[RFC v2 5/7] GRUB accounting

Luca Abeni
2016-04-01T15:18:28Z

Signed-off-by: Luca Abeni <luca.abeni@unitn.it>
---
kernel/sched/deadline.c | 14 ++++++++++++++
1 file changed, 14 insertions(+)

diff --git a/kernel/sched/deadline.c b/kernel/sched/deadline.c
index ca7910a..647d779 100644
--- a/kernel/sched/deadline.c
+++ b/kernel/sched/deadline.c
@@ -783,6 +783,19 @@ int dl_runtime_exceeded(struct sched_dl_entity *dl_se)
extern bool sched_rt_bandwidth_account(struct rt_rq *rt_rq);

/*
+ * This function implements the GRUB accounting rule:
+ * according to the GRUB reclaiming algorithm, the runtime is
+ * not decreased as "dq = -dt", but as "dq = -Uact dt", where
+ * Uact is the (per-runqueue) active utilization.
+ * Since rq->dl.running_bw contains Uact * 2^20, the result
+ * has to be shifted right by 20.
+ */
+u64 grub_reclaim(u64 delta, struct rq *rq)
+{
+ return (delta * rq->dl.running_bw) >> 20;
+}
+
+/*
* Update the current task's runtime statistics (provided it is still
* a -deadline task and has not been removed from the dl_rq).
*/
@@ -821,6 +834,7 @@ static void update_curr_dl(struct rq *rq)

sched_rt_avg_update(rq, delta_exec);

+ delta_exec = grub_reclaim(delta_exec, rq);
dl_se->runtime -= delta_exec;

throttle:
--
2.5.0