[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:  simonmar
                  Type:  task        |           Status:  new
              Priority:  normal      |        Milestone:
             Component:  Runtime     |          Version:  7.8.3
  System                             |         Keywords:
            Resolution:              |     Architecture:  Unknown/Multiple
      Operating System:              |       Difficulty:  Unknown
  Unknown/Multiple                   |       Blocked By:
       Type of failure:              |  Related Tickets:
  None/Unknown                       |
             Test Case:              |
              Blocking:              |
Differential Revisions:              |
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Comment (by thoughtpolice):

 > I'm worried about the overhead of having to pre-allocate a large number
 of page tables for the reserved address space

 Like Reid mentioned, this shouldn't be too much of an issue on Linux, at
 least, until we get the initial page fault to map things in the first
 place. But beyond that, we can possibly mitigate some TLB/mapping thrashes
 a bit on Linux at least using hugetables, which should beef up the page
 sizes from 4k to 1MB or so.

 On older Linux systems though this is a bit of a basket case, since you
 need `hugetblfs`, which is super annoying and before transparent
 hugepages/mmap flags were introduced in glibc.

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Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/9706#comment:11>
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