Commit d59cf4e5 authored by Ben Gamari's avatar Ben Gamari 🐢

Fix "CPP directive" in comment

parent d27e7fdb
......@@ -778,12 +778,12 @@ Note [Black-holing non-updatable thunks]
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We cannot black-hole non-updatable thunks otherwise we run into issues like
#10414. A single-entry (non-updatable) thunk can actually be entered more than
once in a parallel program, if work is duplicated by two threads both entering
the same updatable thunk before the other has blackholed it. So, we must not
eagerly blackhole non-updatable thunks, or the second thread to enter one will
become blocked indefinitely. (They are not blackholed by lazy blackholing
either, since they have no associated update frame.)
Trac #10414. A single-entry (non-updatable) thunk can actually be entered more
than once in a parallel program, if work is duplicated by two threads both
entering the same updatable thunk before the other has blackholed it. So, we
must not eagerly blackhole non-updatable thunks, or the second thread to enter
one will become blocked indefinitely. (They are not blackholed by lazy
blackholing either, since they have no associated update frame.)
For instance, let's consider the following value (in pseudo-Core, example due to
Reid Barton),
......
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