@@ -346,12 +346,12 @@ static void check_preempt_curr_dl(struct rq *rq, struct task_struct *p,
* one, and to (try to!) reconcile itself with its own scheduling
* parameters.
*/
-static inline void setup_new_dl_entity(struct sched_dl_entity *dl_se,
- struct sched_dl_entity *pi_se)
+static inline void setup_new_dl_entity(struct sched_dl_entity *dl_se)
{
struct dl_rq *dl_rq = dl_rq_of_se(dl_se);
struct rq *rq = rq_of_dl_rq(dl_rq);
+ WARN_ON(dl_se->dl_boosted);
WARN_ON(dl_time_before(rq_clock(rq), dl_se->deadline));
/*
@@ -367,8 +367,8 @@ static inline void setup_new_dl_entity(struct sched_dl_entity *dl_se,
* future; in fact, we must consider execution overheads (time
* spent on hardirq context, etc.).
*/
- dl_se->deadline = rq_clock(rq) + pi_se->dl_deadline;
- dl_se->runtime = pi_se->dl_runtime;
+ dl_se->deadline = rq_clock(rq) + dl_se->dl_deadline;
+ dl_se->runtime = dl_se->dl_runtime;
}
/*
@@ -1720,19 +1720,28 @@ static void switched_from_dl(struct rq *rq, struct task_struct *p)
*/
static void switched_to_dl(struct rq *rq, struct task_struct *p)
{
- if (dl_time_before(p->dl.deadline, rq_clock(rq)))
- setup_new_dl_entity(&p->dl, &p->dl);
- if (task_on_rq_queued(p) && rq->curr != p) {
+ if (task_on_rq_queued(p)) {
+ /*
+ * If p is not queued we will update its parameters at next
+ * wakeup. If p is dl_boosted we already updated its params in
+ * rt_mutex_setprio()->enqueue_task(..., ENQUEUE_REPLENISH),
+ * p's deadline being now already after rq_clock(rq).
+ */
+ if (dl_time_before(p->dl.deadline, rq_clock(rq)))
+ setup_new_dl_entity(&p->dl);
+
+ if (rq->curr != p) {
#ifdef CONFIG_SMP
- if (tsk_nr_cpus_allowed(p) > 1 && rq->dl.overloaded)
- queue_push_tasks(rq);
+ if (tsk_nr_cpus_allowed(p) > 1 && rq->dl.overloaded)
+ queue_push_tasks(rq);
#else
- if (dl_task(rq->curr))
- check_preempt_curr_dl(rq, p, 0);
- else
- resched_curr(rq);
+ if (dl_task(rq->curr))
+ check_preempt_curr_dl(rq, p, 0);
+ else
+ resched_curr(rq);
#endif
+ }
}
}
setup_new_dl_entity() takes two parameters, but it only actually uses one of them, under a different name, to setup a new dl_entity, after: 2f9f3fdc928 "sched/deadline: Remove dl_new from struct sched_dl_entity" as we currently do setup_new_dl_entity(&p->dl, &p->dl) However, before Luca's change we were doing setup_new_dl_entity(dl_se, pi_se) in update_dl_entity() for a dl_se->new entity: we were using pi_se's parameters (the potential PI donor) for setting up a new entity. This change removes the useless second parameter of setup_new_dl_entity(). While we are at it we also optimize things further calling setup_new_dl_ entity() only for already queued tasks, since (as pointed out by Xunlei) we already do the very same update at tasks wakeup time anyway. By doing so, we don't need to worry about a potential PI donor anymore, as rt_ mutex_setprio() takes care of that already for us. Cc: Ingo Molnar <mingo@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Luca Abeni <luca.abeni@unitn.it> Cc: Xunlei Pang <xpang@redhat.com> Signed-off-by: Juri Lelli <juri.lelli@arm.com> --- Changes from v4: - remove dead code checking for boosted status, as never triggered after rt_mutex_setprio() Changes from v3: - call setup_new_dl_entity only if task is enqueued already Changes from v2: - optimize by calling rt_mutex_get_top_task only if the task is boosted (as suggested by Steve) Changes from v1: - Steve pointed out that we were actually using the second parameter to permorm initialization - Luca confirmed that behavior is slightly changed w.r.t. before his change - changelog updated and original behavior restored --- kernel/sched/deadline.c | 35 ++++++++++++++++++++++------------- 1 file changed, 22 insertions(+), 13 deletions(-) -- 2.7.0