[openib-general] question - mapping QPIDs back to ptrs

[Roland Dreier]

 > The Chelsio driver is hogging lots of memory right now for mapping
 > PDIDs, QPIDs, CQIDs, and STAG IDs back to their respective kernel
 > structures.  This is done via an array of pointers, indexed by the ID.
 > The critical performance mapping is finding a QP struct from the QPID in
 > the poll path.

mthca rolls its own two-level sparse arrays (the mthca_array_xxx)
stuff, but it would probably be smarter to use the kernel's radix tree
stuff.  I've been meaning to benchmark mthca after converting to radix
trees for those tables, to see if it makes a difference.

 - R.