1.1 --- a/src/share/vm/gc_implementation/g1/g1MMUTracker.cpp Wed Jun 09 13:53:58 2010 -0400
1.2 +++ b/src/share/vm/gc_implementation/g1/g1MMUTracker.cpp Thu Jun 10 08:27:35 2010 -0700
1.3 @@ -81,20 +81,24 @@
1.4
1.5 remove_expired_entries(end);
1.6 if (_no_entries == QueueLength) {
1.7 - // OK, right now when we fill up we bomb out
1.8 - // there are a few ways of dealing with this "gracefully"
1.9 + // OK, we've filled up the queue. There are a few ways
1.10 + // of dealing with this "gracefully"
1.11 // increase the array size (:-)
1.12 // remove the oldest entry (this might allow more GC time for
1.13 - // the time slice than what's allowed)
1.14 + // the time slice than what's allowed) - this is what we
1.15 + // currently do
1.16 // consolidate the two entries with the minimum gap between them
1.17 // (this might allow less GC time than what's allowed)
1.18 - guarantee(NOT_PRODUCT(ScavengeALot ||) G1UseFixedWindowMMUTracker,
1.19 - "array full, currently we can't recover unless +G1UseFixedWindowMMUTracker");
1.20 +
1.21 // In the case where ScavengeALot is true, such overflow is not
1.22 // uncommon; in such cases, we can, without much loss of precision
1.23 // or performance (we are GC'ing most of the time anyway!),
1.24 - // simply overwrite the oldest entry in the tracker: this
1.25 - // is also the behaviour when G1UseFixedWindowMMUTracker is enabled.
1.26 + // simply overwrite the oldest entry in the tracker.
1.27 +
1.28 + if (G1PolicyVerbose > 1) {
1.29 + warning("MMU Tracker Queue overflow. Replacing earliest entry.");
1.30 + }
1.31 +
1.32 _head_index = trim_index(_head_index + 1);
1.33 assert(_head_index == _tail_index, "Because we have a full circular buffer");
1.34 _tail_index = trim_index(_tail_index + 1);
