| /* |
| * Copyright 2003-2008 Sun Microsystems, Inc. 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 Sun Microsystems, Inc., 4150 Network Circle, Santa Clara, |
| * CA 95054 USA or visit www.sun.com if you need additional information or |
| * have any questions. |
| * |
| */ |
| |
| #include "incls/_precompiled.incl" |
| #include "incls/_compactingPermGenGen.cpp.incl" |
| |
| |
| // An ObjectClosure helper: Recursively adjust all pointers in an object |
| // and all objects by referenced it. Clear marks on objects in order to |
| // prevent visiting any object twice. This helper is used when the |
| // RedefineClasses() API has been called. |
| |
| class AdjustSharedObjectClosure : public ObjectClosure { |
| public: |
| void do_object(oop obj) { |
| if (obj->is_shared_readwrite()) { |
| if (obj->mark()->is_marked()) { |
| obj->init_mark(); // Don't revisit this object. |
| obj->adjust_pointers(); // Adjust this object's references. |
| } |
| } |
| } |
| }; |
| |
| |
| // An OopClosure helper: Recursively adjust all pointers in an object |
| // and all objects by referenced it. Clear marks on objects in order |
| // to prevent visiting any object twice. |
| |
| class RecursiveAdjustSharedObjectClosure : public OopClosure { |
| protected: |
| template <class T> inline void do_oop_work(T* p) { |
| oop obj = oopDesc::load_decode_heap_oop_not_null(p); |
| if (obj->is_shared_readwrite()) { |
| if (obj->mark()->is_marked()) { |
| obj->init_mark(); // Don't revisit this object. |
| obj->oop_iterate(this); // Recurse - adjust objects referenced. |
| obj->adjust_pointers(); // Adjust this object's references. |
| |
| // Special case: if a class has a read-only constant pool, |
| // then the read-write objects referenced by the pool must |
| // have their marks reset. |
| |
| if (obj->klass() == Universe::instanceKlassKlassObj()) { |
| instanceKlass* ik = instanceKlass::cast((klassOop)obj); |
| constantPoolOop cp = ik->constants(); |
| if (cp->is_shared_readonly()) { |
| cp->oop_iterate(this); |
| } |
| } |
| } |
| } |
| } |
| public: |
| virtual void do_oop(oop* p) { RecursiveAdjustSharedObjectClosure::do_oop_work(p); } |
| virtual void do_oop(narrowOop* p) { RecursiveAdjustSharedObjectClosure::do_oop_work(p); } |
| }; |
| |
| |
| // We need to go through all placeholders in the system dictionary and |
| // try to resolve them into shared classes. Other threads might be in |
| // the process of loading a shared class and have strong roots on |
| // their stack to the class without having added the class to the |
| // dictionary yet. This means the class will be marked during phase 1 |
| // but will not be unmarked during the application of the |
| // RecursiveAdjustSharedObjectClosure to the SystemDictionary. Note |
| // that we must not call find_shared_class with non-read-only symbols |
| // as doing so can cause hash codes to be computed, destroying |
| // forwarding pointers. |
| class TraversePlaceholdersClosure : public OopClosure { |
| protected: |
| template <class T> inline void do_oop_work(T* p) { |
| oop obj = oopDesc::load_decode_heap_oop_not_null(p); |
| if (obj->klass() == Universe::symbolKlassObj() && |
| obj->is_shared_readonly()) { |
| symbolHandle sym((symbolOop) obj); |
| oop k = SystemDictionary::find_shared_class(sym); |
| if (k != NULL) { |
| RecursiveAdjustSharedObjectClosure clo; |
| clo.do_oop(&k); |
| } |
| } |
| } |
| public: |
| virtual void do_oop(oop* p) { TraversePlaceholdersClosure::do_oop_work(p); } |
| virtual void do_oop(narrowOop* p) { TraversePlaceholdersClosure::do_oop_work(p); } |
| |
| }; |
| |
| |
| void CompactingPermGenGen::initialize_performance_counters() { |
| |
| const char* gen_name = "perm"; |
| |
| // Generation Counters - generation 2, 1 subspace |
| _gen_counters = new GenerationCounters(gen_name, 2, 1, &_virtual_space); |
| |
| _space_counters = new CSpaceCounters(gen_name, 0, |
| _virtual_space.reserved_size(), |
| _the_space, _gen_counters); |
| } |
| |
| void CompactingPermGenGen::update_counters() { |
| if (UsePerfData) { |
