sched: Add support for throttling group entities

Now that consumption is tracked (via update_curr()) we add support to throttle
group entities (and their corresponding cfs_rqs) in the case where this is no
run-time remaining.

Throttled entities are dequeued to prevent scheduling, additionally we mark
them as throttled (using cfs_rq->throttled) to prevent them from becoming
re-enqueued until they are unthrottled.  A list of a task_group's throttled
entities are maintained on the cfs_bandwidth structure.

Note: While the machinery for throttling is added in this patch the act of
throttling an entity exceeding its bandwidth is deferred until later within
the series.

Signed-off-by: Paul Turner <pjt@google.com>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/20110721184757.480608533@google.com
Signed-off-by: Ingo Molnar <mingo@elte.hu>

1 files changed, 7 insertions, 0 deletions

diff --git a/kernel/sched.c b/kernel/sched.c
index a2d55144bd9c..044260a9418d 100644
--- a/kernel/sched.c
+++ b/kernel/sched.c
@@ -260,6 +260,8 @@ struct cfs_bandwidth {
 
         int idle, timer_active;
         struct hrtimer period_timer;
+        struct list_head throttled_cfs_rq;
+
 #endif
 };
 
@@ -399,6 +401,9 @@ struct cfs_rq {
         int runtime_enabled;
         u64 runtime_expires;
         s64 runtime_remaining;
+
+        int throttled;
+        struct list_head throttled_list;
 #endif
 #endif
 };
@@ -441,6 +446,7 @@ static void init_cfs_bandwidth(struct cfs_bandwidth *cfs_b)
         cfs_b->quota = RUNTIME_INF;
         cfs_b->period = ns_to_ktime(default_cfs_period());
 
+        INIT_LIST_HEAD(&cfs_b->throttled_cfs_rq);
         hrtimer_init(&cfs_b->period_timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
         cfs_b->period_timer.function = sched_cfs_period_timer;
 }
@@ -448,6 +454,7 @@ static void init_cfs_bandwidth(struct cfs_bandwidth *cfs_b)
 static void init_cfs_rq_runtime(struct cfs_rq *cfs_rq)
 {
         cfs_rq->runtime_enabled = 0;
+        INIT_LIST_HEAD(&cfs_rq->throttled_list);
 }
 
 /* requires cfs_b->lock, may release to reprogram timer */