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* [PATCH] sched/deadline: Add missing update_rq_clock() in dl_task_timer()
@ 2017-03-07  5:51 Wanpeng Li
  2017-03-07 13:35 ` Matt Fleming
                   ` (3 more replies)
  0 siblings, 4 replies; 6+ messages in thread
From: Wanpeng Li @ 2017-03-07  5:51 UTC (permalink / raw)
  To: linux-kernel, kvm
  Cc: Ingo Molnar, Peter Zijlstra, Wanpeng Li, Juri Lelli,
	Thomas Gleixner, Matt Fleming

From: Wanpeng Li <wanpeng.li@hotmail.com>

The following warning can be triggered by hot-unplugging the CPU
on which an active SCHED_DEADLINE task is running on:

 ------------[ cut here ]------------
 WARNING: CPU: 7 PID: 0 at kernel/sched/sched.h:833 replenish_dl_entity+0x71e/0xc40
 rq->clock_update_flags < RQCF_ACT_SKIP
 CPU: 7 PID: 0 Comm: swapper/7 Tainted: G    B           4.11.0-rc1+ #24
 Hardware name: LENOVO ThinkCentre M8500t-N000/SHARKBAY, BIOS FBKTC1AUS 02/16/2016
 Call Trace:
  <IRQ>
  dump_stack+0x85/0xc4
  __warn+0x172/0x1b0
  warn_slowpath_fmt+0xb4/0xf0
  ? __warn+0x1b0/0x1b0
  ? debug_check_no_locks_freed+0x2c0/0x2c0
  ? cpudl_set+0x3d/0x2b0
  replenish_dl_entity+0x71e/0xc40
  enqueue_task_dl+0x2ea/0x12e0
  ? dl_task_timer+0x777/0x990
  ? __hrtimer_run_queues+0x270/0xa50
  dl_task_timer+0x316/0x990
  ? enqueue_task_dl+0x12e0/0x12e0
  ? enqueue_task_dl+0x12e0/0x12e0
  __hrtimer_run_queues+0x270/0xa50
  ? hrtimer_cancel+0x20/0x20
  ? hrtimer_interrupt+0x119/0x600
  hrtimer_interrupt+0x19c/0x600
  ? trace_hardirqs_off+0xd/0x10
  local_apic_timer_interrupt+0x74/0xe0
  smp_apic_timer_interrupt+0x76/0xa0
  apic_timer_interrupt+0x93/0xa0

The DL task will be migrated to a suitable later deadline rq once the DL 
timer fires and currnet rq is offline. The rq clock of the new rq should 
be updated. This patch fixes it by updating the rq clock after holding 
the new rq's rq lock.

Cc: Juri Lelli <juri.lelli@arm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Matt Fleming <matt@codeblueprint.co.uk>
Signed-off-by: Wanpeng Li <wanpeng.li@hotmail.com>
---
 kernel/sched/deadline.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/kernel/sched/deadline.c b/kernel/sched/deadline.c
index 99b2c33..c6db3fd 100644
--- a/kernel/sched/deadline.c
+++ b/kernel/sched/deadline.c
@@ -638,6 +638,7 @@ static enum hrtimer_restart dl_task_timer(struct hrtimer *timer)
 		lockdep_unpin_lock(&rq->lock, rf.cookie);
 		rq = dl_task_offline_migration(rq, p);
 		rf.cookie = lockdep_pin_lock(&rq->lock);
+		update_rq_clock(rq);
 
 		/*
 		 * Now that the task has been migrated to the new RQ and we
-- 
2.7.4

^ permalink raw reply related	[flat|nested] 6+ messages in thread

* Re: [PATCH] sched/deadline: Add missing update_rq_clock() in dl_task_timer()
  2017-03-07  5:51 [PATCH] sched/deadline: Add missing update_rq_clock() in dl_task_timer() Wanpeng Li
@ 2017-03-07 13:35 ` Matt Fleming
  2017-03-15  7:53 ` Wanpeng Li
                   ` (2 subsequent siblings)
  3 siblings, 0 replies; 6+ messages in thread
From: Matt Fleming @ 2017-03-07 13:35 UTC (permalink / raw)
  To: Wanpeng Li
  Cc: linux-kernel, kvm, Ingo Molnar, Peter Zijlstra, Wanpeng Li,
	Juri Lelli, Thomas Gleixner

