Re: [PATCH 2.6.27-rc3 26/29] mdb: export task_curr

From: Ingo Molnar
Date: Fri Aug 15 2008 - 08:25:39 EST



* jmerkey@xxxxxxxxxxxxxxxxxxxxx <jmerkey@xxxxxxxxxxxxxxxxxxxxx> wrote:

> > On Thu, Aug 14, 2008 at 9:14 AM, <jmerkey@xxxxxxxxxxxxxxxxxxxxx> 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@xxxxxxxxxxxxxxxxxxxxx)
> >>
> >> --- 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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