Update comments around blackholes

Test Plan: validate

Reviewers: austin, bgamari

Subscribers: thomie

Differential Revision: https://phabricator.haskell.org/D1047

1 files changed, 9 insertions, 7 deletions

diff --git a/rts/StgMiscClosures.cmm b/rts/StgMiscClosures.cmm
index dd2570617d..e3be2cb697 100644
--- a/rts/StgMiscClosures.cmm
+++ b/rts/StgMiscClosures.cmm
@@ -355,17 +355,12 @@ retry:
     }
 }
 
-INFO_TABLE(__stg_EAGER_BLACKHOLE,1,0,BLACKHOLE,"BLACKHOLE","BLACKHOLE")
-    (P_ node)
-{
-    jump ENTRY_LBL(stg_BLACKHOLE) (node);
-}
-
 // CAF_BLACKHOLE is allocated when entering a CAF.  The reason it is
 // distinct from BLACKHOLE is so that we can tell the difference
 // between an update frame on the stack that points to a CAF under
 // evaluation, and one that points to a closure that is under
-// evaluation by another thread (a BLACKHOLE).  See threadPaused().
+// evaluation by another thread (a BLACKHOLE).  see Note [suspend
+// duplicate work] in ThreadPaused.c
 //
 INFO_TABLE(stg_CAF_BLACKHOLE,1,0,BLACKHOLE,"BLACKHOLE","BLACKHOLE")
     (P_ node)
@@ -373,6 +368,13 @@ INFO_TABLE(stg_CAF_BLACKHOLE,1,0,BLACKHOLE,"BLACKHOLE","BLACKHOLE")
     jump ENTRY_LBL(stg_BLACKHOLE) (node);
 }
 
+// EAGER_BLACKHOLE exists for the same reason as CAF_BLACKHOLE (see above).
+INFO_TABLE(__stg_EAGER_BLACKHOLE,1,0,BLACKHOLE,"BLACKHOLE","BLACKHOLE")
+    (P_ node)
+{
+    jump ENTRY_LBL(stg_BLACKHOLE) (node);
+}
+
 INFO_TABLE(stg_BLOCKING_QUEUE_CLEAN,4,0,BLOCKING_QUEUE,"BLOCKING_QUEUE","BLOCKING_QUEUE")
 { foreign "C" barf("BLOCKING_QUEUE_CLEAN object entered!") never returns; }