Contributors: 41
| Author |
Tokens |
Token Proportion |
Commits |
Commit Proportion |
| Andrew Morton |
246 |
17.39% |
10 |
8.33% |
| David Hildenbrand |
200 |
14.13% |
7 |
5.83% |
| Matthew Wilcox |
141 |
9.96% |
12 |
10.00% |
| Kirill A. Shutemov |
124 |
8.76% |
7 |
5.83% |
| Rik Van Riel |
119 |
8.41% |
7 |
5.83% |
| Hugh Dickins |
76 |
5.37% |
8 |
6.67% |
| JoonSoo Kim |
63 |
4.45% |
2 |
1.67% |
| Peter Zijlstra |
61 |
4.31% |
5 |
4.17% |
| Andi Kleen |
45 |
3.18% |
3 |
2.50% |
| Linus Torvalds (pre-git) |
38 |
2.69% |
9 |
7.50% |
| MinChan Kim |
38 |
2.69% |
4 |
3.33% |
| Vlastimil Babka |
25 |
1.77% |
1 |
0.83% |
| Mike Frysinger |
23 |
1.63% |
1 |
0.83% |
| Ingo Molnar |
23 |
1.63% |
2 |
1.67% |
| Michel Lespinasse |
21 |
1.48% |
3 |
2.50% |
| Nicholas Piggin |
15 |
1.06% |
2 |
1.67% |
| Song Muchun |
15 |
1.06% |
1 |
0.83% |
| Christoph Hellwig |
14 |
0.99% |
2 |
1.67% |
| Alistair Popple |
13 |
0.92% |
2 |
1.67% |
| Mel Gorman |
12 |
0.85% |
3 |
2.50% |
| Naoya Horiguchi |
12 |
0.85% |
3 |
2.50% |
| Konstantin Khlebnikov |
9 |
0.64% |
2 |
1.67% |
| Yin Fengwei |
8 |
0.57% |
1 |
0.83% |
| Jann Horn |
8 |
0.57% |
1 |
0.83% |
| Balbir Singh |
8 |
0.57% |
2 |
1.67% |
| Miaohe Lin |
7 |
0.49% |
1 |
0.83% |
| Christoph Lameter |
6 |
0.42% |
1 |
0.83% |
| Fengguang Wu |
6 |
0.42% |
1 |
0.83% |
| Andres Lagar-Cavilla |
5 |
0.35% |
1 |
0.83% |
| Shaohua Li |
5 |
0.35% |
1 |
0.83% |
| Jason Gunthorpe |
5 |
0.35% |
1 |
0.83% |
| Greg Kroah-Hartman |
4 |
0.28% |
2 |
1.67% |
| Linus Torvalds |
4 |
0.28% |
2 |
1.67% |
| Johannes Weiner |
3 |
0.21% |
2 |
1.67% |
| Sasha Levin |
3 |
0.21% |
1 |
0.83% |
| Jérôme Glisse |
3 |
0.21% |
1 |
0.83% |
| Yang Shi |
2 |
0.14% |
2 |
1.67% |
| Davidlohr Bueso A |
2 |
0.14% |
1 |
0.83% |
| Richard Kennedy |
1 |
0.07% |
1 |
0.83% |
| Izik Eidus |
1 |
0.07% |
1 |
0.83% |
| Sidhartha Kumar |
1 |
0.07% |
1 |
0.83% |
| Total |
1415 |
|
120 |
|
/* 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>
#include <linux/pagemap.h>
#include <linux/memremap.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. Equals to the count of all anon_vmas that
* have ->parent pointing to this one, including itself.
*
* This counter is used for making decision about reusing anon_vma
* instead of forking new one. See comments in function anon_vma_clone.
