[PATCH 0/7] rcu: Fix expedited GP deadlock

[Frederic Weisbecker <frederic@kernel.org>]

TREE04 can trigger a writer stall if run with memory pressure. This
is due to a circular dependency between waiting for expedited grace
period and polling on expedited grace period when workqueues go back
to mayday serialization.

Here is a proposal fix.

Changes since v2 (no functional changes, just renames and reorganization):

_ Move nocb cleanups to their own series
_ Rename can_queue parameter to use_worker [2/7]
_ Better explain the rename of the mutex [3/7]
_ New commit with just code move to ease review [4/7]
_ Comment declaration of the new rnp->exp_worker field [5/7]

Thanks.

Frederic Weisbecker (7):
  rcu/exp: Fix RCU expedited parallel grace period kworker allocation
    failure recovery
  rcu/exp: Handle RCU expedited grace period kworker allocation failure
  rcu: s/boost_kthread_mutex/kthread_mutex
  rcu/exp: Move expedited kthread worker creation functions above
    rcutree_prepare_cpu()
  rcu/exp: Make parallel exp gp kworker per rcu node
  rcu/exp: Handle parallel exp gp kworkers affinity
  rcu/exp: Remove rcu_par_gp_wq

 kernel/rcu/rcu.h         |   5 --
 kernel/rcu/tree.c        | 175 +++++++++++++++++++++++++++------------
 kernel/rcu/tree.h        |  11 ++-
 kernel/rcu/tree_exp.h    |  78 +++--------------
 kernel/rcu/tree_plugin.h |  52 ++----------
 5 files changed, 142 insertions(+), 179 deletions(-)

-- 
2.34.1