From: "Rafael J. Wysocki" <rjw@rjwysocki.net>
To: Viresh Kumar <viresh.kumar@linaro.org>
Cc: Ingo Molnar <mingo@redhat.com>,
Peter Zijlstra <peterz@infradead.org>,
linaro-kernel@lists.linaro.org, linux-pm@vger.kernel.org,
linux-kernel@vger.kernel.org,
Vincent Guittot <vincent.guittot@linaro.org>,
smuckle.linux@gmail.com, juri.lelli@arm.com,
Morten.Rasmussen@arm.com, patrick.bellasi@arm.com,
eas-dev@lists.linaro.org
Subject: Re: [RFC 3/9] cpufreq: Add dvfs_possible_from_any_cpu policy flag
Date: Wed, 29 Mar 2017 23:22:20 +0200 [thread overview]
Message-ID: <9819718.SkTYBzvS8V@aspire.rjw.lan> (raw)
In-Reply-To: <4f57e9a7dddcd7e0f821c127cd4e9d87c5807c6c.1489058244.git.viresh.kumar@linaro.org>
On Thursday, March 09, 2017 05:15:13 PM Viresh Kumar wrote:
> On many platforms any CPU (from any cpufreq policy) can perform DVFS on
> behalf of other CPUs. Add a flag to identify such cpufreq policies.
>
> Also enable it for cpufreq-dt driver which is used only on ARM platforms
> currently.
>
> Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
> ---
> drivers/cpufreq/cpufreq-dt.c | 1 +
> include/linux/cpufreq.h | 9 +++++++++
> 2 files changed, 10 insertions(+)
>
> diff --git a/drivers/cpufreq/cpufreq-dt.c b/drivers/cpufreq/cpufreq-dt.c
> index c943787d761e..e57b45f20544 100644
> --- a/drivers/cpufreq/cpufreq-dt.c
> +++ b/drivers/cpufreq/cpufreq-dt.c
> @@ -274,6 +274,7 @@ static int cpufreq_init(struct cpufreq_policy *policy)
> transition_latency = CPUFREQ_ETERNAL;
>
> policy->cpuinfo.transition_latency = transition_latency;
> + policy->dvfs_possible_from_any_cpu = true;
>
> return 0;
>
> diff --git a/include/linux/cpufreq.h b/include/linux/cpufreq.h
> index 87165f06a307..9490a314c515 100644
> --- a/include/linux/cpufreq.h
> +++ b/include/linux/cpufreq.h
> @@ -120,6 +120,15 @@ struct cpufreq_policy {
> bool fast_switch_possible;
> bool fast_switch_enabled;
>
> + /*
> + * Remote DVFS flag (Not added to the driver structure as we don't want
> + * to access another structure from scheduler hotpath).
> + *
> + * Should be set if any CPU (from same or different policy) can do DVFS
> + * on behalf of any other CPU.
> + */
> + bool dvfs_possible_from_any_cpu;
We rely on the assumption that any CPU in a policy can do DVFS in there already.
Why is this flag necessary at all?
> +
> /* Cached frequency lookup from cpufreq_driver_resolve_freq. */
> unsigned int cached_target_freq;
> int cached_resolved_idx;
>
Thanks,
Rafael
next prev parent reply other threads:[~2017-03-29 21:29 UTC|newest]
Thread overview: 26+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-03-09 11:45 [RFC 0/9] cpufreq: schedutil: Allow remote wakeups Viresh Kumar
2017-03-09 11:45 ` [RFC 1/9] sched: cpufreq: add cpu to update_util_data Viresh Kumar
2017-03-29 21:18 ` Rafael J. Wysocki
2017-03-09 11:45 ` [RFC 2/9] irq_work: add irq_work_queue_on for !CONFIG_SMP Viresh Kumar
2017-03-29 21:20 ` Rafael J. Wysocki
2017-03-09 11:45 ` [RFC 3/9] cpufreq: Add dvfs_possible_from_any_cpu policy flag Viresh Kumar
2017-03-29 21:22 ` Rafael J. Wysocki [this message]
2017-03-09 11:45 ` [RFC 4/9] sched: cpufreq: extend irq work to support fast switches Viresh Kumar
2017-03-29 21:25 ` Rafael J. Wysocki
2017-03-09 11:45 ` [RFC 5/9] sched: cpufreq: remove smp_processor_id() in remote paths Viresh Kumar
2017-03-29 21:28 ` Rafael J. Wysocki
2017-04-11 10:35 ` Viresh Kumar
2017-04-11 14:00 ` Rafael J. Wysocki
2017-04-12 14:26 ` Viresh Kumar
2017-04-12 22:53 ` Rafael J. Wysocki
2017-03-09 11:45 ` [RFC 6/9] sched: cpufreq: detect, process remote callbacks Viresh Kumar
2017-03-29 21:58 ` Rafael J. Wysocki
2017-03-09 11:45 ` [RFC 7/9] cpufreq: governor: support scheduler cpufreq callbacks on remote CPUs Viresh Kumar
2017-03-29 22:14 ` Rafael J. Wysocki
2017-04-11 11:06 ` Viresh Kumar
2017-03-09 11:45 ` [RFC 8/9] intel_pstate: ignore " Viresh Kumar
2017-03-29 22:15 ` Rafael J. Wysocki
2017-03-09 11:45 ` [RFC 9/9] sched: cpufreq: enable remote sched cpufreq callbacks Viresh Kumar
2017-03-15 11:45 ` [RFC 0/9] cpufreq: schedutil: Allow remote wakeups Rafael J. Wysocki
2017-03-16 3:09 ` Viresh Kumar
2017-03-16 10:04 ` Rafael J. Wysocki
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