Hi,
On 11/19/14, 11:46 PM, pang.xunlei wrote:
Currently, cpudl.free_cpus contains all cpus during init(see cpudl_init()),
so when calling cpudl_find() we have to add rd->span cpumask(cpus_allowed is
undependable when performing clustered scheduling using the cpuset) to avoid
selecting the cpu outside current root domain, see find_later_rq().
This patch adds cpudl_set_freecpu() to initialize cpudl.free_cpus when doing
rq_attach_root(), so we can avoid the extra rd->span operation when calling
cpudl_find().
Signed-off-by: pang.xunlei <pang.xun...@linaro.org>
Reviewed-by: Wanpeng Li <wanpeng...@linux.intel.com>
I think this patch solve one problem I meet in my progress to handle dl
task migration during cpu hotplug.
https://www.mail-archive.com/linux-kernel@vger.kernel.org/msg770579.html
Regards,
Wanpeng Li
---
kernel/sched/core.c | 2 ++
kernel/sched/cpudeadline.c | 18 ++++++++++++++----
kernel/sched/cpudeadline.h | 1 +
kernel/sched/deadline.c | 3 ---
4 files changed, 17 insertions(+), 7 deletions(-)
diff --git a/kernel/sched/core.c b/kernel/sched/core.c
index 240157c..1b417de 100644
--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -5584,6 +5584,8 @@ static void rq_attach_root(struct rq *rq, struct
root_domain *rd)
rq->rd = rd;
cpumask_set_cpu(rq->cpu, rd->span);
+ cpudl_set_freecpu(&rd->cpudl, rq->cpu);
+
if (cpumask_test_cpu(rq->cpu, cpu_active_mask))
set_rq_online(rq);
diff --git a/kernel/sched/cpudeadline.c b/kernel/sched/cpudeadline.c
index 539ca3c..c79f0d7 100644
--- a/kernel/sched/cpudeadline.c
+++ b/kernel/sched/cpudeadline.c
@@ -107,7 +107,9 @@ 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, later_mask, cp->free_cpus)) {
+ if (later_mask &&
+ cpumask_and(later_mask, cp->free_cpus, &p->cpus_allowed) &&
+ cpumask_and(later_mask, later_mask, cpu_active_mask)) {
best_cpu = cpumask_any(later_mask);
goto out;
} else if (cpumask_test_cpu(cpudl_maximum(cp), &p->cpus_allowed) &&
@@ -186,6 +188,16 @@ out:
}
/*
+ * cpudl_set_freecpu - Set the cpudl.free_cpus
+ * @cp: the cpudl max-heap context
+ * @cpu: rd attached cpu
+ */
+void cpudl_set_freecpu(struct cpudl *cp, int cpu)
+{
+ cpumask_set_cpu(cpu, cp->free_cpus);
+}
+
+/*
* cpudl_init - initialize the cpudl structure
* @cp: the cpudl max-heap context
*/
@@ -203,7 +215,7 @@ int cpudl_init(struct cpudl *cp)
if (!cp->elements)
return -ENOMEM;
- if (!alloc_cpumask_var(&cp->free_cpus, GFP_KERNEL)) {
+ if (!zalloc_cpumask_var(&cp->free_cpus, GFP_KERNEL)) {
kfree(cp->elements);
return -ENOMEM;
}
@@ -211,8 +223,6 @@ int cpudl_init(struct cpudl *cp)
for_each_possible_cpu(i)
cp->elements[i].idx = IDX_INVALID;
- cpumask_setall(cp->free_cpus);
-
return 0;
}
diff --git a/kernel/sched/cpudeadline.h b/kernel/sched/cpudeadline.h
index 020039b..4a10a65 100644
--- a/kernel/sched/cpudeadline.h
+++ b/kernel/sched/cpudeadline.h
@@ -24,6 +24,7 @@ int cpudl_find(struct cpudl *cp, struct task_struct *p,
struct cpumask *later_mask);
void cpudl_set(struct cpudl *cp, int cpu, u64 dl, int is_valid);
int cpudl_init(struct cpudl *cp);
+void cpudl_set_freecpu(struct cpudl *cp, int cpu);
void cpudl_cleanup(struct cpudl *cp);
#endif /* CONFIG_SMP */
diff --git a/kernel/sched/deadline.c b/kernel/sched/deadline.c
index 5285332..bd83272 100644
--- a/kernel/sched/deadline.c
+++ b/kernel/sched/deadline.c
@@ -1187,9 +1187,6 @@ static int find_later_rq(struct task_struct *task)
* We have to consider system topology and task affinity
* first, then we can look for a suitable cpu.
*/
- cpumask_copy(later_mask, task_rq(task)->rd->span);
- cpumask_and(later_mask, later_mask, cpu_active_mask);
- cpumask_and(later_mask, later_mask, &task->cpus_allowed);
best_cpu = cpudl_find(&task_rq(task)->rd->cpudl,
task, later_mask);
if (best_cpu == -1)
--
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