[GHC] #16065: Stack squeezing during context switches makes for non-determinism in allocations

[GHC]

#16065: Stack squeezing during context switches makes for non-determinism in
allocations
-------------------------------------+-------------------------------------
        Reporter:  sgraf             |                Owner:  (none)
            Type:  task              |               Status:  new
        Priority:  normal            |            Milestone:  ⊥
       Component:  Runtime System    |              Version:  8.6.3
      Resolution:                    |             Keywords:
Operating System:  Unknown/Multiple  |         Architecture:
                                     |  Unknown/Multiple
 Type of failure:  None/Unknown      |            Test Case:
      Blocked By:                    |             Blocking:
 Related Tickets:  #4450, #8861      |  Differential Rev(s):
       Wiki Page:                    |
-------------------------------------+-------------------------------------

Comment (by simonmar):

 Good catch, but I don't fully understand stack squeezing affects
 allocation. As far as I'm aware it should just reduce the stack size, not
 increase it, so it shouldn't require any extra allocation.

 I'm OK with putting in some fix for this to make the benchmarks stable,
 but I'd like to completely understand the cause first.

-- 
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/16065#comment:1>
GHC <http://www.haskell.org/ghc/>
The Glasgow Haskell Compiler