27/09/2018 12:40, Hideyuki Yamashita: > Dear Thomas, > > Thansk for your answer. > Please see inline. > > > 27/09/2018 03:38, Hideyuki Yamashita: > > > Dear Thomas, > > > > > > Thanks for your answer. > > > It took me a little time to digest answer. > > > Please see inline. > > > > > > > > > > 21/09/2018 09:19, Hideyuki Yamashita: > > > > > Dear Gaetan and Thomas, > > > > > > > > > > Thanks for your answer. > > > > > Please see inline. > > > > > > > > > > > 20/09/2018 11:09, Ga?an Rivet: > > > > > > > On Thu, Sep 20, 2018 at 05:46:37PM +0900, Hideyuki Yamashita > > > > > > > wrote: > > > > > > > > Hello, > > > > > > > > > > > > > > > > From dpdk 18.08 release rte_eth_dev_attach and > > > > > > > > rte_eth_dev_detach becom deprecated API and > > > > > > > > it is recommended to replace with rte_eal_hotplug_add > > > > > > > > and rte_eal_hotplug_remove. > > > > > > > > > > > > > > > > My program uses above mentioned deprecated APIs > > > > > > > > and have to replace those. > > > > > > > > Note that my program uses attach to attach vhost, pcap pmd. > > > > > > > > > > > > > > > > My question is whether it is correct to replace those as > > > > > > > > following: > > > > > > > > find rte_eth_dev_attach function in rte_ethdev.c and > > > > > > > > migrate those content into my program. > > > > > > > > > > > > > > > > e.g. > > > > > > > > lib/librte_ethdev/rte_ethdev.c line 643-686 for attach > > > > > > > > lib/librte_ethdev/rte_ethdev.c line 690-720 for detach > > > > > > > > > > > > > > > > Your advice/guidance are much appreciated. > > > > > > > > Thanks! > > > > > > > > > > > > > > Hello Hideyuki, > > > > > > > > > > > > > > You could use this code for guidance, while leaving the ethdev > > > > > > > specificities such as verifying the eth_dev_count_total(). The > > > > > > > hotplug > > > > > > > function would already return an error if the PMD was not able to > > > > > > > create > > > > > > > the necessary devices. > > > > > > > > > > > > > > The main issue might be to find the port_id of your new port. > > > > > > > You won't be able to use eth_dev_last_created_port, so you would > > > > > > > have to > > > > > > > iterate over the ethdev using RTE_ETH_FOREACH_DEV and find the one > > > > > > > matching your parameters (you might for example match the > > > > > > > rte_device > > > > > > > name with the name you used in hotplug_add, as there is no > > > > > > > standard > > > > > > > naming scheme at the ethdev level). > > > > > First of all, thank for your answering to my question. > > > > > But I have questions. > > > > > (Sorry, I have poor knowledge about dpdk and have many basic > > > > > questions) > > > > > > > > > > Q1. > > > > > Why eth_dev_last_created_port can not be used? > > > > > When I look into rte_eth_dev_atthach in 18.08, it calls > > > > > > > > > > *port_id = eth_dev_last_created_port; > > > > > > > > > > at the end of the function. > > > > > > > > You can have a race condition. > > > Please elaborate me a bit more. > > > > > > Is it correct understanding that race condition > > > includes > > > - read information before port is available > > > - other device may be plugged (or unplugged) > > > and so using "eth_dev_last_created_port" is > > > NOT reliable? > > > > I am thinking about the second one only. > > If we assume there is only one DPDK application > inside the host and within the application, only one thread > handles attach/detach of devices, then is it ok to use > > > > > *port_id = eth_dev_last_created_port; > because there seems no possiblity race condition > takes place?
If you are never probing a new port outside of this thread, I guess it's OK. Take care of not attaching from the interrupt thread too!
