Mercurial > hg > truffle
diff src/share/vm/classfile/systemDictionary.cpp @ 12837:82af7d7a0128
8003420: NPG: make new GC root for pd_set
Summary: Move protection domain oops from system dictionary entries into a seperate set; the system dictionary references entries in that set now. This allows fast iteration during non-classunloading garbage collection. Implementation based on initial prototype from Ioi Lam (iklam).
Reviewed-by: coleenp, iklam
author | tschatzl |
---|---|
date | Wed, 09 Oct 2013 10:57:01 +0200 |
parents | f2110083203d |
children | 1c90f0072f0d |
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--- a/src/share/vm/classfile/systemDictionary.cpp Wed Oct 09 11:18:53 2013 -0700 +++ b/src/share/vm/classfile/systemDictionary.cpp Wed Oct 09 10:57:01 2013 +0200 @@ -1697,6 +1697,24 @@ return newsize; } +#ifdef ASSERT +class VerifySDReachableAndLiveClosure : public OopClosure { +private: + BoolObjectClosure* _is_alive; + + template <class T> void do_oop_work(T* p) { + oop obj = oopDesc::load_decode_heap_oop(p); + guarantee(_is_alive->do_object_b(obj), "Oop in system dictionary must be live"); + } + +public: + VerifySDReachableAndLiveClosure(BoolObjectClosure* is_alive) : OopClosure(), _is_alive(is_alive) { } + + virtual void do_oop(oop* p) { do_oop_work(p); } + virtual void do_oop(narrowOop* p) { do_oop_work(p); } +}; +#endif + // Assumes classes in the SystemDictionary are only unloaded at a safepoint // Note: anonymous classes are not in the SD. bool SystemDictionary::do_unloading(BoolObjectClosure* is_alive) { @@ -1707,7 +1725,15 @@ unloading_occurred = dictionary()->do_unloading(); constraints()->purge_loader_constraints(); resolution_errors()->purge_resolution_errors(); -} + } + // Oops referenced by the system dictionary may get unreachable independently + // of the class loader (eg. cached protection domain oops). So we need to + // explicitly unlink them here instead of in Dictionary::do_unloading. + dictionary()->unlink(is_alive); +#ifdef ASSERT + VerifySDReachableAndLiveClosure cl(is_alive); + dictionary()->oops_do(&cl); +#endif return unloading_occurred; }