[GHC] #9706: New block-structured heap organization for 64-bit

[GHC]

#9706: New block-structured heap organization for 64-bit
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        Reporter:  ezyang            |                   Owner:  gcampax
            Type:  task              |                  Status:  new
        Priority:  normal            |               Milestone:
       Component:  Runtime System    |                 Version:  7.8.3
      Resolution:                    |                Keywords:
Operating System:  Unknown/Multiple  |            Architecture:
                                     |  Unknown/Multiple
 Type of failure:  None/Unknown      |               Test Case:
      Blocked By:                    |                Blocking:
 Related Tickets:                    |  Differential Revisions:  D524
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Comment (by Simon Marlow <marlowsd@…>):

 In [changeset:"0d1a8d09f452977aadef7897aa12a8d41c7a4af0/ghc"
 0d1a8d09/ghc]:
 {{{
 #!CommitTicketReference repository="ghc"
 revision="0d1a8d09f452977aadef7897aa12a8d41c7a4af0"
 Two step allocator for 64-bit systems

 Summary:
 The current OS memory allocator conflates the concepts of allocating
 address space and allocating memory, which makes the HEAP_ALLOCED()
 implementation excessively complicated (as the only thing it cares
 about is address space layout) and slow. Instead, what we want
 is to allocate a single insanely large contiguous block of address
 space (to make HEAP_ALLOCED() checks fast), and then commit subportions
 of that in 1MB blocks as we did before.
 This is currently behind a flag, USE_LARGE_ADDRESS_SPACE, that is only
 enabled for
 certain OSes.

 Test Plan: validate

 Reviewers: simonmar, ezyang, austin

 Subscribers: thomie, carter

 Differential Revision: https://phabricator.haskell.org/D524

 GHC Trac Issues: #9706
 }}}

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Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/9706#comment:20>
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