[dpdk-dev] [PATCH v2 0/3] Allow overriding of build-time constants

[David Marchand]

On Fri, Oct 16, 2020 at 5:56 PM Bruce Richardson
<bruce.richardson at intel.com> wrote:
> > librte_eal.so is indeed built with the 64 value:
> > $ pahole -C rte_mem_config build/install/lib64/librte_eal.so |grep memsegs
> > die__process_function: tag not supported (INVALID)!
> >     struct rte_memseg_list     memsegs[64];          /*   136  8704 */
> >
> >
> > But no trace of the custom value for external applications:
> > $ grep -r RTE_MAX_MEMSEG_LISTS build/install
> > build/install/include/rte_config.h:#ifndef RTE_MAX_MEMSEG_LISTS
> > build/install/include/rte_config.h:#define RTE_MAX_MEMSEG_LISTS 128
> > Binary file build/install/lib64/librte_eal.a matches
> > Binary file build/install/lib64/librte_eal.so.21.0 matches
> >
> > I can see the same using the meson option -Dc_args.
> >
>
> Good point, I had not thought of external apps using these values.
>
> They are mostly for internal use, so maybe its worthwhile looking to not
> have them in a public header file. What do you think? Is it likely that
> apps would be using some of these values, or needs to know the specifics?

Some are publicly exposed, like RTE_MEMPOOL_CACHE_MAX_SIZE,
RTE_PKTMBUF_HEADROOM, RTE_ETHDEV_RXTX_CALLBACKS,
For those, either we propagate the overriden value to the installed
rte_config.h or we refuse customisation.


-- 
David Marchand