/* * Copyright (c) 2012, 2022, Oracle and/or its affiliates. All rights reserved. * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. * * This code is free software; you can redistribute it and/or modify it * under the terms of the GNU General Public License version 2 only, as * published by the Free Software Foundation. * * This code is distributed in the hope that it will be useful, but WITHOUT * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License * version 2 for more details (a copy is included in the LICENSE file that * accompanied this code). * * You should have received a copy of the GNU General Public License version * 2 along with this work; if not, write to the Free Software Foundation, * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. * * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA * or visit www.oracle.com if you need additional information or have any * questions. *
*/
// The CDS archive is divided into the following regions: // rw - read-write metadata // ro - read-only metadata and read-only tables // // ca0 - closed archive heap space #0 // ca1 - closed archive heap space #1 (may be empty) // oa0 - open archive heap space #0 // oa1 - open archive heap space #1 (may be empty) // // bm - bitmap for relocating the above 7 regions. // // The rw and ro regions are linearly allocated, in the order of rw->ro. // These regions are aligned with MetaspaceShared::core_region_alignment(). // // These 2 regions are populated in the following steps: // [0] All classes are loaded in MetaspaceShared::preload_classes(). All metadata are // temporarily allocated outside of the shared regions. // [1] We enter a safepoint and allocate a buffer for the rw/ro regions. // [2] C++ vtables are copied into the rw region. // [3] ArchiveBuilder copies RW metadata into the rw region. // [4] ArchiveBuilder copies RO metadata into the ro region. // [5] SymbolTable, StringTable, SystemDictionary, and a few other read-only data // are copied into the ro region as read-only tables. // // The ca0/ca1 and oa0/oa1 regions are populated inside HeapShared::archive_objects. // Their layout is independent of the rw/ro regions.
// os::vm_allocation_granularity() is usually 4K for most OSes. However, some platforms // such as linux-aarch64 and macos-x64 ... // it can be either 4K or 64K and on macos-aarch64 it is 16K. To generate archives that are // compatible for both settings, an alternative cds core region alignment can be enabled // at building time: // --enable-compactible-cds-alignment // Upon successful configuration, the compactible alignment then can be defined in: // os_linux_aarch64.cpp // os_bsd_x86.cpp
size_t MetaspaceShared::core_region_alignment() { return os::cds_core_region_alignment();
}
void do_cld(ClassLoaderData* cld) { for (Klass* klass = cld->klasses(); klass != NULL; klass = klass->next_link()) { if (klass->is_instance_klass()) {
dump(InstanceKlass::cast(klass));
}
}
}
};
void MetaspaceShared::dump_loaded_classes(constchar* file_name, TRAPS) {
fileStream stream(file_name, "w"); if (stream.is_open()) {
MutexLocker lock(ClassLoaderDataGraph_lock);
MutexLocker lock2(ClassListFile_lock, Mutex::_no_safepoint_check_flag);
DumpClassListCLDClosure collect_classes(&stream);
ClassLoaderDataGraph::loaded_cld_do(&collect_classes);
} else {
THROW_MSG(vmSymbols::java_io_IOException(), "Failed to open file");
}
}
staticbool shared_base_too_high(char* specified_base, char* aligned_base, size_t cds_max) { if (specified_base != NULL && aligned_base < specified_base) { // SharedBaseAddress is very high (e.g., 0xffffffffffffff00) so // align_up(SharedBaseAddress, MetaspaceShared::core_region_alignment()) has wrapped around. returntrue;
} if (max_uintx - uintx(aligned_base) < uintx(cds_max)) { // The end of the archive will wrap around returntrue;
}
// Make sure the default value of SharedBaseAddress specified in globals.hpp is sane.
assert(!shared_base_too_high(specified_base, aligned_base, cds_max), "Sanity");
assert(shared_base_valid(aligned_base), "Sanity"); return aligned_base;
}
void MetaspaceShared::initialize_for_static_dump() {
assert(DumpSharedSpaces, "should be called for dump time only");
log_info(cds)("Core region alignment: " SIZE_FORMAT, core_region_alignment()); // The max allowed size for CDS archive. We use this to limit SharedBaseAddress // to avoid address space wrap around.
size_t cds_max; const size_t reserve_alignment = core_region_alignment();
#ifdef _LP64 const uint64_t UnscaledClassSpaceMax = (uint64_t(max_juint) + 1);
cds_max = align_down(UnscaledClassSpaceMax, reserve_alignment); #else // We don't support archives larger than 256MB on 32-bit due to limited // virtual address space.
cds_max = align_down(256*M, reserve_alignment); #endif
if (HAS_PENDING_EXCEPTION) {
log_warning(cds, heap)("[line %d] extra interned string allocation failed; size too large: %d",
reader.last_line_no(), utf8_length);
CLEAR_PENDING_EXCEPTION;
} else { #if INCLUDE_G1GC if (UseG1GC) {
typeArrayOop body = java_lang_String::value(str); const HeapRegion* hr = G1CollectedHeap::heap()->heap_region_containing(body); if (hr->is_humongous()) { // Don't keep it alive, so it will be GC'ed before we dump the strings, in order // to maximize free heap space and minimize fragmentation.
log_warning(cds, heap)("[line %d] extra interned string ignored; size too large: %d",
reader.last_line_no(), utf8_length); continue;
}
} #endif // Make sure this string is included in the dumped interned string table.
