[v5,0/2] ethdev: make rte_flow API thread safe

  Currently, the rte_flow functions are not defined as thread safe.
DPDK applications either call the functions in single thread or add
locks around the functions for the critical section.

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 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.


Suanming Mou (2):
  eal/windows: add pthread mutex lock
  ethdev: make rte_flow API thread safe

---

v5:
 - Update ethdev patch commnets, doc and release notes.
 - Update fts_mutex -> flow_ops_mutex.
 - Remove PTHREAD_MUTEX_INITIALIZER for windows added in v4.

v4:
 - Add PTHREAD_MUTEX_INITIALIZER for windows pthread mutex.
 - Change RTE_ETH_DEV_FLOW_OPS_THREAD_SAFE to 0x0001, since
   RTE_ETH_DEV_CLOSE_REMOVE has been removed.
 - Update small comments.
 - Update release notes.

v3:
 - Update flow_lock/unlock -> fts_enter/exit.

v2:
 - Using critical section for windows pthread mutex.
 - Update ethdev commnets.

---

 doc/guides/prog_guide/rte_flow.rst       | 12 +++--
 doc/guides/rel_notes/release_20_11.rst   |  6 +++
 lib/librte_eal/windows/include/pthread.h | 33 +++++++++++++
 lib/librte_ethdev/rte_ethdev.c           |  2 +
 lib/librte_ethdev/rte_ethdev.h           |  2 +
 lib/librte_ethdev/rte_ethdev_core.h      |  4 ++
 lib/librte_ethdev/rte_flow.c             | 84 ++++++++++++++++++++++++--------
 7 files changed, 120 insertions(+), 23 deletions(-)
  

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 add
> locks around the functions for the critical section.
> 
> 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 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.
> 
> 
> Suanming Mou (2):
>   eal/windows: add pthread mutex lock
>   ethdev: make rte_flow API thread safe

Applied, thanks