diff options
Diffstat (limited to 'mm/rmap.c')
| -rw-r--r-- | mm/rmap.c | 96 |
1 files changed, 36 insertions, 60 deletions
diff --git a/mm/rmap.c b/mm/rmap.c index face808a489e..807c96bf0dc6 100644 --- a/mm/rmap.c +++ b/mm/rmap.c @@ -24,7 +24,7 @@ * 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) @@ -37,7 +37,7 @@ * 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 */ @@ -87,25 +87,25 @@ static inline void anon_vma_free(struct anon_vma *anon_vma) 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); - anon_vma_unlock(anon_vma); + if (rwsem_is_locked(&anon_vma->root->rwsem)) { + anon_vma_lock_write(anon_vma); + anon_vma_unlock_write(anon_vma); } kmem_cache_free(anon_vma_cachep, anon_vma); @@ -146,7 +146,7 @@ static void anon_vma_chain_link(struct vm_area_struct *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). @@ -181,7 +181,7 @@ int anon_vma_prepare(struct vm_area_struct *vma) 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)) { @@ -191,7 +191,7 @@ int anon_vma_prepare(struct vm_area_struct *vma) avc = NULL; } spin_unlock(&mm->page_table_lock); - anon_vma_unlock(anon_vma); + anon_vma_unlock_write(anon_vma); if (unlikely(allocated)) put_anon_vma(allocated); @@ -219,9 +219,9 @@ static inline struct anon_vma *lock_anon_vma_root(struct anon_vma *root, struct 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; } @@ -229,7 +229,7 @@ static inline struct anon_vma *lock_anon_vma_root(struct anon_vma *root, struct static inline void unlock_anon_vma_root(struct anon_vma *root) { if (root) - mutex_unlock(&root->mutex); + up_write(&root->rwsem); } /* @@ -306,9 +306,9 @@ int anon_vma_fork(struct vm_area_struct *vma, struct vm_area_struct *pvma) 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); + anon_vma_unlock_write(anon_vma); return 0; @@ -349,7 +349,7 @@ void unlink_anon_vmas(struct vm_area_struct *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; @@ -365,7 +365,7 @@ static void anon_vma_ctor(void *data) { 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; } @@ -442,7 +442,7 @@ out: * 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; @@ -457,14 +457,14 @@ struct anon_vma *page_lock_anon_vma(struct page *page) 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; @@ -484,15 +484,15 @@ struct anon_vma *page_lock_anon_vma(struct page *page) /* 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; } @@ -504,9 +504,9 @@ out: 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); } /* @@ -744,7 +744,7 @@ static int page_referenced_anon(struct page *page, 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; @@ -766,7 +766,7 @@ static int page_referenced_anon(struct page *page, break; } - page_unlock_anon_vma(anon_vma); + page_unlock_anon_vma_read(anon_vma); return referenced; } @@ -1126,7 +1126,6 @@ void page_add_file_rmap(struct page *page) */ void page_remove_rmap(struct page *page) { - struct address_space *mapping = page_mapping(page); bool anon = PageAnon(page); bool locked; unsigned long flags; @@ -1144,29 +1143,6 @@ void page_remove_rmap(struct page *page) 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. */ @@ -1315,7 +1291,7 @@ out_mlock: /* * 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. @@ -1480,7 +1456,7 @@ static int try_to_unmap_anon(struct page *page, enum ttu_flags flags) 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; @@ -1507,7 +1483,7 @@ static int try_to_unmap_anon(struct page *page, enum ttu_flags flags) break; } - page_unlock_anon_vma(anon_vma); + page_unlock_anon_vma_read(anon_vma); return ret; } @@ -1702,7 +1678,7 @@ static int rmap_walk_anon(struct page *page, int (*rmap_one)(struct page *, 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 @@ -1710,7 +1686,7 @@ static int rmap_walk_anon(struct page *page, int (*rmap_one)(struct page *, 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); @@ -1718,7 +1694,7 @@ static int rmap_walk_anon(struct page *page, int (*rmap_one)(struct page *, if (ret != SWAP_AGAIN) break; } - anon_vma_unlock(anon_vma); + anon_vma_unlock_read(anon_vma); return ret; } |