assert(str != NULL, "must succeed");
_extra_interned_strings->append(OopHandle(Universe::vm_global(), str));
}
}
}
}
// Read/write a data stream for restoring/preserving metadata pointers and // miscellaneous data from/to the shared archive file.
void MetaspaceShared::serialize(SerializeClosure* soc) { int tag = 0;
soc->do_tag(--tag);
// Verify the sizes of various metadata in the system.
soc->do_tag(sizeof(Method));
soc->do_tag(sizeof(ConstMethod));
soc->do_tag(arrayOopDesc::base_offset_in_bytes(T_BYTE));
soc->do_tag(sizeof(ConstantPool));
soc->do_tag(sizeof(ConstantPoolCache));
soc->do_tag(objArrayOopDesc::base_offset_in_bytes());
soc->do_tag(typeArrayOopDesc::base_offset_in_bytes(T_BYTE));
soc->do_tag(sizeof(Symbol));
// Need to do this first, as subsequent steps may call virtual functions // in archived Metadata objects.
CppVtables::serialize(soc);
soc->do_tag(--tag);
staticvoid rewrite_nofast_bytecode(const methodHandle& method) {
BytecodeStream bcs(method); while (!bcs.is_last_bytecode()) {
Bytecodes::Code opcode = bcs.next(); switch (opcode) { case Bytecodes::_getfield: *bcs.bcp() = Bytecodes::_nofast_getfield; break; case Bytecodes::_putfield: *bcs.bcp() = Bytecodes::_nofast_putfield; break; case Bytecodes::_aload_0: *bcs.bcp() = Bytecodes::_nofast_aload_0; break; case Bytecodes::_iload: { if (!bcs.is_wide()) {
*bcs.bcp() = Bytecodes::_nofast_iload;
} break;
} default: break;
}
}
}
// [1] Rewrite all bytecodes as needed, so that the ConstMethod* will not be modified // at run time by RewriteBytecodes/RewriteFrequentPairs // [2] Assign a fingerprint, so one doesn't need to be assigned at run-time. void MetaspaceShared::rewrite_nofast_bytecodes_and_calculate_fingerprints(Thread* thread, InstanceKlass* ik) { for (int i = 0; i < ik->methods()->length(); i++) {
methodHandle m(thread, ik->methods()->at(i)); if (ik->can_be_verified_at_dumptime() && ik->is_linked()) {
rewrite_nofast_bytecode(m);
}
Fingerprinter fp(m); // The side effect of this call sets method's fingerprint field.
fp.fingerprint();
}
}
class VM_PopulateDumpSharedSpace : public VM_GC_Operation { private:
GrowableArray<MemRegion> *_closed_heap_regions;
GrowableArray<MemRegion> *_open_heap_regions;
// The above code should find all the symbols that are referenced by the // archived classes. We just need to add the extra symbols which // may not be used by any of the archived classes -- these are usually // symbols that we anticipate to be used at run time, so we can store // them in the RO region, to be shared across multiple processes. if (_extra_symbols != NULL) { for (int i = 0; i < _extra_symbols->length(); i++) {
it->push(_extra_symbols->adr_at(i));
}
}
}
};
// Write lambform lines into archive
LambdaFormInvokers::dump_static_archive_invokers(); // Write the other data to the output array.
DumpRegion* ro_region = ArchiveBuilder::current()->ro_region(); char* start = ro_region->top();
WriteClosure wc(ro_region);
MetaspaceShared::serialize(&wc);
// Write the bitmaps for patching the archive heap regions
dump_heap_bitmaps();
// Block concurrent class unloading from changing the _dumptime_table
MutexLocker ml(DumpTimeTable_lock, Mutex::_no_safepoint_check_flag);
SystemDictionaryShared::check_excluded_classes();
// The vtable clones contain addresses of the current process. // We don't want to write these addresses into the archive.
CppVtables::zero_archived_vtables();
// relocate the data so that it can be mapped to MetaspaceShared::requested_base_address() // without runtime relocation.
builder.relocate_to_requested();
// Write the archive file constchar* static_archive = Arguments::GetSharedArchivePath();
assert(static_archive != nullptr, "SharedArchiveFile not set?");
FileMapInfo* mapinfo = new FileMapInfo(static_archive, true);
mapinfo->populate_header(MetaspaceShared::core_region_alignment());
mapinfo->set_serialized_data(serialized_data);
mapinfo->set_cloned_vtables(cloned_vtables);
mapinfo->open_for_write();
builder.write_archive(mapinfo,
_closed_heap_regions,
_open_heap_regions,
_closed_heap_bitmaps,
_open_heap_bitmaps);
if (PrintSystemDictionaryAtExit) {
SystemDictionary::print();
}
if (AllowArchivingWithJavaAgent) {
warning("This archive was created with AllowArchivingWithJavaAgent. It should be used " "for testing purposes only and should not be used in a production environment");
}
// There may be pending VM operations. We have changed some global states // (such as vmClasses::_klasses) that may cause these VM operations // to fail. For safety, forget these operations and exit the VM directly.
