On 27 March 2013 12:09, Tang Yuantian-B29983 <B29983@xxxxxxxxxxxxx> wrote:
> Viresh Kumar <viresh.kumar <at> linaro.org> writes:
>> On Tue, Mar 26, 2013 at 8:06 AM, <Yuantian.Tang <at> freescale.com>
>> > + * struct cpu_data - per CPU data struct
>
>> For your case where you have 8 cpus in a cluster, only one of 8 variables
>
>> would be used... Better to create an array of struct with elements:
>
>> cpu and data.
>
>>
>
> You are right. But we can’t use array struct because we don’t know the cpu
> numbers
>
> in advance. If we allocate it dynamically, there would complicate things.
>
> Besides, this per cpu data struct would not occupy too memory.
>> > + struct device_node *np;
>> > + struct device_node *parent;
>> > + struct cpufreq_frequency_table *table;
Atleast 12 bytes per cpu.
>> > +static DEFINE_PER_CPU(struct cpu_data, cpu_data);
What about:
static DEFINE_PER_CPU(struct cpu_data *, cpu_data);
and allocate them dynamically. So you would save 8 bytes per cpu.
>> > + sizeof(struct cpufreq_frequency_table),
>> > GFP_KERNEL);
>
>> sizeof(*table)
You missed this.
>> > + for (i = 0; i < count; i++) {
>
>> > + table[i].index = i;
>
>> > + clk = of_clk_get(data->parent, i);
>
>> > + table[i].frequency = clk_get_rate(clk) / 1000;
>
>> > + freq_table_redup(table, i);
>
>>
>
>> Don't call it everytime, fix all these in a single call.
>
>>
>
> NO, not all the CPUs use the same frequency table.
>
> Generally, we have one or two frequency tables.
>
> So, this table needs to be established for each cpu.
You didn't get me. Don't call freq_table_redup() for every table
entry. Call it once per policy-init
>> > +static int corenet_cpufreq_verify(struct cpufreq_policy *policy)
>> > +{
>> > + struct cpufreq_frequency_table *table;
>> > +
>> > + table = (&per_cpu(cpu_data, policy->cpu))->table;
>> > + if (!table)
>> > + return -EINVAL;
>
>>
>
>> This should never be true.
>
> don't understand what's your point here. could you elaborate it?
Sure. table should always be vaild. How can this be NULL ever?
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