--- old/src/share/vm/memory/genCollectedHeap.cpp 2015-05-12 11:41:58.749520831 +0200 +++ /dev/null 2015-03-18 17:10:38.111854831 +0100 @@ -1,1336 +0,0 @@ -/* - * Copyright (c) 2000, 2015, 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/symbolTable.hpp" -#include "classfile/systemDictionary.hpp" -#include "classfile/vmSymbols.hpp" -#include "code/codeCache.hpp" -#include "code/icBuffer.hpp" -#include "gc_implementation/shared/collectorCounters.hpp" -#include "gc_implementation/shared/gcTrace.hpp" -#include "gc_implementation/shared/gcTraceTime.hpp" -#include "gc_implementation/shared/vmGCOperations.hpp" -#include "gc_interface/collectedHeap.inline.hpp" -#include "memory/filemap.hpp" -#include "memory/gcLocker.inline.hpp" -#include "memory/genCollectedHeap.hpp" -#include "memory/genOopClosures.inline.hpp" -#include "memory/generationSpec.hpp" -#include "memory/resourceArea.hpp" -#include "memory/strongRootsScope.hpp" -#include "memory/space.hpp" -#include "oops/oop.inline.hpp" -#include "runtime/biasedLocking.hpp" -#include "runtime/fprofiler.hpp" -#include "runtime/handles.hpp" -#include "runtime/handles.inline.hpp" -#include "runtime/java.hpp" -#include "runtime/vmThread.hpp" -#include "services/management.hpp" -#include "services/memoryService.hpp" -#include "utilities/macros.hpp" -#include "utilities/stack.inline.hpp" -#include "utilities/vmError.hpp" -#include "utilities/workgroup.hpp" -#if INCLUDE_ALL_GCS -#include "gc_implementation/concurrentMarkSweep/concurrentMarkSweepThread.hpp" -#include "gc_implementation/concurrentMarkSweep/vmCMSOperations.hpp" -#endif // INCLUDE_ALL_GCS - -NOT_PRODUCT(size_t GenCollectedHeap::_skip_header_HeapWords = 0;) - -// The set of potentially parallel tasks in root scanning. -enum GCH_strong_roots_tasks { - GCH_PS_Universe_oops_do, - GCH_PS_JNIHandles_oops_do, - GCH_PS_ObjectSynchronizer_oops_do, - GCH_PS_FlatProfiler_oops_do, - GCH_PS_Management_oops_do, - GCH_PS_SystemDictionary_oops_do, - GCH_PS_ClassLoaderDataGraph_oops_do, - GCH_PS_jvmti_oops_do, - GCH_PS_CodeCache_oops_do, - GCH_PS_younger_gens, - // Leave this one last. - GCH_PS_NumElements -}; - -GenCollectedHeap::GenCollectedHeap(GenCollectorPolicy *policy) : - CollectedHeap(), - _rem_set(NULL), - _gen_policy(policy), - _process_strong_tasks(new SubTasksDone(GCH_PS_NumElements)), - _full_collections_completed(0) -{ - assert(policy != NULL, "Sanity check"); - if (UseConcMarkSweepGC) { - _workers = new FlexibleWorkGang("GC Thread", ParallelGCThreads, - /* are_GC_task_threads */true, - /* are_ConcurrentGC_threads */false); - _workers->initialize_workers(); - } else { - // Serial GC does not use workers. - _workers = NULL; - } -} - -jint GenCollectedHeap::initialize() { - CollectedHeap::pre_initialize(); - - // While there are no constraints in the GC code that HeapWordSize - // be any particular value, there are multiple other areas in the - // system which believe this to be true (e.g. oop->object_size in some - // cases incorrectly returns the size in wordSize units rather than - // HeapWordSize). - guarantee(HeapWordSize == wordSize, "HeapWordSize must equal wordSize"); - - // Allocate space for the heap. - - char* heap_address; - ReservedSpace heap_rs; - - size_t heap_alignment = collector_policy()->heap_alignment(); - - heap_address = allocate(heap_alignment, &heap_rs); - - if (!heap_rs.is_reserved()) { - vm_shutdown_during_initialization( - "Could not reserve enough space for object heap"); - return JNI_ENOMEM; - } - - initialize_reserved_region((HeapWord*)heap_rs.base(), (HeapWord*)(heap_rs.base() + heap_rs.size())); - - _rem_set = collector_policy()->create_rem_set(reserved_region()); - set_barrier_set(rem_set()->bs()); - - ReservedSpace young_rs = heap_rs.first_part(gen_policy()->young_gen_spec()->max_size(), false, false); - _young_gen = gen_policy()->young_gen_spec()->init(young_rs, 0, rem_set()); - heap_rs = heap_rs.last_part(gen_policy()->young_gen_spec()->max_size()); - - ReservedSpace old_rs = heap_rs.first_part(gen_policy()->old_gen_spec()->max_size(), false, false); - _old_gen = gen_policy()->old_gen_spec()->init(old_rs, 1, rem_set()); - clear_incremental_collection_failed(); - -#if INCLUDE_ALL_GCS - // If we are running CMS, create the collector responsible - // for collecting the CMS generations. - if (collector_policy()->is_concurrent_mark_sweep_policy()) { - bool success = create_cms_collector(); - if (!success) return JNI_ENOMEM; - } -#endif // INCLUDE_ALL_GCS - - return JNI_OK; -} - -char* GenCollectedHeap::allocate(size_t alignment, - ReservedSpace* heap_rs){ - // Now figure out the total size. - const size_t pageSize = UseLargePages ? os::large_page_size() : os::vm_page_size(); - assert(alignment % pageSize == 0, "Must be"); - - GenerationSpec* young_spec = gen_policy()->young_gen_spec(); - GenerationSpec* old_spec = gen_policy()->old_gen_spec(); - - // Check for overflow. - size_t total_reserved = young_spec->max_size() + old_spec->max_size(); - if (total_reserved < young_spec->max_size()) { - vm_exit_during_initialization("The size of the object heap + VM data exceeds " - "the maximum representable size"); - } - assert(total_reserved % alignment == 