Messages in this thread | | | Date | Wed, 17 Jun 2015 11:41:14 +0200 | From | Ingo Molnar <> | Subject | Re: [RFC/INCOMPLETE 01/13] context_tracking: Add context_tracking_assert_state |
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* Andy Lutomirski <luto@kernel.org> wrote:
> This will let us sprinkle sanity checks around the kernel without > making too much of a mess. > > Signed-off-by: Andy Lutomirski <luto@kernel.org> > --- > include/linux/context_tracking.h | 8 ++++++++ > 1 file changed, 8 insertions(+) > > diff --git a/include/linux/context_tracking.h b/include/linux/context_tracking.h > index 2821838256b4..0fbea4b152e1 100644 > --- a/include/linux/context_tracking.h > +++ b/include/linux/context_tracking.h > @@ -57,6 +57,13 @@ static inline void context_tracking_task_switch(struct task_struct *prev, > if (context_tracking_is_enabled()) > __context_tracking_task_switch(prev, next); > } > + > +static inline void context_tracking_assert_state(enum ctx_state state) > +{ > + rcu_lockdep_assert(!context_tracking_is_enabled() || > + this_cpu_read(context_tracking.state) == state, > + "context tracking state was wrong"); > +}
Please don't introduce assert() style debug check interfaces!
(And RCU should be fixed too I suspect.)
They are absolutely horrible on the brain when mixed with WARN_ON() interfaces, which are the dominant runtime check interface in the kernel.
Instead make it something like:
#define ct_state() (this_cpu_read(context_tracking.state))
#define CT_WARN_ON(cond) \ WARN_ON(context_tracking_is_enabled() && (cond))
and then the debug checks can be written as:
CT_WARN_ON(ct_state() != CONTEXT_KERNEL);
This is IMHO _far_ more readable than:
context_tracking_assert_state(CONTEXT_KERNEL);
ok?
(Assuming people will accept 'ct/CT' as an abbreviation for context tracking.)
Thanks,
Ingo
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