[PATCH 2/2] sched/deadline: Fix wrong cpudl_find() in check_preempt_equal_dl()
From: pang.xunlei
Date: Mon Nov 17 2014 - 11:12:08 EST
In check_preempt_equal_dl(), cpudl_find() is called with a NULL later_mask,
thus cpudl_find() here doesn't check cpudl.free_cpus at all.
This patch takles this issue by always passing a non-NULL cpumask to cpudl_find(),
and assigns later_mask in this function.
Signed-off-by: pang.xunlei <pang.xunlei@xxxxxxxxxx>
---
kernel/sched/cpudeadline.c | 14 ++++++--------
kernel/sched/deadline.c | 10 ++++++----
2 files changed, 12 insertions(+), 12 deletions(-)
diff --git a/kernel/sched/cpudeadline.c b/kernel/sched/cpudeadline.c
index 9a69353..623f7b5 100755
--- a/kernel/sched/cpudeadline.c
+++ b/kernel/sched/cpudeadline.c
@@ -97,7 +97,7 @@ static inline int cpudl_maximum(struct cpudl *cp)
* cpudl_find - find the best (later-dl) CPU in the system
* @cp: the cpudl max-heap context
* @p: the task
- * @later_mask: a mask to fill in with the selected CPUs (or NULL)
+ * @later_mask: a mask to fill in with the selected CPUs (not NULL)
*
* Returns: int - best CPU (heap maximum if suitable)
*/
@@ -107,16 +107,14 @@ int cpudl_find(struct cpudl *cp, struct task_struct *p,
int best_cpu = -1;
const struct sched_dl_entity *dl_se = &p->dl;
- if (later_mask && cpumask_and(later_mask, cp->free_cpus,
- &p->cpus_allowed) && cpumask_and(later_mask,
- later_mask, cpu_active_mask)) {
+ cpumask_and(later_mask, cpu_active_mask, &p->cpus_allowed);
+ if (cpumask_and(later_mask, later_mask, cp->free_cpus)) {
best_cpu = cpumask_any(later_mask);
goto out;
- } else if (cpumask_test_cpu(cpudl_maximum(cp), &p->cpus_allowed) &&
- dl_time_before(dl_se->deadline, cp->elements[0].dl)) {
+ } else if (cpumask_and(later_mask, cpumask_of(cpudl_maximum(cp)),
+ &p->cpus_allowed) && dl_time_before(dl_se->deadline,
+ cp->elements[0].dl)) {
best_cpu = cpudl_maximum(cp);
- if (later_mask)
- cpumask_set_cpu(best_cpu, later_mask);
}
out:
diff --git a/kernel/sched/deadline.c b/kernel/sched/deadline.c
index bd83272..3ecf838 100755
--- a/kernel/sched/deadline.c
+++ b/kernel/sched/deadline.c
@@ -965,14 +965,18 @@ out:
return cpu;
}
+static DEFINE_PER_CPU(cpumask_var_t, local_cpu_mask_dl);
+
static void check_preempt_equal_dl(struct rq *rq, struct task_struct *p)
{
+ struct cpumask *later_mask = this_cpu_cpumask_var_ptr(local_cpu_mask_dl);
+
/*
* Current can't be migrated, useless to reschedule,
* let's hope p can move out.
*/
if (rq->curr->nr_cpus_allowed == 1 ||
- cpudl_find(&rq->rd->cpudl, rq->curr, NULL) == -1)
+ cpudl_find(&rq->rd->cpudl, rq->curr, later_mask) == -1)
return;
/*
@@ -980,7 +984,7 @@ static void check_preempt_equal_dl(struct rq *rq, struct task_struct *p)
* see if it is pushed or pulled somewhere else.
*/
if (p->nr_cpus_allowed != 1 &&
- cpudl_find(&rq->rd->cpudl, p, NULL) != -1)
+ cpudl_find(&rq->rd->cpudl, p, later_mask) != -1)
return;
resched_curr(rq);
@@ -1167,8 +1171,6 @@ next_node:
return NULL;
}
-static DEFINE_PER_CPU(cpumask_var_t, local_cpu_mask_dl);
-
static int find_later_rq(struct task_struct *task)
{
struct sched_domain *sd;
--
2.1.0
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