diff options
Diffstat (limited to 'kernel/sched_fair.c')
| -rw-r--r-- | kernel/sched_fair.c | 69 |
1 files changed, 48 insertions, 21 deletions
diff --git a/kernel/sched_fair.c b/kernel/sched_fair.c index bdf6434..bc1563e 100644 --- a/kernel/sched_fair.c +++ b/kernel/sched_fair.c @@ -283,7 +283,7 @@ static void update_min_vruntime(struct cfs_rq *cfs_rq) struct sched_entity, run_node); - if (vruntime == cfs_rq->min_vruntime) + if (!cfs_rq->curr) vruntime = se->vruntime; else vruntime = min_vruntime(vruntime, se->vruntime); @@ -429,7 +429,10 @@ static u64 sched_slice(struct cfs_rq *cfs_rq, struct sched_entity *se) u64 slice = __sched_period(cfs_rq->nr_running + !se->on_rq); for_each_sched_entity(se) { - struct load_weight *load = &cfs_rq->load; + struct load_weight *load; + + cfs_rq = cfs_rq_of(se); + load = &cfs_rq->load; if (unlikely(!se->on_rq)) { struct load_weight lw = cfs_rq->load; @@ -677,9 +680,13 @@ place_entity(struct cfs_rq *cfs_rq, struct sched_entity *se, int initial) unsigned long thresh = sysctl_sched_latency; /* - * convert the sleeper threshold into virtual time + * Convert the sleeper threshold into virtual time. + * SCHED_IDLE is a special sub-class. We care about + * fairness only relative to other SCHED_IDLE tasks, + * all of which have the same weight. */ - if (sched_feat(NORMALIZED_SLEEPER)) + if (sched_feat(NORMALIZED_SLEEPER) && + task_of(se)->policy != SCHED_IDLE) thresh = calc_delta_fair(thresh, se); vruntime -= thresh; @@ -712,7 +719,7 @@ enqueue_entity(struct cfs_rq *cfs_rq, struct sched_entity *se, int wakeup) __enqueue_entity(cfs_rq, se); } -static void clear_buddies(struct cfs_rq *cfs_rq, struct sched_entity *se) +static void __clear_buddies(struct cfs_rq *cfs_rq, struct sched_entity *se) { if (cfs_rq->last == se) cfs_rq->last = NULL; @@ -721,6 +728,12 @@ static void clear_buddies(struct cfs_rq *cfs_rq, struct sched_entity *se) cfs_rq->next = NULL; } +static void clear_buddies(struct cfs_rq *cfs_rq, struct sched_entity *se) +{ + for_each_sched_entity(se) + __clear_buddies(cfs_rq_of(se), se); +} + static void dequeue_entity(struct cfs_rq *cfs_rq, struct sched_entity *se, int sleep) { @@ -761,8 +774,14 @@ check_preempt_tick(struct cfs_rq *cfs_rq, struct sched_entity *curr) ideal_runtime = sched_slice(cfs_rq, curr); delta_exec = curr->sum_exec_runtime - curr->prev_sum_exec_runtime; - if (delta_exec > ideal_runtime) + if (delta_exec > ideal_runtime) { resched_task(rq_of(cfs_rq)->curr); + /* + * The current task ran long enough, ensure it doesn't get + * re-elected due to buddy favours. + */ + clear_buddies(cfs_rq, curr); + } } static void @@ -1172,20 +1191,15 @@ wake_affine(struct sched_domain *this_sd, struct rq *this_rq, int idx, unsigned long load, unsigned long this_load, unsigned int imbalance) { - struct task_struct *curr = this_rq->curr; - struct task_group *tg; unsigned long tl = this_load; unsigned long tl_per_task; + struct task_group *tg; unsigned long weight; int balanced; if (!(this_sd->flags & SD_WAKE_AFFINE) || !sched_feat(AFFINE_WAKEUPS)) return 0; - if (sync && (curr->se.avg_overlap > sysctl_sched_migration_cost || - p->se.avg_overlap > sysctl_sched_migration_cost)) - sync = 0; - /* * If sync wakeup then subtract the (maximum possible) * effect of the currently running task from the load @@ -1387,14 +1401,18 @@ wakeup_preempt_entity(struct sched_entity *curr, struct sched_entity *se) static void set_last_buddy(struct sched_entity *se) { - for_each_sched_entity(se) - cfs_rq_of(se)->last = se; + if (likely(task_of(se)->policy != SCHED_IDLE)) { + for_each_sched_entity(se) + cfs_rq_of(se)->last = se; + } } static void set_next_buddy(struct sched_entity *se) { - for_each_sched_entity(se) - cfs_rq_of(se)->next = se; + if (likely(task_of(se)->policy != SCHED_IDLE)) { + for_each_sched_entity(se) + cfs_rq_of(se)->next = se; + } } /* @@ -1440,18 +1458,22 @@ static void check_preempt_wakeup(struct rq *rq, struct task_struct *p, int sync) return; /* - * Batch tasks do not preempt (their preemption is driven by + * Batch and idle tasks do not preempt (their preemption is driven by * the tick): */ - if (unlikely(p->policy == SCHED_BATCH)) + if (unlikely(p->policy != SCHED_NORMAL)) return; + /* Idle tasks are by definition preempted by everybody. */ + if (unlikely(curr->policy == SCHED_IDLE)) { + resched_task(curr); + return; + } + if (!sched_feat(WAKEUP_PREEMPT)) return; - if (sched_feat(WAKEUP_OVERLAP) && (sync || - (se->avg_overlap < sysctl_sched_migration_cost && - pse->avg_overlap < sysctl_sched_migration_cost))) { + if (sched_feat(WAKEUP_OVERLAP) && sync) { resched_task(curr); return; } @@ -1482,6 +1504,11 @@ static struct task_struct *pick_next_task_fair(struct rq *rq) do { se = pick_next_entity(cfs_rq); + /* + * If se was a buddy, clear it so that it will have to earn + * the favour again. + */ + __clear_buddies(cfs_rq, se); set_next_entity(cfs_rq, se); cfs_rq = group_cfs_rq(se); } while (cfs_rq); |
