diff options
| -rw-r--r-- | kernel/rcutree.c | 24 | ||||
| -rw-r--r-- | kernel/rcutree_plugin.h | 8 |
2 files changed, 24 insertions, 8 deletions
diff --git a/kernel/rcutree.c b/kernel/rcutree.c index 28fd92a9e0d0..51eef4193e7c 100644 --- a/kernel/rcutree.c +++ b/kernel/rcutree.c @@ -95,7 +95,7 @@ static DEFINE_PER_CPU(wait_queue_head_t, rcu_cpu_wq); static DEFINE_PER_CPU(char, rcu_cpu_has_work); static char rcu_kthreads_spawnable; -static void rcu_node_kthread_setaffinity(struct rcu_node *rnp); +static void rcu_node_kthread_setaffinity(struct rcu_node *rnp, int outgoingcpu); static void invoke_rcu_cpu_kthread(void); #define RCU_KTHREAD_PRIO 1 /* RT priority for per-CPU kthreads. */ @@ -1099,7 +1099,7 @@ static void __rcu_offline_cpu(int cpu, struct rcu_state *rsp) kthread_stop(t); rcu_stop_boost_kthread(rnp); } else - rcu_node_kthread_setaffinity(rnp); + rcu_node_kthread_setaffinity(rnp, -1); } /* @@ -1644,8 +1644,12 @@ static int rcu_node_kthread(void *arg) * Set the per-rcu_node kthread's affinity to cover all CPUs that are * served by the rcu_node in question. The CPU hotplug lock is still * held, so the value of rnp->qsmaskinit will be stable. + * + * We don't include outgoingcpu in the affinity set, use -1 if there is + * no outgoing CPU. If there are no CPUs left in the affinity set, + * this function allows the kthread to execute on any CPU. */ -static void rcu_node_kthread_setaffinity(struct rcu_node *rnp) +static void rcu_node_kthread_setaffinity(struct rcu_node *rnp, int outgoingcpu) { cpumask_var_t cm; int cpu; @@ -1657,8 +1661,14 @@ static void rcu_node_kthread_setaffinity(struct rcu_node *rnp) return; cpumask_clear(cm); for (cpu = rnp->grplo; cpu <= rnp->grphi; cpu++, mask >>= 1) - if (mask & 0x1) + if ((mask & 0x1) && cpu != outgoingcpu) cpumask_set_cpu(cpu, cm); + if (cpumask_weight(cm) == 0) { + cpumask_setall(cm); + for (cpu = rnp->grplo; cpu <= rnp->grphi; cpu++) + cpumask_clear_cpu(cpu, cm); + WARN_ON_ONCE(cpumask_weight(cm) == 0); + } set_cpus_allowed_ptr(rnp->node_kthread_task, cm); rcu_boost_kthread_setaffinity(rnp, cm); free_cpumask_var(cm); @@ -2154,7 +2164,11 @@ static int __cpuinit rcu_cpu_notify(struct notifier_block *self, rcu_online_kthreads(cpu); break; case CPU_ONLINE: - rcu_node_kthread_setaffinity(rnp); + case CPU_DOWN_FAILED: + rcu_node_kthread_setaffinity(rnp, -1); + break; + case CPU_DOWN_PREPARE: + rcu_node_kthread_setaffinity(rnp, cpu); break; case CPU_DYING: case CPU_DYING_FROZEN: diff --git a/kernel/rcutree_plugin.h b/kernel/rcutree_plugin.h index 5964f82e2d96..4e486255df63 100644 --- a/kernel/rcutree_plugin.h +++ b/kernel/rcutree_plugin.h @@ -1212,17 +1212,19 @@ static void rcu_initiate_boost(struct rcu_node *rnp) } } +/* + * Set the affinity of the boost kthread. The CPU-hotplug locks are + * held, so no one should be messing with the existence of the boost + * kthread. + */ static void rcu_boost_kthread_setaffinity(struct rcu_node *rnp, cpumask_var_t cm) { - unsigned long flags; struct task_struct *t; - raw_spin_lock_irqsave(&rnp->lock, flags); t = rnp->boost_kthread_task; if (t != NULL) set_cpus_allowed_ptr(rnp->boost_kthread_task, cm); - raw_spin_unlock_irqrestore(&rnp->lock, flags); } #define RCU_BOOST_DELAY_JIFFIES DIV_ROUND_UP(CONFIG_RCU_BOOST_DELAY * HZ, 1000) |