diff options
| author | Frederic Weisbecker <frederic@kernel.org> | 2024-05-30 15:45:45 +0200 |
|---|---|---|
| committer | Neeraj Upadhyay <neeraj.upadhyay@kernel.org> | 2024-07-29 07:34:31 +0530 |
| commit | 7121dd915a262aee1f5a88cf86b1543f3a9439d7 (patch) | |
| tree | 03711242df5dd69dd2300fa108c60a622177bac1 /kernel/rcu/tree_plugin.h | |
| parent | 7be88a857eb84d2e0677690b81ee423dee51c93d (diff) | |
rcu/nocb: Introduce nocb mutex
The barrier_mutex is used currently to protect (de-)offloading
operations and prevent from nocb_lock locking imbalance in rcu_barrier()
and shrinker, and also from misordered RCU barrier invocation.
Now since RCU (de-)offloading is going to happen on offline CPUs, an RCU
barrier will have to be executed while transitionning from offloaded to
de-offloaded state. And this can't happen while holding the
barrier_mutex.
Introduce a NOCB mutex to protect (de-)offloading transitions. The
barrier_mutex is still held for now when necessary to avoid barrier
callbacks reordering and nocb_lock imbalance.
Signed-off-by: Frederic Weisbecker <frederic@kernel.org>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Reviewed-by: Paul E. McKenney <paulmck@kernel.org>
Signed-off-by: Neeraj Upadhyay <neeraj.upadhyay@kernel.org>
Diffstat (limited to 'kernel/rcu/tree_plugin.h')
| -rw-r--r-- | kernel/rcu/tree_plugin.h | 1 |
1 files changed, 1 insertions, 0 deletions
diff --git a/kernel/rcu/tree_plugin.h b/kernel/rcu/tree_plugin.h index f752b2a1d887..c662376c8af0 100644 --- a/kernel/rcu/tree_plugin.h +++ b/kernel/rcu/tree_plugin.h @@ -28,6 +28,7 @@ static bool rcu_rdp_is_offloaded(struct rcu_data *rdp) !(lockdep_is_held(&rcu_state.barrier_mutex) || (IS_ENABLED(CONFIG_HOTPLUG_CPU) && lockdep_is_cpus_held()) || lockdep_is_held(&rdp->nocb_lock) || + lockdep_is_held(&rcu_state.nocb_mutex) || (!(IS_ENABLED(CONFIG_PREEMPT_COUNT) && preemptible()) && rdp == this_cpu_ptr(&rcu_data)) || rcu_current_is_nocb_kthread(rdp)), |