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Release 4.16 include/linux/rmap.h

Directory: include/linux
/* SPDX-License-Identifier: GPL-2.0 */
#ifndef _LINUX_RMAP_H

#define _LINUX_RMAP_H
/*
 * Declarations for Reverse Mapping functions in mm/rmap.c
 */

#include <linux/list.h>
#include <linux/slab.h>
#include <linux/mm.h>
#include <linux/rwsem.h>
#include <linux/memcontrol.h>
#include <linux/highmem.h>

/*
 * The anon_vma heads a list of private "related" vmas, to scan if
 * an anonymous page pointing to this anon_vma needs to be unmapped:
 * the vmas on the list will be related by forking, or by splitting.
 *
 * Since vmas come and go as they are split and merged (particularly
 * in mprotect), the mapping field of an anonymous page cannot point
 * directly to a vma: instead it points to an anon_vma, on whose list
 * the related vmas can be easily linked or unlinked.
 *
 * After unlinking the last vma on the list, we must garbage collect
 * the anon_vma object itself: we're guaranteed no page can be
 * pointing to this anon_vma once its vma list is empty.
 */

struct anon_vma {
	
struct anon_vma *root;		/* Root of this anon_vma tree */
	
struct rw_semaphore rwsem;	/* W: modification, R: walking the list */
	/*
         * The refcount is taken on an anon_vma when there is no
         * guarantee that the vma of page tables will exist for
         * the duration of the operation. A caller that takes
         * the reference is responsible for clearing up the
         * anon_vma if they are the last user on release
         */
	
atomic_t refcount;

	/*
         * Count of child anon_vmas and VMAs which points to this anon_vma.
         *
         * This counter is used for making decision about reusing anon_vma
         * instead of forking new one. See comments in function anon_vma_clone.
         */
	
unsigned degree;

	
struct anon_vma *parent;	/* Parent of this anon_vma */

	/*
         * NOTE: the LSB of the rb_root.rb_node is set by
         * mm_take_all_locks() _after_ taking the above lock. So the
         * rb_root must only be read/written after taking the above lock
         * to be sure to see a valid next pointer. The LSB bit itself
         * is serialized by a system wide lock only visible to
         * mm_take_all_locks() (mm_all_locks_mutex).
         */

	/* Interval tree of private "related" vmas */
	
struct rb_root_cached rb_root;
};

/*
 * The copy-on-write semantics of fork mean that an anon_vma
 * can become associated with multiple processes. Furthermore,
 * each child process will have its own anon_vma, where new
 * pages for that process are instantiated.
 *
 * This structure allows us to find the anon_vmas associated
 * with a VMA, or the VMAs associated with an anon_vma.
 * The "same_vma" list contains the anon_vma_chains linking
 * all the anon_vmas associated with this VMA.
 * The "rb" field indexes on an interval tree the anon_vma_chains
 * which link all the VMAs associated with this anon_vma.
 */

struct anon_vma_chain {
	
struct vm_area_struct *vma;
	
struct anon_vma *anon_vma;
	
struct list_head same_vma;   /* locked by mmap_sem & page_table_lock */
	
struct rb_node rb;			/* locked by anon_vma->rwsem */
	
unsigned long rb_subtree_last;
#ifdef CONFIG_DEBUG_VM_RB
	

unsigned long cached_vma_start, cached_vma_last;
#endif
};


enum ttu_flags {
	
TTU_MIGRATION		= 0x1,	/* migration mode */
	
TTU_MUNLOCK		= 0x2,	/* munlock mode */

	
TTU_SPLIT_HUGE_PMD	= 0x4,	/* split huge PMD if any */
	
TTU_IGNORE_MLOCK	= 0x8,	/* ignore mlock */
	
TTU_IGNORE_ACCESS	= 0x10,	/* don't age */
	
TTU_IGNORE_HWPOISON	= 0x20,	/* corrupted page is recoverable */
	
TTU_BATCH_FLUSH		= 0x40,	/* Batch TLB flushes where possible
                                         * and caller guarantees they will
                                         * do a final flush if necessary */
	
TTU_RMAP_LOCKED		= 0x80,	/* do not grab rmap lock:
                                         * caller holds it */
	
TTU_SPLIT_FREEZE	= 0x100,		/* freeze pte under splitting thp */
};

#ifdef CONFIG_MMU

static inline void get_anon_vma(struct anon_vma *anon_vma) { atomic_inc(&anon_vma->refcount); }

