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

Ruifeng Wang Ruifeng.Wang at arm.com
Wed Apr 29 05:11:00 CEST 2020


> -----Original Message-----
> From: dev <dev-bounces at dpdk.org> On Behalf Of Lukasz Wojciechowski
> Sent: Tuesday, April 28, 2020 9:22 AM
> To: Harry van Haaren <harry.van.haaren at intel.com>; Jerin Jacob
> <jerin.jacob at caviumnetworks.com>
> Cc: dev at dpdk.org; l.wojciechow at partner.samsung.com; stable at dpdk.org
> Subject: [dpdk-dev] [PATCH] eal: fix lcore state bug
>
> 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.
>
> Bugzilla ID: 464
> Fixes: 21698354c832 ("service: introduce service cores concept")
> Fixes: f038a81e1c56 ("service: add unit tests")
> Cc: harry.van.haaren at intel.com
> Cc: stable at dpdk.org
>
> Signed-off-by: Lukasz Wojciechowski <l.wojciechow at partner.samsung.com>
> ---
>  app/test/test_service_cores.c        | 1 +
>  lib/librte_eal/common/rte_service.c  | 2 --
> lib/librte_eal/include/rte_service.h | 4 ++++
>  3 files changed, 5 insertions(+), 2 deletions(-)
>
> diff --git a/app/test/test_service_cores.c b/app/test/test_service_cores.c
> index a922c7ddc..2a4978e29 100644
> --- a/app/test/test_service_cores.c
> +++ b/app/test/test_service_cores.c
> @@ -114,6 +114,7 @@ unregister_all(void)
>  }
>
>  rte_service_lcore_reset_all();
> +rte_eal_mp_wait_lcore();
>
>  return TEST_SUCCESS;
>  }
> diff --git a/lib/librte_eal/common/rte_service.c
> b/lib/librte_eal/common/rte_service.c
> index 70d17a5d7..018876199 100644
> --- a/lib/librte_eal/common/rte_service.c
> +++ b/lib/librte_eal/common/rte_service.c
> @@ -458,8 +458,6 @@ rte_service_runner_func(void *arg)
>  rte_smp_rmb();
>  }
>
> -lcore_config[lcore].state = WAIT;
> -
>  return 0;
>  }
>
> diff --git a/lib/librte_eal/include/rte_service.h
> b/lib/librte_eal/include/rte_service.h
> index d8701dd4c..acdda8c54 100644
> --- a/lib/librte_eal/include/rte_service.h
> +++ b/lib/librte_eal/include/rte_service.h
> @@ -300,6 +300,10 @@ int32_t rte_service_lcore_count(void);
>   * from duty, just unmaps all services / cores, and stops() the service cores.
>   * The runstate of services is not modified.
>   *
> + * The cores that are stopped with this call, are in FINISHED state and
> + * the application must take care of bringing them back to a launchable state:
> + * e.g. call *rte_eal_lcore_wait* on the lcore_id.
> + *
>   * @retval 0 Success
>   */
>  int32_t rte_service_lcore_reset_all(void);
> --
> 2.17.1

Tested-by: Ruifeng Wang <ruifeng.wang at arm.com>

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