| | 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 | #elif MAX_NR_ZONES <= 8 |
| | 21 | #define ZONES_SHIFT 3 |
| | 22 | #else |
| | 23 | #error ZONES_SHIFT -- too many zones configured adjust calculation |
| | 24 | #endif |
| | 25 | |
| | 26 | #ifdef CONFIG_SPARSEMEM |
| | 27 | #include <asm/sparsemem.h> |
| | 28 | |
| | 29 | /* SECTION_SHIFT #bits space required to store a section # */ |
| | 30 | #define SECTIONS_SHIFT (MAX_PHYSMEM_BITS - SECTION_SIZE_BITS) |
| | 31 | |
| | 32 | #endif /* CONFIG_SPARSEMEM */ |
| | 33 | |
| | 34 | /* |
| | 35 | * page->flags layout: |
| | 36 | * |
| | 37 | * There are five possibilities for how page->flags get laid out. The first |
| | 38 | * pair is for the normal case without sparsemem. The second pair is for |
| | 39 | * sparsemem when there is plenty of space for node and section information. |
| | 40 | * The last is when there is insufficient space in page->flags and a separate |
| | 41 | * lookup is necessary. |
| | 42 | * |
| | 43 | * No sparsemem or sparsemem vmemmap: | NODE | ZONE | ... | FLAGS | |
| | 44 | * " plus space for last_cpupid: | NODE | ZONE | LAST_CPUPID ... | FLAGS | |
| | 45 | * classic sparse with space for node:| SECTION | NODE | ZONE | ... | FLAGS | |
| | 46 | * " plus space for last_cpupid: | SECTION | NODE | ZONE | LAST_CPUPID ... | FLAGS | |
| | 47 | * classic sparse no space for node: | SECTION | ZONE | ... | FLAGS | |
| | 48 | */ |
| | 49 | #if defined(CONFIG_SPARSEMEM) && !defined(CONFIG_SPARSEMEM_VMEMMAP) |
| | 50 | #define SECTIONS_WIDTH SECTIONS_SHIFT |
| | 51 | #else |
| | 52 | #define SECTIONS_WIDTH 0 |
| | 53 | #endif |
| | 54 | |
| | 55 | #define ZONES_WIDTH ZONES_SHIFT |
| | 56 | |
| | 57 | #if SECTIONS_WIDTH+ZONES_WIDTH+NODES_SHIFT <= BITS_PER_LONG - NR_PAGEFLAGS |
| | 58 | #define NODES_WIDTH NODES_SHIFT |
| | 59 | #else |
| | 60 | #ifdef CONFIG_SPARSEMEM_VMEMMAP |
| | 61 | #error "Vmemmap: No space for nodes field in page flags" |
| | 62 | #endif |
| | 63 | #define NODES_WIDTH 0 |
| | 64 | #endif |
| | 65 | |
| | 66 | #ifdef CONFIG_NUMA_BALANCING |
| | 67 | #define LAST__PID_SHIFT 8 |
| | 68 | #define LAST__PID_MASK ((1 << LAST__PID_SHIFT)-1) |
| | 69 | |
| | 70 | #define LAST__CPU_SHIFT NR_CPUS_BITS |
| | 71 | #define LAST__CPU_MASK ((1 << LAST__CPU_SHIFT)-1) |
| | 72 | |
| | 73 | #define LAST_CPUPID_SHIFT (LAST__PID_SHIFT+LAST__CPU_SHIFT) |
| | 74 | #else |
| | 75 | #define LAST_CPUPID_SHIFT 0 |
| | 76 | #endif |
| | 77 | |
| | 78 | #if SECTIONS_WIDTH+ZONES_WIDTH+NODES_SHIFT+LAST_CPUPID_SHIFT <= BITS_PER_LONG - NR_PAGEFLAGS |
| | 79 | #define LAST_CPUPID_WIDTH LAST_CPUPID_SHIFT |
| | 80 | #else |
| | 81 | #define LAST_CPUPID_WIDTH 0 |
| | 82 | #endif |
| | 83 | |
| | 84 | /* |
| | 85 | * We are going to use the flags for the page to node mapping if its in |
| | 86 | * there. This includes the case where there is no node, so it is implicit. |
| | 87 | */ |
| | 88 | #if !(NODES_WIDTH > 0 || NODES_SHIFT == 0) |
| | 89 | #define NODE_NOT_IN_PAGE_FLAGS |
| | 90 | #endif |
| | 91 | |
| | 92 | #if defined(CONFIG_NUMA_BALANCING) && LAST_CPUPID_WIDTH == 0 |
| | 93 | #define LAST_CPUPID_NOT_IN_PAGE_FLAGS |
| | 94 | #endif |
| | 95 | |
| | 96 | #endif /* _LINUX_PAGE_FLAGS_LAYOUT */ |
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