--- kernel/sched_rt.c
+++ kernel/sched_rt.c
@@ -603,7 +603,7 @@ static void update_curr_rt(struct rq *rq
if (!task_has_rt_policy(curr))
return;
- delta_exec = rq->clock - curr->se.exec_start;
+ delta_exec = rq->clock_task - curr->se.exec_start;
if (unlikely((s64)delta_exec < 0))
delta_exec = 0;
@@ -612,7 +612,7 @@ static void update_curr_rt(struct rq *rq
curr->se.sum_exec_runtime += delta_exec;
account_group_exec_runtime(curr, delta_exec);
- curr->se.exec_start = rq->clock;
+ curr->se.exec_start = rq->clock_task;
cpuacct_charge(curr, delta_exec);
sched_rt_avg_update(rq, delta_exec);
@@ -954,18 +954,19 @@ select_task_rq_rt(struct rq *rq, struct
* runqueue. Otherwise simply start this RT task
* on its current runqueue.
*
- * We want to avoid overloading runqueues. Even if
- * the RT task is of higher priority than the current RT task.
- * RT tasks behave differently than other tasks. If
- * one gets preempted, we try to push it off to another queue.
- * So trying to keep a preempting RT task on the same
- * cache hot CPU will force the running RT task to
- * a cold CPU. So we waste all the cache for the lower
- * RT task in hopes of saving some of a RT task
- * that is just being woken and probably will have
- * cold cache anyway.
+ * We want to avoid overloading runqueues. If the woken
+ * task is a higher priority, then it will stay on this CPU
+ * and the lower prio task should be moved to another CPU.
+ * Even though this will probably make the lower prio task
+ * lose its cache, we do not want to bounce a higher task
+ * around just because it gave up its CPU, perhaps for a
+ * lock?
+ *
+ * For equal prio tasks, we just let the scheduler sort it out.
*/
if (unlikely(rt_task(rq->curr)) &&
+ (rq->curr->rt.nr_cpus_allowed < 2 ||
+ rq->curr->prio < p->prio) &&
(p->rt.nr_cpus_allowed > 1)) {
int cpu = find_lowest_rq(p);
@@ -1068,7 +1069,7 @@ static struct task_struct *_pick_next_ta
} while (rt_rq);
p = rt_task_of(rt_se);
- p->se.exec_start = rq->clock;
+ p->se.exec_start = rq->clock_task;
return p;
}
@@ -1493,7 +1494,10 @@ static void task_woken_rt(struct rq *rq,
if (!task_running(rq, p) &&
!test_tsk_need_resched(rq->curr) &&
has_pushable_tasks(rq) &&
- p->rt.nr_cpus_allowed > 1)
+ p->rt.nr_cpus_allowed > 1 &&
+ rt_task(rq->curr) &&
+ (rq->curr->rt.nr_cpus_allowed < 2 ||
+ rq->curr->prio < p->prio))
push_rt_tasks(rq);
}
@@ -1731,7 +1735,7 @@ static void set_curr_task_rt(struct rq *
{
struct task_struct *p = rq->curr;
- p->se.exec_start = rq->clock;
+ p->se.exec_start = rq->clock_task;
/* The running task is never eligible for pushing */
dequeue_pushable_task(rq, p);
projects / ziggy471-frankenstein-kernel.git / blobdiff