*/
static int rcu_scheduler_fully_active __read_mostly;
-#ifdef CONFIG_RCU_BOOST
-
-/*
- * Control variables for per-CPU and per-rcu_node kthreads. These
- * handle all flavors of RCU.
- */
-static DEFINE_PER_CPU(struct task_struct *, rcu_cpu_kthread_task);
-DEFINE_PER_CPU(unsigned int, rcu_cpu_kthread_status);
-DEFINE_PER_CPU(unsigned int, rcu_cpu_kthread_loops);
-DEFINE_PER_CPU(char, rcu_cpu_has_work);
-
-#endif /* #ifdef CONFIG_RCU_BOOST */
-
static void rcu_boost_kthread_setaffinity(struct rcu_node *rnp, int outgoingcpu);
static void invoke_rcu_core(void);
static void invoke_rcu_callbacks(struct rcu_state *rsp, struct rcu_data *rdp);
* one since the start of the grace period, this just sets a flag.
* The caller must have disabled preemption.
*/
-void rcu_sched_qs(int cpu)
+void rcu_sched_qs(void)
{
- struct rcu_data *rdp = &per_cpu(rcu_sched_data, cpu);
-
- if (rdp->passed_quiesce == 0)
- trace_rcu_grace_period(TPS("rcu_sched"), rdp->gpnum, TPS("cpuqs"));
- rdp->passed_quiesce = 1;
+ if (!__this_cpu_read(rcu_sched_data.passed_quiesce)) {
+ trace_rcu_grace_period(TPS("rcu_sched"),
+ __this_cpu_read(rcu_sched_data.gpnum),
+ TPS("cpuqs"));
+ __this_cpu_write(rcu_sched_data.passed_quiesce, 1);
+ }
}
-void rcu_bh_qs(int cpu)
+void rcu_bh_qs(void)
{
- struct rcu_data *rdp = &per_cpu(rcu_bh_data, cpu);
-
- if (rdp->passed_quiesce == 0)
- trace_rcu_grace_period(TPS("rcu_bh"), rdp->gpnum, TPS("cpuqs"));
- rdp->passed_quiesce = 1;
+ if (!__this_cpu_read(rcu_bh_data.passed_quiesce)) {
+ trace_rcu_grace_period(TPS("rcu_bh"),
+ __this_cpu_read(rcu_bh_data.gpnum),
+ TPS("cpuqs"));
+ __this_cpu_write(rcu_bh_data.passed_quiesce, 1);
+ }
}
static DEFINE_PER_CPU(int, rcu_sched_qs_mask);
void rcu_note_context_switch(int cpu)
{
trace_rcu_utilization(TPS("Start context switch"));
- rcu_sched_qs(cpu);
+ rcu_sched_qs();
rcu_preempt_note_context_switch(cpu);
if (unlikely(raw_cpu_read(rcu_sched_qs_mask)))
rcu_momentary_dyntick_idle();
atomic_inc(&rdtp->dynticks);
smp_mb__after_atomic(); /* Force ordering with next sojourn. */
WARN_ON_ONCE(atomic_read(&rdtp->dynticks) & 0x1);
+ rcu_dynticks_task_enter();
/*
* It is illegal to enter an extended quiescent state while
static void rcu_eqs_exit_common(struct rcu_dynticks *rdtp, long long oldval,
int user)
{
+ rcu_dynticks_task_exit();
smp_mb__before_atomic(); /* Force ordering w/previous sojourn. */
atomic_inc(&rdtp->dynticks);
/* CPUs seeing atomic_inc() must see later RCU read-side crit sects */
rnp->level, rnp->grplo,
rnp->grphi, rnp->qsmask);
raw_spin_unlock_irq(&rnp->lock);
- cond_resched();
+ cond_resched_rcu_qs();
}
mutex_unlock(&rsp->onoff_mutex);
/* smp_mb() provided by prior unlock-lock pair. */
nocb += rcu_future_gp_cleanup(rsp, rnp);
raw_spin_unlock_irq(&rnp->lock);
- cond_resched();
+ cond_resched_rcu_qs();
}
rnp = rcu_get_root(rsp);
raw_spin_lock_irq(&rnp->lock);
/* Locking provides needed memory barrier. */
if (rcu_gp_init(rsp))
break;
- cond_resched();
- flush_signals(current);
+ cond_resched_rcu_qs();
+ WARN_ON(signal_pending(current));
trace_rcu_grace_period(rsp->name,
ACCESS_ONCE(rsp->gpnum),
TPS("reqwaitsig"));
trace_rcu_grace_period(rsp->name,
ACCESS_ONCE(rsp->gpnum),
TPS("fqsend"));
- cond_resched();
+ cond_resched_rcu_qs();
} else {
/* Deal with stray signal. */
- cond_resched();
- flush_signals(current);
+ cond_resched_rcu_qs();
+ WARN_ON(signal_pending(current));
trace_rcu_grace_period(rsp->name,
ACCESS_ONCE(rsp->gpnum),
TPS("fqswaitsig"));
{
WARN_ON_ONCE(!rcu_gp_in_progress(rsp));
raw_spin_unlock_irqrestore(&rcu_get_root(rsp)->lock, flags);
- wake_up(&rsp->gp_wq); /* Memory barrier implied by wake_up() path. */
+ rcu_gp_kthread_wake(rsp);
}
/*
/* Adjust any no-longer-needed kthreads. */
rcu_boost_kthread_setaffinity(rnp, -1);
- /* Remove the dead CPU from the bitmasks in the rcu_node hierarchy. */
-
/* Exclude any attempts to start a new grace period. */
mutex_lock(&rsp->onoff_mutex);
raw_spin_lock_irqsave(&rsp->orphan_lock, flags);
* at least not while the corresponding CPU is online.
