* [PATCH V3] sched/deadline: Update rq_clock of later_rq when pushing a task
@ 2018-07-20 9:16 Daniel Bristot de Oliveira
2018-07-20 12:46 ` Peter Zijlstra
2018-07-25 14:21 ` [tip:sched/core] " tip-bot for Daniel Bristot de Oliveira
0 siblings, 2 replies; 8+ messages in thread
From: Daniel Bristot de Oliveira @ 2018-07-20 9:16 UTC (permalink / raw)
To: linux-kernel
Cc: Clark Williams, Juri Lelli, Luca Abeni, Tommaso Cucinotta,
Steven Rostedt, Peter Zijlstra, Ingo Molnar, stable
Daniel Casini got this warn while running a DL task here at RetisLab:
[ 461.137582] ------------[ cut here ]------------
[ 461.137583] rq->clock_update_flags < RQCF_ACT_SKIP
[ 461.137599] WARNING: CPU: 4 PID: 2354 at kernel/sched/sched.h:967 assert_clock_updated.isra.32.part.33+0x17/0x20
[a ton of modules]
[ 461.137646] CPU: 4 PID: 2354 Comm: label_image Not tainted 4.18.0-rc4+ #3
[ 461.137647] Hardware name: ASUS All Series/Z87-K, BIOS 0801 09/02/2013
[ 461.137649] RIP: 0010:assert_clock_updated.isra.32.part.33+0x17/0x20
[ 461.137649] Code: ff 48 89 83 08 09 00 00 eb c6 66 0f 1f 84 00 00 00 00 00 55 48 c7 c7 98 7a 6c a5 c6 05 bc 0d 54 01 01 48 89 e5 e8 a9 84 fb ff <0f> 0b 5d c3 0f 1f 44 00 00 0f 1f 44 00 00 83 7e 60 01 74 0a 48 3b
[ 461.137673] RSP: 0018:ffffa77e08cafc68 EFLAGS: 00010082
[ 461.137674] RAX: 0000000000000000 RBX: ffff8b3fc1702d80 RCX: 0000000000000006
[ 461.137674] RDX: 0000000000000007 RSI: 0000000000000096 RDI: ffff8b3fded164b0
[ 461.137675] RBP: ffffa77e08cafc68 R08: 0000000000000026 R09: 0000000000000339
[ 461.137676] R10: ffff8b3fd060d410 R11: 0000000000000026 R12: ffffffffa4e14e20
[ 461.137677] R13: ffff8b3fdec22940 R14: ffff8b3fc1702da0 R15: ffff8b3fdec22940
[ 461.137678] FS: 00007efe43ee5700(0000) GS:ffff8b3fded00000(0000) knlGS:0000000000000000
[ 461.137679] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[ 461.137680] CR2: 00007efe30000010 CR3: 0000000301744003 CR4: 00000000001606e0
[ 461.137680] Call Trace:
[ 461.137684] push_dl_task.part.46+0x3bc/0x460
[ 461.137686] task_woken_dl+0x60/0x80
[ 461.137689] ttwu_do_wakeup+0x4f/0x150
[ 461.137690] ttwu_do_activate+0x77/0x80
[ 461.137692] try_to_wake_up+0x1d6/0x4c0
[ 461.137693] wake_up_q+0x32/0x70
[ 461.137696] do_futex+0x7e7/0xb50
[ 461.137698] __x64_sys_futex+0x8b/0x180
[ 461.137701] do_syscall_64+0x5a/0x110
[ 461.137703] entry_SYSCALL_64_after_hwframe+0x44/0xa9
[ 461.137705] RIP: 0033:0x7efe4918ca26
[ 461.137705] Code: 00 00 00 74 17 49 8b 48 20 44 8b 59 10 41 83 e3 30 41 83 fb 20 74 1e be 85 00 00 00 41 ba 01 00 00 00 41 b9 01 00 00 04 0f 05 <48> 3d 01 f0 ff ff 73 1f 31 c0 c3 be 8c 00 00 00 49 89 c8 4d 31 d2
[ 461.137738] RSP: 002b:00007efe43ee4928 EFLAGS: 00000283 ORIG_RAX: 00000000000000ca
[ 461.137739] RAX: ffffffffffffffda RBX: 0000000005094df0 RCX: 00007efe4918ca26
[ 461.137740] RDX: 0000000000000001 RSI: 0000000000000085 RDI: 0000000005094e24
[ 461.137741] RBP: 00007efe43ee49c0 R08: 0000000005094e20 R09: 0000000004000001
[ 461.137741] R10: 0000000000000001 R11: 0000000000000283 R12: 0000000000000000
[ 461.137742] R13: 0000000005094df8 R14: 0000000000000001 R15: 0000000000448a10
[ 461.137743] ---[ end trace 187df4cad2bf7649 ]---
This warning happened in the push_dl_task(), because
__add_running_bw()->cpufreq_update_util() is getting the rq_clock of
the later_rq before its update, which takes place at activate_task().
