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

["Burakov, Anatoly" <anatoly.burakov@intel.com>]

On 04-Jul-19 10:09 AM, David Marchand wrote:
> 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?
> 

OK, will do both for v2.

-- 
Thanks,
Anatoly