On Sun, 5 Dec 2021 12:33:57 +0530 Jerin Jacob <jerinjac...@gmail.com> wrote:
> On Sat, Dec 4, 2021 at 11:08 PM Stephen Hemminger > <step...@networkplumber.org> wrote: > > > > On Sat, 4 Dec 2021 22:54:58 +0530 > > <jer...@marvell.com> wrote: > > > > > + /** > > > + * Maximum supported traffic class as per PFC (802.1Qbb) > > > specification. > > > + * > > > + * Based on device support and use-case need, there are two > > > different > > > + * ways to enable PFC. The first case is the port level PFC > > > + * configuration, in this case, rte_eth_dev_priority_flow_ctrl_set() > > > + * API shall be used to configure the PFC, and PFC frames will be > > > + * generated using based on VLAN TC value. > > > + * The second case is the queue level PFC configuration, in this > > > case, > > > + * Any packet field content can be used to steer the packet to the > > > + * specific queue using rte_flow or RSS and then use > > > + * rte_eth_dev_priority_flow_ctrl_queue_set() to set the TC mapping > > > + * on each queue. Based on congestion selected on the specific > > > queue, > > > + * configured TC shall be used to generate PFC frames. > > > + * > > > + * When set to non zero value, application must use queue level > > > + * PFC configuration via rte_eth_dev_priority_flow_ctrl_queue_set() > > > API > > > + * instead of port level PFC configuration via > > > + * rte_eth_dev_priority_flow_ctrl_set() API to realize > > > + * PFC configuration. > > > + */ > > > + uint8_t pfc_queue_tc_max; > > > + uint8_t reserved_8s[7]; > > > + uint64_t reserved_64s[1]; /**< Reserved for future fields */ > > > void *reserved_ptrs[2]; /**< Reserved for future fields */ > > > > Not sure you can claim ABI compatibility because the previous versions of > > DPDK > > did not enforce that reserved fields must be zero. The Linux kernel > > learned this when adding flags for new system calls; reserved fields only > > work if you enforce that application must set them to zero. > > In this case it rte_eth_dev_info is an out parameter and implementation of > rte_eth_dev_info_get() already memseting to 0. > Do you still see any other ABI issue? > > See rte_eth_dev_info_get() > /* > * Init dev_info before port_id check since caller does not have > * return status and does not know if get is successful or not. > */ > memset(dev_info, 0, sizeof(struct rte_eth_dev_info)); The concern was from the misreading comment. It talks about what application should do. Could you reword the comment so that it describes what pfc_queue_tc_max is here and move the flow control set part of the comment to where the API for that is.
