[PATCH 0/3] Suppress undesirable hung task warnings.

[Julian Sun]

As suggested by Andrew Morton in [1], we need a general mechanism 
that allows the hung task detector to ignore unnecessary hung 
tasks. This patch set implements this functionality.

Patch 1 introduces a PF_DONT_HUNG flag. The hung task detector will 
ignores all tasks that have the PF_DONT_HUNG flag set.

Patch 2 introduces wait_event_no_hung() and wb_wait_for_completion_no_hung(), 
which enable the hung task detector to ignore hung tasks caused by these
wait events.

Patch 3 uses wb_wait_for_completion_no_hung() in the final phase of memcg 
teardown to eliminate the hung task warning.

Julian Sun (3):
  sched: Introduce a new flag PF_DONT_HUNG.
  writeback: Introduce wb_wait_for_completion_no_hung().
  memcg: Don't trigger hung task when memcg is releasing.

 fs/fs-writeback.c           | 15 +++++++++++++++
 include/linux/backing-dev.h |  1 +
 include/linux/sched.h       | 12 +++++++++++-
 include/linux/wait.h        | 15 +++++++++++++++
 kernel/hung_task.c          |  6 ++++++
 mm/memcontrol.c             |  2 +-
 6 files changed, 49 insertions(+), 2 deletions(-)

-- 
2.39.5