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Re: [Patch 0/2] dynamic debug
- From: Greg KH <greg at kroah dot com>
- To: Jason Baron <jbaron at redhat dot com>
- Cc: linux-kernel at vger dot kernel dot org, gnb at sgi dot com, gregkh at suse dot de, nfsv4 at linux-nfs dot org, systemtap at sources dot redhat dot com
- Date: Thu, 5 Feb 2009 09:58:49 -0800
- Subject: Re: [Patch 0/2] dynamic debug
- References: <20090205164520.GB3114@redhat.com>
On Thu, Feb 05, 2009 at 11:45:20AM -0500, Jason Baron wrote:
> hi,
>
> This patchset combines Greg Bank's dprintk() patchset with the dynamic printk
> patchset. We are renaming the combined solution 'dynamic debug'. As a reminder,
> the patchset allows debug printk style statements to be dynamically
> enabled/disabled at runtime.
>
> The key new feature of this patchset is a richer /debugfs control file
> interface, (an example output from my system is at the bottom), which allows
> fined grained control over the the debug output. The output can be controlled by
> function, file and line number, module, and format string.
That's nice, but do we really need to have that kind of control? It
seems like overkill.
> For example, to enable all debug statement in module 'nf_conntrack':
>
> #echo -n 'module nf_conntrack +p' > /mnt/debugfs/dynamic_debug/control
>
> A further explanation can be found in the documentation patch.
>
> While adding these new features we have dropped a couple that we intend to add
> back in subsequent patches. The ability to turn on/off all debugging at once,
> either via the /debugfs control file, or via the kernel command line.
>
> thanks,
>
> -Jason and Greg
>
>
> # filename:lineno [module]function flags format
> arch/x86/kernel/setup_percpu.c:260 [setup_percpu]numa_set_node - "Setting\040node\040for\040non-present\040cpu\040%d\012"
Why the \040 syntax? Can't we handle a space in a string? Makes it
very hard to grep for things...
I'll give these a spin in my tree to see how it works for now.
thanks,
greg k-h