Re: [dpdk-dev] [PATCH v2 1/6] ethdev: add flow shared action API

["Kinsella, Ray" <mdr@ashroe.eu>]

On 08/07/2020 21:40, Andrey Vesnovaty wrote:
> From: Andrey Vesnovaty <andrey.vesnovaty@gmail.com>
> 
> This commit introduces extension of DPDK flow action API enabling
> sharing of single rte_flow_action in multiple flows. The API intended for
> PMDs where multiple HW offloaded flows can reuse the same HW
> essence/object representing flow action and modification of such an
> essence/object effects all the rules using it.
> 
> Motivation and example
> ===
> Adding or removing one or more queues to RSS used by multiple flow rules
> imposes per rule toll for current DPDK flow API; the scenario requires
> for each flow sharing cloned RSS action:
> - call `rte_flow_destroy()`
> - call `rte_flow_create()` with modified RSS action
> 
> API for sharing action and its in-place update benefits:
> - reduce the overhead of multiple RSS flow rules reconfiguration
> - optimize resource utilization by sharing action across of multiple
>   flows
> 
> Change description
> ===
> 
> Shared action
> ===
> In order to represent flow action shared by multiple flows new action
> type RTE_FLOW_ACTION_TYPE_SHARED is introduced (see `enum
> rte_flow_action_type`).
> Actually the introduced API decouples action from any specific flow and
> enables sharing of single action by its handle across multiple flows.
> 
> Shared action create/use/destroy
> ===
> Shared action may be reused by some or none flow rules at any given
> moment, i.e. shared action reside outside of the context of any flow.
> Shared action represent HW resources/objects used for action offloading
> implementation.
> API for shared action create (see `rte_flow_shared_action_create()`):
> - should allocate HW resources and make related initializations required
>   for shared action implementation.
> - make necessary preparations to maintain shared access to
>   the action resources, configuration and state.
> API for shared action destroy (see `rte_flow_shared_action_destroy()`)
> should release HW resources and make related cleanups required for shared
> action implementation.
> 
> In order to share some flow action reuse the handle of type
> `struct rte_flow_shared_action` returned by
> rte_flow_shared_action_create() as a `conf` field of
> `struct rte_flow_action` (see "example" section).
> 
> If some shared action not used by any flow rule all resources allocated
> by the shared action can be released by rte_flow_shared_action_destroy()
> (see "example" section). The shared action handle passed as argument to
> destroy API should not be used any further i.e. result of the usage is
> undefined.
> 
> Shared action re-configuration
> ===
> Shared action behavior defined by its configuration can be updated via
> rte_flow_shared_action_update() (see "example" section). The shared
> action update operation modifies HW related resources/objects allocated
> on the action creation. The number of operations performed by the update
> operation should not be dependent on number of flows sharing the related
> action. On return of shared action update API action behavior should be
> according to updated configuration for all flows sharing the action.
> 
> Shared action query
> ===
> Provide separate API to query shared action sate (see
> rte_flow_shared_action_update()). Taking a counter as an example: query
> returns value aggregating all counter increments across all flow rules
> sharing the counter.
> 
> PMD support
> ===
> The support of introduced API is pure PMD specific design and
> responsibility for each action type (see struct rte_flow_ops).
> 
> testpmd
> ===
> In order to utilize introduced API testpmd cli may implement following
> extension
> create/update/destroy/query shared action accordingly
> 
> flow shared_action create {port_id} [index] {action}
> flow shared_action update {port_id} {index} {action}
> flow shared_action destroy {port_id} {index}
> flow shared_action query {port_id} {index}
> 
> testpmd example
> ===
> 
> configure rss to queues 1 & 2
> 
> testpmd> flow shared_action create 0 100 rss 1 2
> 
> create flow rule utilizing shared action
> 
> testpmd> flow create 0 ingress \
>     pattern eth dst is 0c:42:a1:15:fd:ac / ipv6 / tcp / end \
