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