Mercurial > hg > graal-compiler
diff src/share/vm/memory/genCollectedHeap.hpp @ 1027:39b01ab7035a
6888898: CMS: ReduceInitialCardMarks unsafe in the presence of cms precleaning
6889757: G1: enable card mark elision for initializing writes from compiled code (ReduceInitialCardMarks)
Summary: Defer the (compiler-elided) card-mark upon a slow-path allocation until after the store and before the next subsequent safepoint; G1 now answers yes to can_elide_tlab_write_barriers().
Reviewed-by: jcoomes, kvn, never
| author | ysr |
|---|---|
| date | Fri, 16 Oct 2009 02:05:46 -0700 |
| parents | 148e5441d916 |
| children | 052a899eec3e |
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--- a/src/share/vm/memory/genCollectedHeap.hpp Wed Oct 07 19:01:55 2009 -0400 +++ b/src/share/vm/memory/genCollectedHeap.hpp Fri Oct 16 02:05:46 2009 -0700 @@ -260,6 +260,17 @@ return true; } + // We don't need barriers for stores to objects in the + // young gen and, a fortiori, for initializing stores to + // objects therein. This applies to {DefNew,ParNew}+{Tenured,CMS} + // only and may need to be re-examined in case other + // kinds of collectors are implemented in the future. + virtual bool can_elide_initializing_store_barrier(oop new_obj) { + assert(UseParNewGC || UseSerialGC || UseConcMarkSweepGC, + "Check can_elide_initializing_store_barrier() for this collector"); + return is_in_youngest((void*)new_obj); + } + // Can a compiler elide a store barrier when it writes // a permanent oop into the heap? Applies when the compiler // is storing x to the heap, where x->is_perm() is true.