| 1bb4a528 | 18-Oct-2021 |
Ferruh Yigit <[email protected]> |
ethdev: fix max Rx packet length
There is a confusion on setting max Rx packet length, this patch aims to
clarify it.
'rte_eth_dev_configure()' API accepts max Rx packet size via
'uint32_t max_rx_p
ethdev: fix max Rx packet length
There is a confusion on setting max Rx packet length, this patch aims to
clarify it.
'rte_eth_dev_configure()' API accepts max Rx packet size via
'uint32_t max_rx_pkt_len' field of the config struct 'struct
rte_eth_conf'.
Also 'rte_eth_dev_set_mtu()' API can be used to set the MTU, and result
stored into '(struct rte_eth_dev)->data->mtu'.
These two APIs are related but they work in a disconnected way, they
store the set values in different variables which makes hard to figure
out which one to use, also having two different method for a related
functionality is confusing for the users.
Other issues causing confusion is:
* maximum transmission unit (MTU) is payload of the Ethernet frame. And
'max_rx_pkt_len' is the size of the Ethernet frame. Difference is
Ethernet frame overhead, and this overhead may be different from
device to device based on what device supports, like VLAN and QinQ.
* 'max_rx_pkt_len' is only valid when application requested jumbo frame,
which adds additional confusion and some APIs and PMDs already
discards this documented behavior.
* For the jumbo frame enabled case, 'max_rx_pkt_len' is an mandatory
field, this adds configuration complexity for application.
As solution, both APIs gets MTU as parameter, and both saves the result
in same variable '(struct rte_eth_dev)->data->mtu'. For this
'max_rx_pkt_len' updated as 'mtu', and it is always valid independent
from jumbo frame.
For 'rte_eth_dev_configure()', 'dev->data->dev_conf.rxmode.mtu' is user
request and it should be used only within configure function and result
should be stored to '(struct rte_eth_dev)->data->mtu'. After that point
both application and PMD uses MTU from this variable.
When application doesn't provide an MTU during 'rte_eth_dev_configure()'
default 'RTE_ETHER_MTU' value is used.
Additional clarification done on scattered Rx configuration, in
relation to MTU and Rx buffer size.
MTU is used to configure the device for physical Rx/Tx size limitation,
Rx buffer is where to store Rx packets, many PMDs use mbuf data buffer
size as Rx buffer size.
PMDs compare MTU against Rx buffer size to decide enabling scattered Rx
or not. If scattered Rx is not supported by device, MTU bigger than Rx
buffer size should fail.
Signed-off-by: Ferruh Yigit <[email protected]>
Acked-by: Ajit Khaparde <[email protected]>
Acked-by: Somnath Kotur <[email protected]>
Acked-by: Huisong Li <[email protected]>
Acked-by: Andrew Rybchenko <[email protected]>
Acked-by: Konstantin Ananyev <[email protected]>
Acked-by: Rosen Xu <[email protected]>
Acked-by: Hyong Youb Kim <[email protected]>
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|
| fbd19135 | 28-Sep-2020 |
Thomas Monjalon <[email protected]> |
ethdev: remove old close behaviour
The temporary flag RTE_ETH_DEV_CLOSE_REMOVE is removed.
It was introduced in DPDK 18.11 in order to give time for PMDs to migrate.
The old behaviour was to free o
ethdev: remove old close behaviour
The temporary flag RTE_ETH_DEV_CLOSE_REMOVE is removed.
It was introduced in DPDK 18.11 in order to give time for PMDs to migrate.
The old behaviour was to free only queues when closing a port.
The new behaviour is calling rte_eth_dev_release_port() which does
three more tasks:
- trigger event callback
- reset state and few pointers
- free all generic port resources
The private port resources must be released in the .dev_close callback.
The .remove callback should:
- call .dev_close callback
- call rte_eth_dev_release_port()
- free multi-port device shared resources
Despite waiting two years, some drivers have not migrated,
so they may hit issues with the incompatible new behaviour.
After sending emails, adding logs, and announcing the deprecation,
the only last solution is to declare these drivers as unmaintained:
ionic, liquidio, nfp
Below is a summary of what to implement in those drivers.
* The freeing of private port resources must be moved
from the ".remove(device)" function to the ".dev_close(port)" function.
* If a generic resource (.mac_addrs or .hash_mac_addrs) cannot be freed,
it must be set to NULL in ".dev_close" function to protect from
subsequent rte_eth_dev_release_port() freeing.
* Note 1:
The generic resources are freed in rte_eth_dev_release_port(),
after ".dev_close" is called in rte_eth_dev_close(), but not when
calling ".dev_close" directly from the ".remove" PMD function.
That's why rte_eth_dev_release_port() must still be called explicitly
from ".remove(device)" after calling the ".dev_close" PMD function.
* Note 2:
If a device can have multiple ports, the common resources must be freed
only in the ".remove(device)" function.
* Note 3:
The port is supposed to be in a stopped state when it is closed.
If it is not the case, it is free to the PMD implementation
how to react when trying to close a non-stopped port:
either try to stop it automatically or just return an error.
Signed-off-by: Thomas Monjalon <[email protected]>
Reviewed-by: Liron Himi <[email protected]>
Reviewed-by: Haiyue Wang <[email protected]>
Acked-by: Jeff Guo <[email protected]>
Acked-by: Andrew Rybchenko <[email protected]>
Reviewed-by: Ferruh Yigit <[email protected]>
Acked-by: Stephen Hemminger <[email protected]>
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