os::_exit(0);
}
class CollectCLDClosure : public CLDClosure {
GrowableArray<ClassLoaderData*> _loaded_cld;
GrowableArray<OopHandle> _loaded_cld_handles; // keep the CLDs alive
Thread* _current_thread; public:
CollectCLDClosure(Thread* thread) : _current_thread(thread) {}
~CollectCLDClosure() { for (int i = 0; i < _loaded_cld_handles.length(); i++) {
_loaded_cld_handles.at(i).release(Universe::vm_global());
}
} void do_cld(ClassLoaderData* cld) {
assert(cld->is_alive(), "must be");
_loaded_cld.append(cld);
_loaded_cld_handles.append(OopHandle(Universe::vm_global(), cld->holder()));
}
// Check if we can eagerly link this class at dump time, so we can avoid the // runtime linking overhead (especially verification) bool MetaspaceShared::may_be_eagerly_linked(InstanceKlass* ik) { if (!ik->can_be_verified_at_dumptime()) { // For old classes, try to leave them in the unlinked state, so // we can still store them in the archive. They must be // linked/verified at runtime. returnfalse;
} if (DynamicDumpSharedSpaces && ik->is_shared_unregistered_class()) { // Linking of unregistered classes at this stage may cause more // classes to be resolved, resulting in calls to ClassLoader.loadClass() // that may not be expected by custom class loaders. // // It's OK to do this for the built-in loaders as we know they can // tolerate this. (Note that unregistered classes are loaded by the NULL // loader during DumpSharedSpaces). returnfalse;
} returntrue;
}
bool MetaspaceShared::link_class_for_cds(InstanceKlass* ik, TRAPS) { // Link the class to cause the bytecodes to be rewritten and the // cpcache to be created. Class verification is done according // to -Xverify setting. bool res = MetaspaceShared::try_link_class(THREAD, ik);
ClassPrelinker::dumptime_resolve_constants(ik, CHECK_(false)); return res;
}
if (!jcmd_request) {
LambdaFormInvokers::regenerate_holder_classes(CHECK);
}
// Collect all loaded ClassLoaderData.
CollectCLDClosure collect_cld(THREAD);
{ // ClassLoaderDataGraph::loaded_cld_do requires ClassLoaderDataGraph_lock. // We cannot link the classes while holding this lock (or else we may run into deadlock). // Therefore, we need to first collect all the CLDs, and then link their classes after // releasing the lock.
MutexLocker lock(ClassLoaderDataGraph_lock);
ClassLoaderDataGraph::loaded_cld_do(&collect_cld);
}
while (true) { bool has_linked = false; for (int i = 0; i < collect_cld.nof_cld(); i++) {
ClassLoaderData* cld = collect_cld.cld_at(i); for (Klass* klass = cld->klasses(); klass != NULL; klass = klass->next_link()) { if (klass->is_instance_klass()) {
InstanceKlass* ik = InstanceKlass::cast(klass); if (may_be_eagerly_linked(ik)) {
has_linked |= link_class_for_cds(ik, CHECK);
}
}
}
}
if (!has_linked) { break;
} // Class linking includes verification which may load more classes. // Keep scanning until we have linked no more classes.
}
}
// Preload classes from a list, populate the shared spaces and dump to a // file. void MetaspaceShared::preload_and_dump() {
EXCEPTION_MARK;
ResourceMark rm(THREAD);
preload_and_dump_impl(THREAD); if (HAS_PENDING_EXCEPTION) { if (PENDING_EXCEPTION->is_a(vmClasses::OutOfMemoryError_klass())) {
vm_direct_exit(-1, err_msg("Out of memory. Please run with a larger Java heap, current MaxHeapSize = "
SIZE_FORMAT "M", MaxHeapSize/M));
} else {
log_error(cds)("%s: %s", PENDING_EXCEPTION->klass()->external_name(),
java_lang_String::as_utf8_string(java_lang_Throwable::message(PENDING_EXCEPTION)));
vm_direct_exit(-1, "VM exits due to exception, use -Xlog:cds,exceptions=trace for detail");
}
} else { // On success, the VM_PopulateDumpSharedSpace op should have // exited the VM.
ShouldNotReachHere();
}
}
#if INCLUDE_CDS_JAVA_HEAP && defined(_LP64) void MetaspaceShared::adjust_heap_sizes_for_dumping() { if (!DumpSharedSpaces || UseCompressedOops) { return;
} // CDS heap dumping requires all string oops to have an offset // from the heap bottom that can be encoded in 32-bit.
julong max_heap_size = (julong)(4 * G);
if (MinHeapSize > max_heap_size) {
log_debug(cds)("Setting MinHeapSize to 4G for CDS dumping, original size = " SIZE_FORMAT "M", MinHeapSize/M);
FLAG_SET_ERGO(MinHeapSize, max_heap_size);
} if (InitialHeapSize > max_heap_size) {
log_debug(cds)("Setting InitialHeapSize to 4G for CDS dumping, original size = "SIZE_FORMAT "M", InitialHeapSize/M);
FLAG_SET_ERGO(InitialHeapSize, max_heap_size);
} if (MaxHeapSize > max_heap_size) {
log_debug(cds)("Setting MaxHeapSize to 4G for CDS dumping, original size = " SIZE_FORMAT "M", MaxHeapSize/M);
FLAG_SET_ERGO(MaxHeapSize, max_heap_size);
}
} #endif// INCLUDE_CDS_JAVA_HEAP && _LP64
void MetaspaceShared::get_default_classlist(char* default_classlist, const size_t buf_size) { // Construct the path to the class list (in jre/lib) // Walk up two directories from the location of the VM and // optionally tack on "lib" (depending on platform)
os::jvm_path(default_classlist, (jint)(buf_size)); for (int i = 0; i < 3; i++) { char *end = strrchr(default_classlist, *os::file_separator()); if (end != NULL) *end = '\0';
}
size_t classlist_path_len = strlen(default_classlist); if (classlist_path_len >= 3) { if (strcmp(default_classlist + classlist_path_len - 3, "lib") != 0) { if (classlist_path_len < buf_size - 4) {
jio_snprintf(default_classlist + classlist_path_len,
buf_size - classlist_path_len, "%slib", os::file_separator());
classlist_path_len += 4;
}
}
} if (classlist_path_len < buf_size - 10) {
jio_snprintf(default_classlist + classlist_path_len,
buf_size - classlist_path_len, "%sclasslist", os::file_separator());
}
}
log_info(cds)("Loading classes to share ...");
_has_error_classes = false; int class_count = ClassListParser::parse_classlist(classlist_path,
ClassListParser::_parse_all, CHECK); if (ExtraSharedClassListFile) {
class_count += ClassListParser::parse_classlist(ExtraSharedClassListFile,
ClassListParser::_parse_all, CHECK);
} if (classlist_path != default_classlist) { struct stat statbuf; if (os::stat(default_classlist, &statbuf) == 0) { // File exists, let's use it.
