On Wed, Sep 26, 2018 at 3:33 PM Stephen Hemminger < step...@networkplumber.org> wrote:
> On Wed, 26 Sep 2018 15:21:52 +0200 > Thomas Monjalon <tho...@monjalon.net> wrote: > > > Hi Alejandro, > > > > 25/09/2018 16:10, Alejandro Lucero: > > > I've a problem when part of device private data needs to be private per > > > process. > > > > It appears we are facing the same issue to support multi-process in tap. > > > > > Current multiprocess support shares device private data between > primary and > > > secondaries but it is all dependent on a pointer initialized to the > same > > > memory address by the multiprocess support code. If there is a > per-process > > > data, If a secondary process changes it the primary gets affected, and > the > > > same for additional secondaries which will affect not just the primary > but > > > other previous secondaries. > > > > Yes, the field rte_eth_dev.data.dev_private is private to the device, > > but shared between processes. > > > > > The solution is to add support for this inside struct rte_eth_dev, > > > something like > > > > > > void *secondary_priv_data; > > > > > > so it is up to the secondaries to use this field if necessary. > > > > I would say it is not only for secondary process. > > What about this name: > > > > rte_eth_dev.process_private > > > > > NFP PMD creates the required rte_eth_devs specifically, similar to > what is > > > done inside rte_ethdev.c but adding initialization for an interface > needed > > > when calling device ethdev_init function. There are other PMDs doing > this > > > but none has this requirement for per-process private data. > > > > Actually tap has a per-process requirement for its file descriptors. > > > > > Please, let me know what you think about this change to struct > rte_ethdev > > > or if you have a better idea for solving this problem. > > > > I support the idea, but we need to agree on name bikeshedding :-) > > Good idea, as long as it stays contained to DPDK. Don't want additional > user API > pointers buried in internal structures (like ethdev). If application > needs device > private data it should manage its own state. > > AFAIK the per-device data is not used by apps but only PMDs, and the new field should be the same.
