1420   }
1421   // It does not make sense to have big object alignment
1422   // since a space lost due to alignment will be greater
1423   // then a saved space from compressed oops.
1424   if ((int)ObjectAlignmentInBytes > 256) {
1425     jio_fprintf(defaultStream::error_stream(),
1426                 "error: ObjectAlignmentInBytes=%d must not be greater than 256\n",
1427                 (int)ObjectAlignmentInBytes);
1428     return false;
1429   }
1430   // In case page size is very small.
1431   if ((int)ObjectAlignmentInBytes >= os::vm_page_size()) {
1432     jio_fprintf(defaultStream::error_stream(),
1433                 "error: ObjectAlignmentInBytes=%d must be less than page size %d\n",
1434                 (int)ObjectAlignmentInBytes, os::vm_page_size());
1435     return false;
1436   }
1437   return true;
1438 }
1439 
1440 uintx Arguments::max_heap_for_compressed_oops() {
1441   // Avoid sign flip.
1442   assert(OopEncodingHeapMax > (uint64_t)os::vm_page_size(), "Unusual page size");
1443   // We need to fit both the NULL page and the heap into the memory budget, while
1444   // keeping alignment constraints of the heap. To guarantee the latter, as the
1445   // NULL page is located before the heap, we pad the NULL page to the conservative
1446   // maximum alignment that the GC may ever impose upon the heap.
1447   size_t displacement_due_to_null_page = align_size_up_(os::vm_page_size(),
1448                                                         _conservative_max_heap_alignment);
1449 
1450   LP64_ONLY(return OopEncodingHeapMax - displacement_due_to_null_page);
1451   NOT_LP64(ShouldNotReachHere(); return 0);
1452 }
1453 
1454 bool Arguments::should_auto_select_low_pause_collector() {
1455   if (UseAutoGCSelectPolicy &&
1456       !FLAG_IS_DEFAULT(MaxGCPauseMillis) &&
1457       (MaxGCPauseMillis <= AutoGCSelectPauseMillis)) {
1458     if (PrintGCDetails) {
1459       // Cannot use gclog_or_tty yet.
1460       tty->print_cr("Automatic selection of the low pause collector"

1420   }
1421   // It does not make sense to have big object alignment
1422   // since a space lost due to alignment will be greater
1423   // then a saved space from compressed oops.
1424   if ((int)ObjectAlignmentInBytes > 256) {
1425     jio_fprintf(defaultStream::error_stream(),
1426                 "error: ObjectAlignmentInBytes=%d must not be greater than 256\n",
1427                 (int)ObjectAlignmentInBytes);
1428     return false;
1429   }
1430   // In case page size is very small.
1431   if ((int)ObjectAlignmentInBytes >= os::vm_page_size()) {
1432     jio_fprintf(defaultStream::error_stream(),
1433                 "error: ObjectAlignmentInBytes=%d must be less than page size %d\n",
1434                 (int)ObjectAlignmentInBytes, os::vm_page_size());
1435     return false;
1436   }
1437   return true;
1438 }
1439 
1440 size_t Arguments::max_heap_for_compressed_oops() {
1441   // Avoid sign flip.
1442   assert(OopEncodingHeapMax > (uint64_t)os::vm_page_size(), "Unusual page size");
1443   // We need to fit both the NULL page and the heap into the memory budget, while
1444   // keeping alignment constraints of the heap. To guarantee the latter, as the
1445   // NULL page is located before the heap, we pad the NULL page to the conservative
1446   // maximum alignment that the GC may ever impose upon the heap.
1447   size_t displacement_due_to_null_page = align_size_up_(os::vm_page_size(),
1448                                                         _conservative_max_heap_alignment);
1449 
1450   LP64_ONLY(return OopEncodingHeapMax - displacement_due_to_null_page);
1451   NOT_LP64(ShouldNotReachHere(); return 0);
1452 }
1453 
1454 bool Arguments::should_auto_select_low_pause_collector() {
1455   if (UseAutoGCSelectPolicy &&
1456       !FLAG_IS_DEFAULT(MaxGCPauseMillis) &&
1457       (MaxGCPauseMillis <= AutoGCSelectPauseMillis)) {
1458     if (PrintGCDetails) {
1459       // Cannot use gclog_or_tty yet.
1460       tty->print_cr("Automatic selection of the low pause collector"