class_count += ClassListParser::parse_classlist(default_classlist,
ClassListParser::_parse_lambda_forms_invokers_only, CHECK);
}
}
// Exercise the manifest processing code to ensure classes used by CDS at runtime // are always archived constchar* dummy = "Manifest-Version: 1.0\n";
CDSProtectionDomain::create_jar_manifest(dummy, strlen(dummy), CHECK);
if (SharedArchiveConfigFile) {
log_info(cds)("Reading extra data from %s ...", SharedArchiveConfigFile);
read_extra_data(THREAD, SharedArchiveConfigFile);
log_info(cds)("Reading extra data: done.");
}
HeapShared::init_for_dumping(CHECK);
// Rewrite and link classes
log_info(cds)("Rewriting and linking classes ...");
// Link any classes which got missed. This would happen if we have loaded classes that // were not explicitly specified in the classlist. E.g., if an interface implemented by class K // fails verification, all other interfaces that were not specified in the classlist but // are implemented by K are not verified.
link_shared_classes(false/*not from jcmd*/, CHECK);
log_info(cds)("Rewriting and linking classes: done");
#if INCLUDE_CDS_JAVA_HEAP if (use_full_module_graph()) {
HeapShared::reset_archived_object_states(CHECK);
} #endif
// Returns true if the class's status has changed. bool MetaspaceShared::try_link_class(JavaThread* current, InstanceKlass* ik) {
ExceptionMark em(current);
JavaThread* THREAD = current; // For exception macros.
Arguments::assert_is_dumping_archive(); if (ik->is_loaded() && !ik->is_linked() && ik->can_be_verified_at_dumptime() &&
!SystemDictionaryShared::has_class_failed_verification(ik)) { bool saved = BytecodeVerificationLocal; if (ik->is_shared_unregistered_class() && ik->class_loader() == NULL) { // The verification decision is based on BytecodeVerificationRemote // for non-system classes. Since we are using the NULL classloader // to load non-system classes for customized class loaders during dumping, // we need to temporarily change BytecodeVerificationLocal to be the same as // BytecodeVerificationRemote. Note this can cause the parent system // classes also being verified. The extra overhead is acceptable during // dumping.
BytecodeVerificationLocal = BytecodeVerificationRemote;
}
ik->link_class(THREAD); if (HAS_PENDING_EXCEPTION) {
ResourceMark rm(THREAD);
log_warning(cds)("Preload Warning: Verification failed for %s",
ik->external_name());
CLEAR_PENDING_EXCEPTION;
SystemDictionaryShared::set_class_has_failed_verification(ik);
_has_error_classes = true;
}
BytecodeVerificationLocal = saved; returntrue;
} else { returnfalse;
}
}
#if INCLUDE_CDS_JAVA_HEAP void VM_PopulateDumpSharedSpace::dump_java_heap_objects(GrowableArray<Klass*>* klasses) { if(!HeapShared::can_write()) {
log_info(cds)( "Archived java heap is not supported as UseG1GC " "and UseCompressedClassPointers are required." "Current settings: UseG1GC=%s, UseCompressedClassPointers=%s.",
BOOL_TO_STR(UseG1GC), BOOL_TO_STR(UseCompressedClassPointers)); return;
} // Find all the interned strings that should be dumped. int i; for (i = 0; i < klasses->length(); i++) {
Klass* k = klasses->at(i); if (k->is_instance_klass()) {
InstanceKlass* ik = InstanceKlass::cast(k); if (ik->is_linked()) {
ik->constants()->add_dumped_interned_strings();
}
}
} if (_extra_interned_strings != NULL) { for (i = 0; i < _extra_interned_strings->length(); i ++) {
OopHandle string = _extra_interned_strings->at(i);
HeapShared::add_to_dumped_interned_strings(string.resolve());
}
}
// The closed and open archive heap space has maximum two regions. // See FileMapInfo::write_heap_regions() for details.