0, - err_msg("Gen size; total_reserved=" SIZE_FORMAT ", alignment=" - SIZE_FORMAT, total_reserved, alignment)); - - *heap_rs = Universe::reserve_heap(total_reserved, alignment); - return heap_rs->base(); -} - -void GenCollectedHeap::post_initialize() { - CollectedHeap::post_initialize(); - ref_processing_init(); - GenCollectorPolicy *policy = (GenCollectorPolicy *)collector_policy(); - guarantee(policy->is_generation_policy(), "Illegal policy type"); - assert((_young_gen->kind() == Generation::DefNew) || - (_young_gen->kind() == Generation::ParNew), - "Wrong youngest generation type"); - DefNewGeneration* def_new_gen = (DefNewGeneration*)_young_gen; - - assert(_old_gen->kind() == Generation::ConcurrentMarkSweep || - _old_gen->kind() == Generation::MarkSweepCompact, - "Wrong generation kind"); - - policy->initialize_size_policy(def_new_gen->eden()->capacity(), - _old_gen->capacity(), - def_new_gen->from()->capacity()); - policy->initialize_gc_policy_counters(); -} - -void GenCollectedHeap::ref_processing_init() { - _young_gen->ref_processor_init(); - _old_gen->ref_processor_init(); -} - -size_t GenCollectedHeap::capacity() const { - return _young_gen->capacity() + _old_gen->capacity(); -} - -size_t GenCollectedHeap::used() const { - return _young_gen->used() + _old_gen->used(); -} - -// Save the "used_region" for generations level and lower. -void GenCollectedHeap::save_used_regions(int level) { - assert(level == 0 || level == 1, "Illegal level parameter"); - if (level == 1) { - _old_gen->save_used_region(); - } - _young_gen->save_used_region(); -} - -size_t GenCollectedHeap::max_capacity() const { - return _young_gen->max_capacity() + _old_gen->max_capacity(); -} - -// Update the _full_collections_completed counter -// at the end of a stop-world full GC. -unsigned int GenCollectedHeap::update_full_collections_completed() { - MonitorLockerEx ml(FullGCCount_lock, Mutex::_no_safepoint_check_flag); - assert(_full_collections_completed <= _total_full_collections, - "Can't complete more collections than were started"); - _full_collections_completed = _total_full_collections; - ml.notify_all(); - return _full_collections_completed; -} - -// Update the _full_collections_completed counter, as appropriate, -// at the end of a concurrent GC cycle. Note the conditional update -// below to allow this method to be called by a concurrent collector -// without synchronizing in any manner with the VM thread (which -// may already have initiated a STW full collection "concurrently"). -unsigned int GenCollectedHeap::update_full_collections_completed(unsigned int count) { - MonitorLockerEx ml(FullGCCount_lock, Mutex::_no_safepoint_check_flag); - assert((_full_collections_completed <= _total_full_collections) && - (count <= _total_full_collections), - "Can't complete more collections than were started"); - if (count > _full_collections_completed) { - _full_collections_completed = count; - ml.notify_all(); - } - return _full_collections_completed; -} - - -#ifndef PRODUCT -// Override of memory state checking method in CollectedHeap: -// Some collectors (CMS for example) can't have badHeapWordVal written -// in the first two words of an object. (For instance , in the case of -// CMS these words hold state used to synchronize between certain -// (concurrent) GC steps and direct allocating mutators.) -// The skip_header_HeapWords() method below, allows us to skip -// over the requisite number of HeapWord's. Note that (for -// generational collectors) this means that those many words are -// skipped in each object, irrespective of the generation in which -// that object lives. The resultant loss of precision seems to be -// harmless and the pain of avoiding that imprecision appears somewhat -// higher than we are prepared to pay for such rudimentary debugging -// support. -void GenCollectedHeap::check_for_non_bad_heap_word_value(HeapWord* addr, - size_t size) { - if (CheckMemoryInitialization && ZapUnusedHeapArea) { - // We are asked to check a size in HeapWords, - // but the memory is mangled in juint words. - juint* start = (juint*) (addr + skip_header_HeapWords()); - juint* end = (juint*) (addr + size); - for (juint* slot = start; slot < end; slot += 1) { - assert(*slot == badHeapWordVal, - "Found non badHeapWordValue in pre-allocation check"); - } - } -} -#endif - -HeapWord* GenCollectedHeap::attempt_allocation(size_t size, - bool is_tlab, - bool first_only) { - HeapWord* res = NULL; - - if (_young_gen->should_allocate(size, is_tlab)) { - res = _young_gen->allocate(size, is_tlab); - if (res != NULL || first_only) { - return res; - } - } - - if (_old_gen->should_allocate(size, is_tlab)) { - res = _old_gen->allocate(size, is_tlab); - } - - return res; -} - -HeapWord* GenCollectedHeap::mem_allocate(size_t size, - bool* gc_overhead_limit_was_exceeded) { - return collector_policy()->mem_allocate_work(size, - false /* is_tlab */, - gc_overhead_limit_was_exceeded); -} - -bool GenCollectedHeap::must_clear_all_soft_refs() { - return _gc_cause == GCCause::_last_ditch_collection; -} - -bool GenCollectedHeap::should_do_concurrent_full_gc(GCCause::Cause cause) { - return UseConcMarkSweepGC && - ((cause == GCCause::_gc_locker && GCLockerInvokesConcurrent) || - (cause == GCCause::_java_lang_system_gc && ExplicitGCInvokesConcurrent)); -} - -void GenCollectedHeap::collect_generation(Generation* gen, bool full, size_t size, - bool is_tlab, bool run_verification, bool clear_soft_refs, - bool restore_marks_for_biased_locking) { - // Timer for individual generations. Last argument is false: no CR - // FIXME: We should try to start the timing earlier to cover more of the GC pause - // The PrintGCDetails logging starts before we have incremented the GC id. We will do that later - // so we can assume here that the next GC id is what we want. - GCTraceTime t1(gen->short_name(), PrintGCDetails, false, NULL, GCId::peek()); - TraceCollectorStats tcs(gen->counters()); - TraceMemoryManagerStats tmms(gen->kind(),gc_cause()); - - size_t prev_used = gen->used(); - gen->stat_record()->invocations++; - gen->stat_record()->accumulated_time.start(); - - // Must be done anew before each collection because - // a previous collection will do mangling and will - // change top of some spaces. - record_gen_tops_before_GC(); - - if (PrintGC && Verbose) { - gclog_or_tty->print("level=%d invoke=%d size=" SIZE_FORMAT, - gen->level(), - gen->stat_record()->invocations, - size * HeapWordSize); - } - - if (run_verification && VerifyBeforeGC) { - HandleMark hm; // Discard invalid handles created during verification - Universe::verify(" VerifyBeforeGC:"); - } - COMPILER2_PRESENT(DerivedPointerTable::clear()); - - if (restore_marks_for_biased_locking) { - // We perform this mark word preservation work lazily - // because it's only at this point that we know whether we - // absolutely have to do it; we want to avoid doing it for - // scavenge-only collections where it's unnecessary - BiasedLocking::preserve_marks(); - } - - // Do collection work - { - // Note on ref discovery: For what appear to be historical reasons, - // GCH enables and disabled (by enqueing) refs discovery. - // In the future this should be moved into the generation's - // collect method so that ref discovery and enqueueing concerns - // are local to a generation. The collect method could return - // an appropriate indication in the case that notification on - // the ref lock was needed. This will make the treatment of - // weak refs more uniform (and indeed remove such concerns - // from GCH). XXX - - HandleMark hm; // Discard invalid handles created during gc - save_marks(); // save marks for all gens - // We want to discover references, but not process them yet. - // This mode is disabled in process_discovered_references if the - // generation does some collection work, or in - // enqueue_discovered_references if the generation returns - // without doing any work. - ReferenceProcessor* rp = gen->ref_processor(); - // If the discovery of ("weak") refs in this generation is - // atomic wrt other collectors in this configuration, we - // are guaranteed to have empty discovered ref lists. - if (rp->discovery_is_atomic()) { - rp->enable_discovery(); - rp->setup_policy(clear_soft_refs); - } else { - // collect() below will enable discovery as appropriate - } - gen->collect(full, clear_soft_refs, size, is_tlab); - if (!rp->enqueuing_is_done()) { - rp->enqueue_discovered_references(); - } else { - rp->set_enqueuing_is_done(false); - } - rp->verify_no_references_recorded(); - } - - COMPILER2_PRESENT(DerivedPointerTable::update_pointers()); - - gen->stat_record()->accumulated_time.stop(); - - update_gc_stats(gen->level(), full); - - if (run_verification && VerifyAfterGC) { - HandleMark hm; // Discard invalid handles created during verification - Universe::verify(" VerifyAfterGC:"); - } - - if (PrintGCDetails) { - gclog_or_tty->print(":"); - gen->print_heap_change(prev_used); - } -} - -void GenCollectedHeap::do_collection(bool full, - bool clear_all_soft_refs, - size_t size, - bool is_tlab, - int max_level) { - ResourceMark rm; - DEBUG_ONLY(Thread* my_thread = Thread::current();) - - assert(SafepointSynchronize::is_at_safepoint(), "should be at safepoint"); - assert(my_thread->is_VM_thread() || - my_thread->is_ConcurrentGC_thread(), - "incorrect thread type capability"); - assert(Heap_lock->is_locked(), - "the requesting thread should have the Heap_lock"); - guarantee(!is_gc_active(), "collection is not reentrant"); - - if (GC_locker::check_active_before_gc()) { - return; // GC is disabled (e.g. JNI GetXXXCritical operation) - } - - const bool do_clear_all_soft_refs = clear_all_soft_refs || - collector_policy()->should_clear_all_soft_refs(); - - ClearedAllSoftRefs casr(do_clear_all_soft_refs, collector_policy()); - - const size_t metadata_prev_used = MetaspaceAux::used_bytes(); - - print_heap_before_gc(); - - { - FlagSetting fl(_is_gc_active, true); - - bool complete = full && (max_level == 1 /* old */); - const char* gc_cause_prefix = complete ? "Full GC" : "GC"; - TraceCPUTime tcpu(PrintGCDetails, true, gclog_or_tty); - // The PrintGCDetails logging starts before we have incremented the GC id. We will do that later - // so we can assume here that the next GC id is what we want. - GCTraceTime t(GCCauseString(gc_cause_prefix, gc_cause()), PrintGCDetails, false, NULL, GCId::peek()); - - gc_prologue(complete); - increment_total_collections(complete); - - size_t gch_prev_used = used(); - bool run_verification = total_collections() >= VerifyGCStartAt; - - bool prepared_for_verification = false; - int max_level_collected = 0; - bool old_collects_young = (max_level == 1) && - full && - _old_gen->full_collects_younger_generations(); - if (!old_collects_young && - _young_gen->should_collect(full, size, is_tlab)) { - if (run_verification && VerifyGCLevel <= 0 && VerifyBeforeGC) { - prepare_for_verify(); - prepared_for_verification = true; - } - - assert(!