Re: [dpdk-dev] [PATCH v2] eal: fix lcore state bug

[David Marchand <david.marchand@redhat.com>]

On Wed, Jul 8, 2020 at 4:52 PM Van Haaren, Harry
<harry.van.haaren@intel.com> wrote:
> > The rte_service_lcore_reset_all function stops execution of services
> > on all lcores and switches them back from ROLE_SERVICE to ROLE_RTE.
> > However the thread loop for slave lcores (eal_thread_loop) distincts these
> > roles to set lcore state after processing delegated function.
> > It sets WAIT state for ROLE_SERVICE, but FINISHED for ROLE_RTE.
> > So changing the role to RTE before stopping work in slave lcores
> > causes lcores to end in FINISHED state. That is why the rte_eal_lcore_wait
> > must be run after rte_service_lcore_reset_all to bring back lcores to
> > launchable (WAIT) state.
> > This has been fixed in test app and clarified in API documentation.
> >
> > Setting the state to WAIT in rte_service_runner_func is premature
> > as the rte_service_runner_func function is still a part of the lcore
> > function delegated to slave lcore. The state is overwritten anyway in
> > slave lcore thread loop. This premature setting state to WAIT might
> > however cause rte_eal_lcore_wait, that was called by the application,
> > to return before slave lcore thread set the FINISHED state. That's
> > why it is removed from librte_eal rte_service_runner_func function.

Thanks for the explanation and fix.

> >
> > Bugzilla ID: 464
> > Fixes: 21698354c832 ("service: introduce service cores concept")
> > Fixes: f038a81e1c56 ("service: add unit tests")
> > Cc: stable@dpdk.org
> >

Reported-by: Sarosh Arif <sarosh.arif@emumba.com>
> > Signed-off-by: Lukasz Wojciechowski <l.wojciechow@partner.samsung.com>
> Acked-by: Harry van Haaren <harry.van.haaren@intel.com>

Applied, thanks Lukasz.


-- 
David Marchand