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| Started by | Xunlei Pang <xlpang@redhat.com> |
|---|---|
| First post | 2016-05-09 06:20 +0200 |
| Last post | 2016-05-10 10:50 +0200 |
| Articles | 3 — 3 participants |
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[PATCH] sched/rt/deadline: Don't push if task's scheduling class was changed Xunlei Pang <xlpang@redhat.com> - 2016-05-09 06:20 +0200
Re: [PATCH] sched/rt/deadline: Don't push if task's scheduling class was changed Steven Rostedt <rostedt@goodmis.org> - 2016-05-09 17:30 +0200
[tip:sched/urgent] sched/rt, sched/dl: Don't push if task's scheduling class was changed tip-bot for Xunlei Pang <tipbot@zytor.com> - 2016-05-10 10:50 +0200
| From | Xunlei Pang <xlpang@redhat.com> |
|---|---|
| Date | 2016-05-09 06:20 +0200 |
| Subject | [PATCH] sched/rt/deadline: Don't push if task's scheduling class was changed |
| Message-ID | <rwKPL-4Mr-3@gated-at.bofh.it> |
We got a warning below:
WARNING: CPU: 1 PID: 2468 at kernel/sched/core.c:1161 set_task_cpu+0x1af/0x1c0
CPU: 1 PID: 2468 Comm: bugon Not tainted 4.6.0-rc3+ #16
Hardware name: Intel Corporation Broadwell Client
0000000000000086 0000000089618374 ffff8800897a7d50 ffffffff8133dc8c
0000000000000000 0000000000000000 ffff8800897a7d90 ffffffff81089921
0000048981037f39 ffff88016c4315c0 ffff88016ecd6e40 0000000000000000
Call Trace:
[<ffffffff8133dc8c>] dump_stack+0x63/0x87
[<ffffffff81089921>] __warn+0xd1/0xf0
[<ffffffff81089a5d>] warn_slowpath_null+0x1d/0x20
[<ffffffff810b48ff>] set_task_cpu+0x1af/0x1c0
[<ffffffff810cc90a>] push_dl_task.part.34+0xea/0x180
[<ffffffff810ccd17>] push_dl_tasks+0x17/0x30
[<ffffffff8118d17a>] __balance_callback+0x45/0x5c
[<ffffffff810b2f46>] __sched_setscheduler+0x906/0xb90
[<ffffffff810b6f50>] SyS_sched_setattr+0x150/0x190
[<ffffffff81003c12>] do_syscall_64+0x62/0x110
[<ffffffff816b5021>] entry_SYSCALL64_slow_path+0x25/0x25
The corresponding warning triggering code:
WARN_ON_ONCE(p->state == TASK_RUNNING &&
p->sched_class == &fair_sched_class &&
(p->on_rq && !task_on_rq_migrating(p)))
This is because in find_lock_later_rq(), the task whose scheduling
class was changed to fair class is still pushed away as deadline.
So, check in find_lock_later_rq() after double_lock_balance(), if the
scheduling class of the deadline task was changed, break and retry.
Apply the same logic to RT.
