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* [PATCH] sched/deadline: Fix missing clock update in migrate_task_rq_dl()
@ 2021-08-04 13:59 Dietmar Eggemann
  2021-08-05  8:16 ` Daniel Bristot de Oliveira
                   ` (2 more replies)
  0 siblings, 3 replies; 5+ messages in thread
From: Dietmar Eggemann @ 2021-08-04 13:59 UTC (permalink / raw)
  To: Ingo Molnar, Peter Zijlstra, Juri Lelli
  Cc: Steven Rostedt, Vincent Guittot, Daniel Bristot de Oliveira,
	Bruno Goncalves, linux-kernel

A missing clock update is causing the following warning:

rq->clock_update_flags < RQCF_ACT_SKIP
WARNING: CPU: 112 PID: 2041 at kernel/sched/sched.h:1453
sub_running_bw.isra.0+0x190/0x1a0
...
CPU: 112 PID: 2041 Comm: sugov:112 Tainted: G W 5.14.0-rc1 #1
Hardware name: WIWYNN Mt.Jade Server System
B81.030Z1.0007/Mt.Jade Motherboard, BIOS 1.6.20210526 (SCP:
1.06.20210526) 2021/05/26
...
Call trace:
  sub_running_bw.isra.0+0x190/0x1a0
  migrate_task_rq_dl+0xf8/0x1e0
  set_task_cpu+0xa8/0x1f0
  try_to_wake_up+0x150/0x3d4
  wake_up_q+0x64/0xc0
  __up_write+0xd0/0x1c0
  up_write+0x4c/0x2b0
  cppc_set_perf+0x120/0x2d0
  cppc_cpufreq_set_target+0xe0/0x1a4 [cppc_cpufreq]
  __cpufreq_driver_target+0x74/0x140
  sugov_work+0x64/0x80
  kthread_worker_fn+0xe0/0x230
  kthread+0x138/0x140
  ret_from_fork+0x10/0x18

The task causing this is the `cppc_fie` DL task introduced by
commit 1eb5dde674f5 ("cpufreq: CPPC: Add support for frequency
invariance").

With CONFIG_ACPI_CPPC_CPUFREQ_FIE=y and schedutil cpufreq governor on
slow-switching system (like on this Ampere Altra WIWYNN Mt. Jade Arm
Server):

DL task `curr=sugov:112` lets `p=cppc_fie` migrate and since the latter
is in `non_contending` state, migrate_task_rq_dl() calls

  sub_running_bw()->__sub_running_bw()->cpufreq_update_util()->
  rq_clock()->assert_clock_updated()

on p.

Fix this by updating the clock for a non_contending task in
migrate_task_rq_dl() before calling sub_running_bw().

Reported-by: Bruno Goncalves <bgoncalv@redhat.com>
Signed-off-by: Dietmar Eggemann <dietmar.eggemann@arm.com>
---
 kernel/sched/deadline.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/kernel/sched/deadline.c b/kernel/sched/deadline.c
index aaacd6cfd42f..4920f498492f 100644
--- a/kernel/sched/deadline.c
+++ b/kernel/sched/deadline.c
@@ -1733,6 +1733,7 @@ static void migrate_task_rq_dl(struct task_struct *p, int new_cpu __maybe_unused
 	 */
 	raw_spin_rq_lock(rq);
 	if (p->dl.dl_non_contending) {
+		update_rq_clock(rq);
 		sub_running_bw(&p->dl, &rq->dl);
 		p->dl.dl_non_contending = 0;
 		/*
-- 
2.25.1


^ permalink raw reply	[flat|nested] 5+ messages in thread

* Re: [PATCH] sched/deadline: Fix missing clock update in migrate_task_rq_dl()
  2021-08-04 13:59 [PATCH] sched/deadline: Fix missing clock update in migrate_task_rq_dl() Dietmar Eggemann
@ 2021-08-05  8:16 ` Daniel Bristot de Oliveira
  2021-08-05  9:35   ` Peter Zijlstra
  2021-08-05  9:40 ` Juri Lelli
  2021-08-06 12:57 ` [tip: sched/core] " tip-bot2 for Dietmar Eggemann
  2 siblings, 1 reply; 5+ messages in thread
From: Daniel Bristot de Oliveira @ 2021-08-05  8:16 UTC (permalink / raw)
  To: Dietmar Eggemann, Ingo Molnar, Peter Zijlstra, Juri Lelli
  Cc: Steven Rostedt, Vincent Guittot, Bruno Goncalves, linux-kernel

