Get rid of the superfluous dst_cpu, move the cpu_mask inside the search
function, and collapse the two redundant pick-next-rt() functions.
Signed-off-by: Gregory Haskins <ghaskins@xxxxxxxxxx>
---
kernel/sched.c | 27 ++++++++++++---------------
kernel/sched_rt.c | 44 --------------------------------------------
2 files changed, 12 insertions(+), 59 deletions(-)
diff --git a/kernel/sched.c b/kernel/sched.c
index 821f115..de5fc1c 100644
--- a/kernel/sched.c
+++ b/kernel/sched.c
@@ -1471,9 +1471,10 @@ next_in_queue:
* Return the highest-prio non-running RT task (if task
* may run on this CPU):
*/
- if (!task_running(src_rq, tmp) &&
- cpu_isset(this_cpu, tmp->cpus_allowed))
- return tmp;
+ if (!task_running(src_rq, tmp)) {
+ if ((this_cpu == -1) || cpu_isset(this_cpu, tmp->cpus_allowed))
+ return tmp;
+ }
curr = curr->next;
if (curr != head)
@@ -1489,20 +1490,21 @@ static int double_lock_balance(struct rq *this_rq, struct rq *busiest);
#define RT_PUSH_MAX_TRIES 3
/* Will lock the rq it finds */
-static struct rq *find_lock_lowest_rq(cpumask_t *cpu_mask,
- struct task_struct *task,
+static struct rq *find_lock_lowest_rq(struct task_struct *task,
struct rq *this_rq)
{
struct rq *lowest_rq = NULL;
- int dst_cpu = -1;
int cpu;
int tries;
+ cpumask_t cpu_mask;
+
+ cpus_and(cpu_mask, cpu_online_map, task->cpus_allowed);
for (tries = 0; tries < RT_PUSH_MAX_TRIES; tries++) {
/*
* Scan each rq for the lowest prio.
*/
- for_each_cpu_mask(cpu, *cpu_mask) {
+ for_each_cpu_mask(cpu, cpu_mask) {
struct rq *rq = &per_cpu(runqueues, cpu);
if (cpu == this_rq->cpu)
@@ -1511,7 +1513,6 @@ static struct rq *find_lock_lowest_rq(cpumask_t *cpu_mask,
/* We look for lowest RT prio or non-rt CPU */
if (rq->curr_prio >= MAX_RT_PRIO) {
lowest_rq = rq;
- dst_cpu = cpu;
break;
}
@@ -1519,7 +1520,6 @@ static struct rq *find_lock_lowest_rq(cpumask_t *cpu_mask,
if (rq->curr_prio > task->prio &&
(!lowest_rq || rq->curr_prio < lowest_rq->curr_prio)) {
lowest_rq = rq;
- dst_cpu = cpu;
}
}
@@ -1535,7 +1535,7 @@ static struct rq *find_lock_lowest_rq(cpumask_t *cpu_mask,
*/
if (unlikely(task_running(this_rq, task) ||
task_rq(task) != this_rq ||
- !cpu_isset(dst_cpu, task->cpus_allowed))) {
+ !cpu_isset(lowest_rq->cpu, task->cpus_allowed))) {
spin_unlock(&lowest_rq->lock);
lowest_rq = NULL;
break;
@@ -1566,21 +1566,18 @@ static int push_rt_task(struct rq *this_rq)
struct rq *lowest_rq;
int dst_cpu;
int ret = 0;
- cpumask_t cpu_mask;
assert_spin_locked(&this_rq->lock);
- next_task = rt_next_highest_task(this_rq);
+ next_task = pick_rt_task(this_rq, -1);
if (!next_task)
return 0;
- cpus_and(cpu_mask, cpu_online_map, next_task->cpus_allowed);
-
/* We might release this_rq lock */
get_task_struct(next_task);
/* find_lock_lowest_rq locks the rq if found */
- lowest_rq = find_lock_lowest_rq(&cpu_mask, next_task, this_rq);
+ lowest_rq = find_lock_lowest_rq(next_task, this_rq);
if (!lowest_rq)
goto out;
diff --git a/kernel/sched_rt.c b/kernel/sched_rt.c
index 546526b..9b677c1 100644
--- a/kernel/sched_rt.c
+++ b/kernel/sched_rt.c
@@ -96,50 +96,6 @@ static struct task_struct *pick_next_task_rt(struct rq *rq)
return next;
}
-#ifdef CONFIG_PREEMPT_RT
-static struct task_struct *rt_next_highest_task(struct rq *rq)
-{
- struct rt_prio_array *array = &rq->rt.active;
- struct task_struct *next;
- struct list_head *queue;
- int idx;
-
- if (likely (rq->rt_nr_running < 2))
- return NULL;
-
- idx = sched_find_first_bit(array->bitmap);
- if (idx >= MAX_RT_PRIO) {
- WARN_ON(1); /* rt_nr_running is bad */
- return NULL;
- }
-
- queue = array->queue + idx;
- next = list_entry(queue->next, struct task_struct, run_list);
- if (unlikely(next != current))
- return next;
-
- if (queue->next->next != queue) {
- /* same prio task */
- next = list_entry(queue->next->next, struct task_struct, run_list);
- goto out;
- }
-
- /* slower, but more flexible */
- idx = find_next_bit(array->bitmap, MAX_RT_PRIO, idx+1);
- if (idx >= MAX_RT_PRIO) {
- WARN_ON(1); /* rt_nr_running was 2 and above! */
- return NULL;
- }
-
- queue = array->queue + idx;
- next = list_entry(queue->next, struct task_struct, run_list);
-
- out:
- return next;
-
-}
-#endif /* CONFIG_PREEMPT_RT */
-
static void put_prev_task_rt(struct rq *rq, struct task_struct *p)
{
update_curr_rt(rq);
-
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