diff options
| -rw-r--r-- | rts/STM.c | 24 |
1 files changed, 3 insertions, 21 deletions
@@ -1460,28 +1460,10 @@ StgBool stmCommitNestedTransaction(Capability *cap, StgTRecHeader *trec) { StgTVar *s; s = e -> tvar; - - // Careful! We might have a read entry here that we don't want - // to spam over the update entry in the enclosing TRec. e.g. in - // - // t <- newTVar 1 - // writeTVar t 2 - // ((readTVar t >> retry) `orElse` return ()) `orElse` return () - // - // - the innermost txn first aborts, giving us a read-only entry - // with e->expected_value == e->new_value == 1 - // - the inner orElse commits into the outer orElse, which - // lands us here. If we unconditionally did - // merge_update_into(), then we would overwrite the outer - // TRec's update, so we must check whether the entry is an - // update or not, and if not, just do merge_read_into. - // - if (entry_is_update(e)) { + if (entry_is_update(e)) { unlock_tvar(cap, trec, s, e -> expected_value, FALSE); - merge_update_into(cap, et, s, e -> expected_value, e -> new_value); - } else { - merge_read_into(cap, et, s, e -> expected_value); - } + } + merge_update_into(cap, et, s, e -> expected_value, e -> new_value); ACQ_ASSERT(s -> current_value != (StgClosure *)trec); }); } else { |