[dpdk-dev] [PATCH v5 2/2] ethdev: make rte_flow API thread safe

[Andrew Rybchenko]

On 10/15/20 11:28 AM, Thomas Monjalon wrote:
> 15/10/2020 03:07, Suanming Mou:
>> Currently, the rte_flow functions are not defined as thread safe.
>> DPDK applications either call the functions in single thread or
>> protect any concurrent calling for the rte_flow operations using
>> a lock.
>>
>> For PMDs support the flow operations thread safe natively, the
>> redundant protection in application hurts the performance of the
>> rte_flow operation functions.
>>
>> And the restriction of thread safe is not guaranteed for the
>> rte_flow functions also limits the applications' expectation.
>>
>> This feature is going to change the rte_flow functions to be thread
>> safe. As different PMDs have different flow operations, some may
>> support thread safe already and others may not. For PMDs don't
>> support flow thread safe operation, a new lock is defined in ethdev
>> in order to protects thread unsafe PMDs from rte_flow level.
>>
>> A new RTE_ETH_DEV_FLOW_OPS_THREAD_SAFE device flag is added to
>> determine whether the PMD supports thread safe flow operation or not.
>> For PMDs support thread safe flow operations, set the
>> RTE_ETH_DEV_FLOW_OPS_THREAD_SAFE flag, rte_flow level functions will
>> skip the thread safe helper lock for these PMDs. Again the rte_flow
>> level thread safe lock only works when PMD operation functions are
>> not thread safe.
>>
>> For the PMDs which don't want the default mutex lock, just set the
>> flag in the PMD, and add the prefer type of lock in the PMD. Then
>> the default mutex lock is easily replaced by the PMD level lock.
>>
>> The change has no effect on the current DPDK applications. No change
>> is required for the current DPDK applications. For the standard posix
>> pthread_mutex, if no lock contention with the added rte_flow level
>> mutex, the mutex only does the atomic increasing in
>> pthread_mutex_lock() and decreasing in
>> pthread_mutex_unlock(). No futex() syscall will be involved.
>>
>> Signed-off-by: Suanming Mou <suanmingm at nvidia.com>
>> Acked-by: Ajit Khaparde <ajit.khaparde at broadcom.com>
>> Acked-by: Ori Kam <orika at nvidia.com>
>> Acked-by: Matan Azrad <matan at nvidia.com>
> Acked-by: Thomas Monjalon <thomas at monjalon.net>

Acked-by: Andrew Rybchenko <andrew.rybchenko at oktetlabs.ru>