Re: What is the point of this function?

2016-06-23 Thread Andrea Benelli 
Ok, thank you!
Il 22 giu 2016 3:08 PM, "Daniel."  ha scritto:

> The function body you see will be use only when CONFIG_SMP is not
> present. Take a look at
> https://www.kernel.org/doc/Documentation/CodingStyle
> Chapter 20: Conditional Compilation
>
> Regards,
>
> 2016-06-21 8:56 GMT-03:00 Andrea Benelli :
> > So, it's just an override?
> > Why return true and not false?
> >
> > Il 21 giu 2016 4:32 AM, "Nathan Williams"  ha
> scritto:
> >>
> >> On Tue, 2016-06-21 at 00:48 +0200, Andrea Benelli wrote:
> >> > Hello, i was looking at the linux/sched.h (kernel version 4.6.2)
> >> > source code and i found this function at line 1174:
> >> >
> >> > static inline bool cpus_share_cache(int this_cpu, int that_cpu)
> >> > {
> >> > return true;
> >> > }
> >> >
> >> > I'm not able to understand the utility of a function that just return
> >> > a true value.
> >> > i've noticed that there are a lot of functions like this (function
> >> > that just return a constant).
> >>
> >> Hi Andrea,
> >>
> >> That's the case for when CONFIG_SMP isn't defined. What happens when
> >> CONFIG_SMP is defined?
> >>
> >> I suggest having a look through the code with a Linux cross reference:
> >>
> >> http://lxr.free-electrons.com/ident?v=4.6;i=cpus_share_cache
> >>
> >> Regards,
> >> Nathan
> >>
> >
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>
>
>
> --
> "Do or do not. There is no try"
>   Yoda Master
>
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Re: What is the point of this function?

2016-06-22 Thread Daniel. 
The function body you see will be use only when CONFIG_SMP is not
present. Take a look at
https://www.kernel.org/doc/Documentation/CodingStyle
Chapter 20: Conditional Compilation

Regards,

2016-06-21 8:56 GMT-03:00 Andrea Benelli :
> So, it's just an override?
> Why return true and not false?
>
> Il 21 giu 2016 4:32 AM, "Nathan Williams"  ha scritto:
>>
>> On Tue, 2016-06-21 at 00:48 +0200, Andrea Benelli wrote:
>> > Hello, i was looking at the linux/sched.h (kernel version 4.6.2)
>> > source code and i found this function at line 1174:
>> >
>> > static inline bool cpus_share_cache(int this_cpu, int that_cpu)
>> > {
>> > return true;
>> > }
>> >
>> > I'm not able to understand the utility of a function that just return
>> > a true value.
>> > i've noticed that there are a lot of functions like this (function
>> > that just return a constant).
>>
>> Hi Andrea,
>>
>> That's the case for when CONFIG_SMP isn't defined. What happens when
>> CONFIG_SMP is defined?
>>
>> I suggest having a look through the code with a Linux cross reference:
>>
>> http://lxr.free-electrons.com/ident?v=4.6;i=cpus_share_cache
>>
>> Regards,
>> Nathan
>>
>
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-- 
"Do or do not. There is no try"
  Yoda Master

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Re: What is the point of this function?

2016-06-21 Thread Andrea Benelli 
So, it's just an override?
Why return true and not false?
Il 21 giu 2016 4:32 AM, "Nathan Williams"  ha scritto:

> On Tue, 2016-06-21 at 00:48 +0200, Andrea Benelli wrote:
> > Hello, i was looking at the linux/sched.h (kernel version 4.6.2)
> > source code and i found this function at line 1174:
> >
> > static inline bool cpus_share_cache(int this_cpu, int that_cpu)
> > {
> > return true;
> > }
> >
> > I'm not able to understand the utility of a function that just return
> > a true value.
> > i've noticed that there are a lot of functions like this (function
> > that just return a constant).
>
> Hi Andrea,
>
> That's the case for when CONFIG_SMP isn't defined. What happens when
> CONFIG_SMP is defined?
>
> I suggest having a look through the code with a Linux cross reference:
>
> http://lxr.free-electrons.com/ident?v=4.6;i=cpus_share_cache
>
> Regards,
> Nathan
>
>
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Re: What is the point of this function?

2016-06-20 Thread Nathan Williams 
On Tue, 2016-06-21 at 00:48 +0200, Andrea Benelli wrote:
> Hello, i was looking at the linux/sched.h (kernel version 4.6.2)
> source code and i found this function at line 1174: 
> 
> static inline bool cpus_share_cache(int this_cpu, int that_cpu)
> {
> return true;
> }
> 
> I'm not able to understand the utility of a function that just return
> a true value. 
> i've noticed that there are a lot of functions like this (function
> that just return a constant). 

Hi Andrea,

That's the case for when CONFIG_SMP isn't defined. What happens when
CONFIG_SMP is defined?

I suggest having a look through the code with a Linux cross reference:

http://lxr.free-electrons.com/ident?v=4.6;i=cpus_share_cache

Regards,
Nathan


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What is the point of this function?

2016-06-20 Thread Andrea Benelli 
Hello, i was looking at the *linux/sched.h* (kernel version 4.6.2) source
code and i found this function at line *1174*:

static inline bool cpus_share_cache(int this_cpu, int that_cpu)
{
return true;
}

I'm not able to understand the utility of a function that just return a
true value.
i've noticed that there are a lot of functions like this (function that
just return a constant).

so...why?
thanks.
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