diff options
Diffstat (limited to 'kernel/sched/core.c')
| -rw-r--r-- | kernel/sched/core.c | 41 |
1 files changed, 33 insertions, 8 deletions
diff --git a/kernel/sched/core.c b/kernel/sched/core.c index c0accc00566e..5eab11d4b747 100644 --- a/kernel/sched/core.c +++ b/kernel/sched/core.c @@ -1814,6 +1814,10 @@ void __dl_clear_params(struct task_struct *p) dl_se->dl_period = 0; dl_se->flags = 0; dl_se->dl_bw = 0; + + dl_se->dl_throttled = 0; + dl_se->dl_new = 1; + dl_se->dl_yielded = 0; } /* @@ -1839,7 +1843,7 @@ static void __sched_fork(unsigned long clone_flags, struct task_struct *p) #endif RB_CLEAR_NODE(&p->dl.rb_node); - hrtimer_init(&p->dl.dl_timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL); + init_dl_task_timer(&p->dl); __dl_clear_params(p); INIT_LIST_HEAD(&p->rt.run_list); @@ -2049,6 +2053,9 @@ static inline int dl_bw_cpus(int i) * allocated bandwidth to reflect the new situation. * * This function is called while holding p's rq->lock. + * + * XXX we should delay bw change until the task's 0-lag point, see + * __setparam_dl(). */ static int dl_overflow(struct task_struct *p, int policy, const struct sched_attr *attr) @@ -3251,15 +3258,31 @@ __setparam_dl(struct task_struct *p, const struct sched_attr *attr) { struct sched_dl_entity *dl_se = &p->dl; - init_dl_task_timer(dl_se); dl_se->dl_runtime = attr->sched_runtime; dl_se->dl_deadline = attr->sched_deadline; dl_se->dl_period = attr->sched_period ?: dl_se->dl_deadline; dl_se->flags = attr->sched_flags; dl_se->dl_bw = to_ratio(dl_se->dl_period, dl_se->dl_runtime); - dl_se->dl_throttled = 0; - dl_se->dl_new = 1; - dl_se->dl_yielded = 0; + + /* + * Changing the parameters of a task is 'tricky' and we're not doing + * the correct thing -- also see task_dead_dl() and switched_from_dl(). + * + * What we SHOULD do is delay the bandwidth release until the 0-lag + * point. This would include retaining the task_struct until that time + * and change dl_overflow() to not immediately decrement the current + * amount. + * + * Instead we retain the current runtime/deadline and let the new + * parameters take effect after the current reservation period lapses. + * This is safe (albeit pessimistic) because the 0-lag point is always + * before the current scheduling deadline. + * + * We can still have temporary overloads because we do not delay the + * change in bandwidth until that time; so admission control is + * not on the safe side. It does however guarantee tasks will never + * consume more than promised. + */ } /* @@ -4642,6 +4665,9 @@ int cpuset_cpumask_can_shrink(const struct cpumask *cur, struct dl_bw *cur_dl_b; unsigned long flags; + if (!cpumask_weight(cur)) + return ret; + rcu_read_lock_sched(); cur_dl_b = dl_bw_of(cpumask_any(cur)); trial_cpus = cpumask_weight(trial); @@ -7292,13 +7318,12 @@ void __might_sleep(const char *file, int line, int preempt_offset) * since we will exit with TASK_RUNNING make sure we enter with it, * otherwise we will destroy state. */ - if (WARN_ONCE(current->state != TASK_RUNNING, + WARN_ONCE(current->state != TASK_RUNNING && current->task_state_change, "do not call blocking ops when !TASK_RUNNING; " "state=%lx set at [<%p>] %pS\n", current->state, (void *)current->task_state_change, - (void *)current->task_state_change)) - __set_current_state(TASK_RUNNING); + (void *)current->task_state_change); ___might_sleep(file, line, preempt_offset); } |