_closed_heap_regions = new GrowableArray<MemRegion>(2);
_open_heap_regions = new GrowableArray<MemRegion>(2);
HeapShared::archive_objects(_closed_heap_regions, _open_heap_regions);
ArchiveBuilder::OtherROAllocMark mark;
HeapShared::write_subgraph_info_table();
}
void VM_PopulateDumpSharedSpace::dump_heap_bitmaps() { if (HeapShared::can_write()) {
_closed_heap_bitmaps = new GrowableArray<ArchiveHeapBitmapInfo>(2);
dump_heap_bitmaps(_closed_heap_regions, _closed_heap_bitmaps);
_open_heap_bitmaps = new GrowableArray<ArchiveHeapBitmapInfo>(2);
dump_heap_bitmaps(_open_heap_regions, _open_heap_bitmaps);
}
}
void VM_PopulateDumpSharedSpace::dump_heap_bitmaps(GrowableArray<MemRegion>* regions,
GrowableArray<ArchiveHeapBitmapInfo>* bitmaps) { for (int i = 0; i < regions->length(); i++) {
MemRegion region = regions->at(i);
ResourceBitMap oopmap = HeapShared::calculate_oopmap(region);
ResourceBitMap ptrmap = HeapShared::calculate_ptrmap(region);
dump_one_heap_bitmap(region, bitmaps, oopmap, true);
dump_one_heap_bitmap(region, bitmaps, ptrmap, false);
}
}
void MetaspaceShared::initialize_runtime_shared_and_meta_spaces() {
assert(UseSharedSpaces, "Must be called when UseSharedSpaces is enabled");
MapArchiveResult result = MAP_ARCHIVE_OTHER_FAILURE;
if (static_mapinfo != NULL) {
log_info(cds)("Core region alignment: " SIZE_FORMAT, static_mapinfo->core_region_alignment());
dynamic_mapinfo = open_dynamic_archive();
// First try to map at the requested address
result = map_archives(static_mapinfo, dynamic_mapinfo, true); if (result == MAP_ARCHIVE_MMAP_FAILURE) { // Mapping has failed (probably due to ASLR). Let's map at an address chosen // by the OS.
log_info(cds)("Try to map archive(s) at an alternative address");
result = map_archives(static_mapinfo, dynamic_mapinfo, false);
}
}
if (result == MAP_ARCHIVE_SUCCESS) { bool dynamic_mapped = (dynamic_mapinfo != NULL && dynamic_mapinfo->is_mapped()); char* cds_base = static_mapinfo->mapped_base(); char* cds_end = dynamic_mapped ? dynamic_mapinfo->mapped_end() : static_mapinfo->mapped_end();
set_shared_metaspace_range(cds_base, static_mapinfo->mapped_end(), cds_end);
_relocation_delta = static_mapinfo->relocation_delta();
_requested_base_address = static_mapinfo->requested_base_address(); if (dynamic_mapped) {
FileMapInfo::set_shared_path_table(dynamic_mapinfo); // turn AutoCreateSharedArchive off if successfully mapped
AutoCreateSharedArchive = false;
} else {
FileMapInfo::set_shared_path_table(static_mapinfo);
}
} else {
set_shared_metaspace_range(NULL, NULL, NULL); if (DynamicDumpSharedSpaces) {
warning("-XX:ArchiveClassesAtExit is unsupported when base CDS archive is not loaded. Run with -Xlog:cds for more info.");
}
UseSharedSpaces = false; // The base archive cannot be mapped. We cannot dump the dynamic shared archive.
AutoCreateSharedArchive = false;
DynamicDumpSharedSpaces = false;
FileMapInfo::fail_continue("Unable to map shared spaces"); if (PrintSharedArchiveAndExit) {
vm_exit_during_initialization("Unable to use shared archive.");
}
}
FileMapInfo* mapinfo = new FileMapInfo(dynamic_archive, false); if (!mapinfo->initialize()) { delete(mapinfo); return NULL;
} return mapinfo;
}
// use_requested_addr: // true = map at FileMapHeader::_requested_base_address // false = map at an alternative address picked by OS.
MapArchiveResult MetaspaceShared::map_archives(FileMapInfo* static_mapinfo, FileMapInfo* dynamic_mapinfo, bool use_requested_addr) { if (use_requested_addr && static_mapinfo->requested_base_address() == NULL) {
log_info(cds)("Archive(s) were created with -XX:SharedBaseAddress=0. Always map at os-selected address."); return MAP_ARCHIVE_MMAP_FAILURE;
}
PRODUCT_ONLY(if (ArchiveRelocationMode == 1 && use_requested_addr) { // For product build only -- this is for benchmarking the cost of doing relocation. // For debug builds, the check is done below, after reserving the space, for better test coverage // (see comment below).
log_info(cds)("ArchiveRelocationMode == 1: always map archive(s) at an alternative address"); return MAP_ARCHIVE_MMAP_FAILURE;
});
if (ArchiveRelocationMode == 2 && !use_requested_addr) {
log_info(cds)("ArchiveRelocationMode == 2: never map archive(s) at an alternative address"); return MAP_ARCHIVE_MMAP_FAILURE;
};
if (dynamic_mapinfo != NULL) { // Ensure that the OS won't be able to allocate new memory spaces between the two // archives, or else it would mess up the simple comparison in MetaspaceObj::is_shared().
assert(static_mapinfo->mapping_end_offset() == dynamic_mapinfo->mapping_base_offset(), "no gap");
}
ReservedSpace total_space_rs, archive_space_rs, class_space_rs;
MapArchiveResult result = MAP_ARCHIVE_OTHER_FAILURE; char* mapped_base_address = reserve_address_space_for_archives(static_mapinfo,
dynamic_mapinfo,
use_requested_addr,
total_space_rs,
archive_space_rs,
class_space_rs); if (mapped_base_address == NULL) {
result = MAP_ARCHIVE_MMAP_FAILURE;
log_debug(cds)("Failed to reserve spaces (use_requested_addr=%u)", (unsigned)use_requested_addr);
} else {
#ifdef ASSERT // Some sanity checks after reserving address spaces for archives // and class space.
