projects / mirror_ubuntu-artful-kernel.git / blame
| Commit | Line | Data |
|---|---|---|
| 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 | * | |
| 35 | * There are three possibilities for how page->flags get | |
| 36 | * laid out. The first is for the normal case, without | |
| 37 | * sparsemem. The second is for sparsemem when there is | |
| 38 | * plenty of space for node and section. The last is when | |
| 39 | * we have run out of space and have to fall back to an | |
| 40 | * alternate (slower) way of determining the node. | |
| 41 | * | |
| 42 | * No sparsemem or sparsemem vmemmap: | NODE | ZONE | ... | FLAGS | | |
| 43 | * classic sparse with space for node:| SECTION | NODE | ZONE | ... | FLAGS | | |
| 44 | * classic sparse no space for node: | SECTION | ZONE | ... | FLAGS | | |
| 45 | */ | |
| 46 | #if defined(CONFIG_SPARSEMEM) && !defined(CONFIG_SPARSEMEM_VMEMMAP) | |
| 47 | #define SECTIONS_WIDTH SECTIONS_SHIFT | |
| 48 | #else | |
| 49 | #define SECTIONS_WIDTH 0 | |
| 50 | #endif | |
| 51 | ||
| 52 | #define ZONES_WIDTH ZONES_SHIFT | |
| 53 | ||
| 54 | #if SECTIONS_WIDTH+ZONES_WIDTH+NODES_SHIFT <= BITS_PER_LONG - NR_PAGEFLAGS | |
| 55 | #define NODES_WIDTH NODES_SHIFT | |
| 56 | #else | |
| 57 | #ifdef CONFIG_SPARSEMEM_VMEMMAP | |
| 58 | #error "Vmemmap: No space for nodes field in page flags" | |
| 59 | #endif | |
| 60 | #define NODES_WIDTH 0 | |
| 61 | #endif | |
| 62 | ||
| 63 | /* | |
| 64 | * We are going to use the flags for the page to node mapping if its in | |
| 65 | * there. This includes the case where there is no node, so it is implicit. | |
| 66 | */ | |
| 67 | #if !(NODES_WIDTH > 0 || NODES_SHIFT == 0) | |
| 68 | #define NODE_NOT_IN_PAGE_FLAGS | |
| 69 | #endif | |
| 70 | ||
| 71 | #endif /* _LINUX_PAGE_FLAGS_LAYOUT */ |