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SubjectRe: [PATCH] context_tracking: Add comments on interface and internals
On Thu, 13 Dec 2012 23:50:23 +0100
Frederic Weisbecker <fweisbec@gmail.com> wrote:

> >
> >> + * This call supports re-entrancy.
> >
> > Presumably the explanation for user_exit() applies here.
>
> Not sure what you mean here.

It's unclear what it means to say "user_enter() supports reentrancy".
I mean, zillions of kernel functions are surely reentrant - so what?
It appears that you had something in mind when pointing this out, but
what was it? The comment over user_exit() appears to tell us.

> > It's mainly this bit which makes me wonder why the code is in lib/. Is
> > there any conceivable prospect that any other subsystem will use this
> > code for anything?
>
> So that's because of that cputime accounting on dynticks CPUs which
> will need to know about user/kernel transitions. I'm preparing that
> for the 3.9 merge window.

Oh. That's really the entire reason for the patch and should have been
in the changelog!


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