On Mon, 06 Mar, at 09:51:28PM, Wanpeng Li wrote:
> From: Wanpeng Li <wanpeng.li@hotmail.com>
> 
> The following warning can be triggered by hot-unplugging the CPU
> on which an active SCHED_DEADLINE task is running on:
> 
>  ------------[ cut here ]------------
>  WARNING: CPU: 7 PID: 0 at kernel/sched/sched.h:833 replenish_dl_entity+0x71e/0xc40
>  rq->clock_update_flags < RQCF_ACT_SKIP
>  CPU: 7 PID: 0 Comm: swapper/7 Tainted: G    B           4.11.0-rc1+ #24
 
[...]

> diff --git a/kernel/sched/deadline.c b/kernel/sched/deadline.c
> index 99b2c33..c6db3fd 100644
> --- a/kernel/sched/deadline.c
> +++ b/kernel/sched/deadline.c
> @@ -638,6 +638,7 @@ static enum hrtimer_restart dl_task_timer(struct hrtimer *timer)
>  		lockdep_unpin_lock(&rq->lock, rf.cookie);
>  		rq = dl_task_offline_migration(rq, p);
>  		rf.cookie = lockdep_pin_lock(&rq->lock);
> +		update_rq_clock(rq);
>  
>  		/*
>  		 * Now that the task has been migrated to the new RQ and we

Yeah, I guess the reason we can't use the rq_repin_lock() function is
because of all the DL double rq locking going on inside of
dl_task_offline_migration().

I'd definitely like someone else to verify, but this looks OK to me.

Reviewed-by: Matt Fleming <matt@codeblueprint.co.uk>

^ permalink raw reply	[flat|nested] 6+ messages in thread

* Re: [PATCH] sched/deadline: Add missing update_rq_clock() in dl_task_timer()
  2017-03-07  5:51 [PATCH] sched/deadline: Add missing update_rq_clock() in dl_task_timer() Wanpeng Li
  2017-03-07 13:35 ` Matt Fleming
@ 2017-03-15  7:53 ` Wanpeng Li
  2017-03-15 10:44   ` Daniel Bristot de Oliveira
  2017-03-15 11:03 ` Juri Lelli
  2017-03-16 11:12 ` [tip:sched/core] " tip-bot for Wanpeng Li
  3 siblings, 1 reply; 6+ messages in thread
From: Wanpeng Li @ 2017-03-15  7:53 UTC (permalink / raw)
  To: linux-kernel, kvm
  Cc: Ingo Molnar, Peter Zijlstra, Wanpeng Li, Juri Lelli,
	Thomas Gleixner, Matt Fleming

