[PATCH] ethdev: add template table resize API

[Ferruh Yigit]

On 12/17/2023 9:32 AM, Gregory Etelson wrote:
> Template table creation API sets table flows capacity.
> If application needs more flows then the table was designed for,
> the following procedures must be completed:
> 1. Create a new template table with larger flows capacity.
> 2. Re-create existing flows in the new table and delete flows from
>    the original table.
> 3. Destroy original table.
> 
> Application cannot always execute that procedure:
> * Port may not have sufficient resources to allocate a new table
>   while maintaining original table.
> * Application may not have existing flows "recipes" to re-create
>   flows in a new table.
> 
> The patch defines a new API that allows application to resize
> existing template table:
> 
> * Resizable template table must be created with the
> RTE_FLOW_TABLE_SPECIALIZE_RESIZABLE_TABLE bit set.
> 
> * Application resizes existing table with the
>   `rte_flow_template_table_resize()` function call.
>   The table resize procedure updates the table maximal flow number
>   only. Other table attributes are not affected by the table resize.
>   ** The table resize procedure must not interrupt
>      existing table flows operations in hardware.
>   ** The table resize procedure must not alter flow handlers held by
>      application.
> 
> * After `rte_flow_template_table_resize()` returned, application must
>   update all existing table flow rules by calling
>   `rte_flow_async_update_resized()`.
>   The table resize procedure does not change application flow handler.
>   However, flow object can reference internal PMD resources that are
>   obsolete after table resize.
>   `rte_flow_async_update_resized()` moves internal flow references
>   to the updated table resources.
>   The flow update must not interrupt hardware flow operations.
> 
> * When all table flow were updated, application must call
>   `rte_flow_template_table_resize_complete()`.
>   The function releases PMD resources related to the original
>   table.
>   Application can start new table resize after
>   `rte_flow_template_table_resize_complete()` returned.
> 

Hi Gregory, Ori,

Why we need three separate APIs,
 rte_flow_template_table_resize
 rte_flow_async_update_resized
 rte_flow_template_table_resize_complete

Why not 'rte_flow_template_table_resize()' update existing flows and
release resources related to the original tables automatically?