20 | #else | |
21 | #error ZONES_SHIFT -- too many zones configured adjust calculation | |
22 | #endif | |
23 | ||
24 | #ifdef CONFIG_SPARSEMEM | |
25 | #include <asm/sparsemem.h> | |
26 | ||
27 | /* SECTION_SHIFT #bits space required to store a section # */ | |
28 | #define SECTIONS_SHIFT (MAX_PHYSMEM_BITS - SECTION_SIZE_BITS) | |
29 | ||
30 | #endif /* CONFIG_SPARSEMEM */ | |
31 | ||
32 | /* | |
33 | * page->flags layout: | |
34 | * | |
75980e97 PZ |
35 | * There are five possibilities for how page->flags get laid out. The first |
36 | * pair is for the normal case without sparsemem. The second pair is for | |
37 | * sparsemem when there is plenty of space for node and section information. | |
38 | * The last is when there is insufficient space in page->flags and a separate | |
39 | * lookup is necessary. | |
bbeae5b0 | 40 | * |
b795854b | 41 | * No sparsemem or sparsemem vmemmap: | NODE | ZONE | ... | FLAGS | |
90572890 | 42 | * " plus space for last_cpupid: | NODE | ZONE | LAST_CPUPID ... | FLAGS | |
b795854b | 43 | * classic sparse with space for node:| SECTION | NODE | ZONE | ... | FLAGS | |
90572890 | 44 | * " plus space for last_cpupid: | SECTION | NODE | ZONE | LAST_CPUPID ... | FLAGS | |
bbeae5b0 PZ |
45 | * classic sparse no space for node: | SECTION | ZONE | ... | FLAGS | |
46 | */ | |
47 | #if defined(CONFIG_SPARSEMEM) && !defined(CONFIG_SPARSEMEM_VMEMMAP) | |
48 | #define SECTIONS_WIDTH SECTIONS_SHIFT | |
49 | #else | |
50 | #define SECTIONS_WIDTH 0 | |
51 | #endif | |
52 | ||
53 | #define ZONES_WIDTH ZONES_SHIFT | |
54 | ||
55 | #if SECTIONS_WIDTH+ZONES_WIDTH+NODES_SHIFT <= BITS_PER_LONG - NR_PAGEFLAGS | |
56 | #define NODES_WIDTH NODES_SHIFT | |
57 | #else | |
58 | #ifdef CONFIG_SPARSEMEM_VMEMMAP | |
59 | #error "Vmemmap: No space for nodes field in page flags" | |
60 | #endif | |
61 | #define NODES_WIDTH 0 | |
62 | #endif | |
63 | ||
75980e97 | 64 | #ifdef CONFIG_NUMA_BALANCING |
b795854b MG |
65 | #define LAST__PID_SHIFT 8 |
66 | #define LAST__PID_MASK ((1 << LAST__PID_SHIFT)-1) | |
67 | ||
90572890 PZ |
68 | #define LAST__CPU_SHIFT NR_CPUS_BITS |
69 | #define LAST__CPU_MASK ((1 << LAST__CPU_SHIFT)-1) | |
b795854b | 70 | |
90572890 | 71 | #define LAST_CPUPID_SHIFT (LAST__PID_SHIFT+LAST__CPU_SHIFT) |
75980e97 | 72 | #else |
90572890 | 73 | #define LAST_CPUPID_SHIFT 0 |
75980e97 PZ |
74 | #endif |
75 | ||
90572890 PZ |
76 | #if SECTIONS_WIDTH+ZONES_WIDTH+NODES_SHIFT+LAST_CPUPID_SHIFT <= BITS_PER_LONG - NR_PAGEFLAGS |
77 | #define LAST_CPUPID_WIDTH LAST_CPUPID_SHIFT | |
75980e97 | 78 | #else |
90572890 | 79 | #define LAST_CPUPID_WIDTH 0 |
75980e97 PZ |
80 | #endif |
81 | ||
bbeae5b0 PZ |
82 | /* |
83 | * We are going to use the flags for the page to node mapping if its in | |
84 | * there. This includes the case where there is no node, so it is implicit. | |
85 | */ | |
86 | #if !(NODES_WIDTH > 0 || NODES_SHIFT == 0) | |
87 | #define NODE_NOT_IN_PAGE_FLAGS | |
88 | #endif | |
89 | ||
90572890 PZ |
90 | #if defined(CONFIG_NUMA_BALANCING) && LAST_CPUPID_WIDTH == 0 |
91 | #define LAST_CPUPID_NOT_IN_PAGE_FLAGS | |
75980e97 PZ |
92 | #endif |
93 | ||
bbeae5b0 | 94 | #endif /* _LINUX_PAGE_FLAGS_LAYOUT */ |