On 8/4/21 3:59 PM, Dietmar Eggemann wrote:
> A missing clock update is causing the following warning:
> 
> rq->clock_update_flags < RQCF_ACT_SKIP
> WARNING: CPU: 112 PID: 2041 at kernel/sched/sched.h:1453
> sub_running_bw.isra.0+0x190/0x1a0
> ...
> CPU: 112 PID: 2041 Comm: sugov:112 Tainted: G W 5.14.0-rc1 #1
> Hardware name: WIWYNN Mt.Jade Server System
> B81.030Z1.0007/Mt.Jade Motherboard, BIOS 1.6.20210526 (SCP:
> 1.06.20210526) 2021/05/26
> ...
> Call trace:
>   sub_running_bw.isra.0+0x190/0x1a0
>   migrate_task_rq_dl+0xf8/0x1e0
>   set_task_cpu+0xa8/0x1f0
>   try_to_wake_up+0x150/0x3d4
>   wake_up_q+0x64/0xc0
>   __up_write+0xd0/0x1c0
>   up_write+0x4c/0x2b0
>   cppc_set_perf+0x120/0x2d0
>   cppc_cpufreq_set_target+0xe0/0x1a4 [cppc_cpufreq]
>   __cpufreq_driver_target+0x74/0x140
>   sugov_work+0x64/0x80
>   kthread_worker_fn+0xe0/0x230
>   kthread+0x138/0x140
>   ret_from_fork+0x10/0x18
> 
> The task causing this is the `cppc_fie` DL task introduced by
> commit 1eb5dde674f5 ("cpufreq: CPPC: Add support for frequency
> invariance").
> 
> With CONFIG_ACPI_CPPC_CPUFREQ_FIE=y and schedutil cpufreq governor on
> slow-switching system (like on this Ampere Altra WIWYNN Mt. Jade Arm
> Server):
> 
> DL task `curr=sugov:112` lets `p=cppc_fie` migrate and since the latter
> is in `non_contending` state, migrate_task_rq_dl() calls
> 
>   sub_running_bw()->__sub_running_bw()->cpufreq_update_util()->
>   rq_clock()->assert_clock_updated()
> 
> on p.
> 
> Fix this by updating the clock for a non_contending task in
> migrate_task_rq_dl() before calling sub_running_bw().
> 
> Reported-by: Bruno Goncalves <bgoncalv@redhat.com>
> Signed-off-by: Dietmar Eggemann <dietmar.eggemann@arm.com>

Reviewed-by: Daniel Bristot de Oliveira <bristot@kernel.org>

-- Daniel

> ---
>  kernel/sched/deadline.c | 1 +
>  1 file changed, 1 insertion(+)
> 
> diff --git a/kernel/sched/deadline.c b/kernel/sched/deadline.c
> index aaacd6cfd42f..4920f498492f 100644
> --- a/kernel/sched/deadline.c
> +++ b/kernel/sched/deadline.c
> @@ -1733,6 +1733,7 @@ static void migrate_task_rq_dl(struct task_struct *p, int new_cpu __maybe_unused
>  	 */
>  	raw_spin_rq_lock(rq);
>  	if (p->dl.dl_non_contending) {
> +		update_rq_clock(rq);
>  		sub_running_bw(&p->dl, &rq->dl);
>  		p->dl.dl_non_contending = 0;
>  		/*
> 


^ permalink raw reply	[flat|nested] 5+ messages in thread

* Re: [PATCH] sched/deadline: Fix missing clock update in migrate_task_rq_dl()
  2021-08-05  8:16 ` Daniel Bristot de Oliveira
@ 2021-08-05  9:35   ` Peter Zijlstra
  0 siblings, 0 replies; 5+ messages in thread
From: Peter Zijlstra @ 2021-08-05  9:35 UTC (permalink / raw)
  To: Daniel Bristot de Oliveira
  Cc: Dietmar Eggemann, Ingo Molnar, Juri Lelli, Steven Rostedt,
	Vincent Guittot, Bruno Goncalves, linux-kernel

