Re: [patch 0/3] dynamic_printk: new feature

[Nick Andrew <nick@nick-andrew.net>]

On Wed, Apr 30, 2008 at 12:45:06PM -0700, Andrew Morton wrote:
> > Add the ability to dynamically enable/disable pr_debug()/dev_dbg() in the
> > kernel.

Yes, that's the kind of thing I've been thinking about adding myself.

> > echo "add module_name" > /sys/kernel/debug/dynamic_printk/modules
> > echo "remove module_name" > /sys/kernel/debug/dynamic_printk/modules

How about not just debug messages but setting a loglevel for each module
(and/or subsystem?); kernel messages emitted beneath the loglevel value
to be discarded.

> We're now in the situation where numerous different subsystems have
> implemented private mechnisms for tuning their printk verbosity levels.

And it grows over time; just in the last week a patch came through to
V4L ...

	From: Andy Walls <awalls@radix.net>

	Replace the unconditional printk() messages with printk() messages that are
	enabled/disabled by a "debug" module parameter.

	[...]
	+#define dprintk(level, fmt, arg...)

> Have you considered the feasibility of ploddingly converting each of those
> drivers, one at a time over to the new infrastructure?  Because that's what
> we should do, I'm afraid.

I can help with that.

Nick.
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