Re: [PATCH proxmox 1/6] log: replace per layer filtering by one global filter

[Gabriel Goller <g.goller@proxmox.com>]

> [snip]
> @@ -153,10 +135,13 @@ impl Logger {
>      ///
>      /// Also configures the `LogTracer` which will convert all `log` events to tracing events.
>      pub fn init(self) -> Result<(), anyhow::Error> {
> -        let registry = tracing_subscriber::registry().with(self.layer);
> +        let registry = tracing_subscriber::registry()
> +            .with(self.layer)
> +            .with(self.global_log_level);
> +
>          tracing::subscriber::set_global_default(registry)?;
>  
> -        LogTracer::init_with_filter(self.global_log_level.as_log())?;
> +        LogTracer::init()?;

Hmm any reason why this was changed?
I'm asking because this means all the log invocations (there aren't many though)
will build a whole tracing record before being filtered by the level filter.
When passing a global log level to the LogTracer, all the levels below will be
optimized away.

I'm a bit afraid that there is a crate that has a log::debug! statement in the
hot-path in a loop somewhere -- that would mean we create a whole tracing record
and discard it on every debug! :)

Note sure if this is a big issue though -- we have very few log invocations
anyway and other crates shouldn't be such a big issue.

>          Ok(())
>      }
>  }
> --