*/
- rcu_sched_qs(cpu);
- rcu_bh_qs(cpu);
+ rcu_sched_qs();
+ rcu_bh_qs();
} else if (!in_softirq()) {
* critical section, so note it.
*/
- rcu_bh_qs(cpu);
+ rcu_bh_qs();
}
rcu_preempt_check_callbacks(cpu);
if (rcu_pending(cpu))
invoke_rcu_core();
+ if (user)
+ rcu_note_voluntary_context_switch(current);
trace_rcu_utilization(TPS("End scheduler-tick"));
}
struct rcu_node *rnp;
rcu_for_each_leaf_node(rsp, rnp) {
- cond_resched();
+ cond_resched_rcu_qs();
mask = 0;
raw_spin_lock_irqsave(&rnp->lock, flags);
smp_mb__after_unlock_lock();
ACCESS_ONCE(rsp->gp_flags) =
ACCESS_ONCE(rsp->gp_flags) | RCU_GP_FLAG_FQS;
raw_spin_unlock_irqrestore(&rnp_old->lock, flags);
- wake_up(&rsp->gp_wq); /* Memory barrier implied by wake_up() path. */
+ rcu_gp_kthread_wake(rsp);
}
/*
* restructure your code to batch your updates, and then use a single
* synchronize_sched() instead.
*
- * Note that it is illegal to call this function while holding any lock
- * that is acquired by a CPU-hotplug notifier. And yes, it is also illegal
- * to call this function from a CPU-hotplug notifier. Failing to observe
- * these restriction will result in deadlock.
- *
* This implementation can be thought of as an application of ticket
* locking to RCU, with sync_sched_expedited_started and
* sync_sched_expedited_done taking on the roles of the halves
*/
void synchronize_sched_expedited(void)
{
+ cpumask_var_t cm;
+ bool cma = false;
+ int cpu;
long firstsnap, s, snap;
int trycount = 0;
struct rcu_state *rsp = &rcu_sched_state;
*/
snap = atomic_long_inc_return(&rsp->expedited_start);
firstsnap = snap;
- get_online_cpus();
+ if (!try_get_online_cpus()) {
+ /* CPU hotplug operation in flight, fall back to normal GP. */
+ wait_rcu_gp(call_rcu_sched);
+ atomic_long_inc(&rsp->expedited_normal);
+ return;
+ }
WARN_ON_ONCE(cpu_is_offline(raw_smp_processor_id()));
+ /* Offline CPUs, idle CPUs, and any CPU we run on are quiescent. */
+ cma = zalloc_cpumask_var(&cm, GFP_KERNEL);
+ if (cma) {
+ cpumask_copy(cm, cpu_online_mask);
+ cpumask_clear_cpu(raw_smp_processor_id(), cm);
+ for_each_cpu(cpu, cm) {
+ struct rcu_dynticks *rdtp = &per_cpu(rcu_dynticks, cpu);
+
+ if (!(atomic_add_return(0, &rdtp->dynticks) & 0x1))
+ cpumask_clear_cpu(cpu, cm);
+ }
+ if (cpumask_weight(cm) == 0)
+ goto all_cpus_idle;
+ }
+
/*
* Each pass through the following loop attempts to force a
* context switch on each CPU.
