Messages in this thread | | | Date | Thu, 14 Jul 2011 22:58:07 +0800 | Subject | Re: [Question] sched: migrate RT task on throttled leaf RT runqueue? | From | Hillf Danton <> |
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On Thu, Jul 14, 2011 at 10:09 PM, Steven Rostedt <rostedt@goodmis.org> wrote: > On Thu, 2011-07-14 at 21:43 +0800, Hillf Danton wrote: >> Hi Steven >> >> When a non-boosted RT task is enqueued, if it is attached to task group, as >> shown in the following diff format for clarity, and even if the RT runqueue >> owned by the task group is throttled, the rt_rq is loaded up as leaf and the >> task is added to pushable list if it is pushable. >> >> Since RT tasks on throttled rt_runqueue will not be picked to be the next task >> when scheduling, could they be migrated by pushing and pulling? > > Note, run queues are not throttled, groups are. And tasks on a throttled > group should not be touched by the push/pull algorithm. >
Task group is one of the hard to understand in RT scheduler, according to the following two functions, if task group is throttled, could say its ->rt_rq[cpu] also throttled, where cpu could be anyone of the active_cpu_mask?
And how to relate rt_rq_throttled(p->rt.rt_rq) to throttled task group?
Thanks, Hillf
/* Change a task's cfs_rq and parent entity if it moves across CPUs/groups */ static inline void set_task_rq(struct task_struct *p, unsigned int cpu) { #ifdef CONFIG_FAIR_GROUP_SCHED p->se.cfs_rq = task_group(p)->cfs_rq[cpu]; p->se.parent = task_group(p)->se[cpu]; #endif
#ifdef CONFIG_RT_GROUP_SCHED p->rt.rt_rq = task_group(p)->rt_rq[cpu]; p->rt.parent = task_group(p)->rt_se[cpu]; #endif }
static inline struct rt_rq *rt_rq_of_se(struct sched_rt_entity *rt_se) { return rt_se->rt_rq; }
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