[GHC] #14702: Runtime is keeping hold to too much memory

[GHC]

#14702: Runtime is keeping hold to too much memory
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        Reporter:  blaze             |                Owner:  blaze
            Type:  bug               |               Status:  new
        Priority:  normal            |            Milestone:
       Component:  Runtime System    |              Version:  8.2.2
      Resolution:                    |             Keywords:
Operating System:  Unknown/Multiple  |         Architecture:
                                     |  Unknown/Multiple
 Type of failure:  Other             |            Test Case:
      Blocked By:                    |             Blocking:
 Related Tickets:                    |  Differential Rev(s):  Phab:D4338
       Wiki Page:                    |
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Comment (by Ben Gamari <ben@…>):

 In [changeset:"0171e09e4d073d8466953ebbf01292e55829fb20/ghc"
 0171e09e/ghc]:
 {{{
 #!CommitTicketReference repository="ghc"
 revision="0171e09e4d073d8466953ebbf01292e55829fb20"
 Make RTS keep less memory (fixes #14702)

 Currently runtime keeps hold to 4*used_memory. This includes, in
 particular, nursery, which can be quite large on multiprocessor
 machines: 16 CPUs x 64Mb each is 1GB. Multiplying it by 4 means whatever
 actual memory usage is, runtime will never release memory under 4GB, and
 this is quite excessive for processes which only need a lot of memory
 shortly (think building data structures from large files).

 This diff makes multiplier to apply only to GC-managed memory, leaving
 all "static" allocations alone.

 Test Plan: make test TEST="T14702"

 Reviewers: bgamari, erikd, simonmar

 Reviewed By: simonmar

 Subscribers: rwbarton, thomie, carter

 GHC Trac Issues: #14702

 Differential Revision: https://phabricator.haskell.org/D4338
 }}}

-- 
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/14702#comment:4>
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