Date: Fri, 15 Aug 2008 14:25:10 +0200
From: Ingo Molnar <mingo@elte.hu>
To: jmerkey@wolfmountaingroup.com
Cc: Pekka Enberg <penberg@cs.helsinki.fi>, linux-kernel@vger.kernel.org,
       jason.wessel@windriver.com
Subject: Re: [PATCH 2.6.27-rc3 26/29] mdb: export task_curr
Message-ID: <20080815122510.GF20442@elte.hu>
References: <200808140614.m7E6EcDS006264@wolfmountaingroup.com> <84144f020808140139v691e6590idd79995168af4e9e@mail.gmail.com> <44303.166.70.238.45.1218724556.squirrel@webmail.wolfmountaingroup.com>
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* jmerkey@wolfmountaingroup.com <jmerkey@wolfmountaingroup.com> wrote:

> > On Thu, Aug 14, 2008 at 9:14 AM,  <jmerkey@wolfmountaingroup.com> wrote:
> >> export the task_curr function to the module based kernel debugger to
> >> enable
> >> process back tracing and state display.
> >>
> >> Signed-off-by: Jeffrey Vernon Merkey (jmerkey@wolfmountaingroup.com)
> >>
> >> --- a/kernel/sched.c    2008-08-13 14:22:32.000000000 -0600
> >> +++ b/kernel/sched.c    2008-08-13 11:56:03.000000000 -0600
> >> @@ -1736,6 +1736,9 @@
> >>  {
> >>        return cpu_curr(task_cpu(p)) == p;
> >>  }
> >> +#if defined(CONFIG_MDB_MODULE)
> >> +EXPORT_SYMBOL_GPL(task_curr);
> >> +#endif
> >
> > We usually don't export symbols conditionally, especially in core kernel
> > code.
> >
> 
> Well,then please suggest how a kernel debugger can be module based and 
> still be able to get this information some other way that's generic 
> and minimal impact.

FYI, there's a built-in kernel debugger in the upstream kernel already: 
kernel/kgdb.c - and it does not need that export.

So if you are interested in kernel debuggers i'd suggest to work with 
the KGDB folks to extend it with whatever feature-set is missing.

They are friendly, very easy to work with and are open to the 
thousands-of-years-old scientific method of not duplicating effort, 
working together, going forward gradually, etc.

	Ingo
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