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From: Daniel Lezcano <daniel.lezcano@linaro.org>
To: Sudeep Holla <sudeep.holla@arm.com>
Cc: viresh.kumar@linaro.org, edubezval@gmail.com,
	kevin.wangtao@linaro.org, leo.yan@linaro.org,
	vincent.guittot@linaro.org, linux-kernel@vger.kernel.org,
	javi.merino@kernel.org, rui.zhang@intel.com,
	daniel.thompson@linaro.org, linux-pm@vger.kernel.org,
	Amit Daniel Kachhap <amit.kachhap@gmail.com>
Subject: Re: [PATCH v3 6/7] thermal/drivers/cpu_cooling: Introduce the cpu idle cooling driver
Date: Fri, 13 Apr 2018 13:47:50 +0200	[thread overview]
Message-ID: <939f7943-feec-aaa2-3bd3-59a6618330c0@linaro.org> (raw)
In-Reply-To: <3f3b3b7a-3b74-aee2-2fac-f2759babe3f0@arm.com>

On 13/04/2018 13:23, Sudeep Holla wrote:
> Hi Daniel,
> 
> On 05/04/18 17:16, Daniel Lezcano wrote:
> 
> [...]
> 
>> +/**
>> + * cpuidle_cooling_register - Idle cooling device initialization function
>> + *
>> + * This function is in charge of creating a cooling device per cluster
>> + * and register it to thermal framework. For this we rely on the
>> + * topology as there is nothing yet describing better the idle state
>> + * power domains.
>> + *
>> + * We create a cpuidle cooling device per cluster. For this reason we
>> + * must, for each cluster, allocate and initialize the cooling device
>> + * and for each cpu belonging to this cluster, do the initialization
>> + * on a cpu basis.
>> + *
>> + * This approach for creating the cooling device is needed as we don't
>> + * have the guarantee the CPU numbering is sequential.
>> + *
>> + * Unfortunately, there is no API to browse from top to bottom the
>> + * topology, cluster->cpu, only the usual for_each_possible_cpu loop.
>> + * In order to solve that, we use a cpumask to flag the cluster_id we
>> + * already processed. The cpumask will always have enough room for all
>> + * the cluster because it is based on NR_CPUS and it is not possible
>> + * to have more clusters than cpus.
>> + *
>> + */
>> +void __init cpuidle_cooling_register(void)
>> +{
>> +	struct cpuidle_cooling_device *idle_cdev = NULL;
>> +	struct thermal_cooling_device *cdev;
>> +	struct device_node *np;
>> +	cpumask_var_t cpumask;
>> +	char dev_name[THERMAL_NAME_LENGTH];
>> +	int ret = -ENOMEM, cpu;
>> +	int cluster_id;
>> +
>> +	if (!zalloc_cpumask_var(&cpumask, GFP_KERNEL))
>> +		return;
>> +
>> +	for_each_possible_cpu(cpu) {
>> +
>> +		cluster_id = topology_physical_package_id(cpu);
>> +		if (cpumask_test_cpu(cluster_id, cpumask))
>> +			continue;
> 
> Sorry for chiming in randomly, I haven't read the patches in detail.
> But it was brought to my notice that topology_physical_package_id is
> being used for cluster ID here. It's completely wrong and will
> changesoon with ACPI topology related changes Jeremy is working on.
> 
> You will get the physical socket number(which is mostly 0 on single SoC
> system). Makes sure that this won't break with that change.
> 
> Please note with cluster id not defined architecturally, relying on that
> is simply problematic.

Ok, noted. At the first glance, it should not be a problem.


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  reply	other threads:[~2018-04-13 11:47 UTC|newest]

Thread overview: 46+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-04-05 16:16 [PATCH v3 0/7] CPU cooling device new strategies Daniel Lezcano
2018-04-05 16:16 ` [PATCH v3 1/7] thermal/drivers/cpu_cooling: Fixup the header and copyright Daniel Lezcano
     [not found]   ` <20180411061514.GL7671@vireshk-i7>
2018-04-11  8:56     ` Daniel Lezcano
2018-04-05 16:16 ` [PATCH v3 2/7] thermal/drivers/cpu_cooling: Add Software Package Data Exchange (SPDX) Daniel Lezcano
2018-04-05 16:16 ` [PATCH v3 3/7] thermal/drivers/cpu_cooling: Remove pointless field Daniel Lezcano
2018-04-05 16:16 ` [PATCH v3 4/7] thermal/drivers/Kconfig: Convert the CPU cooling device to a choice Daniel Lezcano
     [not found]   ` <20180411061851.GM7671@vireshk-i7>
2018-04-11  8:58     ` Daniel Lezcano
2018-04-05 16:16 ` [PATCH v3 5/7] thermal/drivers/cpu_cooling: Add idle cooling device documentation Daniel Lezcano
2018-04-05 16:16 ` [PATCH v3 6/7] thermal/drivers/cpu_cooling: Introduce the cpu idle cooling driver Daniel Lezcano
2018-04-11  8:51   ` Viresh Kumar
2018-04-11  9:29     ` Daniel Lezcano
2018-04-13 11:23   ` Sudeep Holla
2018-04-13 11:47     ` Daniel Lezcano [this message]
2018-04-16  7:37       ` Viresh Kumar
2018-04-16  7:44         ` Daniel Lezcano
2018-04-16  9:34           ` Sudeep Holla
2018-04-16  9:37           ` Viresh Kumar
2018-04-16  9:45             ` Daniel Lezcano
2018-04-16  9:50               ` Viresh Kumar
2018-04-16 10:03                 ` Daniel Lezcano
2018-04-16 10:10                   ` Viresh Kumar
2018-04-16 12:10                     ` Daniel Lezcano
2018-04-16 12:30                       ` Lorenzo Pieralisi
2018-04-16 13:57                         ` Daniel Lezcano
2018-04-16 14:22                           ` Lorenzo Pieralisi
2018-04-17  7:17                             ` Daniel Lezcano
2018-04-17 10:24                               ` Lorenzo Pieralisi
2018-04-16 12:31                       ` Sudeep Holla
2018-04-16 12:49                         ` Daniel Lezcano
2018-04-16 13:03                           ` Sudeep Holla
2018-04-16 12:29                 ` Sudeep Holla
2018-04-13 11:38   ` Daniel Thompson
2018-04-13 11:46     ` Daniel Lezcano
2019-08-05  5:11   ` Martin Kepplinger
2019-08-05  6:53     ` Martin Kepplinger
2019-08-05  7:39       ` Daniel Lezcano
2019-08-05  7:42         ` Martin Kepplinger
2019-08-05  7:58           ` Daniel Lezcano
2019-10-25 11:22             ` Martin Kepplinger
2019-10-25 14:45               ` Daniel Lezcano
2019-10-26 18:23                 ` Martin Kepplinger
2019-10-28 15:16                   ` Daniel Lezcano
2019-08-05  7:37     ` Daniel Lezcano
2019-08-05  7:40       ` Martin Kepplinger
2018-04-05 16:16 ` [PATCH v3 7/7] cpuidle/drivers/cpuidle-arm: Register the cooling device Daniel Lezcano
2018-04-11  8:51   ` Viresh Kumar

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