| _space_counters->update_all(); |
| _gen_counters->update_all(); |
| } |
| } |
| |
| |
| CompactingPermGenGen::CompactingPermGenGen(ReservedSpace rs, |
| ReservedSpace shared_rs, |
| size_t initial_byte_size, |
| int level, GenRemSet* remset, |
| ContiguousSpace* space, |
| PermanentGenerationSpec* spec_) : |
| OneContigSpaceCardGeneration(rs, initial_byte_size, MinPermHeapExpansion, |
| level, remset, space) { |
| |
| set_spec(spec_); |
| if (!UseSharedSpaces && !DumpSharedSpaces) { |
| spec()->disable_sharing(); |
| } |
| |
| // Break virtual space into address ranges for all spaces. |
| |
| if (spec()->enable_shared_spaces()) { |
| shared_end = (HeapWord*)(shared_rs.base() + shared_rs.size()); |
| misccode_end = shared_end; |
| misccode_bottom = misccode_end - heap_word_size(spec()->misc_code_size()); |
| miscdata_end = misccode_bottom; |
| miscdata_bottom = miscdata_end - heap_word_size(spec()->misc_data_size()); |
| readwrite_end = miscdata_bottom; |
| readwrite_bottom = |
| readwrite_end - heap_word_size(spec()->read_write_size()); |
| readonly_end = readwrite_bottom; |
| readonly_bottom = |
| readonly_end - heap_word_size(spec()->read_only_size()); |
| shared_bottom = readonly_bottom; |
| unshared_end = shared_bottom; |
| assert((char*)shared_bottom == shared_rs.base(), "shared space mismatch"); |
| } else { |
| shared_end = (HeapWord*)(rs.base() + rs.size()); |
| misccode_end = shared_end; |
| misccode_bottom = shared_end; |
| miscdata_end = shared_end; |
| miscdata_bottom = shared_end; |
| readwrite_end = shared_end; |
| readwrite_bottom = shared_end; |
| readonly_end = shared_end; |
| readonly_bottom = shared_end; |
| shared_bottom = shared_end; |
| unshared_end = shared_bottom; |
| } |
| unshared_bottom = (HeapWord*) rs.base(); |
| |
| // Verify shared and unshared spaces adjacent. |
| assert((char*)shared_bottom == rs.base()+rs.size(), "shared space mismatch"); |
| assert(unshared_end > unshared_bottom, "shared space mismatch"); |
| |
| // Split reserved memory into pieces. |
| |
| ReservedSpace ro_rs = shared_rs.first_part(spec()->read_only_size(), |
| UseSharedSpaces); |
| ReservedSpace tmp_rs1 = shared_rs.last_part(spec()->read_only_size()); |
| ReservedSpace rw_rs = tmp_rs1.first_part(spec()->read_write_size(), |
| UseSharedSpaces); |
| ReservedSpace tmp_rs2 = tmp_rs1.last_part(spec()->read_write_size()); |
| ReservedSpace md_rs = tmp_rs2.first_part(spec()->misc_data_size(), |
| UseSharedSpaces); |
| ReservedSpace mc_rs = tmp_rs2.last_part(spec()->misc_data_size()); |
| |
| _shared_space_size = spec()->read_only_size() |
| + spec()->read_write_size() |
| + spec()->misc_data_size() |
| + spec()->misc_code_size(); |
| |
| // Allocate the unshared (default) space. |
| _the_space = new ContigPermSpace(_bts, |
| MemRegion(unshared_bottom, heap_word_size(initial_byte_size))); |
| if (_the_space == NULL) |
| vm_exit_during_initialization("Could not allocate an unshared" |
| " CompactingPermGen Space"); |
| |
| // Allocate shared spaces |
| if (spec()->enable_shared_spaces()) { |
| |
| // If mapping a shared file, the space is not committed, don't |
| // mangle. |
| NOT_PRODUCT(bool old_ZapUnusedHeapArea = ZapUnusedHeapArea;) |
| NOT_PRODUCT(if (UseSharedSpaces) ZapUnusedHeapArea = false;) |
| |
| // Commit the memory behind the shared spaces if dumping (not |
| // mapping). |
| if (DumpSharedSpaces) { |
| _ro_vs.initialize(ro_rs, spec()->read_only_size()); |
| _rw_vs.initialize(rw_rs, spec()->read_write_size()); |
| _md_vs.initialize(md_rs, spec()->misc_data_size()); |
| _mc_vs.initialize(mc_rs, spec()->misc_code_size()); |
| } |
| |
| // Allocate the shared spaces. |
| _ro_bts = new BlockOffsetSharedArray( |
| MemRegion(readonly_bottom, |
| heap_word_size(spec()->read_only_size())), |
| heap_word_size(spec()->read_only_size())); |
| _ro_space = new OffsetTableContigSpace(_ro_bts, |
| MemRegion(readonly_bottom, readonly_end)); |
| _rw_bts = new BlockOffsetSharedArray( |
| MemRegion(readwrite_bottom, |
| heap_word_size(spec()->read_write_size())), |