On Thu, Aug 05, 2021 at 10:16:26AM +0200, Daniel Bristot de Oliveira wrote:
> On 8/4/21 3:59 PM, Dietmar Eggemann wrote:
> > A missing clock update is causing the following warning:
> > 
> > rq->clock_update_flags < RQCF_ACT_SKIP
> > WARNING: CPU: 112 PID: 2041 at kernel/sched/sched.h:1453
> > sub_running_bw.isra.0+0x190/0x1a0
> > ...
> > CPU: 112 PID: 2041 Comm: sugov:112 Tainted: G W 5.14.0-rc1 #1
> > Hardware name: WIWYNN Mt.Jade Server System
> > B81.030Z1.0007/Mt.Jade Motherboard, BIOS 1.6.20210526 (SCP:
> > 1.06.20210526) 2021/05/26
> > ...
> > Call trace:
> >   sub_running_bw.isra.0+0x190/0x1a0
> >   migrate_task_rq_dl+0xf8/0x1e0
> >   set_task_cpu+0xa8/0x1f0
> >   try_to_wake_up+0x150/0x3d4
> >   wake_up_q+0x64/0xc0
> >   __up_write+0xd0/0x1c0
> >   up_write+0x4c/0x2b0
> >   cppc_set_perf+0x120/0x2d0
> >   cppc_cpufreq_set_target+0xe0/0x1a4 [cppc_cpufreq]
> >   __cpufreq_driver_target+0x74/0x140
> >   sugov_work+0x64/0x80
> >   kthread_worker_fn+0xe0/0x230
> >   kthread+0x138/0x140
> >   ret_from_fork+0x10/0x18
> > 
> > The task causing this is the `cppc_fie` DL task introduced by
> > commit 1eb5dde674f5 ("cpufreq: CPPC: Add support for frequency
> > invariance").
> > 
> > With CONFIG_ACPI_CPPC_CPUFREQ_FIE=y and schedutil cpufreq governor on
> > slow-switching system (like on this Ampere Altra WIWYNN Mt. Jade Arm
> > Server):
> > 
> > DL task `curr=sugov:112` lets `p=cppc_fie` migrate and since the latter
> > is in `non_contending` state, migrate_task_rq_dl() calls
> > 
> >   sub_running_bw()->__sub_running_bw()->cpufreq_update_util()->
> >   rq_clock()->assert_clock_updated()
> > 
> > on p.
> > 
> > Fix this by updating the clock for a non_contending task in
> > migrate_task_rq_dl() before calling sub_running_bw().
> > 
> > Reported-by: Bruno Goncalves <bgoncalv@redhat.com>
> > Signed-off-by: Dietmar Eggemann <dietmar.eggemann@arm.com>
> 
> Reviewed-by: Daniel Bristot de Oliveira <bristot@kernel.org>

Thanks!

^ permalink raw reply	[flat|nested] 5+ messages in thread

* Re: [PATCH] sched/deadline: Fix missing clock update in migrate_task_rq_dl()
  2021-08-04 13:59 [PATCH] sched/deadline: Fix missing clock update in migrate_task_rq_dl() Dietmar Eggemann
  2021-08-05  8:16 ` Daniel Bristot de Oliveira
@ 2021-08-05  9:40 ` Juri Lelli
  2021-08-06 12:57 ` [tip: sched/core] " tip-bot2 for Dietmar Eggemann
  2 siblings, 0 replies; 5+ messages in thread
From: Juri Lelli @ 2021-08-05  9:40 UTC (permalink / raw)
  To: Dietmar Eggemann
  Cc: Ingo Molnar, Peter Zijlstra, Steven Rostedt, Vincent Guittot,
	Daniel Bristot de Oliveira, Bruno Goncalves, linux-kernel