*/
unsigned long num_children;
/* Count of VMAs whose ->anon_vma pointer points to this object. */
unsigned long num_active_vmas;
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_lock & 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_SPLIT_HUGE_PMD = 0x4, /* split huge PMD if any */
TTU_IGNORE_MLOCK = 0x8, /* ignore mlock */
TTU_SYNC = 0x10, /* avoid racy checks with PVMW_SYNC */
TTU_HWPOISON = 0x20, /* do convert pte to hwpoison entry */
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 */
};
#ifdef CONFIG_MMU
static inline void get_anon_vma(struct anon_vma *anon_vma)
{
atomic_inc(&anon_vma->refcount);
}
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);
}
static inline void anon_vma_lock_write(struct anon_vma *anon_vma)
{
down_write(&anon_vma->root->rwsem);
}
static inline void anon_vma_unlock_write(struct anon_vma *anon_vma)
{
up_write(&anon_vma->root->rwsem);
}
static inline void anon_vma_lock_read(struct anon_vma *anon_vma)
{
down_read(&anon_vma->root->rwsem);
}
static inline int anon_vma_trylock_read(struct anon_vma *anon_vma)
{
return down_read_trylock(&anon_vma->root->rwsem);
}
static inline void anon_vma_unlock_read(struct anon_vma *anon_vma)
{
up_read(&anon_vma->root->rwsem);
}
/*
* 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);
}
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);
}
struct anon_vma *folio_get_anon_vma(struct folio *folio);
/* RMAP flags, currently only relevant for some anon rmap operations. */
typedef int __bitwise rmap_t;
/*
* No special request: if the page is a subpage of a compound page, it is
* mapped via a PTE. The mapped (sub)page is possibly shared between processes.
*/
#define RMAP_NONE ((__force rmap_t)0)
/* The (sub)page is exclusive to a single process. */
#define RMAP_EXCLUSIVE ((__force rmap_t)BIT(0))
/*
* The compound page is not mapped via PTEs, but instead via a single PMD and
* should be accounted accordingly.
*/
#define RMAP_COMPOUND ((__force rmap_t)BIT(1))
/*
* rmap interfaces called when adding or removing pte of page
*/
void folio_move_anon_rmap(struct folio *, struct vm_area_struct *);
void page_add_anon_rmap(struct page *, struct vm_area_struct *,
unsigned long address, rmap_t flags);
void page_add_new_anon_rmap(struct page *, struct vm_area_struct *,
unsigned long address);
void folio_add_new_anon_rmap(struct folio *, struct vm_area_struct *,
unsigned long address);
void page_add_file_rmap(struct page *, struct vm_area_struct *,
bool compound);
void folio_add_file_rmap_range(struct folio *, struct page *, unsigned int nr,
struct vm_area_struct *, bool compound);
void page_remove_rmap(struct page *, struct vm_area_struct *,
bool compound);
void hugepage_add_anon_rmap(struct folio *, struct vm_area_struct *,
unsigned long address, rmap_t flags);
void hugepage_add_new_anon_rmap(struct folio *, struct vm_area_struct *,
unsigned long address);
static inline void __page_dup_rmap(struct page *page, bool compound)
{
if (compound) {
struct folio *folio = (struct folio *)page;
VM_BUG_ON_PAGE(compound && !PageHead(page), page);
atomic_inc(&folio->_entire_mapcount);
} else {
atomic_inc(&page->_mapcount);
}
}
static inline void page_dup_file_rmap(struct page *page, bool compound)
{
__page_dup_rmap(page, compound);
}
/**
* page_try_dup_anon_rmap - try duplicating a mapping of an already mapped
* anonymous page
* @page: the page to duplicate the mapping for
* @compound: the page is mapped as compound or as a small page
* @vma: the source vma
*
* The caller needs to hold the PT lock and the vma->vma_mm->write_protect_seq.
*
* Duplicating the mapping can only fail if the page may be pinned; device
* private pages cannot get pinned and consequently this function cannot fail.
*
* If duplicating the mapping succeeds, the page has to be mapped R/O into
* the parent and the child. It must *not* get mapped writable after this call.
*
* Returns 0 if duplicating the mapping succeeded. Returns -EBUSY otherwise.
*/
static inline int page_try_dup_anon_rmap(struct page *page, bool compound,
struct vm_area_struct *vma)
{
VM_BUG_ON_PAGE(!PageAnon(page), page);
/*
* No need to check+clear for already shared pages, including KSM
* pages.