>   actions shared 100 end / end
> 
> add 2 more queues
> 
> testpmd> flow shared_action modify 0 100 rss 1 2 3 4
> 
> example
> ===
> 
> struct rte_flow_action actions[2];
> struct rte_flow_action action;
> /* skipped: initialize action */
> struct rte_flow_shared_action *handle = rte_flow_shared_action_create(
> 					port_id, &action, &error);
> actions[0].type = RTE_FLOW_ACTION_TYPE_SHARED;
> actions[0].conf = handle;
> actions[1].type = RTE_FLOW_ACTION_TYPE_END;
> /* skipped: init attr0 & pattern0 args */
> struct rte_flow *flow0 = rte_flow_create(port_id, &attr0, pattern0,
> 					actions, error);
> /* create more rules reusing shared action */
> struct rte_flow *flow1 = rte_flow_create(port_id, &attr1, pattern1,
> 					actions, error);
> /* skipped: for flows 2 till N */
> struct rte_flow *flowN = rte_flow_create(port_id, &attrN, patternN,
> 					actions, error);
> /* update shared action */
> struct rte_flow_action updated_action;
> /*
>  * skipped: initialize updated_action according to desired action
>  * configuration change
>  */
> rte_flow_shared_action_update(port_id, handle, &updated_action, error);
> /*
>  * from now on all flows 1 till N will act according to configuration of
>  * updated_action
>  */
> /* skipped: destroy all flows 1 till N */
> rte_flow_shared_action_destroy(port_id, handle, error);
> 
> Signed-off-by: Andrey Vesnovaty <andreyv@mellanox.com>
> ---
>  lib/librte_ethdev/rte_ethdev_version.map |   6 +
>  lib/librte_ethdev/rte_flow.c             |  81 +++++++++++++
>  lib/librte_ethdev/rte_flow.h             | 148 ++++++++++++++++++++++-
>  lib/librte_ethdev/rte_flow_driver.h      |  22 ++++
>  4 files changed, 256 insertions(+), 1 deletion(-)
> 
> diff --git a/lib/librte_ethdev/rte_ethdev_version.map b/lib/librte_ethdev/rte_ethdev_version.map
> index 7155056045..119d84976a 100644
> --- a/lib/librte_ethdev/rte_ethdev_version.map
> +++ b/lib/librte_ethdev/rte_ethdev_version.map
> @@ -241,4 +241,10 @@ EXPERIMENTAL {
>  	__rte_ethdev_trace_rx_burst;
>  	__rte_ethdev_trace_tx_burst;
>  	rte_flow_get_aged_flows;
> +
> +	# added in 20.08
> +	rte_flow_shared_action_create;
> +	rte_flow_shared_action_destroy;
> +	rte_flow_shared_action_update;
> +	rte_flow_shared_action_query;
>  };
> diff --git a/lib/librte_ethdev/rte_flow.c b/lib/librte_ethdev/rte_flow.c
> index 1685be5f73..0ac4d31a13 100644
> --- a/lib/librte_ethdev/rte_flow.c
> +++ b/lib/librte_ethdev/rte_flow.c
> @@ -1250,3 +1250,84 @@ rte_flow_get_aged_flows(uint16_t port_id, void **contexts,
>  				  RTE_FLOW_ERROR_TYPE_UNSPECIFIED,
>  				  NULL, rte_strerror(ENOTSUP));
>  }
> +
> +struct rte_flow_shared_action *
> +rte_flow_shared_action_create(uint16_t port_id,
> +			      const struct rte_flow_action *action,
> +			      struct rte_flow_error *error)
> +{
> +	struct rte_eth_dev *dev = &rte_eth_devices[port_id];
> +	struct rte_flow_shared_action *shared_action;
> +	const struct rte_flow_ops *ops = rte_flow_ops_get(port_id, error);
> +
> +	if (unlikely(!ops))
> +		return NULL;
> +	if (likely(!!ops->shared_action_create)) {
> +		shared_action = ops->shared_action_create(dev, action, error);
> +		if (shared_action == NULL)
> +			flow_err(port_id, -rte_errno, error);
> +		return shared_action;
> +	}
> +	rte_flow_error_set(error, ENOSYS, RTE_FLOW_ERROR_TYPE_UNSPECIFIED,
> +			   NULL, rte_strerror(ENOSYS));
> +	return NULL;
> +}
> +
> +int
> +rte_flow_shared_action_destroy(uint16_t port_id,
> +			      struct rte_flow_shared_action *action,
> +			      struct rte_flow_error *error)
> +{
> +	struct rte_eth_dev *dev = &rte_eth_devices[port_id];
> +	const struct rte_flow_ops *ops = rte_flow_ops_get(port_id, error);
> +
> +	if (unlikely(!ops))
> +		return -rte_errno;
> +	if (likely(!!ops->shared_action_destroy))
> +		return flow_err(port_id,
> +				ops->shared_action_destroy(dev, action, error),
> +				error);
> +	return rte_flow_error_set(error, ENOSYS,
> +				  RTE_FLOW_ERROR_TYPE_UNSPECIFIED,
> +				  NULL, rte_strerror(ENOSYS));
> +}
> +
> +int
> +rte_flow_shared_action_update(uint16_t port_id,
> +			      struct rte_flow_shared_action *action,
> +			      const struct rte_flow_action *update,
> +			      struct rte_flow_error *error)
> +{
> +	struct rte_eth_dev *dev = &rte_eth_devices[port_id];
