diff -r fa2f93f99dbc -r b96466cdfc45 src/hotspot/share/memory/heapShared.cpp --- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/src/hotspot/share/memory/heapShared.cpp Sun Jul 08 12:43:05 2018 -0400 @@ -0,0 +1,506 @@ +/* + * Copyright (c) 2018, 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. + * + */ + +#include "precompiled.hpp" +#include "classfile/javaClasses.inline.hpp" +#include "classfile/vmSymbols.hpp" +#include "logging/log.hpp" +#include "logging/logMessage.hpp" +#include "logging/logStream.hpp" +#include "memory/heapShared.hpp" +#include "memory/iterator.inline.hpp" +#include "memory/metadataFactory.hpp" +#include "memory/metaspaceClosure.hpp" +#include "memory/metaspaceShared.hpp" +#include "memory/resourceArea.hpp" +#include "oops/compressedOops.inline.hpp" +#include "oops/oop.inline.hpp" + +#if INCLUDE_CDS_JAVA_HEAP +KlassSubGraphInfo* HeapShared::_subgraph_info_list = NULL; +int HeapShared::_num_archived_subgraph_info_records = 0; +Array* HeapShared::_archived_subgraph_info_records = NULL; + +// Currently there is only one class mirror (ArchivedModuleGraph) with archived +// sub-graphs. +KlassSubGraphInfo* HeapShared::find_subgraph_info(Klass* k) { + KlassSubGraphInfo* info = _subgraph_info_list; + while (info != NULL) { + if (info->klass() == k) { + return info; + } + info = info->next(); + } + return NULL; +} + +// Get the subgraph_info for Klass k. A new subgraph_info is created if +// there is no existing one for k. The subgraph_info records the relocated +// Klass* of the original k. +KlassSubGraphInfo* HeapShared::get_subgraph_info(Klass* k) { + Klass* relocated_k = MetaspaceShared::get_relocated_klass(k); + KlassSubGraphInfo* info = find_subgraph_info(relocated_k); + if (info != NULL) { + return info; + } + + info = new KlassSubGraphInfo(relocated_k, _subgraph_info_list); + _subgraph_info_list = info; + return info; +} + +int HeapShared::num_of_subgraph_infos() { + int num = 0; + KlassSubGraphInfo* info = _subgraph_info_list; + while (info != NULL) { + num ++; + info = info->next(); + } + return num; +} + +// Add an entry field to the current KlassSubGraphInfo. +void KlassSubGraphInfo::add_subgraph_entry_field(int static_field_offset, oop v) { + assert(DumpSharedSpaces, "dump time only"); + if (_subgraph_entry_fields == NULL) { + _subgraph_entry_fields = + new(ResourceObj::C_HEAP, mtClass) GrowableArray(10, true); + } + _subgraph_entry_fields->append((juint)static_field_offset); + _subgraph_entry_fields->append(CompressedOops::encode(v)); +} + +// Add the Klass* for an object in the current KlassSubGraphInfo's subgraphs. +// Only objects of boot classes can be included in sub-graph. +void KlassSubGraphInfo::add_subgraph_object_klass(Klass* orig_k, Klass *relocated_k) { + assert(DumpSharedSpaces, "dump time only"); + assert(relocated_k == MetaspaceShared::get_relocated_klass(orig_k), + "must be the relocated Klass in the shared space"); + + if (_subgraph_object_klasses == NULL) { + _subgraph_object_klasses = + new(ResourceObj::C_HEAP, mtClass) GrowableArray(50, true); + } + + assert(relocated_k->is_shared(), "must be a shared class"); + if (relocated_k->is_instance_klass()) { + assert(InstanceKlass::cast(relocated_k)->is_shared_boot_class(), + "must be boot class"); + // SystemDictionary::xxx_klass() are not updated, need to check + // the original Klass* + if (orig_k == SystemDictionary::String_klass() || + orig_k == SystemDictionary::Object_klass()) { + // Initialized early during VM initialization. No need to be added + // to the sub-graph object class list. + return; + } + } else if (relocated_k->is_objArray_klass()) { + Klass* abk = ObjArrayKlass::cast(relocated_k)->bottom_klass(); + if (abk->is_instance_klass()) { + assert(InstanceKlass::cast(abk)->is_shared_boot_class(), + "must be boot class"); + } + if (relocated_k == Universe::objectArrayKlassObj()) { + // Initialized early during Universe::genesis. No need to be added + // to the list. + return; + } + } else { + assert(relocated_k->is_typeArray_klass(), "must be"); + // Primitive type arrays are created early during Universe::genesis. + return; + } + + _subgraph_object_klasses->append_if_missing(relocated_k); +} + +// Initialize an archived subgraph_info_record from the given KlassSubGraphInfo. +void ArchivedKlassSubGraphInfoRecord::init(KlassSubGraphInfo* info) { + _k = info->klass(); + _next = NULL; + _entry_field_records = NULL; + _subgraph_klasses = NULL; + + // populate the entry fields + GrowableArray* entry_fields = info->subgraph_entry_fields(); + if (entry_fields != NULL) { + int num_entry_fields = entry_fields->length(); + assert(num_entry_fields % 2 == 0, "sanity"); + _entry_field_records = + MetaspaceShared::new_ro_array(num_entry_fields); + for (int i = 0 ; i < num_entry_fields; i++) { + _entry_field_records->at_put(i, entry_fields->at(i)); + } + } + + // the Klasses of the objects in the sub-graphs + GrowableArray* subgraph_klasses = info->subgraph_object_klasses(); + if (subgraph_klasses != NULL) { + int num_subgraphs_klasses = subgraph_klasses->length(); + _subgraph_klasses = + MetaspaceShared::new_ro_array(num_subgraphs_klasses); + for (int i = 0; i < num_subgraphs_klasses; i++) { + Klass* subgraph_k = subgraph_klasses->at(i); + if (log_is_enabled(Info, cds, heap)) { + ResourceMark rm; + log_info(cds, heap)( + "Archived object klass (%d): %s in %s sub-graphs", + i, subgraph_k->external_name(), _k->external_name()); + } + _subgraph_klasses->at_put(i, subgraph_k); + } + } +} + +// Build the records of archived subgraph infos, which include: +// - Entry points to all subgraphs from the containing class mirror. The entry +// points are static fields in the mirror. For each entry point, the field +// offset and value are recorded in the sub-graph info. The value are stored +// back to the corresponding field at runtime. +// - A list of klasses that need to be loaded/initialized before archived +// java object sub-graph can be accessed at runtime. +// +// The records are saved in the archive file and reloaded at runtime. Currently +// there is only one class mirror (ArchivedModuleGraph) with archived sub-graphs. +// +// Layout of the archived subgraph info records: +// +// records_size | num_records | records* +// ArchivedKlassSubGraphInfoRecord | entry_fields | subgraph_object_klasses +size_t HeapShared::build_archived_subgraph_info_records(int num_records) { + // remember the start address + char* start_p = MetaspaceShared::read_only_space_top(); + + // now populate the archived subgraph infos, which will be saved in the + // archive file + _archived_subgraph_info_records = + MetaspaceShared::new_ro_array(num_records); + KlassSubGraphInfo* info = _subgraph_info_list; + int i = 0; + while (info != NULL) { + assert(i < _archived_subgraph_info_records->length(), "sanity"); + ArchivedKlassSubGraphInfoRecord* record = + _archived_subgraph_info_records->adr_at(i); + record->init(info); + info = info->next(); + i ++; + } + + // _subgraph_info_list is no longer needed + delete _subgraph_info_list; + _subgraph_info_list = NULL; + + char* end_p = MetaspaceShared::read_only_space_top(); + size_t records_size = end_p - start_p; + return records_size; +} + +// Write the subgraph info records in the shared _ro region +void HeapShared::write_archived_subgraph_infos() { + assert(DumpSharedSpaces, "dump time only"); + + Array* records_header = MetaspaceShared::new_ro_array(3); + + _num_archived_subgraph_info_records = num_of_subgraph_infos(); + size_t records_size = build_archived_subgraph_info_records( + _num_archived_subgraph_info_records); + + // Now write the header information: + // records_size, num_records, _archived_subgraph_info_records + assert(records_header != NULL, "sanity"); + intptr_t* p = (intptr_t*)(records_header->data()); + *p = (intptr_t)records_size; + p ++; + *p = (intptr_t)_num_archived_subgraph_info_records; + p ++; + *p = (intptr_t)_archived_subgraph_info_records; +} + +char* HeapShared::read_archived_subgraph_infos(char* buffer) { + Array* records_header = (Array*)buffer; + intptr_t* p = (intptr_t*)(records_header->data()); + size_t records_size = (size_t)(*p); + p ++; + _num_archived_subgraph_info_records = *p; + p ++; + _archived_subgraph_info_records = + (Array*)(*p); + + buffer = (char*)_archived_subgraph_info_records + records_size; + return buffer; +} + +void HeapShared::initialize_from_archived_subgraph(Klass* k) { + if (!MetaspaceShared::open_archive_heap_region_mapped()) { + return; // nothing to do + } + + if (_num_archived_subgraph_info_records == 0) { + return; // no subgraph info records + } + + // Initialize from archived data. Currently only ArchivedModuleGraph + // has archived object subgraphs, which is used during VM initialization + // time when bootstraping the system modules. No lock is needed. + Thread* THREAD = Thread::current(); + for (int i = 0; i < _archived_subgraph_info_records->length(); i++) { + ArchivedKlassSubGraphInfoRecord* record = _archived_subgraph_info_records->adr_at(i); + if (record->klass() == k) { + int i; + // Found the archived subgraph info record for the requesting klass. + // Load/link/initialize the klasses of the objects in the subgraph. + // NULL class loader is used. + Array* klasses = record->subgraph_klasses(); + if (klasses != NULL) { + for (i = 0; i < klasses->length(); i++) { + Klass* obj_k = klasses->at(i); + Klass* resolved_k = SystemDictionary::resolve_or_null( + (obj_k)->name(), THREAD); + if (resolved_k != obj_k) { + return; + } + if ((obj_k)->is_instance_klass()) { + InstanceKlass* ik = InstanceKlass::cast(obj_k); + ik->initialize(THREAD); + } else if ((obj_k)->is_objArray_klass()) { + ObjArrayKlass* oak = ObjArrayKlass::cast(obj_k); + oak->initialize(THREAD); + } + } + } + + if (HAS_PENDING_EXCEPTION) { + CLEAR_PENDING_EXCEPTION; + // None of the field value will be set if there was an exception. + // The java code will not see any of the archived objects in the + // subgraphs referenced from k in this case. + return; + } + + // Load the subgraph entry fields from the record and store them back to + // the corresponding fields within the mirror. + oop m = k->java_mirror(); + Array* entry_field_records = record->entry_field_records(); + if (entry_field_records != NULL) { + int efr_len = entry_field_records->length(); + assert(efr_len % 2 == 0, "sanity"); + for (i = 0; i < efr_len;) { + int field_offset = entry_field_records->at(i); + // The object refereced by the field becomes 'known' by GC from this + // point. All objects in the subgraph reachable from the object are + // also 'known' by GC. + oop v = MetaspaceShared::materialize_archived_object( + CompressedOops::decode(entry_field_records->at(i+1))); + m->obj_field_put(field_offset, v); + i += 2; + } + } + + // Done. Java code can see the archived sub-graphs referenced from k's + // mirror after this point. + return; + } + } +} + +class WalkOopAndArchiveClosure: public BasicOopIterateClosure { + int _level; + KlassSubGraphInfo* _subgraph_info; + oop _orig_referencing_obj; + oop _archived_referencing_obj; + public: + WalkOopAndArchiveClosure(int level, KlassSubGraphInfo* subgraph_info, + oop orig, oop archived) : _level(level), + _subgraph_info(subgraph_info), + _orig_referencing_obj(orig), + _archived_referencing_obj(archived) {} + void do_oop(narrowOop *p) { WalkOopAndArchiveClosure::do_oop_work(p); } + void do_oop( oop *p) { WalkOopAndArchiveClosure::do_oop_work(p); } + + protected: + template void do_oop_work(T *p) { + oop obj = RawAccess<>::oop_load(p); + if (!CompressedOops::is_null(obj)) { + // A java.lang.Class instance can not be included in an archived + // object sub-graph. + if (java_lang_Class::is_instance(obj)) { + tty->print("Unknown java.lang.Class object is in the archived sub-graph\n"); + vm_exit(1); + } + + LogTarget(Debug, cds, heap) log; + LogStream ls(log); + outputStream* out = &ls; + { + ResourceMark rm; + log.print("(%d) %s <--- referenced from: %s", + _level, obj->klass()->external_name(), + CompressedOops::is_null(_orig_referencing_obj) ? + "" : _orig_referencing_obj->klass()->external_name()); + obj->print_on(out); + } + + if (MetaspaceShared::is_archive_object(obj)) { + // The current oop is an archived oop, nothing needs to be done + log.print("--- object is already archived ---"); + return; + } + + size_t field_delta = pointer_delta( + p, _orig_referencing_obj, sizeof(char)); + T* new_p = (T*)(address(_archived_referencing_obj) + field_delta); + oop archived = MetaspaceShared::find_archived_heap_object(obj); + if (archived != NULL) { + // There is an archived copy existing, update reference to point + // to the archived copy + RawAccess::oop_store(new_p, archived); + log.print( + "--- found existing archived copy, store archived " PTR_FORMAT " in " PTR_FORMAT, + p2i(archived), p2i(new_p)); + return; + } + + int l = _level + 1; + Thread* THREAD = Thread::current(); + // Archive the current oop before iterating through its references + archived = MetaspaceShared::archive_heap_object(obj, THREAD); + assert(MetaspaceShared::is_archive_object(archived), "must be archived"); + log.print("=== archiving oop " PTR_FORMAT " ==> " PTR_FORMAT, + p2i(obj), p2i(archived)); + + // Following the references in the current oop and archive any + // encountered objects during the process + WalkOopAndArchiveClosure walker(l, _subgraph_info, obj, archived); + obj->oop_iterate(&walker); + + // Update the reference in the archived copy of the referencing object + RawAccess::oop_store(new_p, archived); + log.print("=== store archived " PTR_FORMAT " in " PTR_FORMAT, + p2i(archived), p2i(new_p)); + + // Add the klass to the list of classes that need to be loaded before + // module system initialization + Klass *orig_k = obj->klass(); + Klass *relocated_k = archived->klass(); + _subgraph_info->add_subgraph_object_klass(orig_k, relocated_k); + } + } +}; + +// +// Start from the given static field in a java mirror and archive the +// complete sub-graph of java heap objects that are reached directly +// or indirectly from the starting object by following references. +// Currently, only ArchivedModuleGraph class instance (mirror) has archived +// object subgraphs. Sub-graph archiving restrictions (current): +// +// - All classes of objects in the archived sub-graph (including the +// entry class) must be boot class only. +// - No java.lang.Class instance (java mirror) can be included inside +// an archived sub-graph. Mirror can only be the sub-graph entry object. +// +// The Java heap object sub-graph archiving process (see +// WalkOopAndArchiveClosure): +// +// 1) Java object sub-graph archiving starts from a given static field +// within a Class instance (java mirror). If the static field is a +// refererence field and points to a non-null java object, proceed to +// the next step. +// +// 2) Archives the referenced java object. If an archived copy of the +// current object already exists, updates the pointer in the archived +// copy of the referencing object to point to the current archived object. +// Otherwise, proceed to the next step. +// +// 3) Follows all references within the current java object and recursively +// archive the sub-graph of objects starting from each reference. +// +// 4) Updates the pointer in the archived copy of referencing object to +// point to the current archived object. +// +// 5) The Klass of the current java object is added to the list of Klasses +// for loading and initialzing before any object in the archived graph can +// be accessed at runtime. +// +void HeapShared::archive_reachable_objects_from_static_field(Klass *k, + int field_offset, + BasicType field_type, + TRAPS) { + assert(DumpSharedSpaces, "dump time only"); + assert(k->is_instance_klass(), "sanity"); + assert(InstanceKlass::cast(k)->is_shared_boot_class(), + "must be boot class"); + + oop m = k->java_mirror(); + oop archived_m = MetaspaceShared::find_archived_heap_object(m); + if (CompressedOops::is_null(archived_m)) { + return; + } + + if (field_type == T_OBJECT) { + // obtain k's subGraph Info + KlassSubGraphInfo* subgraph_info = get_subgraph_info(k); + + // get the object referenced by the field + oop f = m->obj_field(field_offset); + if (!CompressedOops::is_null(f)) { + LogTarget(Debug, cds, heap) log; + LogStream ls(log); + outputStream* out = &ls; + log.print("Start from: "); + f->print_on(out); + + // get the archived copy of the field referenced object + oop af = MetaspaceShared::archive_heap_object(f, THREAD); + if (!MetaspaceShared::is_archive_object(f)) { + WalkOopAndArchiveClosure walker(1, subgraph_info, f, af); + f->oop_iterate(&walker); + } + + // The field value is not preserved in the archived mirror. + // Record the field as a new subGraph entry point. The recorded + // information is restored from the archive at runtime. + subgraph_info->add_subgraph_entry_field(field_offset, af); + Klass *relocated_k = af->klass(); + Klass *orig_k = f->klass(); + subgraph_info->add_subgraph_object_klass(orig_k, relocated_k); + } else { + // The field contains null, we still need to record the entry point, + // so it can be restored at runtime. + subgraph_info->add_subgraph_entry_field(field_offset, NULL); + } + } else { + ShouldNotReachHere(); + } +} + +#define do_module_object_graph(archive_object_graph_do) \ + archive_object_graph_do(SystemDictionary::ArchivedModuleGraph_klass(), jdk_internal_module_ArchivedModuleGraph::archivedSystemModules_offset(), T_OBJECT, CHECK); \ + archive_object_graph_do(SystemDictionary::ArchivedModuleGraph_klass(), jdk_internal_module_ArchivedModuleGraph::archivedModuleFinder_offset(), T_OBJECT, CHECK); \ + archive_object_graph_do(SystemDictionary::ArchivedModuleGraph_klass(), jdk_internal_module_ArchivedModuleGraph::archivedMainModule_offset(), T_OBJECT, CHECK) + +void HeapShared::archive_module_graph_objects(Thread* THREAD) { + do_module_object_graph(archive_reachable_objects_from_static_field); +} +#endif // INCLUDE_CDS_JAVA_HEAP