*/
if (!PageAnonExclusive(page))
goto dup;
/*
* If this page may have been pinned by the parent process,
* don't allow to duplicate the mapping but instead require to e.g.,
* copy the page immediately for the child so that we'll always
* guarantee the pinned page won't be randomly replaced in the
* future on write faults.
*/
if (likely(!is_device_private_page(page) &&
unlikely(page_needs_cow_for_dma(vma, page))))
return -EBUSY;
ClearPageAnonExclusive(page);
/*
* It's okay to share the anon page between both processes, mapping
* the page R/O into both processes.
*/
dup:
__page_dup_rmap(page, compound);
return 0;
}
/**
* page_try_share_anon_rmap - try marking an exclusive anonymous page possibly
* shared to prepare for KSM or temporary unmapping
* @page: the exclusive anonymous page to try marking possibly shared
*
* The caller needs to hold the PT lock and has to have the page table entry
* cleared/invalidated.
*
* This is similar to page_try_dup_anon_rmap(), however, not used during fork()
* to duplicate a mapping, but instead to prepare for KSM or temporarily
* unmapping a page (swap, migration) via page_remove_rmap().
*
* Marking the page shared can only fail if the page may be pinned; device
* private pages cannot get pinned and consequently this function cannot fail.
*
* Returns 0 if marking the page possibly shared succeeded. Returns -EBUSY
* otherwise.
*/
static inline int page_try_share_anon_rmap(struct page *page)
{
VM_BUG_ON_PAGE(!PageAnon(page) || !PageAnonExclusive(page), page);
/* device private pages cannot get pinned via GUP. */
if (unlikely(is_device_private_page(page))) {
ClearPageAnonExclusive(page);
return 0;
}
/*
* We have to make sure that when we clear PageAnonExclusive, that
* the page is not pinned and that concurrent GUP-fast won't succeed in
* concurrently pinning the page.
*
* Conceptually, PageAnonExclusive clearing consists of:
* (A1) Clear PTE
* (A2) Check if the page is pinned; back off if so.
* (A3) Clear PageAnonExclusive
* (A4) Restore PTE (optional, but certainly not writable)
*
* When clearing PageAnonExclusive, we cannot possibly map the page
* writable again, because anon pages that may be shared must never
* be writable. So in any case, if the PTE was writable it cannot
* be writable anymore afterwards and there would be a PTE change. Only
* if the PTE wasn't writable, there might not be a PTE change.
*
* Conceptually, GUP-fast pinning of an anon page consists of:
* (B1) Read the PTE
* (B2) FOLL_WRITE: check if the PTE is not writable; back off if so.
* (B3) Pin the mapped page
* (B4) Check if the PTE changed by re-reading it; back off if so.
* (B5) If the original PTE is not writable, check if
* PageAnonExclusive is not set; back off if so.
*
* If the PTE was writable, we only have to make sure that GUP-fast
* observes a PTE change and properly backs off.
*
* If the PTE was not writable, we have to make sure that GUP-fast either
* detects a (temporary) PTE change or that PageAnonExclusive is cleared
* and properly backs off.
*
* Consequently, when clearing PageAnonExclusive(), we have to make
* sure that (A1), (A2)/(A3) and (A4) happen in the right memory
* order. In GUP-fast pinning code, we have to make sure that (B3),(B4)
* and (B5) happen in the right memory order.
*
* We assume that there might not be a memory barrier after
* clearing/invalidating the PTE (A1) and before restoring the PTE (A4),
* so we use explicit ones here.
*/
/* Paired with the memory barrier in try_grab_folio(). */
if (IS_ENABLED(CONFIG_HAVE_FAST_GUP))
smp_mb();
if (unlikely(page_maybe_dma_pinned(page)))
return -EBUSY;
ClearPageAnonExclusive(page);
/*
* This is conceptually a smp_wmb() paired with the smp_rmb() in
* gup_must_unshare().
