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SubjectRe: [PATCH 1/7] sched/deadline: fix try to pull pinned dl tasks in pull algorithm
Ping Juri for this patchset, :)
On Mon, Apr 06, 2015 at 04:53:13PM +0800, Wanpeng Li wrote:
>Function pick_next_earliest_dl_task is used to pick earliest and pushable
>dl task from overloaded cpus in pull algorithm, however, it traverses
>runqueue rbtree instead of pushable task rbtree which is also ordered by
>tasks' deadlines. This will result in getting no candidates from overloaded
>cpus if all the dl tasks on the overloaded cpus are pinned. This patch fix
>it by traversing pushable task rbtree which is also ordered by tasks'
>deadlines.
>
>Signed-off-by: Wanpeng Li <wanpeng.li@linux.intel.com>
>---
> kernel/sched/deadline.c | 29 ++++++++++++++++++++++++++++-
> 1 file changed, 28 insertions(+), 1 deletion(-)
>
>diff --git a/kernel/sched/deadline.c b/kernel/sched/deadline.c
>index 5e95145..b57ceba 100644
>--- a/kernel/sched/deadline.c
>+++ b/kernel/sched/deadline.c
>@@ -1230,6 +1230,33 @@ next_node:
> return NULL;
> }
>
>+/*
>+ * Return the earliest pushable rq's task, which is suitable to be executed
>+ * on the cpu, NULL otherwse
>+ */
>+static struct task_struct *pick_earliest_pushable_dl_task(struct rq *rq,
>+ int cpu)
>+{
>+ struct rb_node *next_node = rq->dl.pushable_dl_tasks_leftmost;
>+ struct task_struct *p = NULL;
>+
>+ if (!has_pushable_dl_tasks(rq))
>+ return NULL;
>+
>+next_node:
>+ if (next_node) {
>+ p = rb_entry(next_node, struct task_struct, pushable_dl_tasks);
>+
>+ if (pick_dl_task(rq, p, cpu))
>+ return p;
>+
>+ next_node = rb_next(next_node);
>+ goto next_node;
>+ }
>+
>+ return NULL;
>+}
>+
> static DEFINE_PER_CPU(cpumask_var_t, local_cpu_mask_dl);
>
> static int find_later_rq(struct task_struct *task)
>@@ -1514,7 +1541,7 @@ static int pull_dl_task(struct rq *this_rq)
> if (src_rq->dl.dl_nr_running <= 1)
> goto skip;
>
>- p = pick_next_earliest_dl_task(src_rq, this_cpu);
>+ p = pick_earliest_pushable_dl_task(src_rq, this_cpu);
>
> /*
> * We found a task to be pulled if:
>--
>1.9.1


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