1616 }
1617 }
1618
1619 size_t Arguments::max_heap_for_compressed_oops() {
1620 // Avoid sign flip.
1621 assert(OopEncodingHeapMax > (uint64_t)os::vm_page_size(), "Unusual page size");
1622 // We need to fit both the NULL page and the heap into the memory budget, while
1623 // keeping alignment constraints of the heap. To guarantee the latter, as the
1624 // NULL page is located before the heap, we pad the NULL page to the conservative
1625 // maximum alignment that the GC may ever impose upon the heap.
1626 size_t displacement_due_to_null_page = align_up((size_t)os::vm_page_size(),
1627 _conservative_max_heap_alignment);
1628
1629 LP64_ONLY(return OopEncodingHeapMax - displacement_due_to_null_page);
1630 NOT_LP64(ShouldNotReachHere(); return 0);
1631 }
1632
1633 void Arguments::set_use_compressed_oops() {
1634 #ifndef ZERO
1635 #ifdef _LP64
1636 // MaxHeapSize is not set up properly at this point, but
1637 // the only value that can override MaxHeapSize if we are
1638 // to use UseCompressedOops is InitialHeapSize.
1639 size_t max_heap_size = MAX2(MaxHeapSize, InitialHeapSize);
1640
1641 if (max_heap_size <= max_heap_for_compressed_oops()) {
1642 #if !defined(COMPILER1) || defined(TIERED)
1643 if (FLAG_IS_DEFAULT(UseCompressedOops)) {
1644 FLAG_SET_ERGO(bool, UseCompressedOops, true);
1645 }
1646 #endif
1647 } else {
1648 if (UseCompressedOops && !FLAG_IS_DEFAULT(UseCompressedOops)) {
1649 warning("Max heap size too large for Compressed Oops");
1650 FLAG_SET_DEFAULT(UseCompressedOops, false);
1651 FLAG_SET_DEFAULT(UseCompressedClassPointers, false);
1652 }
1653 }
1654 #endif // _LP64
1655 #endif // ZERO
|
1616 }
1617 }
1618
1619 size_t Arguments::max_heap_for_compressed_oops() {
1620 // Avoid sign flip.
1621 assert(OopEncodingHeapMax > (uint64_t)os::vm_page_size(), "Unusual page size");
1622 // We need to fit both the NULL page and the heap into the memory budget, while
1623 // keeping alignment constraints of the heap. To guarantee the latter, as the
1624 // NULL page is located before the heap, we pad the NULL page to the conservative
1625 // maximum alignment that the GC may ever impose upon the heap.
1626 size_t displacement_due_to_null_page = align_up((size_t)os::vm_page_size(),
1627 _conservative_max_heap_alignment);
1628
1629 LP64_ONLY(return OopEncodingHeapMax - displacement_due_to_null_page);
1630 NOT_LP64(ShouldNotReachHere(); return 0);
1631 }
1632
1633 void Arguments::set_use_compressed_oops() {
1634 #ifndef ZERO
1635 #ifdef _LP64
1636 if(AllocateOldGenAt != NULL) {
1637 FLAG_SET_ERGO(bool, UseCompressedOops, false);
1638 return;
1639 }
1640 // MaxHeapSize is not set up properly at this point, but
1641 // the only value that can override MaxHeapSize if we are
1642 // to use UseCompressedOops is InitialHeapSize.
1643 size_t max_heap_size = MAX2(MaxHeapSize, InitialHeapSize);
1644
1645 if (max_heap_size <= max_heap_for_compressed_oops()) {
1646 #if !defined(COMPILER1) || defined(TIERED)
1647 if (FLAG_IS_DEFAULT(UseCompressedOops)) {
1648 FLAG_SET_ERGO(bool, UseCompressedOops, true);
1649 }
1650 #endif
1651 } else {
1652 if (UseCompressedOops && !FLAG_IS_DEFAULT(UseCompressedOops)) {
1653 warning("Max heap size too large for Compressed Oops");
1654 FLAG_SET_DEFAULT(UseCompressedOops, false);
1655 FLAG_SET_DEFAULT(UseCompressedClassPointers, false);
1656 }
1657 }
1658 #endif // _LP64
1659 #endif // ZERO
|