#include "sched.h"
#include <linux/slab.h>
+#include <linux/irq_work.h>
int sched_rr_timeslice = RR_TIMESLICE;
raw_spin_unlock(&rt_b->rt_runtime_lock);
}
-void init_rt_rq(struct rt_rq *rt_rq, struct rq *rq)
+#ifdef CONFIG_SMP
+static void push_irq_work_func(struct irq_work *work);
+#endif
+
+void init_rt_rq(struct rt_rq *rt_rq)
{
struct rt_prio_array *array;
int i;
rt_rq->rt_nr_migratory = 0;
rt_rq->overloaded = 0;
plist_head_init(&rt_rq->pushable_tasks);
+
+#ifdef HAVE_RT_PUSH_IPI
+ rt_rq->push_flags = 0;
+ rt_rq->push_cpu = nr_cpu_ids;
+ raw_spin_lock_init(&rt_rq->push_lock);
+ init_irq_work(&rt_rq->push_work, push_irq_work_func);
#endif
+#endif /* CONFIG_SMP */
/* We start is dequeued state, because no RT tasks are queued */
rt_rq->rt_queued = 0;
if (!rt_se)
goto err_free_rq;
- init_rt_rq(rt_rq, cpu_rq(i));
+ init_rt_rq(rt_rq);
rt_rq->rt_runtime = tg->rt_bandwidth.rt_runtime;
init_tg_rt_entry(tg, rt_rq, rt_se, i, parent->rt_se[i]);
}
;
}
+#ifdef HAVE_RT_PUSH_IPI
+/*
+ * The search for the next cpu always starts at rq->cpu and ends
+ * when we reach rq->cpu again. It will never return rq->cpu.
+ * This returns the next cpu to check, or nr_cpu_ids if the loop
+ * is complete.
+ *
+ * rq->rt.push_cpu holds the last cpu returned by this function,
+ * or if this is the first instance, it must hold rq->cpu.
+ */
+static int rto_next_cpu(struct rq *rq)
+{
+ int prev_cpu = rq->rt.push_cpu;
+ int cpu;
+
+ cpu = cpumask_next(prev_cpu, rq->rd->rto_mask);
+
+ /*
+ * If the previous cpu is less than the rq's CPU, then it already
+ * passed the end of the mask, and has started from the beginning.
+ * We end if the next CPU is greater or equal to rq's CPU.
+ */
+ if (prev_cpu < rq->cpu) {
+ if (cpu >= rq->cpu)
+ return nr_cpu_ids;
+
+ } else if (cpu >= nr_cpu_ids) {
+ /*
+ * We passed the end of the mask, start at the beginning.
+ * If the result is greater or equal to the rq's CPU, then
+ * the loop is finished.
+ */
+ cpu = cpumask_first(rq->rd->rto_mask);
+ if (cpu >= rq->cpu)
+ return nr_cpu_ids;
+ }
+ rq->rt.push_cpu = cpu;
+
+ /* Return cpu to let the caller know if the loop is finished or not */
+ return cpu;
+}
+
+static int find_next_push_cpu(struct rq *rq)
+{
+ struct rq *next_rq;
+ int cpu;
+
+ while (1) {
+ cpu = rto_next_cpu(rq);
+ if (cpu >= nr_cpu_ids)
+ break;
+ next_rq = cpu_rq(cpu);
+
+ /* Make sure the next rq can push to this rq */
+ if (next_rq->rt.highest_prio.next < rq->rt.highest_prio.curr)
+ break;
+ }
+
+ return cpu;
+}
+
+#define RT_PUSH_IPI_EXECUTING 1
+#define RT_PUSH_IPI_RESTART 2
+
+static void tell_cpu_to_push(struct rq *rq)
+{
+ int cpu;
+
+ if (rq->rt.push_flags & RT_PUSH_IPI_EXECUTING) {
+ raw_spin_lock(&rq->rt.push_lock);
+ /* Make sure it's still executing */
+ if (rq->rt.push_flags & RT_PUSH_IPI_EXECUTING) {
+ /*
+ * Tell the IPI to restart the loop as things have
+ * changed since it started.
+ */
+ rq->rt.push_flags |= RT_PUSH_IPI_RESTART;
+ raw_spin_unlock(&rq->rt.push_lock);
+ return;
+ }
+ raw_spin_unlock(&rq->rt.push_lock);
+ }
+
+ /* When here, there's no IPI going around */
+
+ rq->rt.push_cpu = rq->cpu;
+ cpu = find_next_push_cpu(rq);
+ if (cpu >= nr_cpu_ids)
+ return;
+
+ rq->rt.push_flags = RT_PUSH_IPI_EXECUTING;
+
+ irq_work_queue_on(&rq->rt.push_work, cpu);
+}
+
+/* Called from hardirq context */
+static void try_to_push_tasks(void *arg)
+{
+ struct rt_rq *rt_rq = arg;
+ struct rq *rq, *src_rq;
+ int this_cpu;
+ int cpu;
+
+ this_cpu = rt_rq->push_cpu;
+
+ /* Paranoid check */
+ BUG_ON(this_cpu != smp_processor_id());
+
+ rq = cpu_rq(this_cpu);
+ src_rq = rq_of_rt_rq(rt_rq);
+
+again:
+ if (has_pushable_tasks(rq)) {
+ raw_spin_lock(&rq->lock);
+ push_rt_task(rq);
+ raw_spin_unlock(&rq->lock);
+ }
+
+ /* Pass the IPI to the next rt overloaded queue */
+ raw_spin_lock(&rt_rq->push_lock);
+ /*
+ * If the source queue changed since the IPI went out,
+ * we need to restart the search from that CPU again.
+ */
+ if (rt_rq->push_flags & RT_PUSH_IPI_RESTART) {
+ rt_rq->push_flags &= ~RT_PUSH_IPI_RESTART;
+ rt_rq->push_cpu = src_rq->cpu;
+ }
+
+ cpu = find_next_push_cpu(src_rq);
+
+ if (cpu >= nr_cpu_ids)
+ rt_rq->push_flags &= ~RT_PUSH_IPI_EXECUTING;
+ raw_spin_unlock(&rt_rq->push_lock);
+
+ if (cpu >= nr_cpu_ids)
+ return;
+
+ /*
+ * It is possible that a restart caused this CPU to be
+ * chosen again. Don't bother with an IPI, just see if we
+ * have more to push.
+ */
+ if (unlikely(cpu == rq->cpu))
+ goto again;
+
+ /* Try the next RT overloaded CPU */
+ irq_work_queue_on(&rt_rq->push_work, cpu);
+}
+
+static void push_irq_work_func(struct irq_work *work)
+{
+ struct rt_rq *rt_rq = container_of(work, struct rt_rq, push_work);
+
+ try_to_push_tasks(rt_rq);
+}
+#endif /* HAVE_RT_PUSH_IPI */
+
static int pull_rt_task(struct rq *this_rq)
{
int this_cpu = this_rq->cpu, ret = 0, cpu;
*/
smp_rmb();
+#ifdef HAVE_RT_PUSH_IPI
+ if (sched_feat(RT_PUSH_IPI)) {
+ tell_cpu_to_push(this_rq);
+ return 0;
+ }
+#endif
+
for_each_cpu(cpu, this_rq->rd->rto_mask) {
if (this_cpu == cpu)
continue;
projects / karo-tx-linux.git / blobdiff