[GHC] #7670: StablePtrs should be organized by generation for efficient minor collections

[GHC]

#7670: StablePtrs should be organized by generation for efficient minor
collections
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        Reporter:  ezyang            |                Owner:  (none)
            Type:  bug               |               Status:  new
        Priority:  normal            |            Milestone:
       Component:  Runtime System    |              Version:  7.7
      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:                    |
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Comment (by simonmar):

 I can't off-hand think of a reason why no-stable-name-table wouldn't work.
 Seems reasonable to me.

 A per-generation hash table is tricky because each entry is associated
 with two heap objects: the key and the `StableName` object, which may be
 in different generations. The hash table is keyed by the key (we really
 need a different name for that), so obviously it's the `StableName` object
 that might reside in a different generation. You would probably need
 something like a remembered set, to remember which hash table entries
 point to a StableName in a younger generation and therefore might need
 updating during a young-gen collection. I'm sure that's not the only
 design though.

 It's worth considering that you could do no-stable-name-table without per-
 generation hash tables, as an intermediate step.

-- 
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/7670#comment:16>
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