On Thu, May 20, 2021 at 06:02:09PM -0400, Dennis Dalessandro wrote: > > I don't want to encourage other drivers to do the same thing. > > I would imagine they would get the same push back we are getting here. I > don't think this would encourage anyone honestly. Then we are back to making infrastructure that is only useful for one, arguably wrong, driver. > > The correct thing to do today in 2021 is to use the standard NUMA > > memory policy on already node-affine threads. The memory policy goes > > into the kernel and normal non-_node allocations will obey it. When > > combined with an appropriate node-affine HCA this will work as you are > > expecting right now. > > So we shouldn't see any issue in the normal case is what you are > saying. I'd like to believe that, proving it is not easy though. Well, I said you have to setup the userspace properly, I'm not sure it just works out of the box. > > However you can't do anything like that while the kernel has the _node > > annotations, that overrides the NUMA memory policy and breaks the > > policy system! > > Does our driver doing this break the entire system? I'm not sure how that's > possible. It breaks your driver part of it, and if we lift it to the core code then it breaks all drivers, so it is a hard no-go. > Is there an effort to get rid of these per node allocations so > ultimately we won't have a choice at some point? Unlikely, subtle stuff like this will just be left broken in drivers nobody cares about.. Jason
