diff options
Diffstat (limited to '')
| -rw-r--r-- | mm/userfaultfd.c | 17 |
1 files changed, 16 insertions, 1 deletions
diff --git a/mm/userfaultfd.c b/mm/userfaultfd.c index c45b672e10d1..f5c6b3454f76 100644 --- a/mm/userfaultfd.c +++ b/mm/userfaultfd.c @@ -1250,6 +1250,7 @@ retry: */ if (!src_folio) { struct folio *folio; + bool locked; /* * Pin the page while holding the lock to be sure the @@ -1269,12 +1270,26 @@ retry: goto out; } + locked = folio_trylock(folio); + /* + * We avoid waiting for folio lock with a raised + * refcount for large folios because extra refcounts + * will result in split_folio() failing later and + * retrying. If multiple tasks are trying to move a + * large folio we can end up livelocking. + */ + if (!locked && folio_test_large(folio)) { + spin_unlock(src_ptl); + err = -EAGAIN; + goto out; + } + folio_get(folio); src_folio = folio; src_folio_pte = orig_src_pte; spin_unlock(src_ptl); - if (!folio_trylock(src_folio)) { + if (!locked) { pte_unmap(&orig_src_pte); pte_unmap(&orig_dst_pte); src_pte = dst_pte = NULL; |