| heap_word_size(spec()->read_write_size())); |
| _rw_space = new OffsetTableContigSpace(_rw_bts, |
| MemRegion(readwrite_bottom, readwrite_end)); |
| |
| // Restore mangling flag. |
| NOT_PRODUCT(ZapUnusedHeapArea = old_ZapUnusedHeapArea;) |
| |
| if (_ro_space == NULL || _rw_space == NULL) |
| vm_exit_during_initialization("Could not allocate a shared space"); |
| |
| // Cover both shared spaces entirely with cards. |
| _rs->resize_covered_region(MemRegion(readonly_bottom, readwrite_end)); |
| |
| if (UseSharedSpaces) { |
| |
| // Map in the regions in the shared file. |
| FileMapInfo* mapinfo = FileMapInfo::current_info(); |
| size_t image_alignment = mapinfo->alignment(); |
| CollectedHeap* ch = Universe::heap(); |
| if ((!mapinfo->map_space(ro, ro_rs, _ro_space)) || |
| (!mapinfo->map_space(rw, rw_rs, _rw_space)) || |
| (!mapinfo->map_space(md, md_rs, NULL)) || |
| (!mapinfo->map_space(mc, mc_rs, NULL)) || |
| // check the alignment constraints |
| (ch == NULL || ch->kind() != CollectedHeap::GenCollectedHeap || |
| image_alignment != |
| ((GenCollectedHeap*)ch)->gen_policy()->max_alignment())) { |
| // Base addresses didn't match; skip sharing, but continue |
| shared_rs.release(); |
| spec()->disable_sharing(); |
| // 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); |
| } |
| |
| // Note: freeing the block offset array objects does not |
| // currently free up the underlying storage. |
| delete _ro_bts; |
| _ro_bts = NULL; |
| delete _ro_space; |
| _ro_space = NULL; |
| delete _rw_bts; |
| _rw_bts = NULL; |
| delete _rw_space; |
| _rw_space = NULL; |
| shared_end = (HeapWord*)(rs.base() + rs.size()); |
| _rs->resize_covered_region(MemRegion(shared_bottom, shared_bottom)); |
| } |
| } |
| |
| // Reserved region includes shared spaces for oop.is_in_reserved(). |
| _reserved.set_end(shared_end); |
| |
| } else { |
| _ro_space = NULL; |
| _rw_space = NULL; |
| } |
| } |
| |
| |
| // Do a complete scan of the shared read write space to catch all |
| // objects which contain references to any younger generation. Forward |
| // the pointers. Avoid space_iterate, as actually visiting all the |
| // objects in the space will page in more objects than we need. |
| // Instead, use the system dictionary as strong roots into the read |
| // write space. |
| // |
| // If a RedefineClasses() call has been made, then we have to iterate |
| // over the entire shared read-write space in order to find all the |
| // objects that need to be forwarded. For example, it is possible for |
| // an nmethod to be found and marked in GC phase-1 only for the nmethod |
| // to be freed by the time we reach GC phase-3. The underlying method |
| // is still marked, but we can't (easily) find it in GC phase-3 so we |
| // blow up in GC phase-4. With RedefineClasses() we want replaced code |
| // (EMCP or obsolete) to go away (i.e., be collectible) once it is no |
| // longer being executed by any thread so we keep minimal attachments |
| // to the replaced code. However, we can't guarantee when those EMCP |
| // or obsolete methods will be collected so they may still be out there |
| // even after we've severed our minimal attachments. |
| |
| void CompactingPermGenGen::pre_adjust_pointers() { |
| if (spec()->enable_shared_spaces()) { |
| if (JvmtiExport::has_redefined_a_class()) { |
| // RedefineClasses() requires a brute force approach |
| AdjustSharedObjectClosure blk; |
| rw_space()->object_iterate(&blk); |
| } else { |
| RecursiveAdjustSharedObjectClosure blk; |
| Universe::oops_do(&blk); |
| StringTable::oops_do(&blk); |
| SystemDictionary::always_strong_classes_do(&blk); |
| TraversePlaceholdersClosure tpc; |
| SystemDictionary::placeholders_do(&tpc); |
| } |
| } |
| } |
| |
| |
| #ifdef ASSERT |
| class VerifyMarksClearedClosure : public ObjectClosure { |
| public: |
| void do_object(oop obj) { |
| assert(SharedSkipVerify || !obj->mark()->is_marked(), |
| "Shared oop still marked?"); |
| } |
| }; |
| #endif |
| |
| |
| void CompactingPermGenGen::post_compact() { |
| #ifdef ASSERT |