_young_gen->performs_in_place_marking(), "No young generation do in place marking"); - collect_generation(_young_gen, - full, - size, - is_tlab, - run_verification && VerifyGCLevel <= 0, - do_clear_all_soft_refs, - false); - - if (size > 0 && (!is_tlab || _young_gen->supports_tlab_allocation()) && - size * HeapWordSize <= _young_gen->unsafe_max_alloc_nogc()) { - // Allocation request was met by young GC. - size = 0; - } - } - - bool must_restore_marks_for_biased_locking = false; - - if (max_level == 1 && _old_gen->should_collect(full, size, is_tlab)) { - if (!complete) { - // The full_collections increment was missed above. - increment_total_full_collections(); - } - - pre_full_gc_dump(NULL); // do any pre full gc dumps - - if (!prepared_for_verification && run_verification && - VerifyGCLevel <= 1 && VerifyBeforeGC) { - prepare_for_verify(); - } - - assert(_old_gen->performs_in_place_marking(), "All old generations do in place marking"); - collect_generation(_old_gen, - full, - size, - is_tlab, - run_verification && VerifyGCLevel <= 1, - do_clear_all_soft_refs, - true); - - must_restore_marks_for_biased_locking = true; - max_level_collected = 1; - } - - // Update "complete" boolean wrt what actually transpired -- - // for instance, a promotion failure could have led to - // a whole heap collection. - complete = complete || (max_level_collected == 1 /* old */); - - if (complete) { // We did a "major" collection - // FIXME: See comment at pre_full_gc_dump call - post_full_gc_dump(NULL); // do any post full gc dumps - } - - if (PrintGCDetails) { - print_heap_change(gch_prev_used); - - // Print metaspace info for full GC with PrintGCDetails flag. - if (complete) { - MetaspaceAux::print_metaspace_change(metadata_prev_used); - } - } - - // Adjust generation sizes. - if (max_level_collected == 1 /* old */) { - _old_gen->compute_new_size(); - } - _young_gen->compute_new_size(); - - if (complete) { - // Delete metaspaces for unloaded class loaders and clean up loader_data graph - ClassLoaderDataGraph::purge(); - MetaspaceAux::verify_metrics(); - // Resize the metaspace capacity after full collections - MetaspaceGC::compute_new_size(); - update_full_collections_completed(); - } - - // Track memory usage and detect low memory after GC finishes - MemoryService::track_memory_usage(); - - gc_epilogue(complete); - - if (must_restore_marks_for_biased_locking) { - BiasedLocking::restore_marks(); - } - } - - print_heap_after_gc(); - -#ifdef TRACESPINNING - ParallelTaskTerminator::print_termination_counts(); -#endif -} - -HeapWord* GenCollectedHeap::satisfy_failed_allocation(size_t size, bool is_tlab) { - return collector_policy()->satisfy_failed_allocation(size, is_tlab); -} - -void GenCollectedHeap::set_par_threads(uint t) { - assert(t == 0 || !UseSerialGC, "Cannot have parallel threads"); - CollectedHeap::set_par_threads(t); - set_n_termination(t); -} - -void GenCollectedHeap::set_n_termination(uint t) { - _process_strong_tasks->set_n_threads(t); -} - -#ifdef ASSERT -class AssertNonScavengableClosure: public OopClosure { -public: - virtual void do_oop(oop* p) { - assert(!GenCollectedHeap::heap()->is_in_partial_collection(*p), - "Referent should not be scavengable."); } - virtual void do_oop(narrowOop* p) { ShouldNotReachHere(); } -}; -static AssertNonScavengableClosure assert_is_non_scavengable_closure; -#endif - -void GenCollectedHeap::process_roots(bool activate_scope, - ScanningOption so, - OopClosure* strong_roots, - OopClosure* weak_roots, - CLDClosure* strong_cld_closure, - CLDClosure* weak_cld_closure, - CodeBlobClosure* code_roots) { - StrongRootsScope srs(activate_scope); - - // General roots. - assert(Threads::thread_claim_parity() != 0, "must have called prologue code"); - assert(code_roots != NULL, "code root closure should always be set"); - // _n_termination for _process_strong_tasks should be set up stream - // in a method not running in a GC worker. Otherwise the GC worker - // could be trying to change the termination condition while the task - // is executing in another GC worker. - - if (!_process_strong_tasks->is_task_claimed(GCH_PS_ClassLoaderDataGraph_oops_do)) { - ClassLoaderDataGraph::roots_cld_do(strong_cld_closure, weak_cld_closure); - } - - // Some CLDs contained in the thread frames should be considered strong. - // Don't process them if they will be processed during the ClassLoaderDataGraph phase. - CLDClosure* roots_from_clds_p = (strong_cld_closure != weak_cld_closure) ? strong_cld_closure : NULL; - // Only process code roots from thread stacks if we aren't visiting the entire CodeCache anyway - CodeBlobClosure* roots_from_code_p = (so & SO_AllCodeCache) ? NULL : code_roots; - - bool is_par = n_par_threads() > 0; - Threads::possibly_parallel_oops_do(is_par, strong_roots, roots_from_clds_p, roots_from_code_p); - - if (!