Ping, :)
2017-03-07 13:51 GMT+08:00 Wanpeng Li <kernellwp@gmail.com>:
> From: Wanpeng Li <wanpeng.li@hotmail.com>
>
> The following warning can be triggered by hot-unplugging the CPU
> on which an active SCHED_DEADLINE task is running on:
>
>  ------------[ cut here ]------------
>  WARNING: CPU: 7 PID: 0 at kernel/sched/sched.h:833 replenish_dl_entity+0x71e/0xc40
>  rq->clock_update_flags < RQCF_ACT_SKIP
>  CPU: 7 PID: 0 Comm: swapper/7 Tainted: G    B           4.11.0-rc1+ #24
>  Hardware name: LENOVO ThinkCentre M8500t-N000/SHARKBAY, BIOS FBKTC1AUS 02/16/2016
>  Call Trace:
>   <IRQ>
>   dump_stack+0x85/0xc4
>   __warn+0x172/0x1b0
>   warn_slowpath_fmt+0xb4/0xf0
>   ? __warn+0x1b0/0x1b0
>   ? debug_check_no_locks_freed+0x2c0/0x2c0
>   ? cpudl_set+0x3d/0x2b0
>   replenish_dl_entity+0x71e/0xc40
>   enqueue_task_dl+0x2ea/0x12e0
>   ? dl_task_timer+0x777/0x990
>   ? __hrtimer_run_queues+0x270/0xa50
>   dl_task_timer+0x316/0x990
>   ? enqueue_task_dl+0x12e0/0x12e0
>   ? enqueue_task_dl+0x12e0/0x12e0
>   __hrtimer_run_queues+0x270/0xa50
>   ? hrtimer_cancel+0x20/0x20
>   ? hrtimer_interrupt+0x119/0x600
>   hrtimer_interrupt+0x19c/0x600
>   ? trace_hardirqs_off+0xd/0x10
>   local_apic_timer_interrupt+0x74/0xe0
>   smp_apic_timer_interrupt+0x76/0xa0
>   apic_timer_interrupt+0x93/0xa0
>
> The DL task will be migrated to a suitable later deadline rq once the DL
> timer fires and currnet rq is offline. The rq clock of the new rq should
> be updated. This patch fixes it by updating the rq clock after holding
> the new rq's rq lock.
>
> Cc: Juri Lelli <juri.lelli@arm.com>
> Cc: Peter Zijlstra <peterz@infradead.org>
> Cc: Ingo Molnar <mingo@kernel.org>
> Cc: Thomas Gleixner <tglx@linutronix.de>
> Cc: Matt Fleming <matt@codeblueprint.co.uk>
> Signed-off-by: Wanpeng Li <wanpeng.li@hotmail.com>
> ---
>  kernel/sched/deadline.c | 1 +
>  1 file changed, 1 insertion(+)
>
> diff --git a/kernel/sched/deadline.c b/kernel/sched/deadline.c
> index 99b2c33..c6db3fd 100644
> --- a/kernel/sched/deadline.c
> +++ b/kernel/sched/deadline.c
> @@ -638,6 +638,7 @@ static enum hrtimer_restart dl_task_timer(struct hrtimer *timer)
>                 lockdep_unpin_lock(&rq->lock, rf.cookie);
>                 rq = dl_task_offline_migration(rq, p);
>                 rf.cookie = lockdep_pin_lock(&rq->lock);
> +               update_rq_clock(rq);
>
>                 /*
>                  * Now that the task has been migrated to the new RQ and we
> --
> 2.7.4
>

^ permalink raw reply	[flat|nested] 6+ messages in thread

* Re: [PATCH] sched/deadline: Add missing update_rq_clock() in dl_task_timer()
  2017-03-15  7:53 ` Wanpeng Li
@ 2017-03-15 10:44   ` Daniel Bristot de Oliveira
  0 siblings, 0 replies; 6+ messages in thread
From: Daniel Bristot de Oliveira @ 2017-03-15 10:44 UTC (permalink / raw)
  To: Wanpeng Li, linux-kernel, kvm
  Cc: Ingo Molnar, Peter Zijlstra, Wanpeng Li, Juri Lelli,
	Thomas Gleixner, Matt Fleming

