2 files changed, 14 insertions, 4 deletions

diff --git a/kernel/sched.c b/kernel/sched.c
index 0bd8f2c0fb40..e8051bd59acb 100644
--- a/kernel/sched.c
+++ b/kernel/sched.c
@@ -445,6 +445,7 @@ enum {
         SCHED_FEAT_TREE_AVG             = 4,
         SCHED_FEAT_APPROX_AVG           = 8,
         SCHED_FEAT_WAKEUP_PREEMPT       = 16,
+        SCHED_FEAT_PREEMPT_RESTRICT     = 32,
 };
 
 const_debug unsigned int sysctl_sched_features =
@@ -452,7 +453,8 @@ const_debug unsigned int sysctl_sched_features =
                 SCHED_FEAT_START_DEBIT          *1 |
                 SCHED_FEAT_TREE_AVG             *0 |
                 SCHED_FEAT_APPROX_AVG           *0 |
-                SCHED_FEAT_WAKEUP_PREEMPT       *1;
+                SCHED_FEAT_WAKEUP_PREEMPT       *1 |
+                SCHED_FEAT_PREEMPT_RESTRICT     *1;
 
 #define sched_feat(x) (sysctl_sched_features & SCHED_FEAT_##x)
 
diff --git a/kernel/sched_fair.c b/kernel/sched_fair.c
index 3843ec71aad5..f819f943fb86 100644
--- a/kernel/sched_fair.c
+++ b/kernel/sched_fair.c
@@ -526,6 +526,7 @@ dequeue_entity(struct cfs_rq *cfs_rq, struct sched_entity *se, int sleep)
 
         update_stats_dequeue(cfs_rq, se);
         if (sleep) {
+                se->peer_preempt = 0;
 #ifdef CONFIG_SCHEDSTATS
                 if (entity_is_task(se)) {
                         struct task_struct *tsk = task_of(se);
@@ -553,8 +554,10 @@ 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 ||
+                        (sched_feat(PREEMPT_RESTRICT) && curr->peer_preempt))
                 resched_task(rq_of(cfs_rq)->curr);
+        curr->peer_preempt = 0;
 }
 
 static void
@@ -839,8 +842,12 @@ static void check_preempt_wakeup(struct rq *rq, struct task_struct *p)
                 if (unlikely(se->load.weight != NICE_0_LOAD))
                         gran = calc_delta_fair(gran, &se->load);
 
-                if (delta > gran)
-                        resched_task(curr);
+                if (delta > gran) {
+                        int now = !sched_feat(PREEMPT_RESTRICT);
+
+                        if (now || p->prio < curr->prio || !se->peer_preempt++)
+                                resched_task(curr);
+                }
         }
 }
 
@@ -1034,6 +1041,7 @@ static void task_new_fair(struct rq *rq, struct task_struct *p)
         check_spread(cfs_rq, curr);
         __enqueue_entity(cfs_rq, se);
         account_entity_enqueue(cfs_rq, se);
+        se->peer_preempt = 0;
         resched_task(rq->curr);
 }