_process_strong_tasks->is_task_claimed(GCH_PS_Universe_oops_do)) { - Universe::oops_do(strong_roots); - } - // Global (strong) JNI handles - if (!_process_strong_tasks->is_task_claimed(GCH_PS_JNIHandles_oops_do)) { - JNIHandles::oops_do(strong_roots); - } - - if (!_process_strong_tasks->is_task_claimed(GCH_PS_ObjectSynchronizer_oops_do)) { - ObjectSynchronizer::oops_do(strong_roots); - } - if (!_process_strong_tasks->is_task_claimed(GCH_PS_FlatProfiler_oops_do)) { - FlatProfiler::oops_do(strong_roots); - } - if (!_process_strong_tasks->is_task_claimed(GCH_PS_Management_oops_do)) { - Management::oops_do(strong_roots); - } - if (!_process_strong_tasks->is_task_claimed(GCH_PS_jvmti_oops_do)) { - JvmtiExport::oops_do(strong_roots); - } - - if (!_process_strong_tasks->is_task_claimed(GCH_PS_SystemDictionary_oops_do)) { - SystemDictionary::roots_oops_do(strong_roots, weak_roots); - } - - // All threads execute the following. A specific chunk of buckets - // from the StringTable are the individual tasks. - if (weak_roots != NULL) { - if (is_par) { - StringTable::possibly_parallel_oops_do(weak_roots); - } else { - StringTable::oops_do(weak_roots); - } - } - - if (!_process_strong_tasks->is_task_claimed(GCH_PS_CodeCache_oops_do)) { - if (so & SO_ScavengeCodeCache) { - assert(code_roots != NULL, "must supply closure for code cache"); - - // We only visit parts of the CodeCache when scavenging. - CodeCache::scavenge_root_nmethods_do(code_roots); - } - if (so & SO_AllCodeCache) { - assert(code_roots != NULL, "must supply closure for code cache"); - - // CMSCollector uses this to do intermediate-strength collections. - // We scan the entire code cache, since CodeCache::do_unloading is not called. - CodeCache::blobs_do(code_roots); - } - // Verify that the code cache contents are not subject to - // movement by a scavenging collection. - DEBUG_ONLY(CodeBlobToOopClosure assert_code_is_non_scavengable(&assert_is_non_scavengable_closure, !CodeBlobToOopClosure::FixRelocations)); - DEBUG_ONLY(CodeCache::asserted_non_scavengable_nmethods_do(&assert_code_is_non_scavengable)); - } - -} - -void GenCollectedHeap::gen_process_roots(int level, - bool younger_gens_as_roots, - bool activate_scope, - ScanningOption so, - bool only_strong_roots, - OopsInGenClosure* not_older_gens, - OopsInGenClosure* older_gens, - CLDClosure* cld_closure) { - const bool is_adjust_phase = !only_strong_roots && !younger_gens_as_roots; - - bool is_moving_collection = false; - if (level == 0 || is_adjust_phase) { - // young collections are always moving - is_moving_collection = true; - } - - MarkingCodeBlobClosure mark_code_closure(not_older_gens, is_moving_collection); - OopsInGenClosure* weak_roots = only_strong_roots ? NULL : not_older_gens; - CLDClosure* weak_cld_closure = only_strong_roots ? NULL : cld_closure; - - process_roots(activate_scope, so, - not_older_gens, weak_roots, - cld_closure, weak_cld_closure, - &mark_code_closure); - - if (younger_gens_as_roots) { - if (!_process_strong_tasks->is_task_claimed(GCH_PS_younger_gens)) { - if (level == 1) { - not_older_gens->set_generation(_young_gen); - _young_gen->oop_iterate(not_older_gens); - } - not_older_gens->reset_generation(); - } - } - // When collection is parallel, all threads get to cooperate to do - // older-gen scanning. - if (level == 0) { - older_gens->set_generation(_old_gen); - rem_set()->younger_refs_iterate(_old_gen, older_gens); - older_gens->reset_generation(); - } - - _process_strong_tasks->all_tasks_completed(); -} - - -class AlwaysTrueClosure: public BoolObjectClosure { -public: - bool do_object_b(oop p) { return true; } -}; -static AlwaysTrueClosure always_true; - -void GenCollectedHeap::gen_process_weak_roots(OopClosure* root_closure) { - JNIHandles::weak_oops_do(&always_true, root_closure); - _young_gen->ref_processor()->weak_oops_do(root_closure); - _old_gen->ref_processor()->weak_oops_do(root_closure); -} - -#define GCH_SINCE_SAVE_MARKS_ITERATE_DEFN(OopClosureType, nv_suffix) \ -void GenCollectedHeap:: \ -oop_since_save_marks_iterate(int level, \ - OopClosureType* cur, \ - OopClosureType* older) { \ - if (level == 0) { \ - _young_gen->oop_since_save_marks_iterate##nv_suffix(cur); \ - _old_gen->oop_since_save_marks_iterate##nv_suffix(older); \ - } else { \ - _old_gen->oop_since_save_marks_iterate##nv_suffix(cur); \ - } \ -} - -ALL_SINCE_SAVE_MARKS_CLOSURES(GCH_SINCE_SAVE_MARKS_ITERATE_DEFN) - -#undef GCH_SINCE_SAVE_MARKS_ITERATE_DEFN - -bool GenCollectedHeap::no_allocs_since_save_marks(int level) { - if (level == 0 && !