1.1 --- a/src/share/vm/runtime/virtualspace.cpp Tue Jun 22 12:10:07 2010 -0700
1.2 +++ b/src/share/vm/runtime/virtualspace.cpp Wed Jun 23 09:40:11 2010 -0700
1.3 @@ -111,6 +111,35 @@
1.4 return result;
1.5 }
1.6
1.7 +// Helper method.
1.8 +static bool failed_to_reserve_as_requested(char* base, char* requested_address,
1.9 + const size_t size, bool special)
1.10 +{
1.11 + if (base == requested_address || requested_address == NULL)
1.12 + return false; // did not fail
1.13 +
1.14 + if (base != NULL) {
1.15 + // Different reserve address may be acceptable in other cases
1.16 + // but for compressed oops heap should be at requested address.
1.17 + assert(UseCompressedOops, "currently requested address used only for compressed oops");
1.18 + if (PrintCompressedOopsMode) {
1.19 + tty->cr();
1.20 + tty->print_cr("Reserved memory at not requested address: " PTR_FORMAT " vs " PTR_FORMAT, base, requested_address);
1.21 + }
1.22 + // OS ignored requested address. Try different address.
1.23 + if (special) {
1.24 + if (!os::release_memory_special(base, size)) {
1.25 + fatal("os::release_memory_special failed");
1.26 + }
1.27 + } else {
1.28 + if (!os::release_memory(base, size)) {
1.29 + fatal("os::release_memory failed");
1.30 + }
1.31 + }
1.32 + }
1.33 + return true;
1.34 +}
1.35 +
1.36 ReservedSpace::ReservedSpace(const size_t prefix_size,
1.37 const size_t prefix_align,
1.38 const size_t suffix_size,
1.39 @@ -129,6 +158,10 @@
1.40 assert((suffix_align & prefix_align - 1) == 0,
1.41 "suffix_align not divisible by prefix_align");
1.42
1.43 + // Assert that if noaccess_prefix is used, it is the same as prefix_align.
1.44 + assert(noaccess_prefix == 0 ||
1.45 + noaccess_prefix == prefix_align, "noaccess prefix wrong");
1.46 +
1.47 // Add in noaccess_prefix to prefix_size;
1.48 const size_t adjusted_prefix_size = prefix_size + noaccess_prefix;
1.49 const size_t size = adjusted_prefix_size + suffix_size;
1.50 @@ -150,15 +183,16 @@
1.51 _noaccess_prefix = 0;
1.52 _executable = false;
1.53
1.54 - // Assert that if noaccess_prefix is used, it is the same as prefix_align.
1.55 - assert(noaccess_prefix == 0 ||
1.56 - noaccess_prefix == prefix_align, "noaccess prefix wrong");
1.57 -
1.58 // Optimistically try to reserve the exact size needed.
1.59 char* addr;
1.60 if (requested_address != 0) {
1.61 - addr = os::attempt_reserve_memory_at(size,
1.62 - requested_address-noaccess_prefix);
1.63 + requested_address -= noaccess_prefix; // adjust address
1.64 + assert(requested_address != NULL, "huge noaccess prefix?");
1.65 + addr = os::attempt_reserve_memory_at(size, requested_address);
1.66 + if (failed_to_reserve_as_requested(addr, requested_address, size, false)) {
1.67 + // OS ignored requested address. Try different address.
1.68 + addr = NULL;
1.69 + }
1.70 } else {
1.71 addr = os::reserve_memory(size, NULL, prefix_align);
1.72 }
1.73 @@ -222,11 +256,20 @@
1.74 bool special = large && !os::can_commit_large_page_memory();
1.75 char* base = NULL;
1.76
1.77 + if (requested_address != 0) {
1.78 + requested_address -= noaccess_prefix; // adjust requested address
1.79 + assert(requested_address != NULL, "huge noaccess prefix?");
1.80 + }
1.81 +
1.82 if (special) {
1.83
1.84 base = os::reserve_memory_special(size, requested_address, executable);
1.85
1.86 if (base != NULL) {
1.87 + if (failed_to_reserve_as_requested(base, requested_address, size, true)) {
1.88 + // OS ignored requested address. Try different address.
1.89 + return;
1.90 + }
1.91 // Check alignment constraints
1.92 if (alignment > 0) {
1.93 assert((uintptr_t) base % alignment == 0,
1.94 @@ -235,6 +278,13 @@
1.95 _special = true;
1.96 } else {
1.97 // failed; try to reserve regular memory below
1.98 + if (UseLargePages && (!FLAG_IS_DEFAULT(UseLargePages) ||
1.99 + !FLAG_IS_DEFAULT(LargePageSizeInBytes))) {
1.100 + if (PrintCompressedOopsMode) {
1.101 + tty->cr();
1.102 + tty->print_cr("Reserve regular memory without large pages.");
1.103 + }
1.104 + }
1.105 }
1.106 }
1.107
1.108 @@ -248,8 +298,11 @@
1.109 // important. If available space is not detected, return NULL.
1.110
1.111 if (requested_address != 0) {
1.112 - base = os::attempt_reserve_memory_at(size,
1.113 - requested_address-noaccess_prefix);
1.114 + base = os::attempt_reserve_memory_at(size, requested_address);
1.115 + if (failed_to_reserve_as_requested(base, requested_address, size, false)) {
1.116 + // OS ignored requested address. Try different address.
1.117 + base = NULL;
1.118 + }
1.119 } else {
1.120 base = os::reserve_memory(size, NULL, alignment);
1.121 }
1.122 @@ -365,7 +418,12 @@
1.123 }
1.124
1.125 void ReservedSpace::protect_noaccess_prefix(const size_t size) {
1.126 - // If there is noaccess prefix, return.
1.127 + assert( (_noaccess_prefix != 0) == (UseCompressedOops && _base != NULL &&
1.128 + (size_t(_base + _size) > OopEncodingHeapMax) &&
1.129 + Universe::narrow_oop_use_implicit_null_checks()),
1.130 + "noaccess_prefix should be used only with non zero based compressed oops");
1.131 +
1.132 + // If there is no noaccess prefix, return.
1.133 if (_noaccess_prefix == 0) return;
1.134
1.135 assert(_noaccess_prefix >= (size_t)os::vm_page_size(),
1.136 @@ -377,6 +435,10 @@
1.137 _special)) {
1.138 fatal("cannot protect protection page");
1.139 }
1.140 + if (PrintCompressedOopsMode) {
1.141 + tty->cr();
1.142 + tty->print_cr("Protected page at the reserved heap base: " PTR_FORMAT " / " INTX_FORMAT " bytes", _base, _noaccess_prefix);
1.143 + }
1.144
1.145 _base += _noaccess_prefix;
1.146 _size -= _noaccess_prefix;
