On Thu, Jan 17, 2019 at 09:47:37AM +0100, Juri Lelli wrote: > @@ -3233,11 +3233,11 @@ void cpuset_cpus_allowed(struct task_struct *tsk, struct cpumask *pmask) > { > unsigned long flags; > > - spin_lock_irqsave(&callback_lock, flags); > + raw_spin_lock_irqsave(&callback_lock, flags); > rcu_read_lock(); > guarantee_online_cpus(task_cs(tsk), pmask); > rcu_read_unlock(); > - spin_unlock_irqrestore(&callback_lock, flags); > + raw_spin_unlock_irqrestore(&callback_lock, flags); > } > > void cpuset_cpus_allowed_fallback(struct task_struct *tsk) > @@ -3285,11 +3285,11 @@ nodemask_t cpuset_mems_allowed(struct task_struct *tsk) > nodemask_t mask; > unsigned long flags; > > - spin_lock_irqsave(&callback_lock, flags); > + raw_spin_lock_irqsave(&callback_lock, flags); > rcu_read_lock(); > guarantee_online_mems(task_cs(tsk), &mask); > rcu_read_unlock(); > - spin_unlock_irqrestore(&callback_lock, flags); > + raw_spin_unlock_irqrestore(&callback_lock, flags); > > return mask; > } > @@ -3381,14 +3381,14 @@ bool __cpuset_node_allowed(int node, gfp_t gfp_mask) > return true; > > /* Not hardwall and node outside mems_allowed: scan up cpusets */ > - spin_lock_irqsave(&callback_lock, flags); > + raw_spin_lock_irqsave(&callback_lock, flags); > > rcu_read_lock(); > cs = nearest_hardwall_ancestor(task_cs(current)); > allowed = node_isset(node, cs->mems_allowed); > rcu_read_unlock(); > > - spin_unlock_irqrestore(&callback_lock, flags); > + raw_spin_unlock_irqrestore(&callback_lock, flags); > return allowed; > } These three appear to be a user-controlled O(n) (depth of cgroup tree). Which is basically bad for raw_spinlock_t. The Changelog should really have mentioned this; and ideally we'd somehow avoid this.