Mercurial > hg > openjdk > hsx20
changeset 2051:908c5092d72a
7014679: G1: deadlock during concurrent cleanup
Summary: 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
| author | tonyp |
|---|---|
| date | Mon, 31 Jan 2011 16:28:40 -0500 |
| parents | 4e66274b6bb3 |
| children | e9a2b8e0572a |
| files | src/share/vm/gc_implementation/g1/concurrentMarkThread.cpp |
| diffstat | 1 files changed, 8 insertions(+), 3 deletions(-) [+] |
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--- a/src/share/vm/gc_implementation/g1/concurrentMarkThread.cpp Tue Jan 25 17:58:19 2011 -0500 +++ b/src/share/vm/gc_implementation/g1/concurrentMarkThread.cpp Mon Jan 31 16:28:40 2011 -0500 @@ -251,6 +251,14 @@ // 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 @@ 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");