The fix then is to update the rq_clock before calling add_running_bw().
To avoid double rq_clock_update() call, we set ENQUEUE_NOCLOCK flag to
activate_task().
Changes:
v1->v2:
Remove part of the comment regarding the ENQUEUE_NOCLOCK usage (Kirill Tkhai).
v0->v1:
Cosmetic changes in the log, and correct Juri's email (Daniel).
Reported-by: Daniel Casini <daniel.casini@santannapisa.it>
Signed-off-by: Daniel Bristot de Oliveira <bristot@redhat.com>
Acked-by: Juri Lelli <juri.lelli@redhat.com>
Cc: Clark Williams <williams@redhat.com>
Cc: Juri Lelli <juri.lelli@redhat.com>
Cc: Luca Abeni <luca.abeni@santannapisa.it>
Cc: Tommaso Cucinotta <tommaso.cucinotta@santannapisa.it>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: linux-kernel@vger.kernel.org
Cc: <stable@vger.kernel.org> # 4.16+
Fixes: e0367b12674b sched/deadline: Move CPU frequency selection triggering points
---
kernel/sched/deadline.c | 8 +++++++-
1 file changed, 7 insertions(+), 1 deletion(-)
diff --git a/kernel/sched/deadline.c b/kernel/sched/deadline.c
index fbfc3f1d368a..8b50eea4b607 100644
--- a/kernel/sched/deadline.c
+++ b/kernel/sched/deadline.c
@@ -2090,8 +2090,14 @@ static int push_dl_task(struct rq *rq)
sub_rq_bw(&next_task->dl, &rq->dl);
set_task_cpu(next_task, later_rq->cpu);
add_rq_bw(&next_task->dl, &later_rq->dl);
+
+ /*
+ * Update the later_rq clock here, because the clock is used
+ * by the cpufreq_update_util() inside __add_running_bw().
+ */
+ update_rq_clock(later_rq);
add_running_bw(&next_task->dl, &later_rq->dl);
- activate_task(later_rq, next_task, 0);
+ activate_task(later_rq, next_task, ENQUEUE_NOCLOCK);
ret = 1;
resched_curr(later_rq);
--
2.17.1
^ permalink raw reply related [flat|nested] 8+ messages in thread
* Re: [PATCH V3] sched/deadline: Update rq_clock of later_rq when pushing a task
2018-07-20 9:16 [PATCH V3] sched/deadline: Update rq_clock of later_rq when pushing a task Daniel Bristot de Oliveira
@ 2018-07-20 12:46 ` Peter Zijlstra
2018-07-20 12:48 ` Peter Zijlstra
2018-07-25 14:21 ` [tip:sched/core] " tip-bot for Daniel Bristot de Oliveira
1 sibling, 1 reply; 8+ messages in thread
From: Peter Zijlstra @ 2018-07-20 12:46 UTC (permalink / raw)
To: Daniel Bristot de Oliveira
Cc: linux-kernel, Clark Williams, Juri Lelli, Luca Abeni,
Tommaso Cucinotta, Steven Rostedt, Ingo Molnar, stable
On Fri, Jul 20, 2018 at 11:16:30AM +0200, Daniel Bristot de Oliveira wrote:
> diff --git a/kernel/sched/deadline.c b/kernel/sched/deadline.c
> index fbfc3f1d368a..8b50eea4b607 100644
> --- a/kernel/sched/deadline.c
> +++ b/kernel/sched/deadline.c
> @@ -2090,8 +2090,14 @@ static int push_dl_task(struct rq *rq)
> sub_rq_bw(&next_task->dl, &rq->dl);
> set_task_cpu(next_task, later_rq->cpu);
> add_rq_bw(&next_task->dl, &later_rq->dl);
> +
> + /*
> + * Update the later_rq clock here, because the clock is used
> + * by the cpufreq_update_util() inside __add_running_bw().
