Mercurial > hg > graal-jvmci-8
view src/share/vm/memory/metaspaceShared.cpp @ 20304:a22acf6d7598
8048112: G1 Full GC needs to support the case when the very first region is not available
Summary: Refactor preparation for compaction during Full GC so that it lazily initializes the first compaction point. This also avoids problems later when the first region may not be committed. Also reviewed by K. Barrett.
Reviewed-by: brutisso
author | tschatzl |
---|---|
date | Mon, 21 Jul 2014 10:00:31 +0200 |
parents | 78bbf4d43a14 |
children | 52b4284cb496 ca6d25be853b 6e0cb14ce59b |
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/* * Copyright (c) 2012, 2014, 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/dictionary.hpp" #include "classfile/loaderConstraints.hpp" #include "classfile/placeholders.hpp" #include "classfile/symbolTable.hpp" #include "classfile/systemDictionary.hpp" #include "code/codeCache.hpp" #include "memory/filemap.hpp" #include "memory/gcLocker.hpp" #include "memory/metaspace.hpp" #include "memory/metaspaceShared.hpp" #include "oops/objArrayOop.hpp" #include "oops/oop.inline.hpp" #include "runtime/signature.hpp" #include "runtime/vm_operations.hpp" #include "runtime/vmThread.hpp" #include "utilities/hashtable.inline.hpp" PRAGMA_FORMAT_MUTE_WARNINGS_FOR_GCC int MetaspaceShared::_max_alignment = 0; ReservedSpace* MetaspaceShared::_shared_rs = NULL; // 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)); // Dump/restore miscellaneous metadata. Universe::serialize(soc, true); soc->do_tag(--tag); // Dump/restore references to commonly used names and signatures. vmSymbols::serialize(soc); soc->do_tag(--tag); soc->do_tag(666); } // CDS code for dumping shared archive. // Global object for holding classes that have been loaded. Since this // is run at a safepoint just before exit, this is the entire set of classes. static GrowableArray<Klass*>* _global_klass_objects; static void collect_classes(Klass* k) { _global_klass_objects->append_if_missing(k); if (k->oop_is_instance()) { // Add in the array classes too InstanceKlass* ik = InstanceKlass::cast(k); ik->array_klasses_do(collect_classes); } } static void remove_unshareable_in_classes() { for (int i = 0; i < _global_klass_objects->length(); i++) { Klass* k = _global_klass_objects->at(i); k->remove_unshareable_info(); } } // Walk all methods in the class list and assign a fingerprint. // so that this part of the ConstMethod* is read only. static void calculate_fingerprints() { for (int i = 0; i < _global_klass_objects->length(); i++) { Klass* k = _global_klass_objects->at(i); if (k->oop_is_instance()) { InstanceKlass* ik = InstanceKlass::cast(k); for (int i = 0; i < ik->methods()->length(); i++) { Method* m = ik->methods()->at(i); Fingerprinter fp(m); // The side effect of this call sets method's fingerprint field. fp.fingerprint(); } } } } // Patch C++ vtable pointer in metadata. // Klass and other metadata objects contain references to c++ vtables in the // JVM library. // Fix them to point to our constructed vtables. However, don't iterate // across the space while doing this, as that causes the vtables to be // patched, undoing our useful work. Instead, iterate to make a list, // then use the list to do the fixing. // // Our constructed vtables: // Dump time: // 1. init_self_patching_vtbl_list: table of pointers to current virtual method addrs // 2. generate_vtable_methods: create jump table, appended to above vtbl_list // 3. patch_klass_vtables: for Klass list, patch the vtable entry in klass and // associated metadata to point to jump table rather than to current vtbl // Table layout: NOTE FIXED SIZE // 1. vtbl pointers // 2. #Klass X #virtual methods per Klass // 1 entry for each, in the order: // Klass1:method1 entry, Klass1:method2 entry, ... Klass1:method<num_virtuals> entry // Klass2:method1 entry, Klass2:method2 entry, ... Klass2:method<num_virtuals> entry // ... // Klass<vtbl_list_size>:method1 