[GHC] #10317: Event manager: Multishot registrations only fire once

[GHC]

#10317: Event manager: Multishot registrations only fire once
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        Reporter:  bgamari           |                   Owner:
            Type:  bug               |                  Status:  patch
        Priority:  normal            |               Milestone:  7.10.2
       Component:  Compiler          |                 Version:  7.10.1
      Resolution:                    |                Keywords:
Operating System:  Unknown/Multiple  |            Architecture:
 Type of failure:  Incorrect result  |  Unknown/Multiple
  at runtime                         |               Test Case:
      Blocked By:                    |                Blocking:
 Related Tickets:                    |  Differential Revisions:  Phab:D849
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Comment (by Austin Seipp <austin@…>):

 In [changeset:"1c3832597b3e75456fc61628c4cd289d211c733b/ghc"]:
 {{{
 #!CommitTicketReference repository="ghc"
 revision="1c3832597b3e75456fc61628c4cd289d211c733b"
 Fix dropped event registrations

 D347 introduced a bug wherein the event manager would drop registrations
 that
 should be retained during processing. This occurs when an fd has multiple
 registrations, not all of which fire, as well as the case of multi-shot
 registrations.

 I also do some general house-keeping, try to better document things, and
 fix a
 bug which could result in unnecessary calls to `epoll_ctl`

 Reviewed By: austin

 Differential Revision: https://phabricator.haskell.org/D849

 GHC Trac Issues: #10317
 }}}

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Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/10317#comment:7>
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