> + */
> + update_rq_clock(later_rq);
> add_running_bw(&next_task->dl, &later_rq->dl);
> - activate_task(later_rq, next_task, 0);
> + activate_task(later_rq, next_task, ENQUEUE_NOCLOCK);
> ret = 1;
>
> resched_curr(later_rq);
Why isn't push_rt_task() affected by the very same issue?
^ permalink raw reply [flat|nested] 8+ messages in thread
* Re: [PATCH V3] sched/deadline: Update rq_clock of later_rq when pushing a task
2018-07-20 12:46 ` Peter Zijlstra
@ 2018-07-20 12:48 ` Peter Zijlstra
2018-07-20 12:53 ` Juri Lelli
0 siblings, 1 reply; 8+ messages in thread
From: Peter Zijlstra @ 2018-07-20 12:48 UTC (permalink / raw)
To: Daniel Bristot de Oliveira
Cc: linux-kernel, Clark Williams, Juri Lelli, Luca Abeni,
Tommaso Cucinotta, Steven Rostedt, Ingo Molnar, stable
On Fri, Jul 20, 2018 at 02:46:15PM +0200, Peter Zijlstra wrote:
> On Fri, Jul 20, 2018 at 11:16:30AM +0200, Daniel Bristot de Oliveira wrote:
> > diff --git a/kernel/sched/deadline.c b/kernel/sched/deadline.c
> > index fbfc3f1d368a..8b50eea4b607 100644
> > --- a/kernel/sched/deadline.c
> > +++ b/kernel/sched/deadline.c
> > @@ -2090,8 +2090,14 @@ static int push_dl_task(struct rq *rq)
> > sub_rq_bw(&next_task->dl, &rq->dl);
> > set_task_cpu(next_task, later_rq->cpu);
> > add_rq_bw(&next_task->dl, &later_rq->dl);
> > +
> > + /*
> > + * Update the later_rq clock here, because the clock is used
> > + * by the cpufreq_update_util() inside __add_running_bw().
> > + */
> > + update_rq_clock(later_rq);
> > add_running_bw(&next_task->dl, &later_rq->dl);
> > - activate_task(later_rq, next_task, 0);
> > + activate_task(later_rq, next_task, ENQUEUE_NOCLOCK);
> > ret = 1;
> >
> > resched_curr(later_rq);
>
> Why isn't push_rt_task() affected by the very same issue?
Aah, I see, its the add_running_bw() think; for which RT doesn't have a
counter-part.
^ permalink raw reply [flat|nested] 8+ messages in thread
* Re: [PATCH V3] sched/deadline: Update rq_clock of later_rq when pushing a task
2018-07-20 12:48 ` Peter Zijlstra
@ 2018-07-20 12:53 ` Juri Lelli
2018-07-20 15:36 ` Daniel Bristot de Oliveira
0 siblings, 1 reply; 8+ messages in thread
From: Juri Lelli @ 2018-07-20 12:53 UTC (permalink / raw)
To: Peter Zijlstra
Cc: Daniel Bristot de Oliveira, linux-kernel, Clark Williams,
Luca Abeni, Tommaso Cucinotta, Steven Rostedt, Ingo Molnar,
stable
On 20/07/18 14:48, Peter Zijlstra wrote:
> On Fri, Jul 20, 2018 at 02:46:15PM +0200, Peter Zijlstra wrote:
> > On Fri, Jul 20, 2018 at 11:16:30AM +0200, Daniel Bristot de Oliveira wrote:
> > > diff --git a/kernel/sched/deadline.c b/kernel/sched/deadline.c
> > > index fbfc3f1d368a..8b50eea4b607 100644
> > > --- a/kernel/sched/deadline.c
> > > +++ b/kernel/sched/deadline.c
> > > @@ -2090,8 +2090,14 @@ static int push_dl_task(struct rq *rq)
> > > sub_rq_bw(&next_task->dl, &rq->dl);
> > > set_task_cpu(next_task, later_rq->cpu);
> > > add_rq_bw(&next_task->dl, &later_rq->dl);
> > > +
> > > + /*
> > > + * Update the later_rq clock here, because the clock is used
> > > + * by the cpufreq_update_util() inside __add_running_bw().