_young_gen->no_allocs_since_save_marks()) { - return false; - } - return _old_gen->no_allocs_since_save_marks(); -} - -bool GenCollectedHeap::supports_inline_contig_alloc() const { - return _young_gen->supports_inline_contig_alloc(); -} - -HeapWord** GenCollectedHeap::top_addr() const { - return _young_gen->top_addr(); -} - -HeapWord** GenCollectedHeap::end_addr() const { - return _young_gen->end_addr(); -} - -// public collection interfaces - -void GenCollectedHeap::collect(GCCause::Cause cause) { - if (should_do_concurrent_full_gc(cause)) { -#if INCLUDE_ALL_GCS - // mostly concurrent full collection - collect_mostly_concurrent(cause); -#else // INCLUDE_ALL_GCS - ShouldNotReachHere(); -#endif // INCLUDE_ALL_GCS - } else if (cause == GCCause::_wb_young_gc) { - // minor collection for WhiteBox API - collect(cause, 0 /* young */); - } else { -#ifdef ASSERT - if (cause == GCCause::_scavenge_alot) { - // minor collection only - collect(cause, 0 /* young */); - } else { - // Stop-the-world full collection - collect(cause, 1 /* old */); - } -#else - // Stop-the-world full collection - collect(cause, 1 /* old */); -#endif - } -} - -void GenCollectedHeap::collect(GCCause::Cause cause, int max_level) { - // The caller doesn't have the Heap_lock - assert(!Heap_lock->owned_by_self(), "this thread should not own the Heap_lock"); - MutexLocker ml(Heap_lock); - collect_locked(cause, max_level); -} - -void GenCollectedHeap::collect_locked(GCCause::Cause cause) { - // The caller has the Heap_lock - assert(Heap_lock->owned_by_self(), "this thread should own the Heap_lock"); - collect_locked(cause, 1 /* old */); -} - -// this is the private collection interface -// The Heap_lock is expected to be held on entry. - -void GenCollectedHeap::collect_locked(GCCause::Cause cause, int max_level) { - // Read the GC count while holding the Heap_lock - unsigned int gc_count_before = total_collections(); - unsigned int full_gc_count_before = total_full_collections(); - { - MutexUnlocker mu(Heap_lock); // give up heap lock, execute gets it back - VM_GenCollectFull op(gc_count_before, full_gc_count_before, - cause, max_level); - VMThread::execute(&op); - } -} - -#if INCLUDE_ALL_GCS -bool GenCollectedHeap::create_cms_collector() { - - assert(_old_gen->kind() == Generation::ConcurrentMarkSweep, - "Unexpected generation kinds"); - // Skip two header words in the block content verification - NOT_PRODUCT(_skip_header_HeapWords = CMSCollector::skip_header_HeapWords();) - CMSCollector* collector = new CMSCollector( - (ConcurrentMarkSweepGeneration*)_old_gen, - _rem_set->as_CardTableRS(), - (ConcurrentMarkSweepPolicy*) collector_policy()); - - if (collector == NULL || !collector->completed_initialization()) { - if (collector) { - delete collector; // Be nice in embedded situation - } - vm_shutdown_during_initialization("Could not create CMS collector"); - return false; - } - return true; // success -} - -void GenCollectedHeap::collect_mostly_concurrent(GCCause::Cause cause) { - assert(!Heap_lock->owned_by_self(), "Should not own Heap_lock"); - - MutexLocker ml(Heap_lock); - // Read the GC counts while holding the Heap_lock - unsigned int full_gc_count_before = total_full_collections(); - unsigned int gc_count_before = total_collections(); - { - MutexUnlocker mu(Heap_lock); - VM_GenCollectFullConcurrent op(gc_count_before, full_gc_count_before, cause); - VMThread::execute(&op); - } -} -#endif // INCLUDE_ALL_GCS - -void GenCollectedHeap::do_full_collection(bool clear_all_soft_refs) { - do_full_collection(clear_all_soft_refs, 1 /* old */); -} - -void GenCollectedHeap::do_full_collection(bool clear_all_soft_refs, - int max_level) { - int local_max_level; - if (!incremental_collection_will_fail(false /* don't consult_young */) && - gc_cause() == GCCause::_gc_locker) { - local_max_level = 0; - } else { - local_max_level = max_level; - } - - do_collection(true /* full */, - clear_all_soft_refs /* clear_all_soft_refs */, - 0 /* size */, - false /* is_tlab */, - local_max_level /* max_level */); - // Hack XXX FIX ME !!! - // A scavenge may not have been attempted, or may have - // been attempted and failed, because the old gen was too full - if (local_max_level == 0 && gc_cause() == GCCause::_gc_locker && - incremental_collection_will_fail(false /* don't consult_young */)) { - if (PrintGCDetails) { - gclog_or_tty->print_cr("GC locker: Trying a full collection " - "because scavenge failed"); - } - // This time allow the old gen to be collected as well - do_collection(true /* full */, - clear_all_soft_refs /* clear_all_soft_refs */, - 0 /* size */, - false /* is_tlab */, - 1 /* old */ /* max_level */); - } -} - -bool GenCollectedHeap::is_in_young(oop p) { - bool result = ((HeapWord*)p) < _old_gen->reserved().start(); - assert(result == _young_gen->is_in_reserved(p), - err_msg("incorrect test - result=%d, p=" INTPTR_FORMAT, result, p2i((void*)p))); - return result; -} - -// Returns "TRUE" iff "p" points into the committed areas of the heap. -bool GenCollectedHeap::is_in(const void* p) const { - return _young_gen->is_in(p) || _old_gen->is_in(p); -} - -#ifdef ASSERT -// Don't implement this by using is_in_young(). This method is used -// in some cases to check that is_in_young() is correct. -bool GenCollectedHeap::is_in_partial_collection(const void* p) { - assert(is_in_reserved(p) || p == NULL, - "Does not work if address is non-null and outside of the heap"); - return p < _young_gen->reserved().end() && p != NULL; -} -#endif - -void GenCollectedHeap::oop_iterate_no_header(OopClosure* cl) { - NoHeaderExtendedOopClosure