diff options
Diffstat (limited to 'mm/migrate.c')
| -rw-r--r-- | mm/migrate.c | 12 |
1 files changed, 12 insertions, 0 deletions
diff --git a/mm/migrate.c b/mm/migrate.c index 5938db54e1d..b768a1d4fa4 100644 --- a/mm/migrate.c +++ b/mm/migrate.c @@ -543,6 +543,7 @@ static int unmap_and_move(new_page_t get_new_page, unsigned long private, int rcu_locked = 0; int charge = 0; struct mem_cgroup *mem = NULL; + struct anon_vma *anon_vma = NULL; if (!newpage) return -ENOMEM; @@ -599,6 +600,8 @@ static int unmap_and_move(new_page_t get_new_page, unsigned long private, if (PageAnon(page)) { rcu_read_lock(); rcu_locked = 1; + anon_vma = page_anon_vma(page); + atomic_inc(&anon_vma->migrate_refcount); } /* @@ -638,6 +641,15 @@ skip_unmap: if (rc) remove_migration_ptes(page, page); rcu_unlock: + + /* Drop an anon_vma reference if we took one */ + if (anon_vma && atomic_dec_and_lock(&anon_vma->migrate_refcount, &anon_vma->lock)) { + int empty = list_empty(&anon_vma->head); + spin_unlock(&anon_vma->lock); + if (empty) + anon_vma_free(anon_vma); + } + if (rcu_locked) rcu_read_unlock(); uncharge: |