entry, Klass<vtbl_list_size>:method2 entry, // ... Klass<vtbl_list_size>:method<num_virtuals> entry // Sample entry: (Sparc): // save(sp, -256, sp) // ba,pt common_code // mov XXX, %L0 %L0 gets: Klass index <<8 + method index (note: max method index 255) // // Restore time: // 1. initialize_shared_space: reserve space for table // 2. init_self_patching_vtbl_list: update pointers to NEW virtual method addrs in text // // Execution time: // First virtual method call for any object of these metadata types: // 1. object->klass // 2. vtable entry for that klass points to the jump table entries // 3. branches to common_code with %O0/klass, %L0: Klass index <<8 + method index // 4. common_code: // Get address of new vtbl pointer for this Klass from updated table // Update new vtbl pointer in the Klass: future virtual calls go direct // Jump to method, using new vtbl pointer and method index static void* find_matching_vtbl_ptr(void** vtbl_list, void* new_vtable_start, void* obj) { void* old_vtbl_ptr = *(void**)obj; for (int i = 0; i < MetaspaceShared::vtbl_list_size; i++) { if (vtbl_list[i] == old_vtbl_ptr) { return (void**)new_vtable_start + i * MetaspaceShared::num_virtuals; } } ShouldNotReachHere(); return NULL; } // Assumes the vtable is in first slot in object. static void patch_klass_vtables(void** vtbl_list, void* new_vtable_start) { int n = _global_klass_objects->length(); for (int i = 0; i < n; i++) { Klass* obj = _global_klass_objects->at(i); // Note oop_is_instance() is a virtual call. After patching vtables // all virtual calls on the dummy vtables will restore the original! if (obj->oop_is_instance()) { InstanceKlass* ik = InstanceKlass::cast(obj); *(void**)ik = find_matching_vtbl_ptr(vtbl_list, new_vtable_start, ik); ConstantPool* cp = ik->constants(); *(void**)cp = find_matching_vtbl_ptr(vtbl_list, new_vtable_start, cp); for (int j = 0; j < ik->methods()->length(); j++) { Method* m = ik->methods()->at(j); *(void**)m = find_matching_vtbl_ptr(vtbl_list, new_vtable_start, m); } } else { // Array klasses Klass* k = obj; *(void**)k = find_matching_vtbl_ptr(vtbl_list, new_vtable_start, k); } } } // Closure for serializing initialization data out to a data area to be // written to the shared file. class WriteClosure : public SerializeClosure { private: intptr_t* top; char* end; inline void check_space() { if ((char*)top + sizeof(intptr_t) > end) { report_out_of_shared_space(SharedMiscData); } } public: WriteClosure(char* md_top, char* md_end) { top = (intptr_t*)md_top; end = md_end; } char* get_top() { return (char*)top; } void do_ptr(void** p) { check_space(); *top = (intptr_t)*p; ++top; } void do_tag(int tag) { check_space(); *top = (intptr_t)tag; ++top; } void do_region(u_char* start, size_t size) { if ((char*)top + size > end) { report_out_of_shared_space(SharedMiscData); } assert((intptr_t)start % sizeof(intptr_t) == 0, "bad alignment"); assert(size % sizeof(intptr_t) == 0, "bad size"); do_tag((int)size); while (size > 0) { *top = *(intptr_t*)start; ++top; start += sizeof(intptr_t); size -= sizeof(intptr_t); } } bool reading() const { return false; } }; // This is for dumping detailed statistics for the allocations // in the shared spaces. class DumpAllocClosure : public Metaspace::AllocRecordClosure { public: // Here's poor man's enum inheritance #define SHAREDSPACE_OBJ_TYPES_DO(f) \ METASPACE_OBJ_TYPES_DO(f) \ f(SymbolHashentry) \ f(SymbolBuckets) \ f(Other) #define SHAREDSPACE_OBJ_TYPE_DECLARE(name) name ## Type, #define SHAREDSPACE_OBJ_TYPE_NAME_CASE(name) case name ## Type: return #name; enum Type { // Types are MetaspaceObj::ClassType, MetaspaceObj::SymbolType, etc SHAREDSPACE_OBJ_TYPES_DO(SHAREDSPACE_OBJ_TYPE_DECLARE) _number_of_types }; static const char * type_name(Type type) { switch(type) { SHAREDSPACE_OBJ_TYPES_DO(SHAREDSPACE_OBJ_TYPE_NAME_CASE) default: ShouldNotReachHere(); return NULL; } } public: enum { RO = 0, RW = 1 }; int _counts[2][_number_of_types]; int _bytes [2][_number_of_types]; int _which; DumpAllocClosure() { memset(_counts, 0, sizeof(_counts)); memset(_bytes, 0, sizeof(_bytes)); }; void iterate_metaspace(Metaspace* space, int which) { assert(which == RO || which == RW, "sanity"); _which = which; space->iterate(this); } virtual void doit(address ptr, MetaspaceObj::Type type, int byte_size) { assert(int(type) >= 0 && type < MetaspaceObj::_number_of_types, "sanity"); _counts[_which][type] ++; _bytes [_which][type] += byte_size; } void dump_stats(int ro_all, int rw_all, int md_all, int mc_all); }; void DumpAllocClosure::dump_stats(int ro_all, int rw_all, int md_all, int mc_all) { rw_all += (md_all + mc_all); // md and mc are all mapped Read/Write int other_bytes = md_all + mc_all; // Calculate size of data that was not allocated by Metaspace::allocate() int symbol_count = _counts[RO][MetaspaceObj::SymbolType]; int symhash_bytes = symbol_count * sizeof (HashtableEntry<Symbol*, mtSymbol>); int symbuck_count = SymbolTable::the_table()->table_size(); int symbuck_bytes = symbuck_count * sizeof(HashtableBucket<mtSymbol>); _counts[RW][SymbolHashentryType] = symbol_count; _bytes [RW][SymbolHashentryType] = symhash_bytes; other_bytes -= symhash_bytes; _counts[RW][SymbolBucketsType] = symbuck_count; _bytes [RW][SymbolBucketsType] = symbuck_bytes; other_bytes -= symbuck_bytes; // TODO: count things like dictionary, vtable, etc _bytes[RW][OtherType] = other_bytes; // prevent divide-by-zero if (ro_all < 1) { ro_all = 1; } if (rw_all < 1) { rw_all = 1; } int all_ro_count = 0; int all_ro_bytes = 0; int all_rw_count = 0; int all_rw_bytes = 0; // To make fmt_stats be a syntactic constant (for format warnings), use #define. #define fmt_stats "%-20s: %8d %10d %5.1f | %8d %10d %5.1f | %8d %10d %5.1f" const char *sep = "--------------------+---------------------------+---------------------------+--------------------------"; const char *hdr = " ro_cnt ro_bytes % | rw_cnt rw_bytes % | all_cnt all_bytes %"; tty->print_cr("Detailed metadata info (rw includes md and mc):"); tty->print_cr("%s", hdr); tty->print_cr("%s", sep); for (int type = 0; type < int(_number_of_types); type ++) { const char *name = type_name((Type)type); int ro_count = _counts[RO][type]; int ro_bytes = _bytes [RO][type]; int rw_count = _counts[RW][type]; int rw_bytes = _bytes [RW][type]; int count = ro_count + rw_count; int bytes = ro_bytes + rw_bytes; double ro_perc = 100.0 * double(ro_bytes) / double(ro_all); double rw_perc = 100.0 * double(rw_bytes) / double(rw_all); double perc = 100.0 * double(bytes) / double(ro_all + rw_all); tty->print_cr(fmt_stats, name, ro_count, ro_bytes, ro_perc, rw_count, rw_bytes, rw_perc, count, bytes, perc); all_ro_count += ro_count; all_ro_bytes += ro_bytes; all_rw_count += rw_count; all_rw_bytes += rw_bytes; } int all_count = all_ro_count + all_rw_count; int all_bytes = all_ro_bytes + all_rw_bytes; double all_ro_perc = 100.0 * double(all_ro_bytes) / double(ro_all); double all_rw_perc = 100.0 * double(all_rw_bytes) / double(rw_all); double all_perc = 100.0 * double(all_bytes) / double(ro_all + rw_all); tty->print_cr("%s", sep); tty->print_cr(fmt_stats, "Total", all_ro_count, all_ro_bytes, all_ro_perc, all_rw_count, all_rw_bytes, all_rw_perc, all_count, all_bytes, all_perc); assert(all_ro_bytes == ro_all, "everything should have been counted"); assert(all_rw_bytes == rw_all, "everything should have been counted"); #undef fmt_stats } // Populate the shared space. class VM_PopulateDumpSharedSpace: public VM_Operation { private: ClassLoaderData* _loader_data; GrowableArray<Klass*> *_class_promote_order; VirtualSpace _md_vs; VirtualSpace _mc_vs; public: VM_PopulateDumpSharedSpace(ClassLoaderData* loader_data, GrowableArray<Klass*> *class_promote_order) : _loader_data(loader_data) { // Split up and initialize the misc code and data spaces ReservedSpace* shared_rs = MetaspaceShared::shared_rs(); int metadata_size = SharedReadOnlySize+SharedReadWriteSize; ReservedSpace