*/
- while (try_stop_cpus(cpu_online_mask,
+ while (try_stop_cpus(cma ? cm : cpu_online_mask,
synchronize_sched_expedited_cpu_stop,
NULL) == -EAGAIN) {
put_online_cpus();
/* ensure test happens before caller kfree */
smp_mb__before_atomic(); /* ^^^ */
atomic_long_inc(&rsp->expedited_workdone1);
+ free_cpumask_var(cm);
return;
}
} else {
wait_rcu_gp(call_rcu_sched);
atomic_long_inc(&rsp->expedited_normal);
+ free_cpumask_var(cm);
return;
}
/* ensure test happens before caller kfree */
smp_mb__before_atomic(); /* ^^^ */
atomic_long_inc(&rsp->expedited_workdone2);
+ free_cpumask_var(cm);
return;
}
* and they started after our first try, so their grace
* period works for us.
*/
- get_online_cpus();
+ if (!try_get_online_cpus()) {
+ /* CPU hotplug operation in flight, use normal GP. */
+ wait_rcu_gp(call_rcu_sched);
+ atomic_long_inc(&rsp->expedited_normal);
+ free_cpumask_var(cm);
+ return;
+ }
snap = atomic_long_read(&rsp->expedited_start);
smp_mb(); /* ensure read is before try_stop_cpus(). */
}
atomic_long_inc(&rsp->expedited_stoppedcpus);
+all_cpus_idle:
+ free_cpumask_var(cm);
+
/*
* Everyone up to our most recent fetch is covered by our grace
* period. Update the counter, but only if our work is still
continue;
rdp = per_cpu_ptr(rsp->rda, cpu);
if (rcu_is_nocb_cpu(cpu)) {
- _rcu_barrier_trace(rsp, "OnlineNoCB", cpu,
- rsp->n_barrier_done);
- atomic_inc(&rsp->barrier_cpu_count);
- __call_rcu(&rdp->barrier_head, rcu_barrier_callback,
- rsp, cpu, 0);
+ if (!rcu_nocb_cpu_needs_barrier(rsp, cpu)) {
+ _rcu_barrier_trace(rsp, "OfflineNoCB", cpu,
+ rsp->n_barrier_done);
+ } else {
+ _rcu_barrier_trace(rsp, "OnlineNoCB", cpu,
+ rsp->n_barrier_done);
+ atomic_inc(&rsp->barrier_cpu_count);
+ __call_rcu(&rdp->barrier_head,
+ rcu_barrier_callback, rsp, cpu, 0);
+ }
} else if (ACCESS_ONCE(rdp->qlen)) {
_rcu_barrier_trace(rsp, "OnlineQ", cpu,
rsp->n_barrier_done);
case CPU_UP_PREPARE_FROZEN:
rcu_prepare_cpu(cpu);
rcu_prepare_kthreads(cpu);
+ rcu_spawn_all_nocb_kthreads(cpu);
break;
case CPU_ONLINE:
case CPU_DOWN_FAILED:
case CPU_DEAD_FROZEN:
case CPU_UP_CANCELED:
case CPU_UP_CANCELED_FROZEN:
- for_each_rcu_flavor(rsp)
+ for_each_rcu_flavor(rsp) {
rcu_cleanup_dead_cpu(cpu, rsp);
+ do_nocb_deferred_wakeup(per_cpu_ptr(rsp->rda, cpu));
+ }
break;
default:
break;
}
/*
- * Spawn the kthread that handles this RCU flavor's grace periods.
+ * Spawn the kthreads that handle each RCU flavor's grace periods.
*/
static int __init rcu_spawn_gp_kthread(void)
{
struct rcu_state *rsp;
struct task_struct *t;
+ rcu_scheduler_fully_active = 1;
for_each_rcu_flavor(rsp) {
t = kthread_run(rcu_gp_kthread, rsp, "%s", rsp->name);
BUG_ON(IS_ERR(t));
raw_spin_lock_irqsave(&rnp->lock, flags);
rsp->gp_kthread = t;
raw_spin_unlock_irqrestore(&rnp->lock, flags);
- rcu_spawn_nocb_kthreads(rsp);
}
+ rcu_spawn_nocb_kthreads();
+ rcu_spawn_boost_kthreads();
return 0;
}
early_initcall(rcu_spawn_gp_kthread);
git.openpandora.org / pandora-kernel.git / blobdiff