150 lines
4.2 KiB
C
150 lines
4.2 KiB
C
#ifndef _LINUX_RMAP_H
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#define _LINUX_RMAP_H
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/*
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* Declarations for Reverse Mapping functions in mm/rmap.c
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*/
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#include <linux/list.h>
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#include <linux/slab.h>
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#include <linux/mm.h>
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#include <linux/spinlock.h>
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#include <linux/memcontrol.h>
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/*
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* The anon_vma heads a list of private "related" vmas, to scan if
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* an anonymous page pointing to this anon_vma needs to be unmapped:
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* the vmas on the list will be related by forking, or by splitting.
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*
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* Since vmas come and go as they are split and merged (particularly
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* in mprotect), the mapping field of an anonymous page cannot point
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* directly to a vma: instead it points to an anon_vma, on whose list
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* the related vmas can be easily linked or unlinked.
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*
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* After unlinking the last vma on the list, we must garbage collect
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* the anon_vma object itself: we're guaranteed no page can be
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* pointing to this anon_vma once its vma list is empty.
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*/
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struct anon_vma {
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spinlock_t lock; /* Serialize access to vma list */
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/*
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* NOTE: the LSB of the head.next is set by
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* mm_take_all_locks() _after_ taking the above lock. So the
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* head must only be read/written after taking the above lock
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* to be sure to see a valid next pointer. The LSB bit itself
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* is serialized by a system wide lock only visible to
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* mm_take_all_locks() (mm_all_locks_mutex).
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*/
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struct list_head head; /* List of private "related" vmas */
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};
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#ifdef CONFIG_MMU
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static inline void anon_vma_lock(struct vm_area_struct *vma)
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{
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struct anon_vma *anon_vma = vma->anon_vma;
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if (anon_vma)
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spin_lock(&anon_vma->lock);
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}
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static inline void anon_vma_unlock(struct vm_area_struct *vma)
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{
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struct anon_vma *anon_vma = vma->anon_vma;
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if (anon_vma)
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spin_unlock(&anon_vma->lock);
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}
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/*
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* anon_vma helper functions.
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*/
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void anon_vma_init(void); /* create anon_vma_cachep */
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int anon_vma_prepare(struct vm_area_struct *);
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void __anon_vma_merge(struct vm_area_struct *, struct vm_area_struct *);
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void anon_vma_unlink(struct vm_area_struct *);
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void anon_vma_link(struct vm_area_struct *);
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void __anon_vma_link(struct vm_area_struct *);
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extern struct anon_vma *page_lock_anon_vma(struct page *page);
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extern void page_unlock_anon_vma(struct anon_vma *anon_vma);
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/*
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* rmap interfaces called when adding or removing pte of page
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*/
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void page_add_anon_rmap(struct page *, struct vm_area_struct *, unsigned long);
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void page_add_new_anon_rmap(struct page *, struct vm_area_struct *, unsigned long);
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void page_add_file_rmap(struct page *);
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void page_remove_rmap(struct page *, struct vm_area_struct *);
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#ifdef CONFIG_DEBUG_VM
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void page_dup_rmap(struct page *page, struct vm_area_struct *vma, unsigned long address);
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#else
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static inline void page_dup_rmap(struct page *page, struct vm_area_struct *vma, unsigned long address)
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{
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atomic_inc(&page->_mapcount);
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}
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#endif
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/*
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* Called from mm/vmscan.c to handle paging out
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*/
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int page_referenced(struct page *, int is_locked, struct mem_cgroup *cnt);
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int try_to_unmap(struct page *, int ignore_refs);
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/*
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* Called from mm/filemap_xip.c to unmap empty zero page
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*/
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pte_t *page_check_address(struct page *, struct mm_struct *,
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unsigned long, spinlock_t **, int);
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/*
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* Used by swapoff to help locate where page is expected in vma.
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*/
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unsigned long page_address_in_vma(struct page *, struct vm_area_struct *);
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/*
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* Cleans the PTEs of shared mappings.
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* (and since clean PTEs should also be readonly, write protects them too)
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*
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* returns the number of cleaned PTEs.
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*/
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int page_mkclean(struct page *);
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#ifdef CONFIG_UNEVICTABLE_LRU
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/*
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* called in munlock()/munmap() path to check for other vmas holding
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* the page mlocked.
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*/
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int try_to_munlock(struct page *);
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#else
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static inline int try_to_munlock(struct page *page)
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{
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return 0; /* a.k.a. SWAP_SUCCESS */
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}
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#endif
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#else /* !CONFIG_MMU */
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#define anon_vma_init() do {} while (0)
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#define anon_vma_prepare(vma) (0)
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#define anon_vma_link(vma) do {} while (0)
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#define page_referenced(page,l,cnt) TestClearPageReferenced(page)
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#define try_to_unmap(page, refs) SWAP_FAIL
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static inline int page_mkclean(struct page *page)
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{
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return 0;
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}
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#endif /* CONFIG_MMU */
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/*
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* Return values of try_to_unmap
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*/
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#define SWAP_SUCCESS 0
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#define SWAP_AGAIN 1
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#define SWAP_FAIL 2
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#define SWAP_MLOCK 3
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#endif /* _LINUX_RMAP_H */
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