shared_ro_rw = shared_rs->first_part(metadata_size); ReservedSpace misc_section = shared_rs->last_part(metadata_size); // Now split into misc sections. ReservedSpace md_rs = misc_section.first_part(SharedMiscDataSize); ReservedSpace mc_rs = misc_section.last_part(SharedMiscDataSize); _md_vs.initialize(md_rs, SharedMiscDataSize); _mc_vs.initialize(mc_rs, SharedMiscCodeSize); _class_promote_order = class_promote_order; } VMOp_Type type() const { return VMOp_PopulateDumpSharedSpace; } void doit(); // outline because gdb sucks }; // class VM_PopulateDumpSharedSpace void VM_PopulateDumpSharedSpace::doit() { Thread* THREAD = VMThread::vm_thread(); NOT_PRODUCT(SystemDictionary::verify();) // The following guarantee is meant to ensure that no loader constraints // exist yet, since the constraints table is not shared. This becomes // more important now that we don't re-initialize vtables/itables for // shared classes at runtime, where constraints were previously created. guarantee(SystemDictionary::constraints()->number_of_entries() == 0, "loader constraints are not saved"); guarantee(SystemDictionary::placeholders()->number_of_entries() == 0, "placeholders are not saved"); // Revisit and implement this if we prelink method handle call sites: guarantee(SystemDictionary::invoke_method_table() == NULL || SystemDictionary::invoke_method_table()->number_of_entries() == 0, "invoke method table is not saved"); // At this point, many classes have been loaded. // Gather systemDictionary classes in a global array and do everything to // that so we don't have to walk the SystemDictionary again. _global_klass_objects = new GrowableArray<Klass*>(1000); Universe::basic_type_classes_do(collect_classes); SystemDictionary::classes_do(collect_classes); tty->print_cr("Number of classes %d", _global_klass_objects->length()); // Update all the fingerprints in the shared methods. tty->print("Calculating fingerprints ... "); calculate_fingerprints(); tty->print_cr("done. "); // Remove all references outside the metadata tty->print("Removing unshareable information ... "); remove_unshareable_in_classes(); tty->print_cr("done. "); // Set up the share data and shared code segments. char* md_low = _md_vs.low(); char* md_top = md_low; char* md_end = _md_vs.high(); char* mc_low = _mc_vs.low(); char* mc_top = mc_low; char* mc_end = _mc_vs.high(); // Reserve space for the list of Klass*s whose vtables are used // for patching others as needed. void** vtbl_list = (void**)md_top; int vtbl_list_size = MetaspaceShared::vtbl_list_size; Universe::init_self_patching_vtbl_list(vtbl_list, vtbl_list_size); md_top += vtbl_list_size * sizeof(void*); void* vtable = md_top; // Reserve space for a new dummy vtable for klass objects in the // heap. Generate self-patching vtable entries. MetaspaceShared::generate_vtable_methods(vtbl_list, &vtable, &md_top, md_end, &mc_top, mc_end); // Reorder the system dictionary. (Moving the symbols affects // how the hash table indices are calculated.) // Not doing this either. SystemDictionary::reorder_dictionary(); NOT_PRODUCT(SystemDictionary::verify();) // Copy the the symbol table, and the system dictionary to the shared // space in usable form. Copy the hastable // buckets first [read-write], then copy the linked lists of entries // [read-only]. SymbolTable::reverse(md_top); NOT_PRODUCT(SymbolTable::verify()); SymbolTable::copy_buckets(&md_top, md_end); SystemDictionary::reverse(); SystemDictionary::copy_buckets(&md_top, md_end); ClassLoader::verify(); ClassLoader::copy_package_info_buckets(&md_top, md_end); ClassLoader::verify(); SymbolTable::copy_table(&md_top, md_end); SystemDictionary::copy_table(&md_top, md_end); ClassLoader::verify(); ClassLoader::copy_package_info_table(&md_top, md_end); ClassLoader::verify(); // Write the other data to the output array. WriteClosure wc(md_top, md_end); MetaspaceShared::serialize(&wc); md_top = wc.get_top(); // Print shared