6999491: non-zero COOPs are used when they should not
HeapBaseMinAddress should be used only for a default heap size calculation.
Reviewed-by: iveresov, jcoomes, dholmes
diff --git a/hotspot/src/share/vm/memory/universe.cpp b/hotspot/src/share/vm/memory/universe.cpp
index f059576..15c660d 100644
--- a/hotspot/src/share/vm/memory/universe.cpp
+++ b/hotspot/src/share/vm/memory/universe.cpp
@@ -864,7 +864,8 @@
// compressed oops for pstack code.
if (PrintCompressedOopsMode) {
tty->cr();
- tty->print("heap address: "PTR_FORMAT, Universe::heap()->base());
+ tty->print("heap address: " PTR_FORMAT ", size: " SIZE_FORMAT " MB",
+ Universe::heap()->base(), Universe::heap()->reserved_region().byte_size()/M);
}
if ((uint64_t)Universe::heap()->reserved_region().end() > OopEncodingHeapMax) {
// Can't reserve heap below 32Gb.
diff --git a/hotspot/src/share/vm/runtime/arguments.cpp b/hotspot/src/share/vm/runtime/arguments.cpp
index 091db03..7c9ecc5 100644
--- a/hotspot/src/share/vm/runtime/arguments.cpp
+++ b/hotspot/src/share/vm/runtime/arguments.cpp
@@ -1328,8 +1328,11 @@
}
inline uintx max_heap_for_compressed_oops() {
- // Heap should be above HeapBaseMinAddress to get zero based compressed oops.
- LP64_ONLY(return OopEncodingHeapMax - MaxPermSize - os::vm_page_size() - HeapBaseMinAddress);
+ // Avoid sign flip.
+ if (OopEncodingHeapMax < MaxPermSize + os::vm_page_size()) {
+ return 0;
+ }
+ LP64_ONLY(return OopEncodingHeapMax - MaxPermSize - os::vm_page_size());
NOT_LP64(ShouldNotReachHere(); return 0);
}
@@ -1507,7 +1510,13 @@
}
if (UseCompressedOops) {
// Limit the heap size to the maximum possible when using compressed oops
- reasonable_max = MIN2(reasonable_max, (julong)max_heap_for_compressed_oops());
+ julong max_coop_heap = (julong)max_heap_for_compressed_oops();
+ if (HeapBaseMinAddress + MaxHeapSize < max_coop_heap) {
+ // Heap should be above HeapBaseMinAddress to get zero based compressed oops
+ // but it should be not less than default MaxHeapSize.
+ max_coop_heap -= HeapBaseMinAddress;
+ }
+ reasonable_max = MIN2(reasonable_max, max_coop_heap);
}
reasonable_max = os::allocatable_physical_memory(reasonable_max);
