[PATCH] sched: Update task->on_rq when tasks are moving between runqueues

[Olav Haugan]

Task->on_rq has three states:
        0 - Task is not on runqueue (rq)
        1 (TASK_ON_RQ_QUEUED) - Task is on rq
        2 (TASK_ON_RQ_MIGRATING) - Task is on rq but in the process of being
        migrated to another rq

When a task is moving between rqs task->on_rq state should be
TASK_ON_RQ_MIGRATING

Signed-off-by: Olav Haugan <ohau...@codeaurora.org>
---
 kernel/sched/core.c     | 2 ++
 kernel/sched/deadline.c | 4 ++++
 kernel/sched/rt.c       | 4 ++++
 3 files changed, 10 insertions(+)

diff --git a/kernel/sched/core.c b/kernel/sched/core.c
index 10a8faa..5c7b614 100644
--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -1309,7 +1309,9 @@ static void __migrate_swap_task(struct task_struct *p, 
int cpu)
                dst_rq = cpu_rq(cpu);
 
                deactivate_task(src_rq, p, 0);
+               p->on_rq = TASK_ON_RQ_MIGRATING;
                set_task_cpu(p, cpu);
+               p->on_rq = TASK_ON_RQ_QUEUED;
                activate_task(dst_rq, p, 0);
                check_preempt_curr(dst_rq, p, 0);
        } else {
diff --git a/kernel/sched/deadline.c b/kernel/sched/deadline.c
index fc8f010..21297d7 100644
--- a/kernel/sched/deadline.c
+++ b/kernel/sched/deadline.c
@@ -1547,7 +1547,9 @@ retry:
        }
 
        deactivate_task(rq, next_task, 0);
+       next_task->on_rq = TASK_ON_RQ_MIGRATING;
        set_task_cpu(next_task, later_rq->cpu);
+       next_task->on_rq = TASK_ON_RQ_QUEUED;
        activate_task(later_rq, next_task, 0);
        ret = 1;
 
@@ -1635,7 +1637,9 @@ static void pull_dl_task(struct rq *this_rq)
                        resched = true;
 
                        deactivate_task(src_rq, p, 0);
+                       p->on_rq = TASK_ON_RQ_MIGRATING;
                        set_task_cpu(p, this_cpu);
+                       p->on_rq = TASK_ON_RQ_QUEUED;
                        activate_task(this_rq, p, 0);
                        dmin = p->dl.deadline;
 
diff --git a/kernel/sched/rt.c b/kernel/sched/rt.c
index d2ea593..0735040 100644
--- a/kernel/sched/rt.c
+++ b/kernel/sched/rt.c
@@ -1790,7 +1790,9 @@ retry:
        }
 
        deactivate_task(rq, next_task, 0);
+       next_task->on_rq = TASK_ON_RQ_MIGRATING;
        set_task_cpu(next_task, lowest_rq->cpu);
+       next_task->on_rq = TASK_ON_RQ_QUEUED;
        activate_task(lowest_rq, next_task, 0);
        ret = 1;
 
@@ -2044,7 +2046,9 @@ static void pull_rt_task(struct rq *this_rq)
                        resched = true;
 
                        deactivate_task(src_rq, p, 0);
+                       p->on_rq = TASK_ON_RQ_MIGRATING;
                        set_task_cpu(p, this_cpu);
+                       p->on_rq = TASK_ON_RQ_QUEUED;
                        activate_task(this_rq, p, 0);
                        /*
                         * We continue with the search, just in
-- 
2.6.1

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