spaces all the time // To make fmt_space be a syntactic constant (for format warnings), use #define. #define fmt_space "%s space: %9d [ %4.1f%% of total] out of %9d bytes [%4.1f%% used] at " PTR_FORMAT Metaspace* ro_space = _loader_data->ro_metaspace(); Metaspace* rw_space = _loader_data->rw_metaspace(); // Allocated size of each space (may not be all occupied) const size_t ro_alloced = ro_space->capacity_bytes_slow(Metaspace::NonClassType); const size_t rw_alloced = rw_space->capacity_bytes_slow(Metaspace::NonClassType); const size_t md_alloced = md_end-md_low; const size_t mc_alloced = mc_end-mc_low; const size_t total_alloced = ro_alloced + rw_alloced + md_alloced + mc_alloced; // Occupied size of each space. const size_t ro_bytes = ro_space->used_bytes_slow(Metaspace::NonClassType); const size_t rw_bytes = rw_space->used_bytes_slow(Metaspace::NonClassType); const size_t md_bytes = size_t(md_top - md_low); const size_t mc_bytes = size_t(mc_top - mc_low); // Percent of total size const size_t total_bytes = ro_bytes + rw_bytes + md_bytes + mc_bytes; const double ro_t_perc = ro_bytes / double(total_bytes) * 100.0; const double rw_t_perc = rw_bytes / double(total_bytes) * 100.0; const double md_t_perc = md_bytes / double(total_bytes) * 100.0; const double mc_t_perc = mc_bytes / double(total_bytes) * 100.0; // Percent of fullness of each space const double ro_u_perc = ro_bytes / double(ro_alloced) * 100.0; const double rw_u_perc = rw_bytes / double(rw_alloced) * 100.0; const double md_u_perc = md_bytes / double(md_alloced) * 100.0; const double mc_u_perc = mc_bytes / double(mc_alloced) * 100.0; const double total_u_perc = total_bytes / double(total_alloced) * 100.0; tty->print_cr(fmt_space, "ro", ro_bytes, ro_t_perc, ro_alloced, ro_u_perc, ro_space->bottom()); tty->print_cr(fmt_space, "rw", rw_bytes, rw_t_perc, rw_alloced, rw_u_perc, rw_space->bottom()); tty->print_cr(fmt_space, "md", md_bytes, md_t_perc, md_alloced, md_u_perc, md_low); tty->print_cr(fmt_space, "mc", mc_bytes, mc_t_perc, mc_alloced, mc_u_perc, mc_low); tty->print_cr("total : %9d [100.0%% of total] out of %9d bytes [%4.1f%% used]", total_bytes, total_alloced, total_u_perc); // Update the vtable pointers in all of the Klass objects in the // heap. They should point to newly generated vtable. patch_klass_vtables(vtbl_list, vtable); // dunno what this is for. char* saved_vtbl = (char*)os::malloc(vtbl_list_size * sizeof(void*), mtClass); memmove(saved_vtbl, vtbl_list, vtbl_list_size * sizeof(void*)); memset(vtbl_list, 0, vtbl_list_size * sizeof(void*)); // Create and write the archive file that maps the shared spaces. FileMapInfo* mapinfo = new FileMapInfo(); mapinfo->populate_header(MetaspaceShared::max_alignment()); // Pass 1 - update file offsets in header. mapinfo->write_header(); mapinfo->write_space(MetaspaceShared::ro, _loader_data->ro_metaspace(), true); mapinfo->write_space(MetaspaceShared::rw, _loader_data->rw_metaspace(), false); mapinfo->write_region(MetaspaceShared::md, _md_vs.low(), pointer_delta(md_top, _md_vs.low(), sizeof(char)), SharedMiscDataSize, false, false); mapinfo->write_region(MetaspaceShared::mc, _mc_vs.low(), pointer_delta(mc_top, _mc_vs.low(), sizeof(char)), SharedMiscCodeSize, true, true); // Pass 2 - write data. mapinfo->open_for_write(); mapinfo->write_header(); mapinfo->write_space(MetaspaceShared::ro, _loader_data->ro_metaspace(), true); mapinfo->write_space(MetaspaceShared::rw, _loader_data->rw_metaspace(), false); mapinfo->write_region(MetaspaceShared::md, _md_vs.low(), pointer_delta(md_top, _md_vs.low(), sizeof(char)), SharedMiscDataSize, false, false); mapinfo->write_region(MetaspaceShared::mc, _mc_vs.low(), pointer_delta(mc_top, _mc_vs.low(), sizeof(char)), SharedMiscCodeSize, true, true); mapinfo->close(); memmove(vtbl_list, saved_vtbl, vtbl_list_size * sizeof(void*)); if (PrintSharedSpaces) { DumpAllocClosure