[GHC] #15880: GHC.Stats: Add info on amount of pinned memory

[GHC]

#15880: GHC.Stats: Add info on amount of pinned memory
-------------------------------------+-------------------------------------
        Reporter:  nh2               |                Owner:  (none)
            Type:  task              |               Status:  new
        Priority:  normal            |            Milestone:  8.6.3
       Component:  Runtime System    |              Version:  8.6.2
      Resolution:                    |             Keywords:
Operating System:  Unknown/Multiple  |         Architecture:
                                     |  Unknown/Multiple
 Type of failure:  None/Unknown      |            Test Case:
      Blocked By:                    |             Blocking:
 Related Tickets:                    |  Differential Rev(s):
       Wiki Page:                    |
-------------------------------------+-------------------------------------

Comment (by osa1):

 To answer the questions:

 - `gcdetails_mem_in_use_bytes` is simply `mblocks_allocated *
 MBLOCK_SIZE`.
   Because pinned memory is also allocated via the block allocator
   `gcdetails_mem_in_use_bytes` includes pinned memory too.

 - I don't understand this question.

 - You'd need to compute this. In the GC once a pinned object block is
 filled we
   only distinguish a pinned object block from a large object block in one
 place,
   to avoid scavenging pinned blocks. So there's no special accounting for
 pinned
   objects.

   Perhaps you could implement something like `calcTotalLargeObjectsW` by
   checking if a `BF_LARGE` block is also `BF_PINNED`. If it is then add
 number
   of blocks to a counter. Then `num_of_blocks * BLOCK_SIZE` gives you the
 bytes.

-- 
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/15880#comment:1>
GHC <http://www.haskell.org/ghc/>
The Glasgow Haskell Compiler