* Roland Dreier <rdre...@cisco.com>: > > > My colleague points out the following enum in uverbs_main.c: > > > > enum { > > IB_UVERBS_MAJOR = 231, > > IB_UVERBS_BASE_MINOR = 192, > > IB_UVERBS_MAX_DEVICES = 32 > > }; > > > > Experimentally, we've determined that on a system where we > > plugged in 40 IB cards, OFED only reports 32 cards are present. > > wow, 40 HCAs in one system !
HP sell some pretty big systems. :) > > If that enum is indeed the limiting factor, would someone mind > > explaining (or pointing me at TFM ;) why it's limited to 32 > > devices? > > That dates back to when device #s had 8 bits for major and 8 bits for > minor. We got one major assigned for IB, and had to split up the 256 > minors that gave us among userspace verbs, management access, etc. And > 32 seemed like a pretty reasonable limit for most uses. Thanks for the explanation. > Nowadays I guess we should look into expanding that to dynamic device > numbers on overflow, assuming you do have a realistic situation where > someone would want to use that many adapters per system. Think of a large scale-up ia64 box, possibly running some virtualization stack. I'm guessing that it's not just a simple kernel fix though since OFED has to change too, right? /ac -- To unsubscribe from this list: send the line "unsubscribe linux-rdma" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html