Hi,

On 04/08/21 15:59, Dietmar Eggemann wrote:
> A missing clock update is causing the following warning:
> 
> rq->clock_update_flags < RQCF_ACT_SKIP
> WARNING: CPU: 112 PID: 2041 at kernel/sched/sched.h:1453
> sub_running_bw.isra.0+0x190/0x1a0
> ...
> CPU: 112 PID: 2041 Comm: sugov:112 Tainted: G W 5.14.0-rc1 #1
> Hardware name: WIWYNN Mt.Jade Server System
> B81.030Z1.0007/Mt.Jade Motherboard, BIOS 1.6.20210526 (SCP:
> 1.06.20210526) 2021/05/26
> ...
> Call trace:
>   sub_running_bw.isra.0+0x190/0x1a0
>   migrate_task_rq_dl+0xf8/0x1e0
>   set_task_cpu+0xa8/0x1f0
>   try_to_wake_up+0x150/0x3d4
>   wake_up_q+0x64/0xc0
>   __up_write+0xd0/0x1c0
>   up_write+0x4c/0x2b0
>   cppc_set_perf+0x120/0x2d0
>   cppc_cpufreq_set_target+0xe0/0x1a4 [cppc_cpufreq]
>   __cpufreq_driver_target+0x74/0x140
>   sugov_work+0x64/0x80
>   kthread_worker_fn+0xe0/0x230
>   kthread+0x138/0x140
>   ret_from_fork+0x10/0x18
> 
> The task causing this is the `cppc_fie` DL task introduced by
> commit 1eb5dde674f5 ("cpufreq: CPPC: Add support for frequency
> invariance").
> 
> With CONFIG_ACPI_CPPC_CPUFREQ_FIE=y and schedutil cpufreq governor on
> slow-switching system (like on this Ampere Altra WIWYNN Mt. Jade Arm
> Server):
> 
> DL task `curr=sugov:112` lets `p=cppc_fie` migrate and since the latter
> is in `non_contending` state, migrate_task_rq_dl() calls
> 
>   sub_running_bw()->__sub_running_bw()->cpufreq_update_util()->
>   rq_clock()->assert_clock_updated()
> 
> on p.
> 
> Fix this by updating the clock for a non_contending task in
> migrate_task_rq_dl() before calling sub_running_bw().
> 
> Reported-by: Bruno Goncalves <bgoncalv@redhat.com>
> Signed-off-by: Dietmar Eggemann <dietmar.eggemann@arm.com>
> ---
>  kernel/sched/deadline.c | 1 +
>  1 file changed, 1 insertion(+)
> 
> diff --git a/kernel/sched/deadline.c b/kernel/sched/deadline.c
> index aaacd6cfd42f..4920f498492f 100644
> --- a/kernel/sched/deadline.c
> +++ b/kernel/sched/deadline.c
> @@ -1733,6 +1733,7 @@ static void migrate_task_rq_dl(struct task_struct *p, int new_cpu __maybe_unused
>  	 */
>  	raw_spin_rq_lock(rq);
>  	if (p->dl.dl_non_contending) {
> +		update_rq_clock(rq);
>  		sub_running_bw(&p->dl, &rq->dl);
>  		p->dl.dl_non_contending = 0;
>  		/*

Acked-by: Juri Lelli <juri.lelli@redhat.com>

Thanks!
Juri


^ permalink raw reply	[flat|nested] 5+ messages in thread

* [tip: sched/core] sched/deadline: Fix missing clock update in migrate_task_rq_dl()
  2021-08-04 13:59 [PATCH] sched/deadline: Fix missing clock update in migrate_task_rq_dl() Dietmar Eggemann
  2021-08-05  8:16 ` Daniel Bristot de Oliveira
  2021-08-05  9:40 ` Juri Lelli
@ 2021-08-06 12:57 ` tip-bot2 for Dietmar Eggemann
  2 siblings, 0 replies; 5+ messages in thread
From: tip-bot2 for Dietmar Eggemann @ 2021-08-06 12:57 UTC (permalink / raw)
  To: linux-tip-commits
  Cc: Bruno Goncalves, Dietmar Eggemann, Peter Zijlstra (Intel),
	Daniel Bristot de Oliveira, Juri Lelli, x86, linux-kernel

The following commit has been merged into the sched/core branch of tip:

