Re: [dpdk-dev] [PATCH] add flow shared action API

[Jerin Jacob <jerinjacobk@gmail.com>]

On Fri, Jul 3, 2020 at 8:07 PM Andrey Vesnovaty <andreyv@mellanox.com> 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 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 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 for multiple flows.
>
> Shared action create/use/destroy
> ===
> Shared action may be reused by some or none flow rules at any given
> moment, IOW shared action reside outside of the context of any flow.
> Shared action represent HW resources/objects used for action offloading
> implementation. For allocation/release of all HW resources and all
> related initializations/cleanups in PMD space required for shared action
> implementation added new API
> rte_flow_shared_action_create()/rte_flow_shared_action_destroy().
> In addition to the above all preparations needed to maintain shared
> access to the action resources, configuration and state should be done in
> rte_flow_shared_action_create().
>
> 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 i.e. result of the usage is undefined.
>
> Shared action re-configuration
> ===
> Shared action behavior defined by its configuration & and can be updated
> via rte_flow_shared_action_update() (see "example" section). The shared
> action update operation modifies HW related resources/objects allocated
> by the action. 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 updated 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.conf,
>                                 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>
> Signed-off-by: Andrey Vesnovaty <andrey.vesnovaty@gmail.com>
> Signed-off-by: Andrey Vesnovaty <andreyv@mellanox.com>

Duplicate Signoffs.

# Request to CC all the people who are already giving comments to this patch.
# The Following comment is not addressed in this patch.
http://mails.dpdk.org/archives/dev/2020-July/172408.html


> ---
> This patch based on RFC: https://patches.dpdk.org/patch/71820/
>
> ---
>  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 3f32fdecf..e291c2bd9 100644
> --- a/lib/librte_ethdev/rte_ethdev_version.map
> +++ b/lib/librte_ethdev/rte_ethdev_version.map
> @@ -230,4 +230,10 @@ EXPERIMENTAL {
>
>         # added in 20.02
>         rte_flow_dev_dump;
> +
> +       # added in 20.08
> +       rte_flow_shared_action_create;
> +       rte_flow_shared_action_destoy;
> +       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 885a7ff9a..7728057c3 100644
> --- a/lib/librte_ethdev/rte_flow.c
> +++ b/lib/librte_ethdev/rte_flow.c
> @@ -1231,3 +1231,84 @@ rte_flow_dev_dump(uint16_t port_id, FILE *file, struct rte_flow_error *error)
>                                   RTE_FLOW_ERROR_TYPE_UNSPECIFIED,
>                                   NULL, rte_strerror(ENOSYS));
>  }
> +
> +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_destoy(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 void *action_conf,
> +                             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,
> +                               action_conf, 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 5625dc491..98140ebb1 100644
> --- a/lib/librte_ethdev/rte_flow.h
> +++ b/lib/librte_ethdev/rte_flow.h
> @@ -1643,7 +1643,8 @@ 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.
> @@ -2051,6 +2052,14 @@ enum rte_flow_action_type {
>          * See struct rte_flow_action_set_dscp.
>          */
>         RTE_FLOW_ACTION_TYPE_SET_IPV6_DSCP,
> +
> +       /**
> +        * 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,
>  };
>
>  /**
> @@ -2593,6 +2602,20 @@ 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 int rte_flow_dynf_metadata_offs;
>
> @@ -3224,6 +3247,129 @@ rte_flow_conv(enum rte_flow_conv_op op,
>               const void *src,
>               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_destoy(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 *action_conf* 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] action_conf
> + *   Action specification used to modify the action pointed by handle.
> + *   action_conf should be of same type with the action pointed by the *action*
> + *   handle argument, otherwise function behavior undefined.
> + * @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 *action_conf* invalid.
> + *   - (-ENOTSUP) if *action_conf* 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 void *action_conf,
> +                             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 51a9a57a0..c103d159e 100644
> --- a/lib/librte_ethdev/rte_flow_driver.h
> +++ b/lib/librte_ethdev/rte_flow_driver.h
> @@ -101,6 +101,28 @@ struct rte_flow_ops {
>                 (struct rte_eth_dev *dev,
>                  FILE *file,
>                  struct rte_flow_error *error);
> +       /** 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 void *action_conf,
> +               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);
>  };
>
>  /**
> --
> 2.26.2
>