/* ticks this CPU has handled */
/* during and after the last grace */
/* period it is aware of. */
+ struct irq_work defer_qs_iw; /* Obtain later scheduler attention. */
+ bool defer_qs_iw_pending; /* Scheduler attention pending? */
/* 2) batch handling */
struct rcu_segcblist cblist; /* Segmented callback list, with */
}
/*
+ * Minimal handler to give the scheduler a chance to re-evaluate.
+ */
+static void rcu_preempt_deferred_qs_handler(struct irq_work *iwp)
+{
+ struct rcu_data *rdp;
+
+ rdp = container_of(iwp, struct rcu_data, defer_qs_iw);
+ rdp->defer_qs_iw_pending = false;
+}
+
+/*
* Handle special cases during rcu_read_unlock(), such as needing to
* notify RCU core processing or task having blocked during the RCU
* read-side critical section.
// Also if no expediting or NO_HZ_FULL, slow is OK.
set_tsk_need_resched(current);
set_preempt_need_resched();
+ if (IS_ENABLED(CONFIG_IRQ_WORK) &&
+ !rdp->defer_qs_iw_pending && exp) {
+ // Get scheduler to re-evaluate and call hooks.
+ // If !IRQ_WORK, FQS scan will eventually IPI.
+ init_irq_work(&rdp->defer_qs_iw,
+ rcu_preempt_deferred_qs_handler);
+ rdp->defer_qs_iw_pending = true;
+ irq_work_queue_on(&rdp->defer_qs_iw, rdp->cpu);
+ }
}
t->rcu_read_unlock_special.b.deferred_qs = true;
local_irq_restore(flags);