On 03/15/2017 08:53 AM, Wanpeng Li wrote:
> Ping, :)
> 2017-03-07 13:51 GMT+08:00 Wanpeng Li <kernellwp@gmail.com>:
>> From: Wanpeng Li <wanpeng.li@hotmail.com>
>>
>> The following warning can be triggered by hot-unplugging the CPU
>> on which an active SCHED_DEADLINE task is running on:
>>
>>  ------------[ cut here ]------------
>>  WARNING: CPU: 7 PID: 0 at kernel/sched/sched.h:833 replenish_dl_entity+0x71e/0xc40
>>  rq->clock_update_flags < RQCF_ACT_SKIP
>>  CPU: 7 PID: 0 Comm: swapper/7 Tainted: G    B           4.11.0-rc1+ #24
>>  Hardware name: LENOVO ThinkCentre M8500t-N000/SHARKBAY, BIOS FBKTC1AUS 02/16/2016
>>  Call Trace:
>>   <IRQ>
>>   dump_stack+0x85/0xc4
>>   __warn+0x172/0x1b0
>>   warn_slowpath_fmt+0xb4/0xf0
>>   ? __warn+0x1b0/0x1b0
>>   ? debug_check_no_locks_freed+0x2c0/0x2c0
>>   ? cpudl_set+0x3d/0x2b0
>>   replenish_dl_entity+0x71e/0xc40
>>   enqueue_task_dl+0x2ea/0x12e0
>>   ? dl_task_timer+0x777/0x990
>>   ? __hrtimer_run_queues+0x270/0xa50
>>   dl_task_timer+0x316/0x990
>>   ? enqueue_task_dl+0x12e0/0x12e0
>>   ? enqueue_task_dl+0x12e0/0x12e0
>>   __hrtimer_run_queues+0x270/0xa50
>>   ? hrtimer_cancel+0x20/0x20
>>   ? hrtimer_interrupt+0x119/0x600
>>   hrtimer_interrupt+0x19c/0x600
>>   ? trace_hardirqs_off+0xd/0x10
>>   local_apic_timer_interrupt+0x74/0xe0
>>   smp_apic_timer_interrupt+0x76/0xa0
>>   apic_timer_interrupt+0x93/0xa0
>>
>> The DL task will be migrated to a suitable later deadline rq once the DL
>> timer fires and currnet rq is offline. The rq clock of the new rq should
>> be updated. This patch fixes it by updating the rq clock after holding
>> the new rq's rq lock.
>>
>> Cc: Juri Lelli <juri.lelli@arm.com>
>> Cc: Peter Zijlstra <peterz@infradead.org>
>> Cc: Ingo Molnar <mingo@kernel.org>
>> Cc: Thomas Gleixner <tglx@linutronix.de>
>> Cc: Matt Fleming <matt@codeblueprint.co.uk>
>> Signed-off-by: Wanpeng Li <wanpeng.li@hotmail.com>

Reviewed-by: Daniel Bristot de Oliveira <bristot@redhat.com>

-- Daniel

^ permalink raw reply	[flat|nested] 6+ messages in thread

* Re: [PATCH] sched/deadline: Add missing update_rq_clock() in dl_task_timer()
  2017-03-07  5:51 [PATCH] sched/deadline: Add missing update_rq_clock() in dl_task_timer() Wanpeng Li
  2017-03-07 13:35 ` Matt Fleming
  2017-03-15  7:53 ` Wanpeng Li
@ 2017-03-15 11:03 ` Juri Lelli
  2017-03-16 11:12 ` [tip:sched/core] " tip-bot for Wanpeng Li
  3 siblings, 0 replies; 6+ messages in thread
From: Juri Lelli @ 2017-03-15 11:03 UTC (permalink / raw)
  To: Wanpeng Li
  Cc: linux-kernel, kvm, Ingo Molnar, Peter Zijlstra, Wanpeng Li,
	Thomas Gleixner, Matt Fleming

