Mercurial > hg > openjdk > hsx16
changeset 957:4385d4e7497b
6801625: CDS: HeapDump tests crash with internal error in compactingPermGenGen.cpp
Summary: Allow iteration over the shared spaces when using CDS, repealing previous proscription. Deferred further required CDS-related cleanups of perm gen to CR 6897789.
Reviewed-by: phh, jmasa
| author | ysr |
|---|---|
| date | Tue, 03 Nov 2009 16:43:16 -0800 |
| parents | c5388a988d5a |
| children | 248f0ad25d21 |
| files | src/share/vm/memory/compactingPermGenGen.cpp src/share/vm/memory/compactingPermGenGen.hpp src/share/vm/memory/generation.cpp |
| diffstat | 3 files changed, 20 insertions(+), 6 deletions(-) [+] |
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--- a/src/share/vm/memory/compactingPermGenGen.cpp Wed Nov 04 07:07:14 2009 -0800 +++ b/src/share/vm/memory/compactingPermGenGen.cpp Tue Nov 03 16:43:16 2009 -0800 @@ -352,15 +352,19 @@ } +// Do not use in time-critical operations due to the possibility of paging +// in otherwise untouched or previously unread portions of the perm gen, +// for instance, the shared spaces. NOTE: Because CompactingPermGenGen +// derives from OneContigSpaceCardGeneration which is supposed to have a +// single space, and does not override its object_iterate() method, +// object iteration via that interface does not look at the objects in +// the shared spaces when using CDS. This should be fixed; see CR 6897798. void CompactingPermGenGen::space_iterate(SpaceClosure* blk, bool usedOnly) { OneContigSpaceCardGeneration::space_iterate(blk, usedOnly); if (spec()->enable_shared_spaces()) { -#ifdef PRODUCT // Making the rw_space walkable will page in the entire space, and - // is to be avoided. However, this is required for Verify options. - ShouldNotReachHere(); -#endif - + // is to be avoided in the case of time-critical operations. + // However, this is required for Verify and heap dump operations. blk->do_space(ro_space()); blk->do_space(rw_space()); }
--- a/src/share/vm/memory/compactingPermGenGen.hpp Wed Nov 04 07:07:14 2009 -0800 +++ b/src/share/vm/memory/compactingPermGenGen.hpp Tue Nov 03 16:43:16 2009 -0800 @@ -29,6 +29,9 @@ class PermanentGenerationSpec; // This is the "generation" view of a CompactingPermGen. +// NOTE: the shared spaces used for CDS are here handled in +// a somewhat awkward and potentially buggy fashion, see CR 6801625. +// This infelicity should be fixed, see CR 6897789. class CompactingPermGenGen: public OneContigSpaceCardGeneration { friend class VMStructs; // Abstractly, this is a subtype that gets access to protected fields. @@ -47,7 +50,7 @@ OffsetTableContigSpace* _ro_space; OffsetTableContigSpace* _rw_space; - // With shared spaces there is a dicotomy in the use of the + // With shared spaces there is a dichotomy in the use of the // _virtual_space of the generation. There is a portion of the // _virtual_space that is used for the unshared part of the // permanent generation and a portion that is reserved for the shared part.
--- a/src/share/vm/memory/generation.cpp Wed Nov 04 07:07:14 2009 -0800 +++ b/src/share/vm/memory/generation.cpp Tue Nov 03 16:43:16 2009 -0800 @@ -606,6 +606,13 @@ void OneContigSpaceCardGeneration::prepare_for_verify() {} +// Override for a card-table generation with one contiguous +// space. NOTE: For reasons that are lost in the fog of history, +// this code is used when you iterate over perm gen objects, +// even when one uses CDS, where the perm gen has a couple of +// other spaces; this is because CompactingPermGenGen derives +// from OneContigSpaceCardGeneration. This should be cleaned up, +// see CR 6897789.. void OneContigSpaceCardGeneration::object_iterate(ObjectClosure* blk) { _the_space->object_iterate(blk); }