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-rw-r--r--kernel/sched.c4
-rw-r--r--kernel/sched_fair.c24
2 files changed, 16 insertions, 12 deletions
diff --git a/kernel/sched.c b/kernel/sched.c
index b7dff36c7c8c..0bd8f2c0fb40 100644
--- a/kernel/sched.c
+++ b/kernel/sched.c
@@ -444,13 +444,15 @@ enum {
444 SCHED_FEAT_START_DEBIT = 2, 444 SCHED_FEAT_START_DEBIT = 2,
445 SCHED_FEAT_TREE_AVG = 4, 445 SCHED_FEAT_TREE_AVG = 4,
446 SCHED_FEAT_APPROX_AVG = 8, 446 SCHED_FEAT_APPROX_AVG = 8,
447 SCHED_FEAT_WAKEUP_PREEMPT = 16,
447}; 448};
448 449
449const_debug unsigned int sysctl_sched_features = 450const_debug unsigned int sysctl_sched_features =
450 SCHED_FEAT_NEW_FAIR_SLEEPERS *1 | 451 SCHED_FEAT_NEW_FAIR_SLEEPERS *1 |
451 SCHED_FEAT_START_DEBIT *1 | 452 SCHED_FEAT_START_DEBIT *1 |
452 SCHED_FEAT_TREE_AVG *0 | 453 SCHED_FEAT_TREE_AVG *0 |
453 SCHED_FEAT_APPROX_AVG *0; 454 SCHED_FEAT_APPROX_AVG *0 |
455 SCHED_FEAT_WAKEUP_PREEMPT *1;
454 456
455#define sched_feat(x) (sysctl_sched_features & SCHED_FEAT_##x) 457#define sched_feat(x) (sysctl_sched_features & SCHED_FEAT_##x)
456 458
diff --git a/kernel/sched_fair.c b/kernel/sched_fair.c
index 3ac096e74faf..3843ec71aad5 100644
--- a/kernel/sched_fair.c
+++ b/kernel/sched_fair.c
@@ -626,7 +626,7 @@ static void entity_tick(struct cfs_rq *cfs_rq, struct sched_entity *curr)
626 */ 626 */
627 update_curr(cfs_rq); 627 update_curr(cfs_rq);
628 628
629 if (cfs_rq->nr_running > 1) 629 if (cfs_rq->nr_running > 1 || !sched_feat(WAKEUP_PREEMPT))
630 check_preempt_tick(cfs_rq, curr); 630 check_preempt_tick(cfs_rq, curr);
631} 631}
632 632
@@ -828,18 +828,20 @@ static void check_preempt_wakeup(struct rq *rq, struct task_struct *p)
828 return; 828 return;
829 } 829 }
830 830
831 while (!is_same_group(se, pse)) { 831 if (sched_feat(WAKEUP_PREEMPT)) {
832 se = parent_entity(se); 832 while (!is_same_group(se, pse)) {
833 pse = parent_entity(pse); 833 se = parent_entity(se);
834 } 834 pse = parent_entity(pse);
835 }
835 836
836 delta = se->vruntime - pse->vruntime; 837 delta = se->vruntime - pse->vruntime;
837 gran = sysctl_sched_wakeup_granularity; 838 gran = sysctl_sched_wakeup_granularity;
838 if (unlikely(se->load.weight != NICE_0_LOAD)) 839 if (unlikely(se->load.weight != NICE_0_LOAD))
839 gran = calc_delta_fair(gran, &se->load); 840 gran = calc_delta_fair(gran, &se->load);
840 841
841 if (delta > gran) 842 if (delta > gran)
842 resched_task(curr); 843 resched_task(curr);
844 }
843} 845}
844 846
845static struct task_struct *pick_next_task_fair(struct rq *rq) 847static struct task_struct *pick_next_task_fair(struct rq *rq)