> > > + */
> > > + update_rq_clock(later_rq);
> > > add_running_bw(&next_task->dl, &later_rq->dl);
> > > - activate_task(later_rq, next_task, 0);
> > > + activate_task(later_rq, next_task, ENQUEUE_NOCLOCK);
> > > ret = 1;
> > >
> > > resched_curr(later_rq);
> >
> > Why isn't push_rt_task() affected by the very same issue?
>
> Aah, I see, its the add_running_bw() think; for which RT doesn't have a
> counter-part.
Right, but doesn't enqueue_top_rt_rq end-up being called by activate_
task on lowest_rq? Mmm.
^ permalink raw reply [flat|nested] 8+ messages in thread
* Re: [PATCH V3] sched/deadline: Update rq_clock of later_rq when pushing a task
2018-07-20 12:53 ` Juri Lelli
@ 2018-07-20 15:36 ` Daniel Bristot de Oliveira
2018-07-20 15:45 ` Juri Lelli
2018-07-20 15:46 ` Peter Zijlstra
0 siblings, 2 replies; 8+ messages in thread
From: Daniel Bristot de Oliveira @ 2018-07-20 15:36 UTC (permalink / raw)
To: Juri Lelli, Peter Zijlstra
Cc: linux-kernel, Clark Williams, Luca Abeni, Tommaso Cucinotta,
Steven Rostedt, Ingo Molnar, stable
On 07/20/2018 02:53 PM, Juri Lelli wrote:
> On 20/07/18 14:48, Peter Zijlstra wrote:
>> On Fri, Jul 20, 2018 at 02:46:15PM +0200, Peter Zijlstra wrote:
>>> On Fri, Jul 20, 2018 at 11:16:30AM +0200, Daniel Bristot de Oliveira wrote:
>>>> diff --git a/kernel/sched/deadline.c b/kernel/sched/deadline.c
>>>> index fbfc3f1d368a..8b50eea4b607 100644
>>>> --- a/kernel/sched/deadline.c
>>>> +++ b/kernel/sched/deadline.c
>>>> @@ -2090,8 +2090,14 @@ static int push_dl_task(struct rq *rq)
>>>> sub_rq_bw(&next_task->dl, &rq->dl);
>>>> set_task_cpu(next_task, later_rq->cpu);
>>>> add_rq_bw(&next_task->dl, &later_rq->dl);
>>>> +
>>>> + /*
>>>> + * Update the later_rq clock here, because the clock is used
>>>> + * by the cpufreq_update_util() inside __add_running_bw().
>>>> + */
>>>> + update_rq_clock(later_rq);
>>>> add_running_bw(&next_task->dl, &later_rq->dl);
>>>> - activate_task(later_rq, next_task, 0);
>>>> + activate_task(later_rq, next_task, ENQUEUE_NOCLOCK);
>>>> ret = 1;
>>>>
>>>> resched_curr(later_rq);
>>>
>>> Why isn't push_rt_task() affected by the very same issue?
>>
>> Aah, I see, its the add_running_bw() think; for which RT doesn't have a
>> counter-part.
>
> Right, but doesn't enqueue_top_rt_rq end-up being called by activate_
> task on lowest_rq? Mmm.
AFAICS we have:
push_rt_task() {
activate_task() {
enqueue_task(,,(flags=0)) {
if (!(flags & ENQUEUE_NOCLOCK))
update_rq_clock(rq);
enqueue_task_rt() {
enqueue_rt_entity() {
enqueue_top_rt_rq();
}
}
}
}
So we will have the clock updated already...