*/
if (IS_ENABLED(CONFIG_HAVE_FAST_GUP))
smp_mb__after_atomic();
return 0;
}
/*
* Called from mm/vmscan.c to handle paging out
*/
int folio_referenced(struct folio *, int is_locked,
struct mem_cgroup *memcg, unsigned long *vm_flags);
void try_to_migrate(struct folio *folio, enum ttu_flags flags);
void try_to_unmap(struct folio *, enum ttu_flags flags);
int make_device_exclusive_range(struct mm_struct *mm, unsigned long start,
unsigned long end, struct page **pages,
void *arg);
/* Avoid racy checks */
#define PVMW_SYNC (1 << 0)
/* Look for migration entries rather than present PTEs */
#define PVMW_MIGRATION (1 << 1)
struct page_vma_mapped_walk {
unsigned long pfn;
unsigned long nr_pages;
pgoff_t pgoff;
struct vm_area_struct *vma;
unsigned long address;
pmd_t *pmd;
pte_t *pte;
spinlock_t *ptl;
unsigned int flags;
};
#define DEFINE_PAGE_VMA_WALK(name, _page, _vma, _address, _flags) \
struct page_vma_mapped_walk name = { \
.pfn = page_to_pfn(_page), \
.nr_pages = compound_nr(_page), \
.pgoff = page_to_pgoff(_page), \
.vma = _vma, \
.address = _address, \
.flags = _flags, \
}
#define DEFINE_FOLIO_VMA_WALK(name, _folio, _vma, _address, _flags) \
struct page_vma_mapped_walk name = { \
.pfn = folio_pfn(_folio), \
.nr_pages = folio_nr_pages(_folio), \
.pgoff = folio_pgoff(_folio), \
.vma = _vma, \
.address = _address, \
.flags = _flags, \
}
static inline void page_vma_mapped_walk_done(struct page_vma_mapped_walk *pvmw)
{
/* HugeTLB pte is set to the relevant page table entry without pte_mapped. */
if (pvmw->pte && !is_vm_hugetlb_page(pvmw->vma))
pte_unmap(pvmw->pte);
if (pvmw->ptl)
spin_unlock(pvmw->ptl);
}
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 folio_mkclean(struct folio *);
int pfn_mkclean_range(unsigned long pfn, unsigned long nr_pages, pgoff_t pgoff,
struct vm_area_struct *vma);
void remove_migration_ptes(struct folio *src, struct folio *dst, bool locked);
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()
* try_lock: bail out if the rmap lock is contended
* contended: indicate the rmap traversal bailed out due to lock contention
* 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;
bool try_lock;
bool contended;
/*
* Return false if page table scanning in rmap_walk should be stopped.
* Otherwise, return true.
*/
bool (*rmap_one)(struct folio *folio, struct vm_area_struct *vma,
unsigned long addr, void *arg);
int (*done)(struct folio *folio);
struct anon_vma *(*anon_lock)(struct folio *folio,
struct rmap_walk_control *rwc);
bool (*invalid_vma)(struct vm_area_struct *vma, void *arg);
};
void rmap_walk(struct folio *folio, struct rmap_walk_control *rwc);
void rmap_walk_locked(struct folio *folio, struct rmap_walk_control *rwc);
struct anon_vma *folio_lock_anon_vma_read(struct folio *folio,
struct rmap_walk_control *rwc);
#else /* !CONFIG_MMU */
#define anon_vma_init() do {} while (0)
#define anon_vma_prepare(vma) (0)
static inline int folio_referenced(struct folio *folio, int is_locked,
struct mem_cgroup *memcg,
unsigned long *vm_flags)
{
*vm_flags = 0;
return 0;
}
static inline void try_to_unmap(struct folio *folio, enum ttu_flags flags)
{
}
static inline int folio_mkclean(struct folio *folio)
{
return 0;
}
#endif /* CONFIG_MMU */
static inline int page_mkclean(struct page *page)
{
return folio_mkclean(page_folio(page));
}
#endif /* _LINUX_RMAP_H */