Contributors

PersonTokensPropCommitsCommitProp
Rik Van Riel1995.00%150.00%
Peter Zijlstra15.00%150.00%
Total20100.00%2100.00%

void __put_anon_vma(struct anon_vma *anon_vma);
static inline void put_anon_vma(struct anon_vma *anon_vma) { if (atomic_dec_and_test(&anon_vma->refcount)) __put_anon_vma(anon_vma); }

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PersonTokensPropCommitsCommitProp
Peter Zijlstra27100.00%1100.00%
Total27100.00%1100.00%


static inline void anon_vma_lock_write(struct anon_vma *anon_vma) { down_write(&anon_vma->root->rwsem); }

Contributors

PersonTokensPropCommitsCommitProp
Rik Van Riel1986.36%250.00%
Ingo Molnar313.64%250.00%
Total22100.00%4100.00%


static inline void anon_vma_unlock_write(struct anon_vma *anon_vma) { up_write(&anon_vma->root->rwsem); }

Contributors

PersonTokensPropCommitsCommitProp
Rik Van Riel1986.36%250.00%
Ingo Molnar29.09%125.00%
Konstantin Khlebnikov14.55%125.00%
Total22100.00%4100.00%


static inline void anon_vma_lock_read(struct anon_vma *anon_vma) { down_read(&anon_vma->root->rwsem); }

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PersonTokensPropCommitsCommitProp
Ingo Molnar22100.00%1100.00%
Total22100.00%1100.00%


static inline void anon_vma_unlock_read(struct anon_vma *anon_vma) { up_read(&anon_vma->root->rwsem); }

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PersonTokensPropCommitsCommitProp
Ingo Molnar22100.00%1100.00%
Total22100.00%1100.00%

/* * anon_vma helper functions. */ void anon_vma_init(void); /* create anon_vma_cachep */ int __anon_vma_prepare(struct vm_area_struct *); void unlink_anon_vmas(struct vm_area_struct *); int anon_vma_clone(struct vm_area_struct *, struct vm_area_struct *); int anon_vma_fork(struct vm_area_struct *, struct vm_area_struct *);
static inline int anon_vma_prepare(struct vm_area_struct *vma) { if (likely(vma->anon_vma)) return 0; return __anon_vma_prepare(vma); }

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Vlastimil Babka30100.00%1100.00%
Total30100.00%1100.00%


static inline void anon_vma_merge(struct vm_area_struct *vma, struct vm_area_struct *next) { VM_BUG_ON_VMA(vma->anon_vma != next->anon_vma, vma); unlink_anon_vmas(next); }

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PersonTokensPropCommitsCommitProp
Rik Van Riel3291.43%150.00%
Sasha Levin38.57%150.00%
Total35100.00%2100.00%

struct anon_vma *page_get_anon_vma(struct page *page); /* bitflags for do_page_add_anon_rmap() */ #define RMAP_EXCLUSIVE 0x01 #define RMAP_COMPOUND 0x02 /* * rmap interfaces called when adding or removing pte of page */ void page_move_anon_rmap(struct page *, struct vm_area_struct *); void page_add_anon_rmap(struct page *, struct vm_area_struct *, unsigned long, bool); void do_page_add_anon_rmap(struct page *, struct vm_area_struct *, unsigned long, int); void page_add_new_anon_rmap(struct page *, struct vm_area_struct *, unsigned long, bool); void page_add_file_rmap(struct page *, bool); void page_remove_rmap(struct page *, bool); void hugepage_add_anon_rmap(struct page *, struct vm_area_struct *, unsigned long); void hugepage_add_new_anon_rmap(struct page *, struct vm_area_struct *, unsigned long);
static inline void page_dup_rmap(struct page *page, bool compound) { atomic_inc(compound ? compound_mapcount_ptr(page) : &page->_mapcount); }

Contributors

PersonTokensPropCommitsCommitProp
Andrew Morton1756.67%133.33%
Kirill A. Shutemov1033.33%133.33%
Hugh Dickins310.00%133.33%
Total30100.00%3100.00%

/* * Called from mm/vmscan.c to handle paging out */ int page_referenced(struct page *, int is_locked, struct mem_cgroup *memcg, unsigned long *vm_flags); bool try_to_unmap(struct page *, enum ttu_flags flags); /* Avoid racy checks */ #define PVMW_SYNC (1 << 0) /* Look for migarion entries rather than present PTEs */ #define PVMW_MIGRATION (1 << 1) struct page_vma_mapped_walk { struct page *page; struct vm_area_struct *vma; unsigned long address; pmd_t *pmd; pte_t *pte; spinlock_t *ptl; unsigned int flags; };
static inline void page_vma_mapped_walk_done(struct page_vma_mapped_walk *pvmw) { if (pvmw->pte) pte_unmap(pvmw->pte); if (pvmw->ptl) spin_unlock(pvmw->ptl); }

