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8232365: Implementation for JEP 363: Remove the Concurrent Mark Sweep (CMS) Garbage Collector

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Reviewed-by: kbarrett, tschatzl, erikj, coleenp, dholmes
This commit is contained in:
Leo Korinth 2019-11-13 11:37:29 +01:00
parent b8b88853a5
commit 1fc67ab002
239 changed files with 220 additions and 27246 deletions
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36
src/hotspot/share/oops/oop.inline.hpp
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@ -179,26 +179,6 @@ void oopDesc::set_klass_gap(int v) {
set_klass_gap((HeapWord*)this, v);
}
void oopDesc::set_klass_to_list_ptr(oop k) {
// This is only to be used during GC, for from-space objects, so no
// barrier is needed.
if (UseCompressedClassPointers) {
_metadata._compressed_klass = (narrowKlass)CompressedOops::encode(k); // may be null (parnew overflow handling)
} else {
_metadata._klass = (Klass*)(address)k;
}
}
oop oopDesc::list_ptr_from_klass() {
// This is only to be used during GC, for from-space objects.
if (UseCompressedClassPointers) {
return CompressedOops::decode((narrowOop)_metadata._compressed_klass);
} else {
// Special case for GC
return (oop)(address)_metadata._klass;
}
}
bool oopDesc::is_a(Klass* k) const {
return klass()->is_subtype_of(k);
}
@ -244,25 +224,13 @@ int oopDesc::size_given_klass(Klass* klass) {
// skipping the intermediate round to HeapWordSize.
s = (int)(align_up(size_in_bytes, MinObjAlignmentInBytes) / HeapWordSize);
// ParNew (used by CMS), UseParallelGC and UseG1GC can change the length field
// UseParallelGC and UseG1GC can change the length field
// of an "old copy" of an object array in the young gen so it indicates
// the grey portion of an already copied array. This will cause the first
// disjunct below to fail if the two comparands are computed across such
// a concurrent change.
// ParNew also runs with promotion labs (which look like int
// filler arrays) which are subject to changing their declared size
// when finally retiring a PLAB; this also can cause the first disjunct
// to fail for another worker thread that is concurrently walking the block
// offset table. Both these invariant failures are benign for their
// current uses; we relax the assertion checking to cover these two cases below:
// is_objArray() && is_forwarded() // covers first scenario above
// || is_typeArray() // covers second scenario above
// If and when UseParallelGC uses the same obj array oop stealing/chunking
// technique, we will need to suitably modify the assertion.
assert((s == klass->oop_size(this)) ||
(Universe::heap()->is_gc_active() &&
((is_typeArray() && UseConcMarkSweepGC) ||
(is_objArray() && is_forwarded() && (UseConcMarkSweepGC || UseParallelGC || UseG1GC)))),
(Universe::heap()->is_gc_active() && is_objArray() && is_forwarded() && (UseParallelGC || UseG1GC)),
"wrong array object size");
} else {
// Must be zero, so bite the bullet and take the virtual call.