| #ifndef _LINUX_MM_TYPES_H |
| #define _LINUX_MM_TYPES_H |
| |
| #include <linux/types.h> |
| #include <linux/threads.h> |
| #include <linux/list.h> |
| #include <linux/spinlock.h> |
| |
| struct address_space; |
| |
| /* |
| * Each physical page in the system has a struct page associated with |
| * it to keep track of whatever it is we are using the page for at the |
| * moment. Note that we have no way to track which tasks are using |
| * a page, though if it is a pagecache page, rmap structures can tell us |
| * who is mapping it. |
| */ |
| struct page { |
| unsigned long flags; /* Atomic flags, some possibly |
| * updated asynchronously */ |
| atomic_t _count; /* Usage count, see below. */ |
| union { |
| atomic_t _mapcount; /* Count of ptes mapped in mms, |
| * to show when page is mapped |
| * & limit reverse map searches. |
| */ |
| struct { /* SLUB uses */ |
| short unsigned int inuse; |
| short unsigned int offset; |
| }; |
| }; |
| union { |
| struct { |
| unsigned long private; /* Mapping-private opaque data: |
| * usually used for buffer_heads |
| * if PagePrivate set; used for |
| * swp_entry_t if PageSwapCache; |
| * indicates order in the buddy |
| * system if PG_buddy is set. |
| */ |
| struct address_space *mapping; /* If low bit clear, points to |
| * inode address_space, or NULL. |
| * If page mapped as anonymous |
| * memory, low bit is set, and |
| * it points to anon_vma object: |
| * see PAGE_MAPPING_ANON below. |
| */ |
| }; |
| #if NR_CPUS >= CONFIG_SPLIT_PTLOCK_CPUS |
| spinlock_t ptl; |
| #endif |
| struct { /* SLUB uses */ |
| struct page *first_page; /* Compound pages */ |
| struct kmem_cache *slab; /* Pointer to slab */ |
| }; |
| }; |
| union { |
| pgoff_t index; /* Our offset within mapping. */ |
| void *freelist; /* SLUB: pointer to free object */ |
| }; |
| struct list_head lru; /* Pageout list, eg. active_list |
| * protected by zone->lru_lock ! |
| */ |
| /* |
| * On machines where all RAM is mapped into kernel address space, |
| * we can simply calculate the virtual address. On machines with |
| * highmem some memory is mapped into kernel virtual memory |
| * dynamically, so we need a place to store that address. |
| * Note that this field could be 16 bits on x86 ... ;) |
| * |
| * Architectures with slow multiplication can define |
| * WANT_PAGE_VIRTUAL in asm/page.h |
| */ |
| #if defined(WANT_PAGE_VIRTUAL) |
| void *virtual; /* Kernel virtual address (NULL if |
| not kmapped, ie. highmem) */ |
| #endif /* WANT_PAGE_VIRTUAL */ |
| }; |
| |
| #endif /* _LINUX_MM_TYPES_H */ |