1.1 --- a/src/share/vm/memory/universe.cpp Wed Mar 18 11:37:48 2009 -0400
1.2 +++ b/src/share/vm/memory/universe.cpp Thu Mar 19 09:13:24 2009 -0700
1.3 @@ -99,7 +99,8 @@
1.4 size_t Universe::_heap_used_at_last_gc = 0;
1.5
1.6 CollectedHeap* Universe::_collectedHeap = NULL;
1.7 -address Universe::_heap_base = NULL;
1.8 +
1.9 +NarrowOopStruct Universe::_narrow_oop = { NULL, 0, true };
1.10
1.11
1.12 void Universe::basic_type_classes_do(void f(klassOop)) {
1.13 @@ -729,6 +730,53 @@
1.14 return JNI_OK;
1.15 }
1.16
1.17 +// Choose the heap base address and oop encoding mode
1.18 +// when compressed oops are used:
1.19 +// Unscaled - Use 32-bits oops without encoding when
1.20 +// NarrowOopHeapBaseMin + heap_size < 4Gb
1.21 +// ZeroBased - Use zero based compressed oops with encoding when
1.22 +// NarrowOopHeapBaseMin + heap_size < 32Gb
1.23 +// HeapBased - Use compressed oops with heap base + encoding.
1.24 +
1.25 +// 4Gb
1.26 +static const uint64_t NarrowOopHeapMax = (uint64_t(max_juint) + 1);
1.27 +// 32Gb
1.28 +static const uint64_t OopEncodingHeapMax = NarrowOopHeapMax << LogMinObjAlignmentInBytes;
1.29 +
1.30 +char* Universe::preferred_heap_base(size_t heap_size, NARROW_OOP_MODE mode) {
1.31 +#ifdef _LP64
1.32 + if (UseCompressedOops) {
1.33 + assert(mode == UnscaledNarrowOop ||
1.34 + mode == ZeroBasedNarrowOop ||
1.35 + mode == HeapBasedNarrowOop, "mode is invalid");
1.36 +
1.37 + const size_t total_size = heap_size + HeapBaseMinAddress;
1.38 + if (total_size <= OopEncodingHeapMax && (mode != HeapBasedNarrowOop)) {
1.39 + if (total_size <= NarrowOopHeapMax && (mode == UnscaledNarrowOop) &&
1.40 + (Universe::narrow_oop_shift() == 0)) {
1.41 + // Use 32-bits oops without encoding and
1.42 + // place heap's top on the 4Gb boundary
1.43 + return (char*)(NarrowOopHeapMax - heap_size);
1.44 + } else {
1.45 + // Can't reserve with NarrowOopShift == 0
1.46 + Universe::set_narrow_oop_shift(LogMinObjAlignmentInBytes);
1.47 + if (mode == UnscaledNarrowOop ||
1.48 + mode == ZeroBasedNarrowOop && total_size <= NarrowOopHeapMax) {
1.49 + // Use zero based compressed oops with encoding and
1.50 + // place heap's top on the 32Gb boundary in case
1.51 + // total_size > 4Gb or failed to reserve below 4Gb.
1.52 + return (char*)(OopEncodingHeapMax - heap_size);
1.53 + }
1.54 + }
1.55 + } else {
1.56 + // Can't reserve below 32Gb.
1.57 + Universe::set_narrow_oop_shift(LogMinObjAlignmentInBytes);
1.58 + }
1.59 + }
1.60 +#endif
1.61 + return NULL; // also return NULL (don't care) for 32-bit VM
1.62 +}
1.63 +
1.64 jint Universe::initialize_heap() {
1.65
1.66 if (UseParallelGC) {
1.67 @@ -773,6 +821,8 @@
1.68 if (status != JNI_OK) {
1.69 return status;
1.70 }
1.71 +
1.72 +#ifdef _LP64
1.73 if (UseCompressedOops) {
1.74 // Subtract a page because something can get allocated at heap base.
1.75 // This also makes implicit null checking work, because the
1.76 @@ -780,8 +830,49 @@
1.77 // See needs_explicit_null_check.
1.78 // Only set the heap base for compressed oops because it indicates
1.79 // compressed oops for pstack code.
1.80 - Universe::_heap_base = Universe::heap()->base() - os::vm_page_size();
1.81 + if (PrintCompressedOopsMode) {
1.82 + tty->cr();
1.83 + tty->print("heap address: "PTR_FORMAT, Universe::heap()->base());
1.84 + }
1.85 + if ((uint64_t)Universe::heap()->reserved_region().end() > OopEncodingHeapMax) {
1.86 + // Can't reserve heap below 32Gb.
1.87 + Universe::set_narrow_oop_base(Universe::heap()->base() - os::vm_page_size());
1.88 + Universe::set_narrow_oop_shift(LogMinObjAlignmentInBytes);
1.89 + if (PrintCompressedOopsMode) {
1.90 + tty->print(", Compressed Oops with base: "PTR_FORMAT, Universe::narrow_oop_base());
1.91 + }
1.92 + } else {
1.93 + Universe::set_narrow_oop_base(0);
1.94 + if (PrintCompressedOopsMode) {
1.95 + tty->print(", zero based Compressed Oops");
1.96 + }
1.97 +#ifdef _WIN64
1.98 + if (!Universe::narrow_oop_use_implicit_null_checks()) {
1.99 + // Don't need guard page for implicit checks in indexed addressing
1.100 + // mode with zero based Compressed Oops.
1.101 + Universe::set_narrow_oop_use_implicit_null_checks(true);
1.102 + }
1.103 +#endif // _WIN64
1.104 + if((uint64_t)Universe::heap()->reserved_region().end() > NarrowOopHeapMax) {
1.105 + // Can't reserve heap below 4Gb.
1.106 + Universe::set_narrow_oop_shift(LogMinObjAlignmentInBytes);
1.107 + } else {
1.108 + assert(Universe::narrow_oop_shift() == 0, "use unscaled narrow oop");
1.109 + if (PrintCompressedOopsMode) {
1.110 + tty->print(", 32-bits Oops");
1.111 + }
1.112 + }
1.113 + }
1.114 + if (PrintCompressedOopsMode) {
1.115 + tty->cr();
1.116 + tty->cr();
1.117 + }
1.118 }
1.119 + assert(Universe::narrow_oop_base() == (Universe::heap()->base() - os::vm_page_size()) ||
1.120 + Universe::narrow_oop_base() == NULL, "invalid value");
1.121 + assert(Universe::narrow_oop_shift() == LogMinObjAlignmentInBytes ||
1.122 + Universe::narrow_oop_shift() == 0, "invalid value");
1.123 +#endif
1.124
1.125 // We will never reach the CATCH below since Exceptions::_throw will cause
1.126 // the VM to exit if an exception is thrown during initialization
