Re: [dpdk-dev] [PATCH v10 05/27] eal: introduce dtor macros

["Gaëtan Rivet" <gaetan.rivet@6wind.com>]

Hi Thomas,

On Tue, Jul 10, 2018 at 01:40:01PM +0200, Thomas Monjalon wrote:
> 05/07/2018 13:48, Gaetan Rivet:
> > Signed-off-by: Gaetan Rivet <gaetan.rivet@6wind.com>
> 
> Please justify why you need destructors, by providing a commit log.
> 
> > --- a/lib/librte_eal/common/include/rte_common.h
> > +++ b/lib/librte_eal/common/include/rte_common.h
> > @@ -111,6 +111,29 @@ static void __attribute__((constructor(RTE_PRIO(prio)), used)) func(void)
> >  #define RTE_INIT(func) \
> >  	RTE_INIT_PRIO(func, LAST)
> >  
> > +/**
> > + * Run after main() with low priority.
> > + *
> > + * @param func
> > + *   Destructor function name.
> > + * @param prio
> > + *   Priority number must be above 100.
> > + *   Lowest number is the last to run.
> > + */
> > +#define RTE_FINI_PRIO(func, prio) \
> > +static void __attribute__((destructor(RTE_PRIO(prio)), used)) func(void)
> 
> I don't like the name of this macro.
> What about RTE_CLEAN_PRIO?
> 
> 

FINI is symmetrical to INIT in referencing the related ELF section.

RTE_CLEAN presumes that the intended purpose of the function will be to
cleanup resources. As far as we are concerned, this code could send a
signal, dump config info or format / (which would be a pretty advanced
cleanup, granted).

Sometimes, it could be used to release resources, presumably.

I'm not a fan of FINI either, but I appreciate the symmetry.
It's pretty neutral about what it does, as its meaning is literally
"The following function will be part of the .fini section".

Alternatives:

   FINALIZE
   UNINIT

But they have the same issue as RTE_CLEAN, IMO.

-- 
Gaëtan Rivet
6WIND