On Thu, Sep 01, 2016 at 10:25:40AM +0300, Matan Barak wrote:

Well, if I recall, the reason doing so last time was in order to allow 
flexible updating of ib_core independently, which is obviously not a good 
reason (to say the least).

Since the new ABI will probably define new object types (all recent 
proposals go this way), the current approach could lead to either trying to 
map new objects to existing cgroup resource types, which could lead to some 
weird non 1:1 mapping, or having a split definitions - such that each 
driver will declare its objects both in the cgroups mechanism and in its 
driver dispatch table.
Even worse than that, drivers could simply ignore the cgroups support while 
implementing their own resource types and get a very broken containers 
support.

Sorry guys, but arbitrary extensibility for something not finished is the
worst idea ever.  We have two options here:

 a) delay cgroups support until the grand rewrite is done
 b) add it now and deal with the consequences later

That being said, adding random non-Verbs hardwasre to the RDMA core is
the second worst idea ever.  Guess I need to catch up with the
discussion and start using the flame thrower.