From: Dietmar Eggemann <dietmar.eggemann@arm.com>
To: Quentin Perret <qperret@google.com>, Qais Yousef <qais.yousef@arm.com>
Cc: Ingo Molnar <mingo@redhat.com>,
Peter Zijlstra <peterz@infradead.org>,
Steven Rostedt <rostedt@goodmis.org>,
Luis Chamberlain <mcgrof@kernel.org>,
Kees Cook <keescook@chromium.org>,
Iurii Zaikin <yzaikin@google.com>,
Juri Lelli <juri.lelli@redhat.com>,
Vincent Guittot <vincent.guittot@linaro.org>,
Ben Segall <bsegall@google.com>, Mel Gorman <mgorman@suse.de>,
valentin.schneider@arm.com,
Patrick Bellasi <patrick.bellasi@matbug.net>,
linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org,
kernel-team@android.com
Subject: Re: [PATCH] sched/rt: Add a new sysctl to control uclamp_util_min
Date: Tue, 7 Jan 2020 20:30:36 +0100 [thread overview]
Message-ID: <8bb17e84-d43f-615f-d04d-c36bb6ede5e0@arm.com> (raw)
In-Reply-To: <20200107134234.GA158998@google.com>
On 07/01/2020 14:42, Quentin Perret wrote:
> Hi Qais,
>
> On Friday 20 Dec 2019 at 16:48:38 (+0000), Qais Yousef wrote:
[...]
>> diff --git a/kernel/sched/rt.c b/kernel/sched/rt.c
>> index e591d40fd645..19572dfc175b 100644
>> --- a/kernel/sched/rt.c
>> +++ b/kernel/sched/rt.c
>> @@ -2147,6 +2147,12 @@ static void pull_rt_task(struct rq *this_rq)
>> */
>> static void task_woken_rt(struct rq *rq, struct task_struct *p)
>> {
>> + /*
>> + * When sysctl_sched_rt_uclamp_util_min value is changed by the user,
>> + * we apply any new value on the next wakeup, which is here.
>> + */
>> + uclamp_rt_sync_default_util_min(p);
>
> The task has already been enqueued and sugov has been called by then I
> think, so this is a bit late. You could do that in uclamp_rq_inc() maybe?
That's probably better.
Just to be sure ...we want this feature (an existing rt task gets its
UCLAMP_MIN value set when the sysctl changes) because there could be rt
tasks running before the sysctl is set?
>> +
>> if (!task_running(rq, p) &&
>> !test_tsk_need_resched(rq->curr) &&
>> p->nr_cpus_allowed > 1 &&
>> diff --git a/kernel/sched/sched.h b/kernel/sched/sched.h
>> index 280a3c735935..337bf17b1a9d 100644
>> --- a/kernel/sched/sched.h
>> +++ b/kernel/sched/sched.h
>> @@ -2300,6 +2300,8 @@ static inline void cpufreq_update_util(struct rq *rq, unsigned int flags) {}
>> #endif /* CONFIG_CPU_FREQ */
>>
>> #ifdef CONFIG_UCLAMP_TASK
>> +void uclamp_rt_sync_default_util_min(struct task_struct *p);
>> +
>> unsigned int uclamp_eff_value(struct task_struct *p, enum uclamp_id clamp_id);
>>
>> static __always_inline
>> @@ -2330,6 +2332,8 @@ static inline unsigned int uclamp_util(struct rq *rq, unsigned int util)
>> return uclamp_util_with(rq, util, NULL);
>> }
>> #else /* CONFIG_UCLAMP_TASK */
>> +void uclamp_rt_sync_default_util_min(struct task_struct *p) {}
-void uclamp_rt_sync_default_util_min(struct task_struct *p) {}
+static inline void uclamp_rt_sync_default_util_min(struct task_struct
*p) {}
[...]
next prev parent reply other threads:[~2020-01-07 19:30 UTC|newest]
Thread overview: 25+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-12-20 16:48 [PATCH] sched/rt: Add a new sysctl to control uclamp_util_min Qais Yousef
2020-01-07 13:42 ` Quentin Perret
2020-01-07 19:30 ` Dietmar Eggemann [this message]
2020-01-08 9:51 ` Quentin Perret
2020-01-08 19:16 ` Patrick Bellasi
2020-01-09 11:36 ` Qais Yousef
2020-01-09 11:16 ` Qais Yousef
2020-01-09 11:12 ` Qais Yousef
2020-01-08 13:44 ` Peter Zijlstra
2020-01-08 19:08 ` Patrick Bellasi
2020-01-09 13:00 ` Qais Yousef
2020-01-10 13:39 ` Peter Zijlstra
2020-01-12 23:35 ` Qais Yousef
2020-01-10 13:42 ` Peter Zijlstra
2020-01-12 23:31 ` Qais Yousef
2020-01-08 18:56 ` Patrick Bellasi
2020-01-09 1:35 ` Valentin Schneider
2020-01-09 9:21 ` Patrick Bellasi
2020-01-09 13:38 ` Qais Yousef
2020-01-14 21:34 ` Qais Yousef
2020-01-22 10:19 ` Patrick Bellasi
2020-01-22 11:45 ` Qais Yousef
2020-01-22 12:44 ` Patrick Bellasi
2020-01-22 14:57 ` Qais Yousef
2020-01-09 13:15 ` Qais Yousef
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