• Eric Paris's avatar
    inotify: use GFP_NOFS under potential memory pressure · f44aebcc
    Eric Paris authored
    inotify can have a watchs removed under filesystem reclaim.
    [ INFO: inconsistent lock state ]
    2.6.31-rc2 #16
    inconsistent {IN-RECLAIM_FS-W} -> {RECLAIM_FS-ON-W} usage.
    khubd/217 [HC0[0]:SC0[0]:HE1:SE1] takes:
     (iprune_mutex){+.+.?.}, at: [<c10ba899>] invalidate_inodes+0x20/0xe3
    {IN-RECLAIM_FS-W} state was registered at:
      [<c10536ab>] __lock_acquire+0x2c9/0xac4
      [<c1053f45>] lock_acquire+0x9f/0xc2
      [<c1308872>] __mutex_lock_common+0x2d/0x323
      [<c1308c00>] mutex_lock_nested+0x2e/0x36
      [<c10ba6ff>] shrink_icache_memory+0x38/0x1b2
      [<c108bfb6>] shrink_slab+0xe2/0x13c
      [<c108c3e1>] kswapd+0x3d1/0x55d
      [<c10449b5>] kthread+0x66/0x6b
      [<c1003fdf>] kernel_thread_helper+0x7/0x10
      [<ffffffff>] 0xffffffff
    Two things are needed to fix this.  First we need a method to tell
    fsnotify_create_event() to use GFP_NOFS and second we need to stop using
    one global IN_IGNORED event and allocate them one at a time.  This solves
    current issues with multiple IN_IGNORED on a queue having tail drop
    problems and simplifies the allocations since we don't have to worry about
    two tasks opperating on the IGNORED event concurrently.
    Signed-off-by: default avatarEric Paris <eparis@redhat.com>
notification.c 12.2 KB