dac; dac.iterate_metaspace(_loader_data->ro_metaspace(), DumpAllocClosure::RO); dac.iterate_metaspace(_loader_data->rw_metaspace(), DumpAllocClosure::RW); dac.dump_stats(int(ro_bytes), int(rw_bytes), int(md_bytes), int(mc_bytes)); } #undef fmt_space } static void link_shared_classes(Klass* obj, TRAPS) { Klass* k = obj; if (k->oop_is_instance()) { InstanceKlass* ik = (InstanceKlass*) k; // Link the class to cause the bytecodes to be rewritten and the // cpcache to be created. if (ik->init_state() < InstanceKlass::linked) { ik->link_class(THREAD); guarantee(!HAS_PENDING_EXCEPTION, "exception in class rewriting"); } } } // Support for a simple checksum of the contents of the class list // file to prevent trivial tampering. The algorithm matches that in // the MakeClassList program used by the J2SE build process. #define JSUM_SEED ((jlong)CONST64(0xcafebabebabecafe)) static jlong jsum(jlong start, const char *buf, const int len) { jlong h = start; char *p = (char *)buf, *e = p + len; while (p < e) { char c = *p++; if (c <= ' ') { /* Skip spaces and control characters */ continue; } h = 31 * h + c; } return h; } // Preload classes from a list, populate the shared spaces and dump to a // file. void MetaspaceShared::preload_and_dump(TRAPS) { TraceTime timer("Dump Shared Spaces", TraceStartupTime); ResourceMark rm; // Preload classes to be shared. // Should use some os:: method rather than fopen() here. aB. // 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) char class_list_path[JVM_MAXPATHLEN]; os::jvm_path(class_list_path, sizeof(class_list_path)); for (int i = 0; i < 3; i++) { char *end = strrchr(class_list_path, *os::file_separator()); if (end != NULL) *end = '\0'; } int class_list_path_len = (int)strlen(class_list_path); if (class_list_path_len >= 3) { if (strcmp(class_list_path + class_list_path_len - 3, "lib") != 0) { strcat(class_list_path, os::file_separator()); strcat(class_list_path, "lib"); } } strcat(class_list_path, os::file_separator()); strcat(class_list_path, "classlist"); FILE* file = fopen(class_list_path, "r"); if (file != NULL) { jlong computed_jsum = JSUM_SEED; jlong file_jsum = 0; char class_name[256]; int class_count = 0; GrowableArray<Klass*>* class_promote_order = new GrowableArray<Klass*>(); // sun.io.Converters static const char obj_array_sig[] = "[[Ljava/lang/Object;"; SymbolTable::new_permanent_symbol(obj_array_sig, THREAD); // java.util.HashMap static const char map_entry_array_sig[] = "[Ljava/util/Map$Entry;"; SymbolTable::new_permanent_symbol(map_entry_array_sig, THREAD); tty->print("Loading classes to share ... "); while ((fgets(class_name, sizeof class_name, file)) != NULL) { if (*class_name == '#') { jint fsh, fsl; if (sscanf(class_name, "# %8x%8x\n", &fsh, &fsl) == 2) { file_jsum = ((jlong)(fsh) << 32) | (fsl & 0xffffffff); } continue; } // Remove trailing newline size_t name_len = strlen(class_name); class_name[name_len-1] = '\0'; computed_jsum = jsum(computed_jsum, class_name, (const int)name_len - 1); // Got a class name - load it. TempNewSymbol class_name_symbol = SymbolTable::new_permanent_symbol(class_name, THREAD); guarantee(!HAS_PENDING_EXCEPTION, "Exception creating a symbol."); Klass* klass = SystemDictionary::resolve_or_null(class_name_symbol, THREAD); guarantee(!HAS_PENDING_EXCEPTION, "Exception resolving a class."); if (klass != NULL) { if (PrintSharedSpaces && Verbose && WizardMode) { tty->print_cr("Shared spaces preloaded: %s", class_name); } InstanceKlass* ik = InstanceKlass::cast(klass); // Should be class load order as per -XX:+TraceClassLoadingPreorder class_promote_order->append(ik); // Link the class to cause the bytecodes to be rewritten and the // cpcache to be created. The linking is done as soon as classes // are loaded in order that the related data structures (klass and // cpCache) are located together. if (ik->init_state() < InstanceKlass::linked) { ik->link_class(THREAD); guarantee(!