Signed-off-by: Xunlei Pang <xlpang@redhat.com>
---
kernel/sched/deadline.c | 1 +
kernel/sched/rt.c | 1 +
2 files changed, 2 insertions(+)
diff --git a/kernel/sched/deadline.c b/kernel/sched/deadline.c
index 169d40d..57eb3e4 100644
--- a/kernel/sched/deadline.c
+++ b/kernel/sched/deadline.c
@@ -1385,6 +1385,7 @@ static struct rq *find_lock_later_rq(struct task_struct *task, struct rq *rq)
!cpumask_test_cpu(later_rq->cpu,
&task->cpus_allowed) ||
task_running(rq, task) ||
+ !dl_task(task) ||
!task_on_rq_queued(task))) {
double_unlock_balance(rq, later_rq);
later_rq = NULL;
diff --git a/kernel/sched/rt.c b/kernel/sched/rt.c
index ecfc83d..c10a6f5 100644
--- a/kernel/sched/rt.c
+++ b/kernel/sched/rt.c
@@ -1720,6 +1720,7 @@ static struct rq *find_lock_lowest_rq(struct task_struct *task, struct rq *rq)
!cpumask_test_cpu(lowest_rq->cpu,
tsk_cpus_allowed(task)) ||
task_running(rq, task) ||
+ !rt_task(task) ||
!task_on_rq_queued(task))) {
double_unlock_balance(rq, lowest_rq);
--
1.8.3.1
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| From | Steven Rostedt <rostedt@goodmis.org> |
|---|---|
| Date | 2016-05-09 17:30 +0200 |
| Subject | Re: [PATCH] sched/rt/deadline: Don't push if task's scheduling class was changed |
| Message-ID | <rwVia-8if-13@gated-at.bofh.it> |
| In reply to | #1396576 |
On Mon, 9 May 2016 12:11:31 +0800
Xunlei Pang <xlpang@redhat.com> wrote:
> We got a warning below:
> WARNING: CPU: 1 PID: 2468 at kernel/sched/core.c:1161 set_task_cpu+0x1af/0x1c0
> CPU: 1 PID: 2468 Comm: bugon Not tainted 4.6.0-rc3+ #16
> Hardware name: Intel Corporation Broadwell Client
> 0000000000000086 0000000089618374 ffff8800897a7d50 ffffffff8133dc8c
> 0000000000000000 0000000000000000 ffff8800897a7d90 ffffffff81089921
> 0000048981037f39 ffff88016c4315c0 ffff88016ecd6e40 0000000000000000
> Call Trace:
> [<ffffffff8133dc8c>] dump_stack+0x63/0x87
> [<ffffffff81089921>] __warn+0xd1/0xf0
> [<ffffffff81089a5d>] warn_slowpath_null+0x1d/0x20
> [<ffffffff810b48ff>] set_task_cpu+0x1af/0x1c0
> [<ffffffff810cc90a>] push_dl_task.part.34+0xea/0x180
> [<ffffffff810ccd17>] push_dl_tasks+0x17/0x30
> [<ffffffff8118d17a>] __balance_callback+0x45/0x5c
> [<ffffffff810b2f46>] __sched_setscheduler+0x906/0xb90
> [<ffffffff810b6f50>] SyS_sched_setattr+0x150/0x190
> [<ffffffff81003c12>] do_syscall_64+0x62/0x110
> [<ffffffff816b5021>] entry_SYSCALL64_slow_path+0x25/0x25
>
> The corresponding warning triggering code:
> WARN_ON_ONCE(p->state == TASK_RUNNING &&
> p->sched_class == &fair_sched_class &&
> (p->on_rq && !task_on_rq_migrating(p)))
>
> This is because in find_lock_later_rq(), the task whose scheduling
> class was changed to fair class is still pushed away as deadline.
>
> So, check in find_lock_later_rq() after double_lock_balance(), if the
> scheduling class of the deadline task was changed, break and retry.
> Apply the same logic to RT.
