Mercurial > hg > openjdk > hsx21
changeset 1502:f16f1d7893de
6941378: G1: change default value of G1UseFixedWindowMMUTracker to true
Summary: Rather than changing the default value of the G1UseFixedWindowMMUTracker, the flag and associated guarantee have been removed.
Reviewed-by: jcoomes, tonyp, ysr
| author | johnc |
|---|---|
| date | Mon, 24 May 2010 17:11:22 -0700 |
| parents | c9a07413e82b |
| children | 5b77884bd4b7 |
| files | src/share/vm/gc_implementation/g1/g1MMUTracker.cpp src/share/vm/gc_implementation/g1/g1_globals.hpp |
| diffstat | 2 files changed, 11 insertions(+), 10 deletions(-) [+] |
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--- a/src/share/vm/gc_implementation/g1/g1MMUTracker.cpp Thu May 20 08:32:11 2010 -0700 +++ b/src/share/vm/gc_implementation/g1/g1MMUTracker.cpp Mon May 24 17:11:22 2010 -0700 @@ -81,20 +81,24 @@ remove_expired_entries(end); if (_no_entries == QueueLength) { - // OK, right now when we fill up we bomb out - // there are a few ways of dealing with this "gracefully" + // OK, we've filled up the queue. There are a few ways + // of dealing with this "gracefully" // increase the array size (:-) // remove the oldest entry (this might allow more GC time for - // the time slice than what's allowed) + // the time slice than what's allowed) - this is what we + // currently do // consolidate the two entries with the minimum gap between them // (this might allow less GC time than what's allowed) - guarantee(NOT_PRODUCT(ScavengeALot ||) G1UseFixedWindowMMUTracker, - "array full, currently we can't recover unless +G1UseFixedWindowMMUTracker"); + // In the case where ScavengeALot is true, such overflow is not // uncommon; in such cases, we can, without much loss of precision // or performance (we are GC'ing most of the time anyway!), - // simply overwrite the oldest entry in the tracker: this - // is also the behaviour when G1UseFixedWindowMMUTracker is enabled. + // simply overwrite the oldest entry in the tracker. + + if (G1PolicyVerbose > 1) { + warning("MMU Tracker Queue overflow. Replacing earliest entry."); + } + _head_index = trim_index(_head_index + 1); assert(_head_index == _tail_index, "Because we have a full circular buffer"); _tail_index = trim_index(_tail_index + 1);
--- a/src/share/vm/gc_implementation/g1/g1_globals.hpp Thu May 20 08:32:11 2010 -0700 +++ b/src/share/vm/gc_implementation/g1/g1_globals.hpp Mon May 24 17:11:22 2010 -0700 @@ -254,9 +254,6 @@ "If non-0 is the size of the G1 survivor space, " \ "otherwise SurvivorRatio is used to determine the size") \ \ - product(bool, G1UseFixedWindowMMUTracker, false, \ - "If the MMU tracker's memory is full, forget the oldest entry") \ - \ product(uintx, G1HeapRegionSize, 0, \ "Size of the G1 regions.") \ \