Commit-ID:     b4da13aa28d4fd0071247b7b41c579ee8a86c81a
Gitweb:        https://git.kernel.org/tip/b4da13aa28d4fd0071247b7b41c579ee8a86c81a
Author:        Dietmar Eggemann <dietmar.eggemann@arm.com>
AuthorDate:    Wed, 04 Aug 2021 15:59:25 +02:00
Committer:     Peter Zijlstra <peterz@infradead.org>
CommitterDate: Fri, 06 Aug 2021 14:25:24 +02:00

sched/deadline: Fix missing clock update in migrate_task_rq_dl()

A missing clock update is causing the following warning:

rq->clock_update_flags < RQCF_ACT_SKIP
WARNING: CPU: 112 PID: 2041 at kernel/sched/sched.h:1453
sub_running_bw.isra.0+0x190/0x1a0
...
CPU: 112 PID: 2041 Comm: sugov:112 Tainted: G W 5.14.0-rc1 #1
Hardware name: WIWYNN Mt.Jade Server System
B81.030Z1.0007/Mt.Jade Motherboard, BIOS 1.6.20210526 (SCP:
1.06.20210526) 2021/05/26
...
Call trace:
  sub_running_bw.isra.0+0x190/0x1a0
  migrate_task_rq_dl+0xf8/0x1e0
  set_task_cpu+0xa8/0x1f0
  try_to_wake_up+0x150/0x3d4
  wake_up_q+0x64/0xc0
  __up_write+0xd0/0x1c0
  up_write+0x4c/0x2b0
  cppc_set_perf+0x120/0x2d0
  cppc_cpufreq_set_target+0xe0/0x1a4 [cppc_cpufreq]
  __cpufreq_driver_target+0x74/0x140
  sugov_work+0x64/0x80
  kthread_worker_fn+0xe0/0x230
  kthread+0x138/0x140
  ret_from_fork+0x10/0x18

The task causing this is the `cppc_fie` DL task introduced by
commit 1eb5dde674f5 ("cpufreq: CPPC: Add support for frequency
invariance").

With CONFIG_ACPI_CPPC_CPUFREQ_FIE=y and schedutil cpufreq governor on
slow-switching system (like on this Ampere Altra WIWYNN Mt. Jade Arm
Server):

DL task `curr=sugov:112` lets `p=cppc_fie` migrate and since the latter
is in `non_contending` state, migrate_task_rq_dl() calls

  sub_running_bw()->__sub_running_bw()->cpufreq_update_util()->
  rq_clock()->assert_clock_updated()

on p.

Fix this by updating the clock for a non_contending task in
migrate_task_rq_dl() before calling sub_running_bw().

Reported-by: Bruno Goncalves <bgoncalv@redhat.com>
Signed-off-by: Dietmar Eggemann <dietmar.eggemann@arm.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Daniel Bristot de Oliveira <bristot@kernel.org>
Acked-by: Juri Lelli <juri.lelli@redhat.com>
Link: https://lore.kernel.org/r/20210804135925.3734605-1-dietmar.eggemann@arm.com
---
 kernel/sched/deadline.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/kernel/sched/deadline.c b/kernel/sched/deadline.c
index 5cafc64..e943146 100644
--- a/kernel/sched/deadline.c
+++ b/kernel/sched/deadline.c
@@ -1733,6 +1733,7 @@ static void migrate_task_rq_dl(struct task_struct *p, int new_cpu __maybe_unused
 	 */
 	raw_spin_rq_lock(rq);
 	if (p->dl.dl_non_contending) {
+		update_rq_clock(rq);
 		sub_running_bw(&p->dl, &rq->dl);
 		p->dl.dl_non_contending = 0;
 		/*

^ permalink raw reply	[flat|nested] 5+ messages in thread

end of thread, other threads:[~2021-08-06 12:58 UTC | newest]

Thread overview: 5+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2021-08-04 13:59 [PATCH] sched/deadline: Fix missing clock update in migrate_task_rq_dl() Dietmar Eggemann
2021-08-05  8:16 ` Daniel Bristot de Oliveira
2021-08-05  9:35   ` Peter Zijlstra
2021-08-05  9:40 ` Juri Lelli
2021-08-06 12:57 ` [tip: sched/core] " tip-bot2 for Dietmar Eggemann

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