> +	const struct rte_flow_ops *ops = rte_flow_ops_get(port_id, error);
> +
> +	if (unlikely(!ops))
> +		return -rte_errno;
> +	if (likely(!!ops->shared_action_update))
> +		return flow_err(port_id, ops->shared_action_update(dev, action,
> +				update, error),
> +			error);
> +	return rte_flow_error_set(error, ENOSYS,
> +				  RTE_FLOW_ERROR_TYPE_UNSPECIFIED,
> +				  NULL, rte_strerror(ENOSYS));
> +}
> +
> +int
> +rte_flow_shared_action_query(uint16_t port_id,
> +			     const struct rte_flow_shared_action *action,
> +			     void *data,
> +			     struct rte_flow_error *error)
> +{
> +	struct rte_eth_dev *dev = &rte_eth_devices[port_id];
> +	const struct rte_flow_ops *ops = rte_flow_ops_get(port_id, error);
> +
> +	if (unlikely(!ops))
> +		return -rte_errno;
> +	if (likely(!!ops->shared_action_query))
> +		return flow_err(port_id, ops->shared_action_query(dev, action,
> +				data, error),
> +			error);
> +	return rte_flow_error_set(error, ENOSYS,
> +				  RTE_FLOW_ERROR_TYPE_UNSPECIFIED,
> +				  NULL, rte_strerror(ENOSYS));
> +}
> diff --git a/lib/librte_ethdev/rte_flow.h b/lib/librte_ethdev/rte_flow.h
> index b0e4199192..257456b14a 100644
> --- a/lib/librte_ethdev/rte_flow.h
> +++ b/lib/librte_ethdev/rte_flow.h
> @@ -1681,7 +1681,8 @@ enum rte_flow_action_type {
>  	/**
>  	 * Enables counters for this flow rule.
>  	 *
> -	 * These counters can be retrieved and reset through rte_flow_query(),
> +	 * These counters can be retrieved and reset through rte_flow_query() or
> +	 * rte_flow_shared_action_query() if the action provided via handle,
>  	 * see struct rte_flow_query_count.
>  	 *
>  	 * See struct rte_flow_action_count.
> @@ -2099,6 +2100,14 @@ enum rte_flow_action_type {
>  	 * see enum RTE_ETH_EVENT_FLOW_AGED
>  	 */
>  	RTE_FLOW_ACTION_TYPE_AGE,
> +
> +	/**
> +	 * Describes action shared a cross multiple flow rules.
> +	 *
> +	 * Enables multiple rules reference the same action by handle (see
> +	 * struct rte_flow_shared_action).
> +	 */
> +	RTE_FLOW_ACTION_TYPE_SHARED,
>  };
>  
>  /**
> @@ -2660,6 +2669,20 @@ struct rte_flow_action_set_dscp {
>  	uint8_t dscp;
>  };
>  
> +
> +/**
> + * RTE_FLOW_ACTION_TYPE_SHARED
> + *
> + * Opaque type returned after successfully creating a shared action.
> + *
> + * This handle can be used to manage and query the related action:
> + * - share it a cross multiple flow rules
> + * - update action configuration
> + * - query action data
> + * - destroy action
> + */
> +struct rte_flow_shared_action;
> +
>  /* Mbuf dynamic field offset for metadata. */
>  extern int32_t rte_flow_dynf_metadata_offs;
>  
> @@ -3324,6 +3347,129 @@ int
>  rte_flow_get_aged_flows(uint16_t port_id, void **contexts,
>  			uint32_t nb_contexts, struct rte_flow_error *error);
>  
> +/**
> + * @warning
> + * @b EXPERIMENTAL: this API may change without prior notice.
> + *
> + * Create shared action for reuse in multiple flow rules.
> + *
> + * @param[in] port_id
> + *    The port identifier of the Ethernet device.
> + * @param[in] action
> + *   Action configuration for shared action creation.
> + * @param[out] error
> + *   Perform verbose error reporting if not NULL. PMDs initialize this
> + *   structure in case of error only.
> + * @return
> + *   A valid handle in case of success, NULL otherwise and rte_errno is set
> + *   to one of the error codes defined:
> + *   - (ENOSYS) if underlying device does not support this functionality.
> + *   - (EIO) if underlying device is removed.
> + *   - (EINVAL) if *action* invalid.
> + *   - (ENOTSUP) if *action* valid but unsupported.
> + */
> +__rte_experimental
> +struct rte_flow_shared_action *
> +rte_flow_shared_action_create(uint16_t port_id,
> +			      const struct rte_flow_action *action,
> +			      struct rte_flow_error *error);
> +
> +/**
> + * @warning
> + * @b EXPERIMENTAL: this API may change without prior notice.
> + *
> + * Destroys the shared action by handle.
> + *
> + * @param[in] port_id
> + *    The port identifier of the Ethernet device.
> + * @param[in] action
> + *   Handle for the shared action to be destroyed.
> + * @param[out] error
> + *   Perform verbose error reporting if not NULL. PMDs initialize this
> + *   structure in case of error only.
> + * @return
> + *   - (0) if success.