no_header_cl(cl); - oop_iterate(&no_header_cl); -} - -void GenCollectedHeap::oop_iterate(ExtendedOopClosure* cl) { - _young_gen->oop_iterate(cl); - _old_gen->oop_iterate(cl); -} - -void GenCollectedHeap::object_iterate(ObjectClosure* cl) { - _young_gen->object_iterate(cl); - _old_gen->object_iterate(cl); -} - -void GenCollectedHeap::safe_object_iterate(ObjectClosure* cl) { - _young_gen->safe_object_iterate(cl); - _old_gen->safe_object_iterate(cl); -} - -Space* GenCollectedHeap::space_containing(const void* addr) const { - Space* res = _young_gen->space_containing(addr); - if (res != NULL) { - return res; - } - res = _old_gen->space_containing(addr); - assert(res != NULL, "Could not find containing space"); - return res; -} - -HeapWord* GenCollectedHeap::block_start(const void* addr) const { - assert(is_in_reserved(addr), "block_start of address outside of heap"); - if (_young_gen->is_in_reserved(addr)) { - assert(_young_gen->is_in(addr), "addr should be in allocated part of generation"); - return _young_gen->block_start(addr); - } - - assert(_old_gen->is_in_reserved(addr), "Some generation should contain the address"); - assert(_old_gen->is_in(addr), "addr should be in allocated part of generation"); - return _old_gen->block_start(addr); -} - -size_t GenCollectedHeap::block_size(const HeapWord* addr) const { - assert(is_in_reserved(addr), "block_size of address outside of heap"); - if (_young_gen->is_in_reserved(addr)) { - assert(_young_gen->is_in(addr), "addr should be in allocated part of generation"); - return _young_gen->block_size(addr); - } - - assert(_old_gen->is_in_reserved(addr), "Some generation should contain the address"); - assert(_old_gen->is_in(addr), "addr should be in allocated part of generation"); - return _old_gen->block_size(addr); -} - -bool GenCollectedHeap::block_is_obj(const HeapWord* addr) const { - assert(is_in_reserved(addr), "block_is_obj of address outside of heap"); - assert(block_start(addr) == addr, "addr must be a block start"); - if (_young_gen->is_in_reserved(addr)) { - return _young_gen->block_is_obj(addr); - } - - assert(_old_gen->is_in_reserved(addr), "Some generation should contain the address"); - return _old_gen->block_is_obj(addr); -} - -bool GenCollectedHeap::supports_tlab_allocation() const { - assert(!_old_gen->supports_tlab_allocation(), "Old gen supports TLAB allocation?!"); - return _young_gen->supports_tlab_allocation(); -} - -size_t GenCollectedHeap::tlab_capacity(Thread* thr) const { - assert(!_old_gen->supports_tlab_allocation(), "Old gen supports TLAB allocation?!"); - if (_young_gen->supports_tlab_allocation()) { - return _young_gen->tlab_capacity(); - } - return 0; -} - -size_t GenCollectedHeap::tlab_used(Thread* thr) const { - assert(!_old_gen->supports_tlab_allocation(), "Old gen supports TLAB allocation?!"); - if (_young_gen->supports_tlab_allocation()) { - return _young_gen->tlab_used(); - } - return 0; -} - -size_t GenCollectedHeap::unsafe_max_tlab_alloc(Thread* thr) const { - assert(!_old_gen->supports_tlab_allocation(), "Old gen supports TLAB allocation?!"); - if (_young_gen->supports_tlab_allocation()) { - return _young_gen->unsafe_max_tlab_alloc(); - } - return 0; -} - -HeapWord* GenCollectedHeap::allocate_new_tlab(size_t size) { - bool gc_overhead_limit_was_exceeded; - return collector_policy()->mem_allocate_work(size /* size */, - true /* is_tlab */, - &gc_overhead_limit_was_exceeded); -} - -// Requires "*prev_ptr" to be non-NULL. Deletes and a block of minimal size -// from the list headed by "*prev_ptr". -static ScratchBlock *removeSmallestScratch(ScratchBlock **prev_ptr) { - bool first = true; - size_t min_size = 0; // "first" makes this conceptually infinite. - ScratchBlock **smallest_ptr, *smallest; - ScratchBlock *cur = *prev_ptr; - while (cur) { - assert(*prev_ptr == cur, "just checking"); - if (first || cur->num_words < min_size) { - smallest_ptr = prev_ptr; - smallest = cur; - min_size = smallest->num_words; - first = false; - } - prev_ptr = &cur->next; - cur = cur->next; - } - smallest = *smallest_ptr; - *smallest_ptr = smallest->next; - return smallest; -} - -// Sort the scratch block list headed by res into decreasing size order, -// and set "res" to the result. -static void sort_scratch_list(ScratchBlock*& list) { - ScratchBlock* sorted = NULL; - ScratchBlock* unsorted = list; - while (unsorted) { - ScratchBlock *smallest = removeSmallestScratch(&unsorted); - smallest->next = sorted; - sorted = smallest; - } - list = sorted; -} - -ScratchBlock* GenCollectedHeap::gather_scratch(Generation* requestor, - size_t max_alloc_words) { - ScratchBlock* res = NULL; - _young_gen->contribute_scratch(res, requestor, max_alloc_words); - _old_gen->contribute_scratch(res, requestor, max_alloc_words); - sort_scratch_list(res); - return res; -} - -void GenCollectedHeap::release_scratch() { - _young_gen->reset_scratch(); - _old_gen->reset_scratch(); -} - -class GenPrepareForVerifyClosure: public GenCollectedHeap::GenClosure { - void do_generation(Generation* gen) { - gen->prepare_for_verify(); - } -}; - -void GenCollectedHeap::prepare_for_verify() { - ensure_parsability(false); // no need to retire TLABs - GenPrepareForVerifyClosure