struct rcu_dynticks *rdtp = &per_cpu(rcu_dynticks, cpu);
if (raw_smp_processor_id() == cpu ||
- !(atomic_add_return(0, &rdtp->dynticks) & 0x1))
+ !(atomic_add_return(0, &rdtp->dynticks) & 0x1) ||
+ !(rnp->qsmaskinitnext & rdp->grpmask))
mask_ofl_test |= rdp->grpmask;
}
mask_ofl_ipi = rnp->expmask & ~mask_ofl_test;
mask_ofl_ipi &= ~mask;
continue;
}
- /* Failed, raced with offline. */
+ /* Failed, raced with CPU hotplug operation. */
raw_spin_lock_irqsave_rcu_node(rnp, flags);
- if (cpu_online(cpu) &&
+ if ((rnp->qsmaskinitnext & mask) &&
(rnp->expmask & mask)) {
+ /* Online, so delay for a bit and try again. */
raw_spin_unlock_irqrestore_rcu_node(rnp, flags);
schedule_timeout_uninterruptible(1);
- if (cpu_online(cpu) &&
- (rnp->expmask & mask))
- goto retry_ipi;
- raw_spin_lock_irqsave_rcu_node(rnp, flags);
+ goto retry_ipi;
}
+ /* CPU really is offline, so we can ignore it. */
if (!(rnp->expmask & mask))
mask_ofl_ipi &= ~mask;
raw_spin_unlock_irqrestore_rcu_node(rnp, flags);
jiffies_stall);
if (ret > 0 || sync_rcu_preempt_exp_done(rnp_root))
return;
- if (ret < 0) {
- /* Hit a signal, disable CPU stall warnings. */
- swait_event(rsp->expedited_wq,
- sync_rcu_preempt_exp_done(rnp_root));
- return;
- }
+ WARN_ON(ret < 0); /* workqueues should not be signaled. */
+ if (rcu_cpu_stall_suppress)
+ continue;
+ panic_on_rcu_stall();
pr_err("INFO: %s detected expedited stalls on CPUs/tasks: {",
rsp->name);
ndetected = 0;
* next GP, to proceed.
*/
mutex_lock(&rsp->exp_wake_mutex);
- mutex_unlock(&rsp->exp_mutex);
rcu_for_each_node_breadth_first(rsp, rnp) {
if (ULONG_CMP_LT(READ_ONCE(rnp->exp_seq_rq), s)) {
mutex_unlock(&rsp->exp_wake_mutex);
}
+/* Let the workqueue handler know what it is supposed to do. */
+struct rcu_exp_work {
+ smp_call_func_t rew_func;
+ struct rcu_state *rew_rsp;
+ unsigned long rew_s;
+ struct work_struct rew_work;
+};
+
+/*
+ * Work-queue handler to drive an expedited grace period forward.
+ */
+static void wait_rcu_exp_gp(struct work_struct *wp)
+{
+ struct rcu_exp_work *rewp;
+
+ /* Initialize the rcu_node tree in preparation for the wait. */
+ rewp = container_of(wp, struct rcu_exp_work, rew_work);
+ sync_rcu_exp_select_cpus(rewp->rew_rsp, rewp->rew_func);
+
+ /* Wait and clean up, including waking everyone. */
+ rcu_exp_wait_wake(rewp->rew_rsp, rewp->rew_s);
+}
+
+/*
+ * Given an rcu_state pointer and a smp_call_function() handler, kick
+ * off the specified flavor of expedited grace period.
+ */
+static void _synchronize_rcu_expedited(struct rcu_state *rsp,
+ smp_call_func_t func)
+{
+ struct rcu_data *rdp;
+ struct rcu_exp_work rew;
+ struct rcu_node *rnp;
+ unsigned long s;
+
+ /* If expedited grace periods are prohibited, fall back to normal. */
+ if (rcu_gp_is_normal()) {
+ wait_rcu_gp(rsp->call);
+ return;
+ }
+
+ /* Take a snapshot of the sequence number. */
+ s = rcu_exp_gp_seq_snap(rsp);
+ if (exp_funnel_lock(rsp, s))
+ return; /* Someone else did our work for us. */
+
+ /* Marshall arguments and schedule the expedited grace period. */
+ rew.rew_func = func;
+ rew.rew_rsp = rsp;
+ rew.rew_s = s;
+ INIT_WORK_ONSTACK(&rew.rew_work, wait_rcu_exp_gp);
+ schedule_work(&rew.rew_work);
+
+ /* Wait for expedited grace period to complete. */
+ rdp = per_cpu_ptr(rsp->rda, raw_smp_processor_id());
+ rnp = rcu_get_root(rsp);
+ wait_event(rnp->exp_wq[(s >> 1) & 0x3],
+ sync_exp_work_done(rsp,
+ &rdp->exp_workdone0, s));
+
+ /* Let the next expedited grace period start. */
+ mutex_unlock(&rsp->exp_mutex);
+}
+
/**
* synchronize_sched_expedited - Brute-force RCU-sched grace period
*
*/
void synchronize_sched_expedited(void)
{
- unsigned long s;
struct rcu_state *rsp = &rcu_sched_state;
/* If only one CPU, this is automatically a grace period. */
if (rcu_blocking_is_gp())
return;
- /* If expedited grace periods are prohibited, fall back to normal. */
- if (rcu_gp_is_normal()) {
- wait_rcu_gp(call_rcu_sched);
- return;
- }
-
- /* Take a snapshot of the sequence number. */
- s = rcu_exp_gp_seq_snap(rsp);
- if (exp_funnel_lock(rsp, s))
- return; /* Someone else did our work for us. */
-
- /* Initialize the rcu_node tree in preparation for the wait. */
- sync_rcu_exp_select_cpus(rsp, sync_sched_exp_handler);
-
- /* Wait and clean up, including waking everyone. */
- rcu_exp_wait_wake(rsp, s);
+ _synchronize_rcu_expedited(rsp, sync_sched_exp_handler);
}
EXPORT_SYMBOL_GPL(synchronize_sched_expedited);
void synchronize_rcu_expedited(void)
{
struct rcu_state *rsp = rcu_state_p;
- unsigned long s;
-
- /* If expedited grace periods are prohibited, fall back to normal. */
- if (rcu_gp_is_normal()) {
- wait_rcu_gp(call_rcu);
- return;
- }
-
- s = rcu_exp_gp_seq_snap(rsp);
- if (exp_funnel_lock(rsp, s))
- return; /* Someone else did our work for us. */
-
- /* Initialize the rcu_node tree in preparation for the wait. */
- sync_rcu_exp_select_cpus(rsp, sync_rcu_exp_handler);
- /* Wait for ->blkd_tasks lists to drain, then wake everyone up. */
- rcu_exp_wait_wake(rsp, s);
+ _synchronize_rcu_expedited(rsp, sync_rcu_exp_handler);
}
EXPORT_SYMBOL_GPL(synchronize_rcu_expedited);
projects / cascardo / linux.git / blobdiff