* mm->mmap_sem
* page->flags PG_locked (lock_page)
* mapping->i_mmap_mutex
- * anon_vma->mutex
+ * anon_vma->rwsem
* mm->page_table_lock or pte_lock
* zone->lru_lock (in mark_page_accessed, isolate_lru_page)
* swap_lock (in swap_duplicate, swap_info_get)
* in arch-dependent flush_dcache_mmap_lock,
* within bdi.wb->list_lock in __sync_single_inode)
*
- * anon_vma->mutex,mapping->i_mutex (memory_failure, collect_procs_anon)
+ * anon_vma->rwsem,mapping->i_mutex (memory_failure, collect_procs_anon)
* ->tasklist_lock
* pte map lock
*/
VM_BUG_ON(atomic_read(&anon_vma->refcount));
/*
- * Synchronize against page_lock_anon_vma() such that
+ * Synchronize against page_lock_anon_vma_read() such that
* we can safely hold the lock without the anon_vma getting
* freed.
*
* Relies on the full mb implied by the atomic_dec_and_test() from
* put_anon_vma() against the acquire barrier implied by
- * mutex_trylock() from page_lock_anon_vma(). This orders:
+ * down_read_trylock() from page_lock_anon_vma_read(). This orders:
*
- * page_lock_anon_vma() VS put_anon_vma()
- * mutex_trylock() atomic_dec_and_test()
+ * page_lock_anon_vma_read() VS put_anon_vma()
+ * down_read_trylock() atomic_dec_and_test()
* LOCK MB
- * atomic_read() mutex_is_locked()
+ * atomic_read() rwsem_is_locked()
*
* LOCK should suffice since the actual taking of the lock must
* happen _before_ what follows.
*/
- if (mutex_is_locked(&anon_vma->root->mutex)) {
- anon_vma_lock(anon_vma);
+ if (rwsem_is_locked(&anon_vma->root->rwsem)) {
+ anon_vma_lock_write(anon_vma);
anon_vma_unlock(anon_vma);
}
* allocate a new one.
*
* Anon-vma allocations are very subtle, because we may have
- * optimistically looked up an anon_vma in page_lock_anon_vma()
+ * optimistically looked up an anon_vma in page_lock_anon_vma_read()
* and that may actually touch the spinlock even in the newly
* allocated vma (it depends on RCU to make sure that the
* anon_vma isn't actually destroyed).
allocated = anon_vma;
}
- anon_vma_lock(anon_vma);
+ anon_vma_lock_write(anon_vma);
/* page_table_lock to protect against threads */
spin_lock(&mm->page_table_lock);
if (likely(!vma->anon_vma)) {
struct anon_vma *new_root = anon_vma->root;
if (new_root != root) {
if (WARN_ON_ONCE(root))
- mutex_unlock(&root->mutex);
+ up_write(&root->rwsem);
root = new_root;
- mutex_lock(&root->mutex);
+ down_write(&root->rwsem);
}
return root;
}
static inline void unlock_anon_vma_root(struct anon_vma *root)
{
if (root)
- mutex_unlock(&root->mutex);
+ up_write(&root->rwsem);
}
/*
get_anon_vma(anon_vma->root);
/* Mark this anon_vma as the one where our new (COWed) pages go. */
vma->anon_vma = anon_vma;
- anon_vma_lock(anon_vma);
+ anon_vma_lock_write(anon_vma);
anon_vma_chain_link(vma, avc, anon_vma);
anon_vma_unlock(anon_vma);
/*
* Iterate the list once more, it now only contains empty and unlinked
* anon_vmas, destroy them. Could not do before due to __put_anon_vma()
- * needing to acquire the anon_vma->root->mutex.
+ * needing to write-acquire the anon_vma->root->rwsem.
*/
list_for_each_entry_safe(avc, next, &vma->anon_vma_chain, same_vma) {
struct anon_vma *anon_vma = avc->anon_vma;
{
struct anon_vma *anon_vma = data;
- mutex_init(&anon_vma->mutex);
+ init_rwsem(&anon_vma->rwsem);
atomic_set(&anon_vma->refcount, 0);
anon_vma->rb_root = RB_ROOT;
}
* atomic op -- the trylock. If we fail the trylock, we fall back to getting a
* reference like with page_get_anon_vma() and then block on the mutex.
*/
-struct anon_vma *page_lock_anon_vma(struct page *page)
+struct anon_vma *page_lock_anon_vma_read(struct page *page)
{
struct anon_vma *anon_vma = NULL;
struct anon_vma *root_anon_vma;
anon_vma = (struct anon_vma *) (anon_mapping - PAGE_MAPPING_ANON);
root_anon_vma = ACCESS_ONCE(anon_vma->root);
- if (mutex_trylock(&root_anon_vma->mutex)) {
+ if (down_read_trylock(&root_anon_vma->rwsem)) {
/*
* If the page is still mapped, then this anon_vma is still
* its anon_vma, and holding the mutex ensures that it will
* not go away, see anon_vma_free().
