* Using a DSA from the registry is cumbersome. You essentially need another batch of shared memory to keep track of the pointers and do locking, so it might not be tremendously useful on its own. AFAICT the easiest thing to do is to store the DSA pointers in a dshash table, which is what I've done in the test.
I am considering whether it would be better to avoid creating another DSM segment to track the DSA handle. Would it make more sense to track the DSAs in a separate dshash registry similar to DSM segments?
Should this also consider the case where dsa is already mapped, to avoid the error on attaching to the DSA twice? IIUC, that would require calling dsa equivalent of dsm_find_mapping().