Am I missing something?
Thanks,
-- Daniel
^ permalink raw reply [flat|nested] 8+ messages in thread
* Re: [PATCH V3] sched/deadline: Update rq_clock of later_rq when pushing a task
2018-07-20 15:36 ` Daniel Bristot de Oliveira
@ 2018-07-20 15:45 ` Juri Lelli
2018-07-20 15:46 ` Peter Zijlstra
1 sibling, 0 replies; 8+ messages in thread
From: Juri Lelli @ 2018-07-20 15:45 UTC (permalink / raw)
To: Daniel Bristot de Oliveira
Cc: Peter Zijlstra, linux-kernel, Clark Williams, Luca Abeni,
Tommaso Cucinotta, Steven Rostedt, Ingo Molnar, stable
On 20/07/18 17:36, Daniel Bristot de Oliveira wrote:
> On 07/20/2018 02:53 PM, Juri Lelli wrote:
> > On 20/07/18 14:48, Peter Zijlstra wrote:
> >> On Fri, Jul 20, 2018 at 02:46:15PM +0200, Peter Zijlstra wrote:
> >>> On Fri, Jul 20, 2018 at 11:16:30AM +0200, Daniel Bristot de Oliveira wrote:
> >>>> diff --git a/kernel/sched/deadline.c b/kernel/sched/deadline.c
> >>>> index fbfc3f1d368a..8b50eea4b607 100644
> >>>> --- a/kernel/sched/deadline.c
> >>>> +++ b/kernel/sched/deadline.c
> >>>> @@ -2090,8 +2090,14 @@ static int push_dl_task(struct rq *rq)
> >>>> sub_rq_bw(&next_task->dl, &rq->dl);
> >>>> set_task_cpu(next_task, later_rq->cpu);
> >>>> add_rq_bw(&next_task->dl, &later_rq->dl);
> >>>> +
> >>>> + /*
> >>>> + * Update the later_rq clock here, because the clock is used
> >>>> + * by the cpufreq_update_util() inside __add_running_bw().
> >>>> + */
> >>>> + update_rq_clock(later_rq);
> >>>> add_running_bw(&next_task->dl, &later_rq->dl);
> >>>> - activate_task(later_rq, next_task, 0);
> >>>> + activate_task(later_rq, next_task, ENQUEUE_NOCLOCK);
> >>>> ret = 1;
> >>>>
> >>>> resched_curr(later_rq);
> >>>
> >>> Why isn't push_rt_task() affected by the very same issue?
> >>
> >> Aah, I see, its the add_running_bw() think; for which RT doesn't have a
> >> counter-part.
> >
> > Right, but doesn't enqueue_top_rt_rq end-up being called by activate_
> > task on lowest_rq? Mmm.
>
>
> AFAICS we have:
>
> push_rt_task() {
> activate_task() {
> enqueue_task(,,(flags=0)) {
> if (!(flags & ENQUEUE_NOCLOCK))
> update_rq_clock(rq);
> enqueue_task_rt() {
> enqueue_rt_entity() {
> enqueue_top_rt_rq();
> }
> }
> }
> }
>
> So we will have the clock updated already...
>
> Am I missing something?
Ah, indeed.
^ permalink raw reply [flat|nested] 8+ messages in thread
* Re: [PATCH V3] sched/deadline: Update rq_clock of later_rq when pushing a task
2018-07-20 15:36 ` Daniel Bristot de Oliveira
2018-07-20 15:45 ` Juri Lelli
@ 2018-07-20 15:46 ` Peter Zijlstra
1 sibling, 0 replies; 8+ messages in thread
From: Peter Zijlstra @ 2018-07-20 15:46 UTC (permalink / raw)
To: Daniel Bristot de Oliveira
Cc: Juri Lelli, linux-kernel, Clark Williams, Luca Abeni,
Tommaso Cucinotta, Steven Rostedt, Ingo Molnar, stable
On Fri, Jul 20, 2018 at 05:36:06PM +0200, Daniel Bristot de Oliveira wrote:
> Am I missing something?