*/
if (!page_mapped(page)) {
- mutex_unlock(&root_anon_vma->mutex);
+ up_read(&root_anon_vma->rwsem);
anon_vma = NULL;
}
goto out;
/* we pinned the anon_vma, its safe to sleep */
rcu_read_unlock();
- anon_vma_lock(anon_vma);
+ anon_vma_lock_read(anon_vma);
if (atomic_dec_and_test(&anon_vma->refcount)) {
/*
* Oops, we held the last refcount, release the lock
* and bail -- can't simply use put_anon_vma() because
- * we'll deadlock on the anon_vma_lock() recursion.
+ * we'll deadlock on the anon_vma_lock_write() recursion.
*/
- anon_vma_unlock(anon_vma);
+ anon_vma_unlock_read(anon_vma);
__put_anon_vma(anon_vma);
anon_vma = NULL;
}
return anon_vma;
}
-void page_unlock_anon_vma(struct anon_vma *anon_vma)
+void page_unlock_anon_vma_read(struct anon_vma *anon_vma)
{
- anon_vma_unlock(anon_vma);
+ anon_vma_unlock_read(anon_vma);
}
/*
struct anon_vma_chain *avc;
int referenced = 0;
- anon_vma = page_lock_anon_vma(page);
+ anon_vma = page_lock_anon_vma_read(page);
if (!anon_vma)
return referenced;
break;
}
- page_unlock_anon_vma(anon_vma);
+ page_unlock_anon_vma_read(anon_vma);
return referenced;
}
*/
void page_remove_rmap(struct page *page)
{
- struct address_space *mapping = page_mapping(page);
bool anon = PageAnon(page);
bool locked;
unsigned long flags;
if (!atomic_add_negative(-1, &page->_mapcount))
goto out;
- /*
- * Now that the last pte has gone, s390 must transfer dirty
- * flag from storage key to struct page. We can usually skip
- * this if the page is anon, so about to be freed; but perhaps
- * not if it's in swapcache - there might be another pte slot
- * containing the swap entry, but page not yet written to swap.
- *
- * And we can skip it on file pages, so long as the filesystem
- * participates in dirty tracking (note that this is not only an
- * optimization but also solves problems caused by dirty flag in
- * storage key getting set by a write from inside kernel); but need to
- * catch shm and tmpfs and ramfs pages which have been modified since
- * creation by read fault.
- *
- * Note that mapping must be decided above, before decrementing
- * mapcount (which luckily provides a barrier): once page is unmapped,
- * it could be truncated and page->mapping reset to NULL at any moment.
- * Note also that we are relying on page_mapping(page) to set mapping
- * to &swapper_space when PageSwapCache(page).
- */
- if (mapping && !mapping_cap_account_dirty(mapping) &&
- page_test_and_clear_dirty(page_to_pfn(page), 1))
- set_page_dirty(page);
/*
* Hugepages are not counted in NR_ANON_PAGES nor NR_FILE_MAPPED
* and not charged by memcg for now.
/*
* We need mmap_sem locking, Otherwise VM_LOCKED check makes
* unstable result and race. Plus, We can't wait here because
- * we now hold anon_vma->mutex or mapping->i_mmap_mutex.
+ * we now hold anon_vma->rwsem or mapping->i_mmap_mutex.
* if trylock failed, the page remain in evictable lru and later
* vmscan could retry to move the page to unevictable lru if the
* page is actually mlocked.
struct anon_vma_chain *avc;
int ret = SWAP_AGAIN;
- anon_vma = page_lock_anon_vma(page);
+ anon_vma = page_lock_anon_vma_read(page);
if (!anon_vma)
return ret;
break;
}
- page_unlock_anon_vma(anon_vma);
+ page_unlock_anon_vma_read(anon_vma);
return ret;
}
int ret = SWAP_AGAIN;
/*
- * Note: remove_migration_ptes() cannot use page_lock_anon_vma()
+ * Note: remove_migration_ptes() cannot use page_lock_anon_vma_read()
* because that depends on page_mapped(); but not all its usages
* are holding mmap_sem. Users without mmap_sem are required to
* take a reference count to prevent the anon_vma disappearing
anon_vma = page_anon_vma(page);
if (!anon_vma)
return ret;
- anon_vma_lock(anon_vma);
+ anon_vma_lock_read(anon_vma);
anon_vma_interval_tree_foreach(avc, &anon_vma->rb_root, pgoff, pgoff) {
struct vm_area_struct *vma = avc->vma;
unsigned long address = vma_address(page, vma);
if (ret != SWAP_AGAIN)
break;
}
- anon_vma_unlock(anon_vma);
+ anon_vma_unlock_read(anon_vma);
return ret;
}
projects / deliverable / linux.git / blobdiff