assert(archive_space_rs.is_reserved(), "Sanity"); if (Metaspace::using_class_space()) { // Class space must closely follow the archive space. Both spaces // must be aligned correctly.
assert(class_space_rs.is_reserved(), "A class space should have been reserved");
assert(class_space_rs.base() >= archive_space_rs.end(), "class space should follow the cds archive space");
assert(is_aligned(archive_space_rs.base(),
core_region_alignment()), "Archive space misaligned");
assert(is_aligned(class_space_rs.base(),
Metaspace::reserve_alignment()), "class space misaligned");
} #endif// ASSERT
if (MetaspaceShared::use_windows_memory_mapping()) { // We have now reserved address space for the archives, and will map in // the archive files into this space. // // Special handling for Windows: on Windows we cannot map a file view // into an existing memory mapping. So, we unmap the address range we // just reserved again, which will make it available for mapping the // archives. // Reserving this range has not been for naught however since it makes // us reasonably sure the address range is available. // // But still it may fail, since between unmapping the range and mapping // in the archive someone else may grab the address space. Therefore // there is a fallback in FileMap::map_region() where we just read in // the archive files sequentially instead of mapping it in. We couple // this with use_requested_addr, since we're going to patch all the // pointers anyway so there's no benefit to mmap. if (use_requested_addr) {
assert(!total_space_rs.is_reserved(), "Should not be reserved for Windows");
log_info(cds)("Windows mmap workaround: releasing archive space.");
archive_space_rs.release();
}
}
MapArchiveResult static_result = map_archive(static_mapinfo, mapped_base_address, archive_space_rs);
MapArchiveResult dynamic_result = (static_result == MAP_ARCHIVE_SUCCESS) ?
map_archive(dynamic_mapinfo, mapped_base_address, archive_space_rs) : MAP_ARCHIVE_OTHER_FAILURE;
DEBUG_ONLY(if (ArchiveRelocationMode == 1 && use_requested_addr) { // This is for simulating mmap failures at the requested address. In // debug builds, we do it here (after all archives have possibly been // mapped), so we can thoroughly test the code for failure handling // (releasing all allocated resource, etc).
log_info(cds)("ArchiveRelocationMode == 1: always map archive(s) at an alternative address"); if (static_result == MAP_ARCHIVE_SUCCESS) {
static_result = MAP_ARCHIVE_MMAP_FAILURE;
} if (dynamic_result == MAP_ARCHIVE_SUCCESS) {
dynamic_result = MAP_ARCHIVE_MMAP_FAILURE;
}
});
if (static_result == MAP_ARCHIVE_SUCCESS) { if (dynamic_result == MAP_ARCHIVE_SUCCESS) {
result = MAP_ARCHIVE_SUCCESS;
} elseif (dynamic_result == MAP_ARCHIVE_OTHER_FAILURE) {
assert(dynamic_mapinfo != NULL && !dynamic_mapinfo->is_mapped(), "must have failed"); // No need to retry mapping the dynamic archive again, as it will never succeed // (bad file, etc) -- just keep the base archive.
log_warning(cds, dynamic)("Unable to use shared archive. The top archive failed to load: %s",
dynamic_mapinfo->full_path());
result = MAP_ARCHIVE_SUCCESS; // TODO, we can give the unused space for the dynamic archive to class_space_rs, but there's no // easy API to do that right now.
} else {
result = MAP_ARCHIVE_MMAP_FAILURE;
}
} elseif (static_result == MAP_ARCHIVE_OTHER_FAILURE) {
result = MAP_ARCHIVE_OTHER_FAILURE;
} else {
result = MAP_ARCHIVE_MMAP_FAILURE;
}
}
if (result == MAP_ARCHIVE_SUCCESS) {
SharedBaseAddress = (size_t)mapped_base_address;
LP64_ONLY({ if (Metaspace::using_class_space()) { // Set up ccs in metaspace.
Metaspace::initialize_class_space(class_space_rs);
// Set up compressed Klass pointer encoding: the encoding range must // cover both archive and class space.
address cds_base = (address)static_mapinfo->mapped_base();
address ccs_end = (address)class_space_rs.end();
assert(ccs_end > cds_base, "Sanity check");
CompressedKlassPointers::initialize(cds_base, ccs_end - cds_base);
// map_heap_regions() compares the current narrow oop and klass encodings // with the archived ones, so it must be done after all encodings are determined.