Contributors

PersonTokensPropCommitsCommitProp
Kirill A. Shutemov38100.00%1100.00%
Total38100.00%1100.00%

bool page_vma_mapped_walk(struct page_vma_mapped_walk *pvmw); /* * Used by swapoff to help locate where page is expected in vma. */ unsigned long page_address_in_vma(struct page *, struct vm_area_struct *); /* * Cleans the PTEs of shared mappings. * (and since clean PTEs should also be readonly, write protects them too) * * returns the number of cleaned PTEs. */ int page_mkclean(struct page *); /* * called in munlock()/munmap() path to check for other vmas holding * the page mlocked. */ void try_to_munlock(struct page *); void remove_migration_ptes(struct page *old, struct page *new, bool locked); /* * Called by memory-failure.c to kill processes. */ struct anon_vma *page_lock_anon_vma_read(struct page *page); void page_unlock_anon_vma_read(struct anon_vma *anon_vma); int page_mapped_in_vma(struct page *page, struct vm_area_struct *vma); /* * rmap_walk_control: To control rmap traversing for specific needs * * arg: passed to rmap_one() and invalid_vma() * rmap_one: executed on each vma where page is mapped * done: for checking traversing termination condition * anon_lock: for getting anon_lock by optimized way rather than default * invalid_vma: for skipping uninterested vma */ struct rmap_walk_control { void *arg; /* * Return false if page table scanning in rmap_walk should be stopped. * Otherwise, return true. */ bool (*rmap_one)(struct page *page, struct vm_area_struct *vma, unsigned long addr, void *arg); int (*done)(struct page *page); struct anon_vma *(*anon_lock)(struct page *page); bool (*invalid_vma)(struct vm_area_struct *vma, void *arg); }; void rmap_walk(struct page *page, struct rmap_walk_control *rwc); void rmap_walk_locked(struct page *page, struct rmap_walk_control *rwc); #else /* !CONFIG_MMU */ #define anon_vma_init() do {} while (0) #define anon_vma_prepare(vma) (0) #define anon_vma_link(vma) do {} while (0)
static inline int page_referenced(struct page *page, int is_locked, struct mem_cgroup *memcg, unsigned long *vm_flags) { *vm_flags = 0; return 0; }

Contributors

PersonTokensPropCommitsCommitProp
Mike Frysinger2472.73%114.29%
Andrew Morton412.12%114.29%
Johannes Weiner26.06%228.57%
Fengguang Wu13.03%114.29%
Balbir Singh13.03%114.29%
Hugh Dickins13.03%114.29%
Total33100.00%7100.00%

#define try_to_unmap(page, refs) false
static inline int page_mkclean(struct page *page) { return 0; }

Contributors

PersonTokensPropCommitsCommitProp
Peter Zijlstra15100.00%1100.00%
Total15100.00%1100.00%

#endif /* CONFIG_MMU */ #endif /* _LINUX_RMAP_H */

Overall Contributors

PersonTokensPropCommitsCommitProp
Rik Van Riel16616.96%711.29%
Andrew Morton16116.45%58.06%
Kirill A. Shutemov16016.34%812.90%
Peter Zijlstra686.95%46.45%
JoonSoo Kim646.54%23.23%
Ingo Molnar565.72%23.23%
Hugh Dickins454.60%34.84%
Andi Kleen363.68%34.84%
Naoya Horiguchi363.68%23.23%
MinChan Kim323.27%58.06%
Vlastimil Babka313.17%11.61%
Nicholas Piggin252.55%23.23%
Mike Frysinger242.45%11.61%
Michel Lespinasse202.04%23.23%
Konstantin Khlebnikov111.12%23.23%
Balbir Singh80.82%11.61%
Shaohua Li80.82%11.61%
Fengguang Wu60.61%11.61%
Mel Gorman60.61%23.23%
Johannes Weiner30.31%23.23%
Christoph Lameter30.31%11.61%
Sasha Levin30.31%11.61%
Chris Wright30.31%11.61%
Davidlohr Bueso A20.20%11.61%
Richard Kennedy10.10%11.61%
Greg Kroah-Hartman10.10%11.61%
Total979100.00%62100.00%
Directory: include/linux
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