Re: [dpdk-dev] [PATCH 1/2] eal: add internal locks for timer lib into EAL

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

On Tue, Jun 25, 2019 at 6:12 PM Anatoly Burakov <anatoly.burakov@intel.com>
wrote:

> Currently, timer library has a memory leak because there is no
> way to concurrently initialize/deinitialize shared memory because
> of race conditions [1].
>
> Add a spinlock to the shared mem config to have a way to
> exclusively initialize/deinitialize the timer library without
> any races.
>
> [1] See the following email thread:
> https://mails.dpdk.org/archives/dev/2019-May/131498.html
>
> Signed-off-by: Anatoly Burakov <anatoly.burakov@intel.com>
> ---
>  lib/librte_eal/common/eal_common_mcfg.c        | 14 ++++++++++++++
>  lib/librte_eal/common/eal_memcfg.h             |  2 ++
>  .../common/include/rte_eal_memconfig.h         | 18 ++++++++++++++++++
>  lib/librte_eal/rte_eal_version.map             |  2 ++
>  4 files changed, 36 insertions(+)
>
> diff --git a/lib/librte_eal/common/eal_common_mcfg.c
> b/lib/librte_eal/common/eal_common_mcfg.c
> index 1825d9083..066549432 100644
> --- a/lib/librte_eal/common/eal_common_mcfg.c
> +++ b/lib/librte_eal/common/eal_common_mcfg.c
> @@ -147,3 +147,17 @@ rte_mcfg_mempool_write_unlock(void)
>         struct rte_mem_config *mcfg =
> rte_eal_get_configuration()->mem_config;
>         rte_rwlock_write_unlock(&mcfg->mplock);
>  }
> +
> +void
> +rte_mcfg_timer_lock(void)
> +{
> +       struct rte_mem_config *mcfg =
> rte_eal_get_configuration()->mem_config;
> +       rte_spinlock_lock(&mcfg->tlock);
> +}
> +
> +void
> +rte_mcfg_timer_unlock(void)
> +{
> +       struct rte_mem_config *mcfg =
> rte_eal_get_configuration()->mem_config;
> +       rte_spinlock_unlock(&mcfg->tlock);
> +}
> diff --git a/lib/librte_eal/common/eal_memcfg.h
> b/lib/librte_eal/common/eal_memcfg.h
> index e1aae32df..00370cece 100644
> --- a/lib/librte_eal/common/eal_memcfg.h
> +++ b/lib/librte_eal/common/eal_memcfg.h
> @@ -11,6 +11,7 @@
>  #include <rte_memory.h>
>  #include <rte_memzone.h>
>  #include <rte_pause.h>
> +#include <rte_spinlock.h>
>  #include <rte_rwlock.h>
>  #include <rte_tailq.h>
>
> @@ -38,6 +39,7 @@ struct rte_mem_config {
>         rte_rwlock_t mlock;   /**< only used by memzone LIB for
> thread-safe. */
>         rte_rwlock_t qlock;   /**< used for tailq operation for thread
> safe. */
>         rte_rwlock_t mplock;  /**< only used by mempool LIB for
> thread-safe. */
> +       rte_spinlock_t tlock; /**< needed for timer lib thread safety. */
>

>         rte_rwlock_t memory_hotplug_lock;
>         /**< indicates whether memory hotplug request is in progress. */
> diff --git a/lib/librte_eal/common/include/rte_eal_memconfig.h
> b/lib/librte_eal/common/include/rte_eal_memconfig.h
> index 1b615c892..05a32e12a 100644
> --- a/lib/librte_eal/common/include/rte_eal_memconfig.h
> +++ b/lib/librte_eal/common/include/rte_eal_memconfig.h
> @@ -109,6 +109,24 @@ rte_mcfg_mempool_write_lock(void);
>  void
>  rte_mcfg_mempool_write_unlock(void);
>
> +/**
> + * @warning
> + * @b EXPERIMENTAL: this API may change without prior notice
> + *
> + * Lock the internal EAL Timer Library lock for exclusive access.
> + */
> +void __rte_experimental
>

As mentionned by Erik,

rte_experimental
void

+rte_mcfg_timer_lock(void);
> +
> +/**
> + * @warning
> + * @b EXPERIMENTAL: this API may change without prior notice
> + *
> + * Unlock the internal EAL Timer Library lock for exclusive access.
> + */
> +void __rte_experimental
>

rte_experimental
void



> +rte_mcfg_timer_unlock(void);
> +
>  #ifdef __cplusplus
>  }
>  #endif
> diff --git a/lib/librte_eal/rte_eal_version.map
> b/lib/librte_eal/rte_eal_version.map
> index c28951f65..bc08fc4df 100644
> --- a/lib/librte_eal/rte_eal_version.map
> +++ b/lib/librte_eal/rte_eal_version.map
> @@ -367,6 +367,8 @@ EXPERIMENTAL {
>         rte_malloc_heap_memory_detach;
>         rte_malloc_heap_memory_remove;
>         rte_malloc_heap_socket_is_external;
> +       rte_mcfg_timer_lock;
> +       rte_mcfg_timer_unlock;
>         rte_mem_alloc_validator_register;
>         rte_mem_alloc_validator_unregister;
>         rte_mem_check_dma_mask;
> --
> 2.17.1
>

Can you put this at the end of the EXPERIMENTAL block under the 19.08
comment?


-- 
David Marchand