static_mapinfo->map_or_load_heap_regions();
}
});
log_info(cds)("optimized module handling: %s", MetaspaceShared::use_optimized_module_handling() ? "enabled" : "disabled");
log_info(cds)("full module graph: %s", MetaspaceShared::use_full_module_graph() ? "enabled" : "disabled");
} else {
unmap_archive(static_mapinfo);
unmap_archive(dynamic_mapinfo);
release_reserved_spaces(total_space_rs, archive_space_rs, class_space_rs);
}
return result;
}
// This will reserve two address spaces suitable to house Klass structures, one // for the cds archives (static archive and optionally dynamic archive) and // optionally one move for ccs. // // Since both spaces must fall within the compressed class pointer encoding // range, they are allocated close to each other. // // Space for archives will be reserved first, followed by a potential gap, // followed by the space for ccs: // // +-- Base address A B End // | | | | // v v v v // +-------------+--------------+ +----------------------+ // | static arc | [dyn. arch] | [gap] | compr. class space | // +-------------+--------------+ +----------------------+ // // (The gap may result from different alignment requirements between metaspace // and CDS) // // If UseCompressedClassPointers is disabled, only one address space will be // reserved: // // +-- Base address End // | | // v v // +-------------+--------------+ // | static arc | [dyn. arch] | // +-------------+--------------+ // // Base address: If use_archive_base_addr address is true, the Base address is // determined by the address stored in the static archive. If // use_archive_base_addr address is false, this base address is determined // by the platform. // // If UseCompressedClassPointers=1, the range encompassing both spaces will be // suitable to en/decode narrow Klass pointers: the base will be valid for // encoding, the range [Base, End) not surpass KlassEncodingMetaspaceMax. // // Return: // // - On success: // - total_space_rs will be reserved as whole for archive_space_rs and // class_space_rs if UseCompressedClassPointers is true. // On Windows, try reserve archive_space_rs and class_space_rs // separately first if use_archive_base_addr is true. // - archive_space_rs will be reserved and large enough to host static and // if needed dynamic archive: [Base, A). // archive_space_rs.base and size will be aligned to CDS reserve // granularity. // - class_space_rs: If UseCompressedClassPointers=1, class_space_rs will // be reserved. Its start address will be aligned to metaspace reserve // alignment, which may differ from CDS alignment. It will follow the cds // archive space, close enough such that narrow class pointer encoding // covers both spaces. // If UseCompressedClassPointers=0, class_space_rs remains unreserved. // - On error: NULL is returned and the spaces remain unreserved. char* MetaspaceShared::reserve_address_space_for_archives(FileMapInfo* static_mapinfo,
FileMapInfo* dynamic_mapinfo, bool use_archive_base_addr,
ReservedSpace& total_space_rs,
ReservedSpace& archive_space_rs,
ReservedSpace& class_space_rs) {
// Size and requested location of the archive_space_rs (for both static and dynamic archives)
assert(static_mapinfo->mapping_base_offset() == 0, "Must be");
size_t archive_end_offset = (dynamic_mapinfo == NULL) ? static_mapinfo->mapping_end_offset() : dynamic_mapinfo->mapping_end_offset();
size_t archive_space_size = align_up(archive_end_offset, archive_space_alignment);
// If a base address is given, it must have valid alignment and be suitable as encoding base. if (base_address != NULL) {
assert(is_aligned(base_address, archive_space_alignment), "Archive base address invalid: " PTR_FORMAT ".", p2i(base_address)); if (Metaspace::using_class_space()) {
assert(CompressedKlassPointers::is_valid_base(base_address), "Archive base address invalid: " PTR_FORMAT ".", p2i(base_address));
}
}
if (!Metaspace::using_class_space()) { // Get the simple case out of the way first: // no compressed class space, simple allocation.
archive_space_rs = ReservedSpace(archive_space_size, archive_space_alignment,
os::vm_page_size(), (char*)base_address); if (archive_space_rs.is_reserved()) {
assert(base_address == NULL ||
(address)archive_space_rs.base() == base_address, "Sanity"); // Register archive space with NMT.
MemTracker::record_virtual_memory_type(archive_space_rs.base(), mtClassShared); return archive_space_rs.base();
} return NULL;
}
#ifdef _LP64
// Complex case: two spaces adjacent to each other, both to be addressable // with narrow class pointers. // We reserve the whole range spanning both spaces, then split that range up.
// To simplify matters, lets assume that metaspace alignment will always be // equal or a multiple of archive alignment.
assert(is_power_of_2(class_space_alignment) &&
is_power_of_2(archive_space_alignment) &&
class_space_alignment >= archive_space_alignment, "Sanity");
assert(total_range_size > ccs_begin_offset, "must be"); if (use_windows_memory_mapping() && use_archive_base_addr) { if (base_address != nullptr) { // On Windows, we cannot safely split a reserved memory space into two (see JDK-8255917). // Hence, we optimistically reserve archive space and class space side-by-side. We only // do this for use_archive_base_addr=true since for use_archive_base_addr=false case // caller will not split the combined space for mapping, instead read the archive data // via sequential file IO.
address ccs_base = base_address + archive_space_size + gap_size;
archive_space_rs = ReservedSpace(archive_space_size, archive_space_alignment,
os::vm_page_size(), (char*)base_address);
class_space_rs = ReservedSpace(class_space_size, class_space_alignment,
os::vm_page_size(), (char*)ccs_base);
} if (!archive_space_rs.is_reserved() || !class_space_rs.is_reserved()) {
release_reserved_spaces(total_space_rs, archive_space_rs, class_space_rs); return NULL;
}
} else { if (use_archive_base_addr && base_address != nullptr) {
total_space_rs = ReservedSpace(total_range_size, archive_space_alignment,
os::vm_page_size(), (char*) base_address);
} else { // Reserve at any address, but leave it up to the platform to choose a good one.
total_space_rs = Metaspace::reserve_address_space_for_compressed_classes(total_range_size);
}
if (!total_space_rs.is_reserved()) { return NULL;
}
// Now split up the space into ccs and cds archive. For simplicity, just leave // the gap reserved at the end of the archive space. Do not do real splitting.
