Messages in this thread Patch in this message | | | From | "yingooyim" <> | Subject | [PATCH] cgroup/cpu: Fix tg_has_rt_task() malfunction | Date | Wed, 21 Sep 2016 13:35:12 +0900 |
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Hi, I am a graduate student of System Software Lab. at Konkuk University (http://sslab.konkuk.ac.kr).
This patch is to fix the malfunction of tg_has_rt_tasks(). The tg_has_rt_tasks() function is supposed to determine whether a task group includes an "rt task" or not. However, it returns true for "dl task" too. The origin of this problem is that rt_task() called by tg_has_rt_tasks() returns true for dl tasks. Because of this problem, tg_rt_schedulable() that calls tg_has_rt_tasks() returns –EBUSY if we try to initialize an rt task group, while a dl task is running. That is, you cannot run an rt task group when there exists a dl task in the system. Our patch provided in this post simply makes the tg_has_rt_tasks() function return false for dl tasks by calling dl_task() in the conditional statement.
Previously we have provided another patch for rt_task() (more precisely rt_prio()) to resolve this problem as follows: https://patchwork.kernel.org/patch/9299267/ However, a dependency issue were raised. So, we think that it is better to modify tg_has_rt_tasks() instead of rt_task() itself.
Signed-off-by: Yin-goo Yim <ygyim@konkuk.ac.kr> ---- kernel/sched/core.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/kernel/sched/core.c b/kernel/sched/core.c index 2a906f2..ee5ab2f 100644 --- a/kernel/sched/core.c +++ b/kernel/sched/core.c @@ -7846,7 +7846,7 @@ static inline int tg_has_rt_tasks(struct task_group *tg) return 0;
for_each_process_thread(g, p) { - if (rt_task(p) && task_group(p) == tg) + if (rt_task(p) && !dl_task(p) && task_group(p) == tg) return 1; }
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