19/01/2018 16:27, Neil Horman: > On Fri, Jan 19, 2018 at 03:13:47PM +0100, Thomas Monjalon wrote: > > 19/01/2018 14:30, Neil Horman: > > > So it seems like the real point of contention that we need to settle here > > > is, > > > what codifies an 'owner'. Must it be a specific execution context, or > > > can we > > > define any arbitrary section of code as being an owner? I would agrue > > > against > > > the latter. > > > > This is the first thing explained in the cover letter: > > "2. The port usage synchronization will be managed by the port owner." > > There is no intent to manage the threads synchronization for a given port. > > It is the responsibility of the owner (a code object) to configure its > > port via only one thread. > > It is consistent with not trying to manage threads synchronization > > for Rx/Tx on a given queue. > > > > > Yes, in his cover letter, and I contend that notion is an invalid design > point. > By codifying an area of code as an 'owner', rather than an execution context, > you're defining the notion of heirarchy, not ownership. That is to say, > you want to codify the notion that there are top level ports that the > application might see, and some of those top level ports are parents to > subordinate ports, which only the parent port should access directly. If > thats > all you want to encode, there are far easier ways to do it: > > struct rte_eth_shared_data { > < existing bits > > struct rte_eth_port_list { > struct rte_eth_port_list *children; > struct rte_eth_port_list *parent; > }; > }; > > > Build an api around a structure like that, so that the parent/child > relationship > is globally clear, and this would be much easier, especially if you want to > continue asserting that the notion of synchronization/exclusion is an exercise > left to the application.
Not only Neil. An owner can be something else than a port. An owner can be an app process (multi-processes). An owner can be a library. The intent is really to solve the generic problem of which code is managing a port.