>
> Signed-off-by: Xunlei Pang <xlpang@redhat.com>
Reviewed-by: Steven Rostedt <rostedt@goodmis.org>
-- Steve
> ---
> kernel/sched/deadline.c | 1 +
> kernel/sched/rt.c | 1 +
> 2 files changed, 2 insertions(+)
>
> diff --git a/kernel/sched/deadline.c b/kernel/sched/deadline.c
> index 169d40d..57eb3e4 100644
> --- a/kernel/sched/deadline.c
> +++ b/kernel/sched/deadline.c
> @@ -1385,6 +1385,7 @@ static struct rq *find_lock_later_rq(struct task_struct *task, struct rq *rq)
> !cpumask_test_cpu(later_rq->cpu,
> &task->cpus_allowed) ||
> task_running(rq, task) ||
> + !dl_task(task) ||
> !task_on_rq_queued(task))) {
> double_unlock_balance(rq, later_rq);
> later_rq = NULL;
> diff --git a/kernel/sched/rt.c b/kernel/sched/rt.c
> index ecfc83d..c10a6f5 100644
> --- a/kernel/sched/rt.c
> +++ b/kernel/sched/rt.c
> @@ -1720,6 +1720,7 @@ static struct rq *find_lock_lowest_rq(struct task_struct *task, struct rq *rq)
> !cpumask_test_cpu(lowest_rq->cpu,
> tsk_cpus_allowed(task)) ||
> task_running(rq, task) ||
> + !rt_task(task) ||
> !task_on_rq_queued(task))) {
>
> double_unlock_balance(rq, lowest_rq);
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| From | tip-bot for Xunlei Pang <tipbot@zytor.com> |
|---|---|
| Date | 2016-05-10 10:50 +0200 |
| Subject | [tip:sched/urgent] sched/rt, sched/dl: Don't push if task's scheduling class was changed |
| Message-ID | <rxbwD-7k3-31@gated-at.bofh.it> |
| In reply to | #1396576 |
Commit-ID: 13b5ab02ae118fc8dfdc2b8597688ec4a11d5b53
Gitweb: http://git.kernel.org/tip/13b5ab02ae118fc8dfdc2b8597688ec4a11d5b53
Author: Xunlei Pang <xlpang@redhat.com>
AuthorDate: Mon, 9 May 2016 12:11:31 +0800
Committer: Ingo Molnar <mingo@kernel.org>
CommitDate: Tue, 10 May 2016 10:02:46 +0200
sched/rt, sched/dl: Don't push if task's scheduling class was changed
We got this warning:
WARNING: CPU: 1 PID: 2468 at kernel/sched/core.c:1161 set_task_cpu+0x1af/0x1c0
[...]
Call Trace:
dump_stack+0x63/0x87
__warn+0xd1/0xf0
warn_slowpath_null+0x1d/0x20
set_task_cpu+0x1af/0x1c0
push_dl_task.part.34+0xea/0x180
push_dl_tasks+0x17/0x30
__balance_callback+0x45/0x5c
__sched_setscheduler+0x906/0xb90
SyS_sched_setattr+0x150/0x190
do_syscall_64+0x62/0x110
entry_SYSCALL64_slow_path+0x25/0x25
This corresponds to:
WARN_ON_ONCE(p->state == TASK_RUNNING &&
p->sched_class == &fair_sched_class &&
(p->on_rq && !task_on_rq_migrating(p)))
It happens because in find_lock_later_rq(), the task whose scheduling
class was changed to fair class is still pushed away as if it were
a deadline task ...
So, check in find_lock_later_rq() after double_lock_balance(), if the
scheduling class of the deadline task was changed, break and retry.
Apply the same logic to RT tasks.
Signed-off-by: Xunlei Pang <xlpang@redhat.com>
Reviewed-by: Steven Rostedt <rostedt@goodmis.org>
Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Juri Lelli <juri.lelli@arm.com>
Link: http://lkml.kernel.org/r/1462767091-1215-1-git-send-email-xlpang@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
---
kernel/sched/deadline.c | 1 +
kernel/sched/rt.c | 1 +
2 files changed, 2 insertions(+)
diff --git a/kernel/sched/deadline.c b/kernel/sched/deadline.c
index affd97e..686ec8a 100644
--- a/kernel/sched/deadline.c
+++ b/kernel/sched/deadline.c
@@ -1394,6 +1394,7 @@ static struct rq *find_lock_later_rq(struct task_struct *task, struct rq *rq)
!cpumask_test_cpu(later_rq->cpu,
&task->cpus_allowed) ||
task_running(rq, task) ||
+ !dl_task(task) ||
!task_on_rq_queued(task))) {
double_unlock_balance(rq, later_rq);
later_rq = NULL;
diff --git a/kernel/sched/rt.c b/kernel/sched/rt.c
index c41ea7a..ec4f538d 100644
--- a/kernel/sched/rt.c
+++ b/kernel/sched/rt.c
@@ -1729,6 +1729,7 @@ static struct rq *find_lock_lowest_rq(struct task_struct *task, struct rq *rq)
!cpumask_test_cpu(lowest_rq->cpu,
tsk_cpus_allowed(task)) ||
task_running(rq, task) ||
+ !rt_task(task) ||
!task_on_rq_queued(task))) {
double_unlock_balance(rq, lowest_rq);
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