Hi,

On 06/03/17 21:51, Wanpeng Li wrote:
> From: Wanpeng Li <wanpeng.li@hotmail.com>
> 
> The following warning can be triggered by hot-unplugging the CPU
> on which an active SCHED_DEADLINE task is running on:
> 
>  ------------[ cut here ]------------
>  WARNING: CPU: 7 PID: 0 at kernel/sched/sched.h:833 replenish_dl_entity+0x71e/0xc40
>  rq->clock_update_flags < RQCF_ACT_SKIP
>  CPU: 7 PID: 0 Comm: swapper/7 Tainted: G    B           4.11.0-rc1+ #24
>  Hardware name: LENOVO ThinkCentre M8500t-N000/SHARKBAY, BIOS FBKTC1AUS 02/16/2016
>  Call Trace:
>   <IRQ>
>   dump_stack+0x85/0xc4
>   __warn+0x172/0x1b0
>   warn_slowpath_fmt+0xb4/0xf0
>   ? __warn+0x1b0/0x1b0
>   ? debug_check_no_locks_freed+0x2c0/0x2c0
>   ? cpudl_set+0x3d/0x2b0
>   replenish_dl_entity+0x71e/0xc40
>   enqueue_task_dl+0x2ea/0x12e0
>   ? dl_task_timer+0x777/0x990
>   ? __hrtimer_run_queues+0x270/0xa50
>   dl_task_timer+0x316/0x990
>   ? enqueue_task_dl+0x12e0/0x12e0
>   ? enqueue_task_dl+0x12e0/0x12e0
>   __hrtimer_run_queues+0x270/0xa50
>   ? hrtimer_cancel+0x20/0x20
>   ? hrtimer_interrupt+0x119/0x600
>   hrtimer_interrupt+0x19c/0x600
>   ? trace_hardirqs_off+0xd/0x10
>   local_apic_timer_interrupt+0x74/0xe0
>   smp_apic_timer_interrupt+0x76/0xa0
>   apic_timer_interrupt+0x93/0xa0
> 
> The DL task will be migrated to a suitable later deadline rq once the DL 
> timer fires and currnet rq is offline. The rq clock of the new rq should 
> be updated. This patch fixes it by updating the rq clock after holding 
> the new rq's rq lock.
> 
> Cc: Juri Lelli <juri.lelli@arm.com>
> Cc: Peter Zijlstra <peterz@infradead.org>
> Cc: Ingo Molnar <mingo@kernel.org>
> Cc: Thomas Gleixner <tglx@linutronix.de>
> Cc: Matt Fleming <matt@codeblueprint.co.uk>
> Signed-off-by: Wanpeng Li <wanpeng.li@hotmail.com>
> ---
>  kernel/sched/deadline.c | 1 +
>  1 file changed, 1 insertion(+)
> 
> diff --git a/kernel/sched/deadline.c b/kernel/sched/deadline.c
> index 99b2c33..c6db3fd 100644
> --- a/kernel/sched/deadline.c
> +++ b/kernel/sched/deadline.c
> @@ -638,6 +638,7 @@ static enum hrtimer_restart dl_task_timer(struct hrtimer *timer)
>  		lockdep_unpin_lock(&rq->lock, rf.cookie);
>  		rq = dl_task_offline_migration(rq, p);
>  		rf.cookie = lockdep_pin_lock(&rq->lock);
> +		update_rq_clock(rq);

Looks good to me.

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

Thanks,

- Juri

^ permalink raw reply	[flat|nested] 6+ messages in thread

* [tip:sched/core] sched/deadline: Add missing update_rq_clock() in dl_task_timer()
  2017-03-07  5:51 [PATCH] sched/deadline: Add missing update_rq_clock() in dl_task_timer() Wanpeng Li
                   ` (2 preceding siblings ...)
  2017-03-15 11:03 ` Juri Lelli
@ 2017-03-16 11:12 ` tip-bot for Wanpeng Li
  3 siblings, 0 replies; 6+ messages in thread
From: tip-bot for Wanpeng Li @ 2017-03-16 11:12 UTC (permalink / raw)
  To: linux-tip-commits
  Cc: efault, peterz, juri.lelli, matt, linux-kernel, wanpeng.li,
	mingo, torvalds, hpa, tglx

