[NET]: Inline net_device_stats
[linux-2.6.git] / include / linux / mm_types.h
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 */