Re: [PATCH v2] drivers/bus: set device NUMA node to unknown by default

[David Marchand <david.marchand@redhat.com>]

On Tue, Oct 4, 2022 at 4:59 PM Olivier Matz <olivier.matz@6wind.com> wrote:
>
> The dev->device.numa_node field is set by each bus driver for
> every device it manages to indicate on which NUMA node this device lies.
>
> When this information is unknown, the assigned value is not consistent
> across the bus drivers.
>
> Set the default value to SOCKET_ID_ANY (-1) by all bus drivers
> when the NUMA information is unavailable. This change impacts
> rte_eth_dev_socket_id() in the same manner.
>
> Signed-off-by: Olivier Matz <olivier.matz@6wind.com>
> ---
>
> v2
> * use SOCKET_ID_ANY instead of -1 in drivers/dma/idxd (David)
> * document the behavior change of rte_eth_dev_socket_id()
> * fix few examples where rte_eth_dev_socket_id() was expected to
>   return 0 on unknown socket

Cc: ethdev maintainers.

[snip]

> diff --git a/doc/guides/rel_notes/release_22_11.rst b/doc/guides/rel_notes/release_22_11.rst
> index 53fe21453c..d52f823694 100644
> --- a/doc/guides/rel_notes/release_22_11.rst
> +++ b/doc/guides/rel_notes/release_22_11.rst
> @@ -317,6 +317,12 @@ ABI Changes
>  * eventdev: Added ``weight`` and ``affinity`` fields
>    to ``rte_event_queue_conf`` structure.
>
> +* bus: Changed the device numa node to -1 when NUMA information is unavailable.
> +  The ``dev->device.numa_node`` field is set by each bus driver for
> +  every device it manages to indicate on which NUMA node this device lies.
> +  When this information is unknown, the assigned value was not consistent
> +  across the bus drivers. This similarly impacts ``rte_eth_dev_socket_id()``.
> +
>
>  Known Issues
>  ------------

[snip]

> diff --git a/lib/ethdev/rte_ethdev.h b/lib/ethdev/rte_ethdev.h
> index a21f58b9cd..dd8d25d6d4 100644
> --- a/lib/ethdev/rte_ethdev.h
> +++ b/lib/ethdev/rte_ethdev.h
> @@ -2445,8 +2445,8 @@ int rte_eth_hairpin_unbind(uint16_t tx_port, uint16_t rx_port);
>   *   The port identifier of the Ethernet device
>   * @return
>   *   The NUMA socket ID to which the Ethernet device is connected or
> - *   a default of zero if the socket could not be determined.
> - *   -1 is returned is the port_id value is out of range.
> + *   a default of -1 (SOCKET_ID_ANY) if the socket could not be determined.
> + *   -1 is also returned if the port_id is invalid.
>   */
>  int rte_eth_dev_socket_id(uint16_t port_id);

It would be better to distinguish the two cases, using rte_errno.
Something like:

diff --git a/lib/ethdev/rte_ethdev.c b/lib/ethdev/rte_ethdev.c
index 2821770e2d..1baf302804 100644
--- a/lib/ethdev/rte_ethdev.c
+++ b/lib/ethdev/rte_ethdev.c
@@ -562,8 +562,16 @@ rte_eth_dev_owner_get(const uint16_t port_id,
struct rte_eth_dev_owner *owner)
 int
 rte_eth_dev_socket_id(uint16_t port_id)
 {
-       RTE_ETH_VALID_PORTID_OR_ERR_RET(port_id, -1);
-       return rte_eth_devices[port_id].data->numa_node;
+       int socket_id = SOCKET_ID_ANY;
+
+       if (!rte_eth_dev_is_valid_port(port_id))
+               rte_errno = EINVAL;
+       } else {
+               socket_id = rte_eth_devices[port_id].data->numa_node;
+               if (socket_id == SOCKET_ID_ANY)
+                       rte_errno = 0;
+       }
+       return socket_id;
 }

 void *
diff --git a/lib/ethdev/rte_ethdev.h b/lib/ethdev/rte_ethdev.h
index dd8d25d6d4..03456b2dbb 100644
--- a/lib/ethdev/rte_ethdev.h
+++ b/lib/ethdev/rte_ethdev.h
@@ -2444,9 +2444,11 @@ int rte_eth_hairpin_unbind(uint16_t tx_port,
uint16_t rx_port);
  * @param port_id
  *   The port identifier of the Ethernet device
  * @return
- *   The NUMA socket ID to which the Ethernet device is connected or
- *   a default of -1 (SOCKET_ID_ANY) if the socket could not be determined.
- *   -1 is also returned if the port_id is invalid.
+ *   - The NUMA socket ID which the Ethernet device is connected to.
+ *   - -1 (which translates to SOCKET_ID_ANY) if the socket could not be
+ *     determined. rte_errno is then set to:
+ *     - EINVAL is the port_id is invalid,
+ *     - 0 is the socket could not be determined,
  */
 int rte_eth_dev_socket_id(uint16_t port_id);

WDYT?


-- 
David Marchand