Mercurial > hg > graal-jvmci-8
diff src/share/vm/memory/compactingPermGenGen.cpp @ 0:a61af66fc99e jdk7-b24
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author | duke |
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date | Sat, 01 Dec 2007 00:00:00 +0000 |
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children | 2c106685d6d0 |
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--- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/src/share/vm/memory/compactingPermGenGen.cpp Sat Dec 01 00:00:00 2007 +0000 @@ -0,0 +1,457 @@ +/* + * Copyright 2003-2006 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" + + +// 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 { +public: + void do_oop(oop* o) { + oop obj = *o; + 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); + } + } + } + } + }; +}; + + +// 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 { + public: + void do_oop(oop* o) { + oop obj = *o; + 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); + } + } + } +}; + + +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. + +void CompactingPermGenGen::pre_adjust_pointers() { + if (spec()->enable_shared_spaces()) { + 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; +} + + + +bool CompactingPermGenGen::grow_by(size_t bytes) { + // Don't allow _virtual_size to expand into shared spaces. + size_t max_bytes = _virtual_space.uncommitted_size() - _shared_space_size; + if (bytes > _shared_space_size) { + bytes = _shared_space_size; + } + return OneContigSpaceCardGeneration::grow_by(bytes); +} + + +void CompactingPermGenGen::grow_to_reserved() { + // Don't allow _virtual_size to expand into shared spaces. + if (_virtual_space.uncommitted_size() > _shared_space_size) { + size_t remaining_bytes = + _virtual_space.uncommitted_size() - _shared_space_size; + bool success = OneContigSpaceCardGeneration::grow_by(remaining_bytes); + DEBUG_ONLY(if (!success) warning("grow to reserved failed");) + } +} + + +// 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;