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7014679: G1: deadlock during concurrent cleanup

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There's a potential deadlock between the concurrent cleanup thread and the GC workers that are trying to allocate and waiting for more free regions to be made available.

Reviewed-by: iveresov, jcoomes
This commit is contained in:
Antonios Printezis 2011-01-31 16:28:40 -05:00
parent 7b4f8073f0
commit d18d952e56
1 changed files with 8 additions and 3 deletions
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11
hotspot/src/share/vm/gc_implementation/g1/concurrentMarkThread.cpp
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@ -251,6 +251,14 @@ void ConcurrentMarkThread::run() {
// Now do the remainder of the cleanup operation.
_cm->completeCleanup();
// Notify anyone who's waiting that there are no more free
// regions coming. We have to do this before we join the STS,
// otherwise we might deadlock: a GC worker could be blocked
// waiting for the notification whereas this thread will be
// blocked for the pause to finish while it's trying to join
// the STS, which is conditional on the GC workers finishing.
g1h->reset_free_regions_coming();
_sts.join();
g1_policy->record_concurrent_mark_cleanup_completed();
_sts.leave();
@ -262,9 +270,6 @@ void ConcurrentMarkThread::run() {
gclog_or_tty->print_cr("[GC concurrent-cleanup-end, %1.7lf]",
cleanup_end_sec - cleanup_start_sec);
}
// We're done: no more free regions coming.
g1h->reset_free_regions_coming();
}
guarantee(cm()->cleanup_list_is_empty(),
"at this point there should be no regions on the cleanup list");