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 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. 40 * 41 * No sparsemem or sparsemem vmemmap: | NODE | ZONE | ... | FLAGS | 42 * " plus space for last_cpupid: | NODE | ZONE | LAST_CPUPID ... | FLAGS | 43 * classic sparse with space for node:| SECTION | NODE | ZONE | ... | FLAGS | 44 * " plus space for last_cpupid: | SECTION | NODE | ZONE | LAST_CPUPID ... | FLAGS | 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 64 #ifdef CONFIG_NUMA_BALANCING 65 #define LAST__PID_SHIFT 8 66 #define LAST__PID_MASK ((1 << LAST__PID_SHIFT)-1) 67 68 #define LAST__CPU_SHIFT NR_CPUS_BITS 69 #define LAST__CPU_MASK ((1 << LAST__CPU_SHIFT)-1) 70 71 #define LAST_CPUPID_SHIFT (LAST__PID_SHIFT+LAST__CPU_SHIFT) 72 #else 73 #define LAST_CPUPID_SHIFT 0 74 #endif 75 76 #if SECTIONS_WIDTH+ZONES_WIDTH+NODES_SHIFT+LAST_CPUPID_SHIFT <= BITS_PER_LONG - NR_PAGEFLAGS 77 #define LAST_CPUPID_WIDTH LAST_CPUPID_SHIFT 78 #else 79 #define LAST_CPUPID_WIDTH 0 80 #endif 81 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 90 #if defined(CONFIG_NUMA_BALANCING) && LAST_CPUPID_WIDTH == 0 91 #define LAST_CPUPID_NOT_IN_PAGE_FLAGS 92 #endif 93 94 #endif /* _LINUX_PAGE_FLAGS_LAYOUT */ 95