Messages in this thread | | | Date | Wed, 17 Jun 2015 08:27:56 -0700 | From | "Paul E. McKenney" <> | Subject | Re: [RFC/INCOMPLETE 01/13] context_tracking: Add context_tracking_assert_state |
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On Wed, Jun 17, 2015 at 11:41:14AM +0200, Ingo Molnar wrote: > > * 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.)
The thought is to rename rcu_lockdep_assert() to RCU_LOCKDEP_WARN() by analogy to WARN()? Easy to do if so! Or am I missing the point?
Thanx, Paul
> 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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