Commit-ID:  dcc3b5ffe1b32771c9a22e2c916fb94c4fcf5b79
Gitweb:     http://git.kernel.org/tip/dcc3b5ffe1b32771c9a22e2c916fb94c4fcf5b79
Author:     Wanpeng Li <wanpeng.li@hotmail.com>
AuthorDate: Mon, 6 Mar 2017 21:51:28 -0800
Committer:  Ingo Molnar <mingo@kernel.org>
CommitDate: Thu, 16 Mar 2017 09:20:59 +0100

sched/deadline: Add missing update_rq_clock() in dl_task_timer()

The following warning can be triggered by hot-unplugging the CPU
on which an active SCHED_DEADLINE task is running on:

 ------------[ cut here ]------------
 WARNING: CPU: 7 PID: 0 at kernel/sched/sched.h:833 replenish_dl_entity+0x71e/0xc40
 rq->clock_update_flags < RQCF_ACT_SKIP
 CPU: 7 PID: 0 Comm: swapper/7 Tainted: G    B           4.11.0-rc1+ #24
 Hardware name: LENOVO ThinkCentre M8500t-N000/SHARKBAY, BIOS FBKTC1AUS 02/16/2016
 Call Trace:
  <IRQ>
  dump_stack+0x85/0xc4
  __warn+0x172/0x1b0
  warn_slowpath_fmt+0xb4/0xf0
  ? __warn+0x1b0/0x1b0
  ? debug_check_no_locks_freed+0x2c0/0x2c0
  ? cpudl_set+0x3d/0x2b0
  replenish_dl_entity+0x71e/0xc40
  enqueue_task_dl+0x2ea/0x12e0
  ? dl_task_timer+0x777/0x990
  ? __hrtimer_run_queues+0x270/0xa50
  dl_task_timer+0x316/0x990
  ? enqueue_task_dl+0x12e0/0x12e0
  ? enqueue_task_dl+0x12e0/0x12e0
  __hrtimer_run_queues+0x270/0xa50
  ? hrtimer_cancel+0x20/0x20
  ? hrtimer_interrupt+0x119/0x600
  hrtimer_interrupt+0x19c/0x600
  ? trace_hardirqs_off+0xd/0x10
  local_apic_timer_interrupt+0x74/0xe0
  smp_apic_timer_interrupt+0x76/0xa0
  apic_timer_interrupt+0x93/0xa0

The DL task will be migrated to a suitable later deadline rq once the DL
timer fires and currnet rq is offline. The rq clock of the new rq should
be updated. This patch fixes it by updating the rq clock after holding
the new rq's rq lock.

Signed-off-by: Wanpeng Li <wanpeng.li@hotmail.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Matt Fleming <matt@codeblueprint.co.uk>
Cc: Juri Lelli <juri.lelli@arm.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/1488865888-15894-1-git-send-email-wanpeng.li@hotmail.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
---
 kernel/sched/deadline.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/kernel/sched/deadline.c b/kernel/sched/deadline.c
index 99b2c33..c6db3fd 100644
--- a/kernel/sched/deadline.c
+++ b/kernel/sched/deadline.c
@@ -638,6 +638,7 @@ static enum hrtimer_restart dl_task_timer(struct hrtimer *timer)
 		lockdep_unpin_lock(&rq->lock, rf.cookie);
 		rq = dl_task_offline_migration(rq, p);
 		rf.cookie = lockdep_pin_lock(&rq->lock);
+		update_rq_clock(rq);
 
 		/*
 		 * Now that the task has been migrated to the new RQ and we

^ permalink raw reply related	[flat|nested] 6+ messages in thread

end of thread, other threads:[~2017-03-16 11:14 UTC | newest]

Thread overview: 6+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2017-03-07  5:51 [PATCH] sched/deadline: Add missing update_rq_clock() in dl_task_timer() Wanpeng Li
2017-03-07 13:35 ` Matt Fleming
2017-03-15  7:53 ` Wanpeng Li
2017-03-15 10:44   ` Daniel Bristot de Oliveira
2017-03-15 11:03 ` Juri Lelli
2017-03-16 11:12 ` [tip:sched/core] " tip-bot for Wanpeng Li

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