Re: [Xen-devel] [PATCH v2 52/52] xen: make some console related parameters settable at runtime

[Juergen Gross <jgross@xxxxxxxx>]

On 15/08/17 17:59, Jan Beulich wrote:
>>>> On 15.08.17 at 17:52, <jgross@xxxxxxxx> wrote:
>> On 15/08/17 17:45, Jan Beulich wrote:
>>>>>> On 14.08.17 at 09:08, <jgross@xxxxxxxx> wrote:
>>>> --- a/xen/drivers/char/console.c
>>>> +++ b/xen/drivers/char/console.c
>>>> @@ -41,6 +41,7 @@ string_param("console", opt_console);
>>>>  /*         boots. Any other value, or omitting the char, enables 
>> auto-switch 
>>>> */
>>>>  static unsigned char __read_mostly opt_conswitch[3] = "a";
>>>>  string_param("conswitch", opt_conswitch);
>>>> +string_param_runtime("conswitch", opt_conswitch);
>>>
>>> Do you envision parameters which can only be set at runtime?
>>> Otherwise, to avoid the two going out of sync (as well as the
>>> redundancy) wouldn't it make sense for xyz_param_runtime()
>>> to do what it does now _and_ invoke xyz_param()?
>>
>> There might be params requiring another handler (e.g. taking a lock,
>> allocating some memory, ...).
>>
>> Having a macro for doing both (like above case) seems appropriate.
>> Any naming ideas? E.g.:
>>
>> string_param_anytime() ?
> 
> How about xyz_param_runtime_only() to cover the case where
> you really need separate handlers? Yet even then one would have
> to specify the string twice, i.e. the name you suggest might be
> good to use when it takes two handler arguments.

I think for now we could use *_param_runtime() for boot- and
runtime-changes. We can add another set of macros if we need them.


Juergen

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