Commit-ID: 91ec6778ec4f963fcb2c2793610919b572f633b0
Gitweb: http://git.kernel.org/tip/91ec6778ec4f963fcb2c2793610919b572f633b0
Author: Juri Lelli <juri.lelli@xxxxxxx>
AuthorDate: Fri, 19 Sep 2014 10:22:41 +0100
Committer: Ingo Molnar <mingo@xxxxxxxxxx>
CommitDate: Wed, 24 Sep 2014 14:46:57 +0200
sched/deadline: Fix inter- exclusive cpusets migrations
Users can perform clustered scheduling using the cpuset facility.
After an exclusive cpuset is created, task migrations happen only
between CPUs belonging to the same cpuset. Inter- cpuset migrations
can only happen when the user requires so, moving a task between
different cpusets. This behaviour is broken in SCHED_DEADLINE, as
currently spurious inter- cpuset migration may happen without user
intervention.
This patch fix the problem (and shuffles the code a bit to improve
clarity).
Signed-off-by: Juri Lelli <juri.lelli@xxxxxxx>
Signed-off-by: Peter Zijlstra (Intel) <peterz@xxxxxxxxxxxxx>
Cc: raistlin@xxxxxxxx
Cc: michael@xxxxxxxxxxxxxxxxxxxx
Cc: fchecconi@xxxxxxxxx
Cc: daniel.wagner@xxxxxxxxxxxx
Cc: vincent@xxxxxxxxxxx
Cc: luca.abeni@xxxxxxxx
Cc: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Link: http://lkml.kernel.org/r/1411118561-26323-4-git-send-email-juri.lelli@xxxxxxx
Signed-off-by: Ingo Molnar <mingo@xxxxxxxxxx>
---
kernel/sched/cpudeadline.c | 4 +---
kernel/sched/deadline.c | 7 +++++++
2 files changed, 8 insertions(+), 3 deletions(-)
diff --git a/kernel/sched/cpudeadline.c b/kernel/sched/cpudeadline.c
index bd95963..539ca3c 100644
--- a/kernel/sched/cpudeadline.c
+++ b/kernel/sched/cpudeadline.c
@@ -107,9 +107,7 @@ 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)) {
+ if (later_mask && 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) &&
diff --git a/kernel/sched/deadline.c b/kernel/sched/deadline.c
index efb9412..abfaf3d 100644
--- a/kernel/sched/deadline.c
+++ b/kernel/sched/deadline.c
@@ -1164,6 +1164,13 @@ static int find_later_rq(struct task_struct *task)
if (task->nr_cpus_allowed == 1)
return -1;
+ /*
+ * 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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