Commits
Paul E. McKenney committed ad7c946b35a
rcu: Create RCU-specific workqueues with rescuers RCU's expedited grace periods can participate in out-of-memory deadlocks due to all available system_wq kthreads being blocked and there not being memory available to create more. This commit prevents such deadlocks by allocating an RCU-specific workqueue_struct at early boot time, and providing it with a rescuer to ensure forward progress. This uses the shiny new init_rescuer() function provided by Tejun (but indirectly). This commit also causes SRCU to use this new RCU-specific workqueue_struct. Note that SRCU's use of workqueues never blocks them waiting for readers, so this should be safe from a forward-progress viewpoint. Note that this moves SRCU from system_power_efficient_wq to a normal workqueue. In the unlikely event that this results in measurable degradation, a separate power-efficient workqueue will be creates for SRCU. Reported-by: Prateek Sood <prsood@codeaurora.org> Reported-by: Tejun Heo <tj@kernel.org> Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Acked-by: Tejun Heo <tj@kernel.org>