[GHC] #7847: Maintain per-generation lists of weak pointers

[GHC]

#7847: Maintain per-generation lists of weak pointers
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    Reporter:  akio              |       Owner:                              
        Type:  feature request   |      Status:  infoneeded                  
    Priority:  normal            |   Milestone:                              
   Component:  Runtime System    |     Version:  7.7                         
    Keywords:                    |          Os:  Unknown/Multiple            
Architecture:  Unknown/Multiple  |     Failure:  Compile-time performance bug
  Difficulty:  Unknown           |    Testcase:                              
   Blockedby:                    |    Blocking:                              
     Related:                    |  
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Changes (by simonmar):

  * status:  patch => infoneeded
  * difficulty:  => Unknown


Comment:

 patch 0001 looks good to me.

 On patch 0002:

 * Why do we have `dead_weak_ptr_list_tail` rather than just consing new
 items on the front of the list?

 If you haven't already, I recommend testing these patches with
 `libraries/base/tests/memo001.hs` and `libraries/base/tests/memo002.hs`.
 Those are pretty good stress tests of the weak pointer implementation.

-- 
Ticket URL: <http://hackage.haskell.org/trac/ghc/ticket/7847#comment:9>
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