archive_space_rs = total_space_rs.first_part(ccs_begin_offset,
(size_t)archive_space_alignment);
class_space_rs = total_space_rs.last_part(ccs_begin_offset);
MemTracker::record_virtual_memory_split_reserved(total_space_rs.base(), total_space_rs.size(),
ccs_begin_offset);
}
assert(is_aligned(archive_space_rs.base(), archive_space_alignment), "Sanity");
assert(is_aligned(archive_space_rs.size(), archive_space_alignment), "Sanity");
assert(is_aligned(class_space_rs.base(), class_space_alignment), "Sanity");
assert(is_aligned(class_space_rs.size(), class_space_alignment), "Sanity");
// NMT: fix up the space tags
MemTracker::record_virtual_memory_type(archive_space_rs.base(), mtClassShared);
MemTracker::record_virtual_memory_type(class_space_rs.base(), mtClass);
return archive_space_rs.base();
#else
ShouldNotReachHere(); return NULL; #endif
}
void MetaspaceShared::release_reserved_spaces(ReservedSpace& total_space_rs,
ReservedSpace& archive_space_rs,
ReservedSpace& class_space_rs) { if (total_space_rs.is_reserved()) {
log_debug(cds)("Released shared space (archive + class) " INTPTR_FORMAT, p2i(total_space_rs.base()));
total_space_rs.release();
} else { if (archive_space_rs.is_reserved()) {
log_debug(cds)("Released shared space (archive) " INTPTR_FORMAT, p2i(archive_space_rs.base()));
archive_space_rs.release();
} if (class_space_rs.is_reserved()) {
log_debug(cds)("Released shared space (classes) " INTPTR_FORMAT, p2i(class_space_rs.base()));
class_space_rs.release();
}
}
}
MapArchiveResult MetaspaceShared::map_archive(FileMapInfo* mapinfo, char* mapped_base_address, ReservedSpace rs) {
assert(UseSharedSpaces, "must be runtime"); if (mapinfo == NULL) { return MAP_ARCHIVE_SUCCESS; // The dynamic archive has not been specified. No error has happened -- trivially succeeded.
}
// Verify various attributes of the archive, plus initialize the // shared string/symbol tables. char* buffer = static_mapinfo->serialized_data();
intptr_t* array = (intptr_t*)buffer;
ReadClosure rc(&array);
serialize(&rc);
// Initialize the run-time symbol table.
SymbolTable::create_table();
// Finish up archived heap initialization. These must be // done after ReadClosure.
static_mapinfo->patch_heap_embedded_pointers();
ArchiveHeapLoader::finish_initialization();
// Set up LambdaFormInvokers::_lambdaform_lines for dynamic dump if (DynamicDumpSharedSpaces) { // Read stored LF format lines stored in static archive
LambdaFormInvokers::read_static_archive_invokers();
}
if (PrintSharedArchiveAndExit) { // Print archive names if (dynamic_mapinfo != nullptr) {
tty->print_cr("\n\nBase archive name: %s", Arguments::GetSharedArchivePath());
tty->print_cr("Base archive version %d", static_mapinfo->version());
} else {
tty->print_cr("Static archive name: %s", static_mapinfo->full_path());
tty->print_cr("Static archive version %d", static_mapinfo->version());
}
SystemDictionaryShared::print_shared_archive(tty); if (dynamic_mapinfo != nullptr) {
tty->print_cr("\n\nDynamic archive name: %s", dynamic_mapinfo->full_path());
tty->print_cr("Dynamic archive version %d", dynamic_mapinfo->version());
SystemDictionaryShared::print_shared_archive(tty, false/*dynamic*/);
}
// collect shared symbols and strings
CountSharedSymbols cl;
SymbolTable::shared_symbols_do(&cl);
tty->print_cr("Number of shared symbols: %d", cl.total());
tty->print_cr("Number of shared strings: %zu", StringTable::shared_entry_count());
tty->print_cr("VM version: %s\r\n", static_mapinfo->vm_version()); if (FileMapInfo::current_info() == NULL || _archive_loading_failed) {
tty->print_cr("archive is invalid");
vm_exit(1);
} else {
tty->print_cr("archive is valid");
vm_exit(0);
}
}
}
// JVM/TI RedefineClasses() support: bool MetaspaceShared::remap_shared_readonly_as_readwrite() {
assert(SafepointSynchronize::is_at_safepoint(), "must be at safepoint");
if (UseSharedSpaces) { // remap the shared readonly space to shared readwrite, private
FileMapInfo* mapinfo = FileMapInfo::current_info(); if (!mapinfo->remap_shared_readonly_as_readwrite()) { returnfalse;
} if (FileMapInfo::dynamic_info() != NULL) {
mapinfo = FileMapInfo::dynamic_info(); if (!mapinfo->remap_shared_readonly_as_readwrite()) { returnfalse;
}
}
_remapped_readwrite = true;
} returntrue;
}
bool MetaspaceShared::use_full_module_graph() { #if INCLUDE_CDS_JAVA_HEAP if (ClassLoaderDataShared::is_full_module_graph_loaded()) { returntrue;
} #endif bool result = _use_optimized_module_handling && _use_full_module_graph; if (DumpSharedSpaces) {
result &= HeapShared::can_write();
} elseif (UseSharedSpaces) {
result &= ArchiveHeapLoader::can_use();
} else {
result = false;
}
if (result && UseSharedSpaces) { // Classes used by the archived full module graph are loaded in JVMTI early phase.
assert(!(JvmtiExport::should_post_class_file_load_hook() && JvmtiExport::has_early_class_hook_env()), "CDS should be disabled if early class hooks are enabled");
} return result;
}
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