Author: Remi Meier <remi.me...@inf.ethz.ch>
Branch: use-gcc
Changeset: r1901:cff6245b0bb4
Date: 2015-07-29 13:29 +0200
http://bitbucket.org/pypy/stmgc/changeset/cff6245b0bb4/
Log: another subtle race fixed, hopefully completing the previous commit
diff --git a/c8/stm/core.c b/c8/stm/core.c
--- a/c8/stm/core.c
+++ b/c8/stm/core.c
@@ -1341,7 +1341,9 @@
/* before releasing _stm_detached_inevitable_from_thread, perform
the commit. Otherwise, the same thread whose (inev) transaction we try
to commit here may start a new one in another segment *but* w/o
- the committed data from its previous inev transaction. */
+ the committed data from its previous inev transaction. (the
+ stm_validate() at the start of a new transaction is happy even
+ if there is an inevitable tx running) */
bool was_inev = STM_PSEGMENT->transaction_state == TS_INEVITABLE;
_validate_and_add_to_commit_log();
@@ -1636,6 +1638,16 @@
if (!_validate_and_turn_inevitable())
return;
}
+
+ /* There may be a concurrent commit of a detached Tx going on.
+ Here, we may be right after the _validate_and_add_to_commit_log
+ and before resetting _stm_detached_inevitable_from_thread to
+ 0. We have to wait for this to happen bc. otherwise, eg.
+ _stm_detach_inevitable_transaction is not safe to do yet */
+ while (_stm_detached_inevitable_from_thread == -1)
+ spin_loop();
+ assert(_stm_detached_inevitable_from_thread == 0);
+
soon_finished_or_inevitable_thread_segment();
STM_PSEGMENT->transaction_state = TS_INEVITABLE;
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