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| author | Simon Marlow <marlowsd@gmail.com> | 2009-02-11 15:24:21 +0000 |
|---|---|---|
| committer | Simon Marlow <marlowsd@gmail.com> | 2009-02-11 15:24:21 +0000 |
| commit | a67183b75f1527edd88b071b879c2d07e8ac7653 (patch) | |
| tree | e4bf207972d58ce83500f1e4539c844c55fa77b0 /rts/parallel | |
| parent | 2af2966da98c9c0da9e33c6aead9e1f86f94a362 (diff) | |
| download | haskell-a67183b75f1527edd88b071b879c2d07e8ac7653.tar.gz | |
one more bugfix: a load/load memory barrier is required in stealWSDeque_()
Diffstat (limited to 'rts/parallel')
| -rw-r--r-- | rts/parallel/WSDeque.c | 5 |
1 files changed, 4 insertions, 1 deletions
diff --git a/rts/parallel/WSDeque.c b/rts/parallel/WSDeque.c index 4ae9417fdb..f77ff0987d 100644 --- a/rts/parallel/WSDeque.c +++ b/rts/parallel/WSDeque.c @@ -186,8 +186,11 @@ stealWSDeque_ (WSDeque *q) // Can't do this on someone else's spark pool: // ASSERT_WSDEQUE_INVARIANTS(q); - b = q->bottom; + // NB. these loads must be ordered, otherwise there is a race + // between steal and pop. t = q->top; + load_load_barrier(); + b = q->bottom; // NB. b and t are unsigned; we need a signed value for the test // below, because it is possible that t > b during a |