Re: [PATCH] Dynamic Debug: Introduce global fake module parammodule.ddebug

From: Jason Baron
Date: Thu Aug 05 2010 - 13:27:00 EST

On Thu, Aug 05, 2010 at 06:05:40PM +0200, Thomas Renninger wrote:
> On Thursday 05 August 2010 17:39:10 Jason Baron wrote:
> > On Mon, Jul 26, 2010 at 02:14:30PM +0200, Thomas Renninger wrote:
> > > This patch is based on 2.6.35-rc5 + this patchset I posted recently:
> > > [patch 0/3] Dynamic Debug providing early boot debug messages via
> > > boot parameter
> > >
> > > It would be great to see these getting merged into 2.6.36...
> ...
> > patch looks pretty good to me. I'm not sure how we reserve the
> > 'ddebug' keyword.
> Yep, I also was not sure about that.
> > However, I think its probably ok, if we mention it
> > in 'kernel-parameters.txt' and in the dynamic debug documentation.
> I added some documentation to the dynamic debug docu file and posted
> the patch again (as a reply on my initial post, should be the same mail
> thread).
> > Also, ddebug could show up in /sys/module/$(modulename}/parameters/ ,
> > but this can probably be done in a followup patch.
> This was intentional.
> At the time /sys is available one can also use
> /sys/kernel/debug/dynamic_debug/control
> echo "module my_module_to_debug +p"
> >/sys/kernel/debug/dynamic_debug/control
> would exactly do the same as /sys/module/$(modulename}/parameters
> The advantage of not having it, is it saves quite some resources, in
> fact it uses none.
> Otherwise every module would have an addtional parameter added with a
> sysfs file associated with it with no additional functional gain.
> > Also, if 'ddebug' alone is set on the kernel command line, i'd like to
> > see us enable all debug statements. We could implement this by adding
> > a special 'meta' module to the control file which is just has a module
> > name of of 'All' or something like that. This could also be done in a
> > subsequent patch.
> Is there a single query which could do it?

I don't think so.

> If not, possibly a keyword like file/module called "all" could be added.
> Then you could simply do that by ddebug_query="all +p"

ok. that makes sense. I would make the all mode apply to all future
modules that get loaded as well, just to be clear...

> > We also need to at least remove the 'dynamic_printk' doc from
> > kernel-parameters.txt.
> Don't know about this one.
> So, I have your acked-by for this one?

Acked-by: Jason Baron <jbaron@xxxxxxxxxx>

> Let's get this pushed into a tree, with some luck it still could make it
> into 2.6.36? The other three have been taken by Pekka? He said something
> about taking them, but I haven't received any confirmation.
> Ah no, he acked-by them only.
> As these are rather general ones, which tree should they go through,
> possibly Andrew could take them?
> I can resubmit, if someone could tell me a list/maintainer that fits
> best, so that they really make it in...
> Thanks,
> Thomas

right, originally Greg KH, pulled these into his tree. Greg, can you take
a look at pulling these into your tree? So it would be this patch, and the

Subject: [patch 0/3] Dynamic Debug providing early boot debug messages via boot parameter


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