Re: [RFC PATCH v2 1/3] getcpu_cache system call: cache CPU number of running thread

[Mathieu Desnoyers]

----- On Jan 27, 2016, at 12:37 PM, Thomas Gleixner tglx@xxxxxxxxxxxxx wrote:

> On Wed, 27 Jan 2016, Thomas Gleixner wrote:
> 
>> On Wed, 27 Jan 2016, Mathieu Desnoyers wrote:
>> > ----- On Jan 27, 2016, at 12:22 PM, Thomas Gleixner tglx@xxxxxxxxxxxxx wrote:
>> > Sounds fair. What is the recommended typing for "ptr" then ?
>> > uint32_t ** or uint32_t * ?
>> > 
>> > It would be expected to pass a "uint32_t *" for the set
>> > operation, but the "get" operation requires a "uint32_t **".
>> 
>> Well, you can't change the types depending on the opcode, so you need to stick
>> with **.
> 
> Alternatively you make it:
> 
>  (opcode, *newptr, **oldptr, flags);

I'm tempted to stick to (opcode, **ptr, flags), because
other syscalls that have "*newptr", "**oldptr"
typically have them because they save the current state
into oldptr, and set the new state, which is really
not the case here. To eliminate any risk of confusion,
I am tempted to keep a single "**ptr".

Unless someone has a better idea...

Thanks,

Mathieu

-- 
Mathieu Desnoyers
EfficiOS Inc.
http://www.efficios.com