(HAS_PENDING_EXCEPTION), "exception in class rewriting"); } // TODO: Resolve klasses in constant pool ik->constants()->resolve_class_constants(THREAD); class_count++; } else { if (PrintSharedSpaces && Verbose && WizardMode) { tty->cr(); tty->print_cr(" Preload failed: %s", class_name); } } file_jsum = 0; // Checksum must be on last line of file } if (computed_jsum != file_jsum) { tty->cr(); tty->print_cr("Preload failed: checksum of class list was incorrect."); exit(1); } tty->print_cr("done. "); if (PrintSharedSpaces) { tty->print_cr("Shared spaces: preloaded %d classes", class_count); } // Rewrite and unlink classes. tty->print("Rewriting and linking classes ... "); // Link any classes which got missed. (It's not quite clear why // they got missed.) This iteration would be unsafe if we weren't // single-threaded at this point; however we can't do it on the VM // thread because it requires object allocation. SystemDictionary::classes_do(link_shared_classes, CATCH); tty->print_cr("done. "); // Create and dump the shared spaces. Everything so far is loaded // with the null class loader. ClassLoaderData* loader_data = ClassLoaderData::the_null_class_loader_data(); VM_PopulateDumpSharedSpace op(loader_data, class_promote_order); VMThread::execute(&op); } else { char errmsg[JVM_MAXPATHLEN]; os::lasterror(errmsg, JVM_MAXPATHLEN); tty->print_cr("Loading classlist failed: %s", errmsg); exit(1); } // Since various initialization steps have been undone by this process, // it is not reasonable to continue running a java process. exit(0); } // Closure for serializing initialization data in from a data area // (ptr_array) read from the shared file. class ReadClosure : public SerializeClosure { private: intptr_t** _ptr_array; inline intptr_t nextPtr() { return *(*_ptr_array)++; } public: ReadClosure(intptr_t** ptr_array) { _ptr_array = ptr_array; } void do_ptr(void** p) { assert(*p == NULL, "initializing previous initialized pointer."); intptr_t obj = nextPtr(); assert((intptr_t)obj >= 0 || (intptr_t)obj < -100, "hit tag while initializing ptrs."); *p = (void*)obj; } void do_tag(int tag) { int old_tag; old_tag = (int)(intptr_t)nextPtr(); // do_int(&old_tag); assert(tag == old_tag, "old tag doesn't match"); FileMapInfo::assert_mark(tag == old_tag); } void do_region(u_char* start, size_t size) { assert((intptr_t)start % sizeof(intptr_t) == 0, "bad alignment"); assert(size % sizeof(intptr_t) == 0, "bad size"); do_tag((int)size); while (size > 0) { *(intptr_t*)start = nextPtr(); start += sizeof(intptr_t); size -= sizeof(intptr_t); } } bool reading() const { return true; } }; // Return true if given address is in the mapped shared space. bool MetaspaceShared::is_in_shared_space(const void* p) { return UseSharedSpaces && FileMapInfo::current_info()->is_in_shared_space(p); } void MetaspaceShared::print_shared_spaces() { if (UseSharedSpaces) { FileMapInfo::current_info()->print_shared_spaces(); } } // Map shared spaces at requested addresses and return if succeeded. // Need to keep the bounds of the ro and rw space for the Metaspace::contains // call, or is_in_shared_space. bool MetaspaceShared::map_shared_spaces(FileMapInfo* mapinfo) { size_t image_alignment = mapinfo->alignment(); #ifndef _WINDOWS // Map in the shared memory and then map the regions on top of it. // On Windows, don't map the memory here because it will cause the // mappings of the regions to fail. ReservedSpace shared_rs = mapinfo->reserve_shared_memory(); if (!shared_rs.is_reserved()) return false; #endif assert(!DumpSharedSpaces, "Should not be called with DumpSharedSpaces"); char* _ro_base = NULL; char* _rw_base = NULL; char* _md_base = NULL; char* _mc_base = NULL; // Map each shared region if ((_ro_base = mapinfo->map_region(ro)) != NULL && (_rw_base = mapinfo->map_region(rw)) != NULL && (_md_base = mapinfo->map_region(md)) != NULL && (_mc_base = mapinfo->map_region(mc)) != NULL && (image_alignment == (size_t)max_alignment())) { // Success (no need to do anything) return true; } else { // If there was a failure in