Nothing, I was missing why exactly this was deadline only. Figured it
out now :-)
^ permalink raw reply [flat|nested] 8+ messages in thread
* [tip:sched/core] sched/deadline: Update rq_clock of later_rq when pushing a task
2018-07-20 9:16 [PATCH V3] sched/deadline: Update rq_clock of later_rq when pushing a task Daniel Bristot de Oliveira
2018-07-20 12:46 ` Peter Zijlstra
@ 2018-07-25 14:21 ` tip-bot for Daniel Bristot de Oliveira
1 sibling, 0 replies; 8+ messages in thread
From: tip-bot for Daniel Bristot de Oliveira @ 2018-07-25 14:21 UTC (permalink / raw)
To: linux-tip-commits
Cc: daniel.casini, tglx, rostedt, tommaso.cucinotta, juri.lelli,
peterz, hpa, linux-kernel, mingo, bristot, williams, torvalds,
luca.abeni
Commit-ID: 840d719604b0925ca23dde95f1767e4528668369
Gitweb: https://git.kernel.org/tip/840d719604b0925ca23dde95f1767e4528668369
Author: Daniel Bristot de Oliveira <bristot@redhat.com>
AuthorDate: Fri, 20 Jul 2018 11:16:30 +0200
Committer: Ingo Molnar <mingo@kernel.org>
CommitDate: Wed, 25 Jul 2018 11:29:08 +0200
sched/deadline: Update rq_clock of later_rq when pushing a task
Daniel Casini got this warn while running a DL task here at RetisLab:
[ 461.137582] ------------[ cut here ]------------
[ 461.137583] rq->clock_update_flags < RQCF_ACT_SKIP
[ 461.137599] WARNING: CPU: 4 PID: 2354 at kernel/sched/sched.h:967 assert_clock_updated.isra.32.part.33+0x17/0x20
[a ton of modules]
[ 461.137646] CPU: 4 PID: 2354 Comm: label_image Not tainted 4.18.0-rc4+ #3
[ 461.137647] Hardware name: ASUS All Series/Z87-K, BIOS 0801 09/02/2013
[ 461.137649] RIP: 0010:assert_clock_updated.isra.32.part.33+0x17/0x20
[ 461.137649] Code: ff 48 89 83 08 09 00 00 eb c6 66 0f 1f 84 00 00 00 00 00 55 48 c7 c7 98 7a 6c a5 c6 05 bc 0d 54 01 01 48 89 e5 e8 a9 84 fb ff <0f> 0b 5d c3 0f 1f 44 00 00 0f 1f 44 00 00 83 7e 60 01 74 0a 48 3b
[ 461.137673] RSP: 0018:ffffa77e08cafc68 EFLAGS: 00010082
[ 461.137674] RAX: 0000000000000000 RBX: ffff8b3fc1702d80 RCX: 0000000000000006
[ 461.137674] RDX: 0000000000000007 RSI: 0000000000000096 RDI: ffff8b3fded164b0
[ 461.137675] RBP: ffffa77e08cafc68 R08: 0000000000000026 R09: 0000000000000339
[ 461.137676] R10: ffff8b3fd060d410 R11: 0000000000000026 R12: ffffffffa4e14e20
[ 461.137677] R13: ffff8b3fdec22940 R14: ffff8b3fc1702da0 R15: ffff8b3fdec22940
[ 461.137678] FS: 00007efe43ee5700(0000) GS:ffff8b3fded00000(0000) knlGS:0000000000000000
[ 461.137679] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[ 461.137680] CR2: 00007efe30000010 CR3: 0000000301744003 CR4: 00000000001606e0
[ 461.137680] Call Trace:
[ 461.137684] push_dl_task.part.46+0x3bc/0x460
[ 461.137686] task_woken_dl+0x60/0x80
[ 461.137689] ttwu_do_wakeup+0x4f/0x150
[ 461.137690] ttwu_do_activate+0x77/0x80
[ 461.137692] try_to_wake_up+0x1d6/0x4c0
[ 461.137693] wake_up_q+0x32/0x70
[ 461.137696] do_futex+0x7e7/0xb50
[ 461.137698] __x64_sys_futex+0x8b/0x180
[ 461.137701] do_syscall_64+0x5a/0x110
[ 461.137703] entry_SYSCALL_64_after_hwframe+0x44/0xa9
[ 461.137705] RIP: 0033:0x7efe4918ca26
