Re: [PATCH 1/4] printk: Introduce per-console loglevel setting

[Tetsuo Handa]

Petr Mladek wrote:
> It might be even more straightforward when the per-console value
> defines the effective console level. I mean the following semantic:
> 
>    + "console_loglevel" would define the default loglevel used
>      by consoles at runtime.
> 
>    + the per-console loglevel could override the default
>      console_loglevel.
> 
>    + We would need a custom handler for the sysctl "console_loglevel".
>      It would write the given value to the global console_loglevel
>      variable and for all already registered consoles (con->loglevel).

But some functions change console_loglevel without sysctl (e.g.
console_verbose() when reporting hung tasks and panic()). Should
con->loglevel be changed (which might result in too much messages to
slow consoles) when console_loglevel changes?

> 
>      The value will be used also for all newly registered consoles
>      when they do not have any custom one.
> 
> 
>    + The handler for "loglevel" early param should behave the same
>      as the sysctl handler.
> 
> 
> IMHO, there is no perfect solution. The advantage of the above
> proposal is that you "see" and "use" exactly what you "set".