diff options
| -rw-r--r-- | mm/migrate.c | 11 |
1 files changed, 9 insertions, 2 deletions
diff --git a/mm/migrate.c b/mm/migrate.c index 37c73b90200..e2fdbce1874 100644 --- a/mm/migrate.c +++ b/mm/migrate.c @@ -611,6 +611,7 @@ static int unmap_and_move(new_page_t get_new_page, unsigned long private, int rc = 0; int *result = NULL; struct page *newpage = get_new_page(page, private, &result); + int rcu_locked = 0; if (!newpage) return -ENOMEM; @@ -636,8 +637,13 @@ static int unmap_and_move(new_page_t get_new_page, unsigned long private, * we cannot notice that anon_vma is freed while we migrates a page. * This rcu_read_lock() delays freeing anon_vma pointer until the end * of migration. File cache pages are no problem because of page_lock() + * File Caches may use write_page() or lock_page() in migration, then, + * just care Anon page here. */ - rcu_read_lock(); + if (PageAnon(page)) { + rcu_read_lock(); + rcu_locked = 1; + } /* * This is a corner case handling. * When a new swap-cache is read into, it is linked to LRU @@ -656,7 +662,8 @@ static int unmap_and_move(new_page_t get_new_page, unsigned long private, if (rc) remove_migration_ptes(page, page); rcu_unlock: - rcu_read_unlock(); + if (rcu_locked) + rcu_read_unlock(); unlock: |