> + *   - (-ENOSYS) if underlying device does not support this functionality.
> + *   - (-EIO) if underlying device is removed.
> + *   - (-ENOENT) if action pointed by *action* handle was not found.
> + *   - (-ETOOMANYREFS) if action pointed by *action* handle still used by one or
> + *     more rules
> + *   rte_errno is also set.
> + */
> +__rte_experimental
> +int
> +rte_flow_shared_action_destroy(uint16_t port_id,
> +			      struct rte_flow_shared_action *action,
> +			      struct rte_flow_error *error);
> +
> +/**
> + * @warning
> + * @b EXPERIMENTAL: this API may change without prior notice.
> + *
> + * Updates inplace the shared action configuration pointed by *action* handle
> + * with the configuration provided as *update* argument.
> + * The update of the shared action configuration effects all flow rules reusing
> + * the action via handle.
> + *
> + * @param[in] port_id
> + *    The port identifier of the Ethernet device.
> + * @param[in] action
> + *   Handle for the shared action to be updated.
> + * @param[in] update
> + *   Action specification used to modify the action pointed by handle.
> + *   *update* should be of same type with the action pointed by the *action*
> + *   handle argument, otherwise considered as invalid.
> + * @param[out] error
> + *   Perform verbose error reporting if not NULL. PMDs initialize this
> + *   structure in case of error only.
> + * @return
> + *   - (0) if success.
> + *   - (-ENOSYS) if underlying device does not support this functionality.
> + *   - (-EIO) if underlying device is removed.
> + *   - (-EINVAL) if *update* invalid.
> + *   - (-ENOTSUP) if *update* valid but unsupported.
> + *   - (-ENOENT) if action pointed by *ctx* was not found.
> + *   rte_errno is also set.
> + */
> +__rte_experimental
> +int
> +rte_flow_shared_action_update(uint16_t port_id,
> +			      struct rte_flow_shared_action *action,
> +			      const struct rte_flow_action *update,
> +			      struct rte_flow_error *error);
> +
> +/**
> + * @warning
> + * @b EXPERIMENTAL: this API may change without prior notice.
> + *
> + * Query the shared action by handle.
> + *
> + * This function allows retrieving action-specific data such as counters.
> + * Data is gathered by special action which may be present/referenced in
> + * more than one flow rule definition.
> + *
> + * \see RTE_FLOW_ACTION_TYPE_COUNT
> + *
> + * @param port_id
> + *   Port identifier of Ethernet device.
> + * @param[in] action
> + *   Handle for the shared action to query.
> + * @param[in, out] data
> + *   Pointer to storage for the associated query data type.
> + * @param[out] error
> + *   Perform verbose error reporting if not NULL. PMDs initialize this
> + *   structure in case of error only.
> + *
> + * @return
> + *   0 on success, a negative errno value otherwise and rte_errno is set.
> + */
> +__rte_experimental
> +int
> +rte_flow_shared_action_query(uint16_t port_id,
> +			     const struct rte_flow_shared_action *action,
> +			     void *data,
> +			     struct rte_flow_error *error);
> +
>  #ifdef __cplusplus
>  }
>  #endif
> diff --git a/lib/librte_ethdev/rte_flow_driver.h b/lib/librte_ethdev/rte_flow_driver.h
> index 881cc469b7..a2cae1b53c 100644
> --- a/lib/librte_ethdev/rte_flow_driver.h
> +++ b/lib/librte_ethdev/rte_flow_driver.h
> @@ -107,6 +107,28 @@ struct rte_flow_ops {
>  		 void **context,
>  		 uint32_t nb_contexts,
>  		 struct rte_flow_error *err);
> +	/** See rte_flow_shared_action_create() */
> +	struct rte_flow_shared_action *(*shared_action_create)
> +		(struct rte_eth_dev *dev,
> +		const struct rte_flow_action *action,
> +		struct rte_flow_error *error);
> +	/** See rte_flow_shared_action_destroy() */
> +	int (*shared_action_destroy)
> +		(struct rte_eth_dev *dev,
> +		 struct rte_flow_shared_action *shared_action,
> +		 struct rte_flow_error *error);
> +	/** See rte_flow_shared_action_update() */
> +	int (*shared_action_update)
> +		(struct rte_eth_dev *dev,
> +		 struct rte_flow_shared_action *shared_action,
> +		 const struct rte_flow_action *update,
> +		 struct rte_flow_error *error);
> +	/** See rte_flow_shared_action_query() */
> +	int (*shared_action_query)
> +		(struct rte_eth_dev *dev,
> +		 const struct rte_flow_shared_action *shared_action,
> +		 void *data,
> +		 struct rte_flow_error *error);
>  };
>  
>  /**
> 

The modification of "struct rte_flow_ops", looks fine. 

Acked-by: Ray Kinsella <mdr@ashroe.eu>