[ 461.137705] Code: 00 00 00 74 17 49 8b 48 20 44 8b 59 10 41 83 e3 30 41 83 fb 20 74 1e be 85 00 00 00 41 ba 01 00 00 00 41 b9 01 00 00 04 0f 05 <48> 3d 01 f0 ff ff 73 1f 31 c0 c3 be 8c 00 00 00 49 89 c8 4d 31 d2
[ 461.137738] RSP: 002b:00007efe43ee4928 EFLAGS: 00000283 ORIG_RAX: 00000000000000ca
[ 461.137739] RAX: ffffffffffffffda RBX: 0000000005094df0 RCX: 00007efe4918ca26
[ 461.137740] RDX: 0000000000000001 RSI: 0000000000000085 RDI: 0000000005094e24
[ 461.137741] RBP: 00007efe43ee49c0 R08: 0000000005094e20 R09: 0000000004000001
[ 461.137741] R10: 0000000000000001 R11: 0000000000000283 R12: 0000000000000000
[ 461.137742] R13: 0000000005094df8 R14: 0000000000000001 R15: 0000000000448a10
[ 461.137743] ---[ end trace 187df4cad2bf7649 ]---
This warning happened in the push_dl_task(), because
__add_running_bw()->cpufreq_update_util() is getting the rq_clock of
the later_rq before its update, which takes place at activate_task().
The fix then is to update the rq_clock before calling add_running_bw().
To avoid double rq_clock_update() call, we set ENQUEUE_NOCLOCK flag to
activate_task().
Reported-by: Daniel Casini <daniel.casini@santannapisa.it>
Signed-off-by: Daniel Bristot de Oliveira <bristot@redhat.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Juri Lelli <juri.lelli@redhat.com>
Cc: Clark Williams <williams@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Luca Abeni <luca.abeni@santannapisa.it>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Tommaso Cucinotta <tommaso.cucinotta@santannapisa.it>
Fixes: e0367b12674b sched/deadline: Move CPU frequency selection triggering points
Link: http://lkml.kernel.org/r/ca31d073a4788acf0684a8b255f14fea775ccf20.1532077269.git.bristot@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
---
kernel/sched/deadline.c | 8 +++++++-
1 file changed, 7 insertions(+), 1 deletion(-)
diff --git a/kernel/sched/deadline.c b/kernel/sched/deadline.c
index 10c7b51c0d1f..b5fbdde6afa9 100644
--- a/kernel/sched/deadline.c
+++ b/kernel/sched/deadline.c
@@ -2090,8 +2090,14 @@ retry:
sub_rq_bw(&next_task->dl, &rq->dl);
set_task_cpu(next_task, later_rq->cpu);
add_rq_bw(&next_task->dl, &later_rq->dl);
+
+ /*
+ * Update the later_rq clock here, because the clock is used
+ * by the cpufreq_update_util() inside __add_running_bw().
+ */
+ update_rq_clock(later_rq);
add_running_bw(&next_task->dl, &later_rq->dl);
- activate_task(later_rq, next_task, 0);
+ activate_task(later_rq, next_task, ENQUEUE_NOCLOCK);
ret = 1;
resched_curr(later_rq);
^ permalink raw reply related [flat|nested] 8+ messages in thread
end of thread, other threads:[~2018-07-25 14:22 UTC | newest]
Thread overview: 8+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2018-07-20 9:16 [PATCH V3] sched/deadline: Update rq_clock of later_rq when pushing a task Daniel Bristot de Oliveira
2018-07-20 12:46 ` Peter Zijlstra
2018-07-20 12:48 ` Peter Zijlstra
2018-07-20 12:53 ` Juri Lelli
2018-07-20 15:36 ` Daniel Bristot de Oliveira
2018-07-20 15:45 ` Juri Lelli
2018-07-20 15:46 ` Peter Zijlstra
2018-07-25 14:21 ` [tip:sched/core] " tip-bot for Daniel Bristot de Oliveira
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