[RFC PATCH 12/12 v1] Intercept RT provocatively

From: Yuyang Du
Date: Mon May 05 2014 - 04:09:27 EST


Signed-off-by: Yuyang Du <yuyang.du@xxxxxxxxx>
---
kernel/sched/rt.c | 25 +++++++++++++++++++++++++
1 file changed, 25 insertions(+)

diff --git a/kernel/sched/rt.c b/kernel/sched/rt.c
index bd2267a..f8141fb 100644
--- a/kernel/sched/rt.c
+++ b/kernel/sched/rt.c
@@ -1217,6 +1217,9 @@ select_task_rq_rt(struct task_struct *p, int cpu, int sd_flag, int flags)
{
struct task_struct *curr;
struct rq *rq;
+#ifdef CONFIG_WORKLOAD_CONSOLIDATION
+ int do_find = 0;
+#endif

if (p->nr_cpus_allowed == 1)
goto out;
@@ -1230,6 +1233,11 @@ select_task_rq_rt(struct task_struct *p, int cpu, int sd_flag, int flags)
rcu_read_lock();
curr = ACCESS_ONCE(rq->curr); /* unlocked access */

+#ifdef CONFIG_WORKLOAD_CONSOLIDATION
+ if (workload_consolidation_cpu_shielded(cpu))
+ do_find = 1;
+#endif
+
/*
* If the current task on @p's runqueue is an RT task, then
* try to see if we can wake this RT task up on another
@@ -1252,9 +1260,15 @@ select_task_rq_rt(struct task_struct *p, int cpu, int sd_flag, int flags)
* This test is optimistic, if we get it wrong the load-balancer
* will have to sort it out.
*/
+#ifdef CONFIG_WORKLOAD_CONSOLIDATION
+ if (do_find || (curr && unlikely(rt_task(curr)) &&
+ (curr->nr_cpus_allowed < 2 ||
+ curr->prio <= p->prio))) {
+#else
if (curr && unlikely(rt_task(curr)) &&
(curr->nr_cpus_allowed < 2 ||
curr->prio <= p->prio)) {
+#endif
int target = find_lowest_rq(p);

if (target != -1)
@@ -1460,6 +1474,12 @@ static int find_lowest_rq(struct task_struct *task)
if (!cpupri_find(&task_rq(task)->rd->cpupri, task, lowest_mask))
return -1; /* No targets found */

+#ifdef CONFIG_WORKLOAD_CONSOLIDATION
+ workload_consolidation_nonshielded_mask(this_cpu, lowest_mask);
+ if (!cpumask_weight(lowest_mask))
+ return -1;
+#endif
+
/*
* At this point we have built a mask of cpus representing the
* lowest priority tasks in the system. Now we want to elect
@@ -1687,6 +1707,11 @@ static int pull_rt_task(struct rq *this_rq)
if (likely(!rt_overloaded(this_rq)))
return 0;

+#ifdef CONFIG_WORKLOAD_CONSOLIDATION
+ if (workload_consolidation_cpu_shielded(this_cpu))
+ return 0;
+#endif
+
/*
* Match the barrier from rt_set_overloaded; this guarantees that if we
* see overloaded we must also see the rto_mask bit.
--
1.7.9.5

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