From: Daniel Lezcano <daniel.lezcano@linaro.org>
To: Viresh Kumar <viresh.kumar@linaro.org>
Cc: edubezval@gmail.com, kevin.wangtao@linaro.org,
leo.yan@linaro.org, vincent.guittot@linaro.org,
amit.kachhap@gmail.com, linux-kernel@vger.kernel.org,
javi.merino@kernel.org, rui.zhang@intel.com,
daniel.thompson@linaro.org, linux-pm@vger.kernel.org
Subject: Re: [PATCH V2 6/7] thermal/drivers/cpu_cooling: Introduce the cpu idle cooling driver
Date: Wed, 4 Apr 2018 10:50:02 +0200 [thread overview]
Message-ID: <78504a65-d21a-eea0-d8af-6e12d5747b87@linaro.org> (raw)
In-Reply-To: <20180226043021.GK26947@vireshk-i7>
On 26/02/2018 05:30, Viresh Kumar wrote:
[ ... ]
>>>> +
>>>> + for_each_possible_cpu(cpu) {
>>>> + cpumask = topology_core_cpumask(cpu);
>>>> +
>>>> + cct = per_cpu_ptr(&cpuidle_cooling_tsk, cpu);
>>>> +
>>>> + /*
>>>> + * This condition makes the first cpu belonging to the
>>>> + * cluster to create a cooling device and allocates
>>>> + * the structure. Others CPUs belonging to the same
>>>> + * cluster will just increment the refcount on the
>>>> + * cooling device structure and initialize it.
>>>> + */
>>>> + if (cpu == cpumask_first(cpumask)) {
>>>
>>> Your function still have few assumptions of cpu numbering and it will
>>> break in few cases. What if the CPUs on a big Little system (4x4) are
>>> present in this order: B L L L L B B B ??
>>>
>>> This configuration can happen if CPUs in DT are marked as: 0-3 LITTLE,
>>> 4-7 big and a big CPU is used by the boot loader to bring up Linux.
>>
>> Ok, how can I sort it out ?
>
> I would do something like this:
>
> cpumask_copy(possible, cpu_possible_mask);
>
> while (!cpumask_empty(possible)) {
> first = cpumask_first(possible);
> cpumask = topology_core_cpumask(first);
> cpumask_andnot(possible, possible, cpumask);
>
> allocate_cooling_dev(first); //This is most of this function in your patch.
>
> while (!cpumask_empty(cpumask)) {
> temp = cpumask_first(possible);
> //rest init "temp"
> cpumask_clear_cpu(temp, cpumask);
> }
>
> //Everything done, register cooling device for cpumask.
> }
Mmh, that sounds very complex. May be it is simpler to count the number
of cluster and initialize the idle_cdev for each cluster and then go for
this loop with the cluster cpumask.
--
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next prev parent reply other threads:[~2018-04-04 8:50 UTC|newest]
Thread overview: 22+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <1519226968-19821-1-git-send-email-daniel.lezcano@linaro.org>
[not found] ` <1519226968-19821-6-git-send-email-daniel.lezcano@linaro.org>
2018-03-06 23:19 ` [PATCH V2 5/7] thermal/drivers/cpu_cooling: Add idle cooling device documentation Pavel Machek
2018-03-07 11:42 ` Daniel Lezcano
2018-03-08 8:59 ` Pavel Machek
2018-03-08 11:54 ` Daniel Thompson
2018-03-07 17:09 ` [PATCH V2 0/7] CPU cooling device new strategies Eduardo Valentin
2018-03-07 18:57 ` Daniel Lezcano
2018-03-08 12:03 ` Daniel Thompson
2018-03-26 14:30 ` Leo Yan
2018-03-27 9:35 ` Daniel Lezcano
[not found] ` <1519226968-19821-7-git-send-email-daniel.lezcano@linaro.org>
[not found] ` <20180223073432.GF26947@vireshk-i7>
[not found] ` <faaf027c-e01c-6801-9a0c-ab7e0ba669a1@linaro.org>
2018-02-26 4:30 ` [PATCH V2 6/7] thermal/drivers/cpu_cooling: Introduce the cpu idle cooling driver Viresh Kumar
2018-03-13 19:15 ` Daniel Lezcano
2018-04-04 8:50 ` Daniel Lezcano [this message]
2018-04-05 4:49 ` Viresh Kumar
2018-03-27 3:43 ` Leo Yan
2018-03-27 11:10 ` Daniel Lezcano
2018-03-27 2:03 ` Leo Yan
2018-03-27 10:26 ` Daniel Lezcano
2018-03-27 12:28 ` Juri Lelli
2018-03-27 12:31 ` Daniel Lezcano
2018-03-27 13:08 ` Juri Lelli
2018-03-27 3:35 ` Leo Yan
2018-03-27 10:56 ` Daniel Lezcano
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