From: K Prateek Nayak <kprateek.nayak@amd.com>
To: Juri Lelli <juri.lelli@redhat.com>
Cc: Andrea Righi <arighi@nvidia.com>,
John Stultz <jstultz@google.com>,
"Peter Zijlstra" <peterz@infradead.org>,
LKML <linux-kernel@vger.kernel.org>,
Valentin Schneider <valentin.schneider@arm.com>,
Connor O'Brien <connoro@google.com>,
Ingo Molnar <mingo@redhat.com>,
Thomas Gleixner <tglx@linutronix.de>,
Vincent Guittot <vincent.guittot@linaro.org>,
"Valentin Schneider" <vschneid@redhat.com>,
Suleiman Souhlal <suleiman@google.com>,
Metin Kaya <Metin.Kaya@arm.com>,
Dietmar Eggemann <dietmar.eggemann@arm.com>,
Steven Rostedt <rostedt@goodmis.org>,
Zimuzo Ezeozue <zezeozue@google.com>,
Waiman Long <longman@redhat.com>,
Boqun Feng <boqun.feng@gmail.com>,
"Paul E. McKenney" <paulmck@kernel.org>,
Joel Fernandes <joelagnelf@nvidia.com>,
"Qais Yousef" <qyousef@layalina.io>,
Xuewen Yan <xuewen.yan94@gmail.com>,
kuyo chang <kuyo.chang@mediatek.com>, hupu <hupu.gm@gmail.com>,
Zhan Xusheng <zhanxusheng@xiaomi.com>,
"zhidao su (Xiaomi)" <soolaugust@gmail.com>,
Hui Su <sh_def@163.com>,
"Shubhang Kaushik (Ampere)" <sh@gentwo.org>,
<kernel-team@android.com>
Subject: Re: [PATCH v33 7/7] sched/proxy: Add deactivated (sleeping) owner handling to find_proxy_task()
Date: Thu, 29 Oct 2026 08:57:11 +0530 [thread overview]
Message-ID: <faec8c94-0837-430b-ba60-00fa4a8a5eb4@amd.com> (raw)
In-Reply-To: <auHQJ8vq6VtL2Uf0@jlelli-thinkpadt14gen4.remote.csb>
Hello Juri,
On 10/28/2026 4:06 PM, Juri Lelli wrote:
>> Ack! But this is only needed for wakeup so just:
>>
>> diff --git a/kernel/sched/deadline.c b/kernel/sched/deadline.c
>> index c0ebdcde5fe5..20c388b55c50 100644
>> --- a/kernel/sched/deadline.c
>> +++ b/kernel/sched/deadline.c
>> @@ -2657,7 +2657,7 @@ static void migrate_task_rq_dl(struct task_struct *p, int new_cpu __maybe_unused
>> struct rq_flags rf;
>> struct rq *rq;
>>
>> - if (READ_ONCE(p->__state) != TASK_WAKING)
>> + if (task_on_rq_migrating(rq))
>> return;
>>
>> rq = task_rq(p);
>> ---
>>
>> should be enough then?
>
> It is enough, but I now fear too 'broad'? :)
>
> Looks like dl_task_offline_migration() ends up here via set_task_cpu();
> in that case the task was throttled and found the cpu was running on has
> been hotplugged so it needs a new cpu at replenishment. All bandwidth
> accouting is done by dl_task_offline_migration() itself, the task is not
> WAKING so migrate_task_rq_dl() has nothing to do and bails early
> correctly. If we use task_on_rq_migrating() it won't bail early anymore
> and double subtracting? Adding !p->is_blocked seems to cover this case
> as well?
Ack! '!task_on_migrating(p) && p->is_blocked' should cover all cases.
That said, the way dl_task_offline_migration() migrates the throttled
task off an offline rq is interesting :-)
--
Thanks and Regards,
Prateek
next prev parent reply other threads:[~2026-10-29 3:27 UTC|newest]
Thread overview: 30+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-10-23 22:04 [PATCH v33 0/7] Sleeping Owner Handling for Proxy Execution (v33) John Stultz
2026-10-23 22:04 ` [PATCH v33 1/7] sched/psi: Preserve sleep-persistent PSI flags on off-CPU sleeping dequeues John Stultz
2026-10-24 11:44 ` Peter Zijlstra
2026-10-26 5:00 ` K Prateek Nayak
2026-10-26 4:32 ` K Prateek Nayak
2026-10-26 5:16 ` Zhan Xusheng
2026-10-29 22:02 ` Tejun Heo
2026-10-23 22:04 ` [PATCH v33 2/7] sched/core: Use the scheduling context for remote ticks John Stultz
2026-10-24 13:44 ` Kayra Cizmeci
2026-10-23 22:04 ` [PATCH v33 3/7] sched/core: Activate blocked donor when no owner is found John Stultz
2026-10-24 8:33 ` Andrea Righi
2026-10-26 3:02 ` K Prateek Nayak
2026-10-23 22:04 ` [PATCH v33 4/7] sched/proxy: Set TASK_RUNNING when shortcuting return migration John Stultz
2026-10-24 8:36 ` Andrea Righi
2026-10-26 3:09 ` K Prateek Nayak
2026-10-23 22:04 ` [PATCH v33 5/7] sched/proxy: Break cyclic proxy chains by deactivating blocked tasks John Stultz
2026-10-24 21:19 ` Kayra Cizmeci
2026-10-23 22:04 ` [PATCH v33 6/7] sched/proxy: Detect cycles in proxy walks earlier John Stultz
2026-10-24 15:34 ` Kayra Cizmeci
2026-10-23 22:04 ` [PATCH v33 7/7] sched/proxy: Add deactivated (sleeping) owner handling to find_proxy_task() John Stultz
2026-10-24 9:07 ` Andrea Righi
2026-10-26 4:26 ` K Prateek Nayak
2026-10-27 16:22 ` Juri Lelli
2026-10-28 3:36 ` K Prateek Nayak
2026-10-28 10:01 ` Juri Lelli
2026-10-28 10:11 ` K Prateek Nayak
2026-10-28 10:36 ` Juri Lelli
2026-10-29 3:27 ` K Prateek Nayak [this message]
2026-10-26 7:40 ` K Prateek Nayak
2026-10-26 19:59 ` Kayra Cizmeci
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