mapping any of the spaces, unmap the ones // that succeeded if (_ro_base != NULL) mapinfo->unmap_region(ro); if (_rw_base != NULL) mapinfo->unmap_region(rw); if (_md_base != NULL) mapinfo->unmap_region(md); if (_mc_base != NULL) mapinfo->unmap_region(mc); #ifndef _WINDOWS // Release the entire mapped region shared_rs.release(); #endif // If -Xshare:on is specified, print out the error message and exit VM, // otherwise, set UseSharedSpaces to false and continue. if (RequireSharedSpaces) { vm_exit_during_initialization("Unable to use shared archive.", NULL); } else { FLAG_SET_DEFAULT(UseSharedSpaces, false); } return false; } } // Read the miscellaneous data from the shared file, and // serialize it out to its various destinations. void MetaspaceShared::initialize_shared_spaces() { FileMapInfo *mapinfo = FileMapInfo::current_info(); char* buffer = mapinfo->region_base(md); // Skip over (reserve space for) a list of addresses of C++ vtables // for Klass objects. They get filled in later. void** vtbl_list = (void**)buffer; buffer += MetaspaceShared::vtbl_list_size * sizeof(void*); Universe::init_self_patching_vtbl_list(vtbl_list, vtbl_list_size); // Skip over (reserve space for) dummy C++ vtables Klass objects. // They are used as is. intptr_t vtable_size = *(intptr_t*)buffer; buffer += sizeof(intptr_t); buffer += vtable_size; // Create the symbol table using the bucket array at this spot in the // misc data space. Since the symbol table is often modified, this // region (of mapped pages) will be copy-on-write. int symbolTableLen = *(intptr_t*)buffer; buffer += sizeof(intptr_t); int number_of_entries = *(intptr_t*)buffer; buffer += sizeof(intptr_t); SymbolTable::create_table((HashtableBucket<mtSymbol>*)buffer, symbolTableLen, number_of_entries); buffer += symbolTableLen; // Create the shared dictionary using the bucket array at this spot in // the misc data space. Since the shared dictionary table is never // modified, this region (of mapped pages) will be (effectively, if // not explicitly) read-only. int sharedDictionaryLen = *(intptr_t*)buffer; buffer += sizeof(intptr_t); number_of_entries = *(intptr_t*)buffer; buffer += sizeof(intptr_t); SystemDictionary::set_shared_dictionary((HashtableBucket<mtClass>*)buffer, sharedDictionaryLen, number_of_entries); buffer += sharedDictionaryLen; // Create the package info table using the bucket array at this spot in // the misc data space. Since the package info table is never // modified, this region (of mapped pages) will be (effectively, if // not explicitly) read-only. int pkgInfoLen = *(intptr_t*)buffer; buffer += sizeof(intptr_t); number_of_entries = *(intptr_t*)buffer; buffer += sizeof(intptr_t); ClassLoader::create_package_info_table((HashtableBucket<mtClass>*)buffer, pkgInfoLen, number_of_entries); buffer += pkgInfoLen; ClassLoader::verify(); // The following data in the shared misc data region are the linked // list elements (HashtableEntry objects) for the symbol table, string // table, and shared dictionary. The heap objects refered to by the // symbol table, string table, and shared dictionary are permanent and // unmovable. Since new entries added to the string and symbol tables // are always added at the beginning of the linked lists, THESE LINKED // LIST ELEMENTS ARE READ-ONLY. int len = *(intptr_t*)buffer; // skip over symbol table entries buffer += sizeof(intptr_t); buffer += len; len = *(intptr_t*)buffer; // skip over shared dictionary entries buffer += sizeof(intptr_t); buffer += len; len = *(intptr_t*)buffer; // skip over package info table entries buffer += sizeof(intptr_t); buffer += len; len = *(intptr_t*)buffer; // skip over package info table char[] arrays. buffer += sizeof(intptr_t); buffer += len; intptr_t* array = (intptr_t*)buffer; ReadClosure rc(&array); serialize(&rc); // Close the mapinfo file mapinfo->close(); } // 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()) { return false; } } return true; }