1 #ifndef PAGE_FLAGS_LAYOUT_H
2 #define PAGE_FLAGS_LAYOUT_H
4 #include <linux/numa.h>
5 #include <generated/bounds.h>
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
16 #elif MAX_NR_ZONES <= 2
18 #elif MAX_NR_ZONES <= 4
21 #error ZONES_SHIFT -- too many zones configured adjust calculation
24 #ifdef CONFIG_SPARSEMEM
25 #include <asm/sparsemem.h>
27 /* SECTION_SHIFT #bits space required to store a section # */
28 #define SECTIONS_SHIFT (MAX_PHYSMEM_BITS - SECTION_SIZE_BITS)
30 #endif /* CONFIG_SPARSEMEM */
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.
41 * No sparsemem or sparsemem vmemmap: | NODE | ZONE | ... | FLAGS |
42 * " plus space for last_nid: | NODE | ZONE | LAST_NID ... | FLAGS |
43 * classic sparse with space for node:| SECTION | NODE | ZONE | ... | FLAGS |
44 * " plus space for last_nid: | SECTION | NODE | ZONE | LAST_NID ... | FLAGS |
45 * classic sparse no space for node: | SECTION | ZONE | ... | FLAGS |
47 #if defined(CONFIG_SPARSEMEM) && !defined(CONFIG_SPARSEMEM_VMEMMAP)
48 #define SECTIONS_WIDTH SECTIONS_SHIFT
50 #define SECTIONS_WIDTH 0
53 #define ZONES_WIDTH ZONES_SHIFT
55 #if SECTIONS_WIDTH+ZONES_WIDTH+NODES_SHIFT <= BITS_PER_LONG - NR_PAGEFLAGS
56 #define NODES_WIDTH NODES_SHIFT
58 #ifdef CONFIG_SPARSEMEM_VMEMMAP
59 #error "Vmemmap: No space for nodes field in page flags"
64 #ifdef CONFIG_NUMA_BALANCING
65 #define LAST_NID_SHIFT NODES_SHIFT
67 #define LAST_NID_SHIFT 0
70 #if SECTIONS_WIDTH+ZONES_WIDTH+NODES_SHIFT+LAST_NID_SHIFT <= BITS_PER_LONG - NR_PAGEFLAGS
71 #define LAST_NID_WIDTH LAST_NID_SHIFT
73 #define LAST_NID_WIDTH 0
77 * We are going to use the flags for the page to node mapping if its in
78 * there. This includes the case where there is no node, so it is implicit.
80 #if !(NODES_WIDTH > 0 || NODES_SHIFT == 0)
81 #define NODE_NOT_IN_PAGE_FLAGS
84 #if defined(CONFIG_NUMA_BALANCING) && LAST_NID_WIDTH == 0
85 #define LAST_NID_NOT_IN_PAGE_FLAGS
88 #endif /* _LINUX_PAGE_FLAGS_LAYOUT */
This page took 0.033472 seconds and 5 git commands to generate.