| if (!SharedSkipVerify && spec()->enable_shared_spaces()) { |
| VerifyMarksClearedClosure blk; |
| rw_space()->object_iterate(&blk); |
| } |
| #endif |
| } |
| |
| |
| void CompactingPermGenGen::space_iterate(SpaceClosure* blk, bool usedOnly) { |
| OneContigSpaceCardGeneration::space_iterate(blk, usedOnly); |
| if (spec()->enable_shared_spaces()) { |
| #ifdef PRODUCT |
| // Making the rw_space walkable will page in the entire space, and |
| // is to be avoided. However, this is required for Verify options. |
| ShouldNotReachHere(); |
| #endif |
| |
| blk->do_space(ro_space()); |
| blk->do_space(rw_space()); |
| } |
| } |
| |
| |
| void CompactingPermGenGen::print_on(outputStream* st) const { |
| OneContigSpaceCardGeneration::print_on(st); |
| if (spec()->enable_shared_spaces()) { |
| st->print(" ro"); |
| ro_space()->print_on(st); |
| st->print(" rw"); |
| rw_space()->print_on(st); |
| } else { |
| st->print_cr("No shared spaces configured."); |
| } |
| } |
| |
| |
| // References from the perm gen to the younger generation objects may |
| // occur in static fields in Java classes or in constant pool references |
| // to String objects. |
| |
| void CompactingPermGenGen::younger_refs_iterate(OopsInGenClosure* blk) { |
| OneContigSpaceCardGeneration::younger_refs_iterate(blk); |
| if (spec()->enable_shared_spaces()) { |
| blk->set_generation(this); |
| // ro_space has no younger gen refs. |
| _rs->younger_refs_in_space_iterate(rw_space(), blk); |
| blk->reset_generation(); |
| } |
| } |
| |
| |
| // Shared spaces are addressed in pre_adjust_pointers. |
| void CompactingPermGenGen::adjust_pointers() { |
| the_space()->adjust_pointers(); |
| } |
| |
| |
| void CompactingPermGenGen::compact() { |
| the_space()->compact(); |
| } |
| |
| |
| size_t CompactingPermGenGen::contiguous_available() const { |
| // Don't include shared spaces. |
| return OneContigSpaceCardGeneration::contiguous_available() |
| - _shared_space_size; |
| } |
| |
| size_t CompactingPermGenGen::max_capacity() const { |
| // Don't include shared spaces. |
| assert(UseSharedSpaces || (_shared_space_size == 0), |
| "If not used, the size of shared spaces should be 0"); |
| return OneContigSpaceCardGeneration::max_capacity() |
| - _shared_space_size; |
| } |
| |
| |
| // No young generation references, clear this generation's main space's |
| // card table entries. Do NOT clear the card table entries for the |
| // read-only space (always clear) or the read-write space (valuable |
| // information). |
| |
| void CompactingPermGenGen::clear_remembered_set() { |
| _rs->clear(MemRegion(the_space()->bottom(), the_space()->end())); |
| } |
| |
| |
| // Objects in this generation's main space may have moved, invalidate |
| // that space's cards. Do NOT invalidate the card table entries for the |
| // read-only or read-write spaces, as those objects never move. |
| |
| void CompactingPermGenGen::invalidate_remembered_set() { |
| _rs->invalidate(used_region()); |
| } |
| |
| |
| void CompactingPermGenGen::verify(bool allow_dirty) { |
| the_space()->verify(allow_dirty); |
| if (!SharedSkipVerify && spec()->enable_shared_spaces()) { |
| ro_space()->verify(allow_dirty); |
| rw_space()->verify(allow_dirty); |
| } |
| } |
| |
| |
| HeapWord* CompactingPermGenGen::unshared_bottom; |
| HeapWord* CompactingPermGenGen::unshared_end; |
| HeapWord* CompactingPermGenGen::shared_bottom; |
| HeapWord* CompactingPermGenGen::shared_end; |
| HeapWord* CompactingPermGenGen::readonly_bottom; |
| HeapWord* CompactingPermGenGen::readonly_end; |
| HeapWord* CompactingPermGenGen::readwrite_bottom; |
| HeapWord* CompactingPermGenGen::readwrite_end; |
| HeapWord* CompactingPermGenGen::miscdata_bottom; |
| HeapWord* CompactingPermGenGen::miscdata_end; |
| HeapWord* CompactingPermGenGen::misccode_bottom; |
| HeapWord* CompactingPermGenGen::misccode_end; |
| |
| // JVM/TI RedefineClasses() support: |
| bool CompactingPermGenGen::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; |
| } |
| |
| void** CompactingPermGenGen::_vtbl_list; |
