Heiko Carstens | 5b99cd0 | 2006-09-27 01:50:01 -0700 | [diff] [blame] | 1 | #ifndef _LINUX_MM_TYPES_H |
| 2 | #define _LINUX_MM_TYPES_H |
| 3 | |
| 4 | #include <linux/types.h> |
| 5 | #include <linux/threads.h> |
| 6 | #include <linux/list.h> |
| 7 | #include <linux/spinlock.h> |
| 8 | |
| 9 | struct address_space; |
| 10 | |
| 11 | /* |
| 12 | * Each physical page in the system has a struct page associated with |
| 13 | * it to keep track of whatever it is we are using the page for at the |
| 14 | * moment. Note that we have no way to track which tasks are using |
| 15 | * a page, though if it is a pagecache page, rmap structures can tell us |
| 16 | * who is mapping it. |
| 17 | */ |
| 18 | struct page { |
| 19 | unsigned long flags; /* Atomic flags, some possibly |
| 20 | * updated asynchronously */ |
| 21 | atomic_t _count; /* Usage count, see below. */ |
| 22 | atomic_t _mapcount; /* Count of ptes mapped in mms, |
| 23 | * to show when page is mapped |
| 24 | * & limit reverse map searches. |
| 25 | */ |
| 26 | union { |
| 27 | struct { |
| 28 | unsigned long private; /* Mapping-private opaque data: |
| 29 | * usually used for buffer_heads |
| 30 | * if PagePrivate set; used for |
| 31 | * swp_entry_t if PageSwapCache; |
| 32 | * indicates order in the buddy |
| 33 | * system if PG_buddy is set. |
| 34 | */ |
| 35 | struct address_space *mapping; /* If low bit clear, points to |
| 36 | * inode address_space, or NULL. |
| 37 | * If page mapped as anonymous |
| 38 | * memory, low bit is set, and |
| 39 | * it points to anon_vma object: |
| 40 | * see PAGE_MAPPING_ANON below. |
| 41 | */ |
| 42 | }; |
| 43 | #if NR_CPUS >= CONFIG_SPLIT_PTLOCK_CPUS |
| 44 | spinlock_t ptl; |
| 45 | #endif |
| 46 | }; |
| 47 | pgoff_t index; /* Our offset within mapping. */ |
| 48 | struct list_head lru; /* Pageout list, eg. active_list |
| 49 | * protected by zone->lru_lock ! |
| 50 | */ |
| 51 | /* |
| 52 | * On machines where all RAM is mapped into kernel address space, |
| 53 | * we can simply calculate the virtual address. On machines with |
| 54 | * highmem some memory is mapped into kernel virtual memory |
| 55 | * dynamically, so we need a place to store that address. |
| 56 | * Note that this field could be 16 bits on x86 ... ;) |
| 57 | * |
| 58 | * Architectures with slow multiplication can define |
| 59 | * WANT_PAGE_VIRTUAL in asm/page.h |
| 60 | */ |
| 61 | #if defined(WANT_PAGE_VIRTUAL) |
| 62 | void *virtual; /* Kernel virtual address (NULL if |
| 63 | not kmapped, ie. highmem) */ |
| 64 | #endif /* WANT_PAGE_VIRTUAL */ |
| 65 | }; |
| 66 | |
| 67 | #endif /* _LINUX_MM_TYPES_H */ |