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

[Lukasz Wojciechowski]

W dniu 08.07.2020 o 19:10, David Marchand pisze:
> On Wed, Jul 8, 2020 at 4:52 PM Van Haaren, Harry
> <harry.van.haaren at 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 at dpdk.org
>>>
> Reported-by: Sarosh Arif <sarosh.arif at emumba.com>
>>> Signed-off-by: Lukasz Wojciechowski <l.wojciechow at partner.samsung.com>
>> Acked-by: Harry van Haaren <harry.van.haaren at intel.com>
> Applied, thanks Lukasz.
>
Great, thank you

-- 
Lukasz Wojciechowski
Principal Software Engineer

Samsung R&D Institute Poland
Samsung Electronics
Office +48 22 377 88 25
l.wojciechow at partner.samsung.com