Re: like pg_shmem_allocations, but fine-grained for DSM registry ?

I think this will need some rework to deal with the addition of
GetNamedDSA() and GetNamedDSHash() [0].  We probably want to add a "type"
column to show whether the entry is for a DSM, DSA, or dshash table.  And
for DSAs and dshash tables, we probably want to use dsa_get_total_size()
for the "size" column.

[0] https://postgr.es/m/flat/aEC8HGy2tRQjZg_8@nathan

-- 
nathan