aboutsummaryrefslogtreecommitdiff
path: root/kernel
diff options
context:
space:
mode:
Diffstat (limited to 'kernel')
-rw-r--r--kernel/sched.c1
-rw-r--r--kernel/sched_fair.c26
2 files changed, 23 insertions, 4 deletions
diff --git a/kernel/sched.c b/kernel/sched.c
index 9fe473a190d..b533d6db78a 100644
--- a/kernel/sched.c
+++ b/kernel/sched.c
@@ -1587,6 +1587,7 @@ static void __sched_fork(struct task_struct *p)
p->se.wait_start_fair = 0;
p->se.exec_start = 0;
p->se.sum_exec_runtime = 0;
+ p->se.prev_sum_exec_runtime = 0;
p->se.delta_exec = 0;
p->se.delta_fair_run = 0;
p->se.delta_fair_sleep = 0;
diff --git a/kernel/sched_fair.c b/kernel/sched_fair.c
index 9f53d49f3aa..721fe774487 100644
--- a/kernel/sched_fair.c
+++ b/kernel/sched_fair.c
@@ -668,7 +668,7 @@ dequeue_entity(struct cfs_rq *cfs_rq, struct sched_entity *se, int sleep)
/*
* Preempt the current task with a newly woken task if needed:
*/
-static void
+static int
__check_preempt_curr_fair(struct cfs_rq *cfs_rq, struct sched_entity *se,
struct sched_entity *curr, unsigned long granularity)
{
@@ -679,8 +679,11 @@ __check_preempt_curr_fair(struct cfs_rq *cfs_rq, struct sched_entity *se,
* preempt the current task unless the best task has
* a larger than sched_granularity fairness advantage:
*/
- if (__delta > niced_granularity(curr, granularity))
+ if (__delta > niced_granularity(curr, granularity)) {
resched_task(rq_of(cfs_rq)->curr);
+ return 1;
+ }
+ return 0;
}
static inline void
@@ -725,6 +728,7 @@ static void put_prev_entity(struct cfs_rq *cfs_rq, struct sched_entity *prev)
static void entity_tick(struct cfs_rq *cfs_rq, struct sched_entity *curr)
{
+ unsigned long gran, ideal_runtime, delta_exec;
struct sched_entity *next;
/*
@@ -741,8 +745,22 @@ static void entity_tick(struct cfs_rq *cfs_rq, struct sched_entity *curr)
if (next == curr)
return;
- __check_preempt_curr_fair(cfs_rq, next, curr,
- sched_granularity(cfs_rq));
+ gran = sched_granularity(cfs_rq);
+ ideal_runtime = niced_granularity(curr,
+ max(sysctl_sched_latency / cfs_rq->nr_running,
+ (unsigned long)sysctl_sched_min_granularity));
+ /*
+ * If we executed more than what the latency constraint suggests,
+ * reduce the rescheduling granularity. This way the total latency
+ * of how much a task is not scheduled converges to
+ * sysctl_sched_latency:
+ */
+ delta_exec = curr->sum_exec_runtime - curr->prev_sum_exec_runtime;
+ if (delta_exec > ideal_runtime)
+ gran = 0;
+
+ if (__check_preempt_curr_fair(cfs_rq, next, curr, gran))
+ curr->prev_sum_exec_runtime = curr->sum_exec_runtime;
}
/**************************************************