blk; - generation_iterate(&blk, false); -} - -void GenCollectedHeap::generation_iterate(GenClosure* cl, - bool old_to_young) { - if (old_to_young) { - cl->do_generation(_old_gen); - cl->do_generation(_young_gen); - } else { - cl->do_generation(_young_gen); - cl->do_generation(_old_gen); - } -} - -bool GenCollectedHeap::is_maximal_no_gc() const { - return _young_gen->is_maximal_no_gc() && _old_gen->is_maximal_no_gc(); -} - -void GenCollectedHeap::save_marks() { - _young_gen->save_marks(); - _old_gen->save_marks(); -} - -GenCollectedHeap* GenCollectedHeap::heap() { - CollectedHeap* heap = Universe::heap(); - assert(heap != NULL, "Uninitialized access to GenCollectedHeap::heap()"); - assert(heap->kind() == CollectedHeap::GenCollectedHeap, "Not a GenCollectedHeap"); - return (GenCollectedHeap*)heap; -} - -void GenCollectedHeap::prepare_for_compaction() { - // Start by compacting into same gen. - CompactPoint cp(_old_gen); - _old_gen->prepare_for_compaction(&cp); - _young_gen->prepare_for_compaction(&cp); -} - -GCStats* GenCollectedHeap::gc_stats(int level) const { - if (level == 0) { - return _young_gen->gc_stats(); - } else { - return _old_gen->gc_stats(); - } -} - -void GenCollectedHeap::verify(bool silent, VerifyOption option /* ignored */) { - if (!silent) { - gclog_or_tty->print("%s", _old_gen->name()); - gclog_or_tty->print(" "); - } - _old_gen->verify(); - - if (!silent) { - gclog_or_tty->print("%s", _young_gen->name()); - gclog_or_tty->print(" "); - } - _young_gen->verify(); - - if (!silent) { - gclog_or_tty->print("remset "); - } - rem_set()->verify(); -} - -void GenCollectedHeap::print_on(outputStream* st) const { - _young_gen->print_on(st); - _old_gen->print_on(st); - MetaspaceAux::print_on(st); -} - -void GenCollectedHeap::gc_threads_do(ThreadClosure* tc) const { - if (workers() != NULL) { - workers()->threads_do(tc); - } -#if INCLUDE_ALL_GCS - if (UseConcMarkSweepGC) { - ConcurrentMarkSweepThread::threads_do(tc); - } -#endif // INCLUDE_ALL_GCS -} - -void GenCollectedHeap::print_gc_threads_on(outputStream* st) const { -#if INCLUDE_ALL_GCS - if (UseConcMarkSweepGC) { - workers()->print_worker_threads_on(st); - ConcurrentMarkSweepThread::print_all_on(st); - } -#endif // INCLUDE_ALL_GCS -} - -void GenCollectedHeap::print_on_error(outputStream* st) const { - this->CollectedHeap::print_on_error(st); - -#if INCLUDE_ALL_GCS - if (UseConcMarkSweepGC) { - st->cr(); - CMSCollector::print_on_error(st); - } -#endif // INCLUDE_ALL_GCS -} - -void GenCollectedHeap::print_tracing_info() const { - if (TraceYoungGenTime) { - _young_gen->print_summary_info(); - } - if (TraceOldGenTime) { - _old_gen->print_summary_info(); - } -} - -void GenCollectedHeap::print_heap_change(size_t prev_used) const { - if (PrintGCDetails && Verbose) { - gclog_or_tty->print(" " SIZE_FORMAT - "->" SIZE_FORMAT - "(" SIZE_FORMAT ")", - prev_used, used(), capacity()); - } else { - gclog_or_tty->print(" " SIZE_FORMAT "K" - "->" SIZE_FORMAT "K" - "(" SIZE_FORMAT "K)", - prev_used / K, used() / K, capacity() / K); - } -} - -class GenGCPrologueClosure: public GenCollectedHeap::GenClosure { - private: - bool _full; - public: - void do_generation(Generation* gen) { - gen->gc_prologue(_full); - } - GenGCPrologueClosure(bool full) : _full(full) {}; -}; - -void GenCollectedHeap::gc_prologue(bool full) { - assert(InlineCacheBuffer::is_empty(), "should have cleaned up ICBuffer"); - - always_do_update_barrier = false; - // Fill TLAB's and such - CollectedHeap::accumulate_statistics_all_tlabs(); - ensure_parsability(true); // retire TLABs - - // Walk generations - GenGCPrologueClosure blk(full); - generation_iterate(&blk, false); // not old-to-young. -}; - -class GenGCEpilogueClosure: public GenCollectedHeap::GenClosure { - private: - bool _full; - public: - void do_generation(Generation* gen) { - gen->gc_epilogue(_full); - } - GenGCEpilogueClosure(bool full) : _full(full) {}; -}; - -void GenCollectedHeap::gc_epilogue(bool full) { -#ifdef COMPILER2 - assert(DerivedPointerTable::is_empty(), "derived pointer present"); - size_t actual_gap = pointer_delta((HeapWord*) (max_uintx-3), *(end_addr())); - guarantee(actual_gap > (size_t)FastAllocateSizeLimit, "inline allocation wraps"); -#endif /* COMPILER2 */ - - resize_all_tlabs(); - - GenGCEpilogueClosure blk(full); - generation_iterate(&blk, false); // not old-to-young. - - if (!CleanChunkPoolAsync) { - Chunk::clean_chunk_pool(); - } - - MetaspaceCounters::update_performance_counters(); - CompressedClassSpaceCounters::update_performance_counters(); - - always_do_update_barrier = UseConcMarkSweepGC; -}; - -#ifndef PRODUCT -class GenGCSaveTopsBeforeGCClosure: public GenCollectedHeap::GenClosure { - private: - public: - void do_generation(Generation* gen) { - gen->record_spaces_top(); - } -}; - -void GenCollectedHeap::record_gen_tops_before_GC() { - if (ZapUnusedHeapArea) { - GenGCSaveTopsBeforeGCClosure blk; - generation_iterate(&blk, false); // not old-to-young. - } -} -#endif // not PRODUCT - -class GenEnsureParsabilityClosure: public GenCollectedHeap::GenClosure { - public: - void do_generation(Generation* gen) { - gen->ensure_parsability(); - } -}; - -void GenCollectedHeap::ensure_parsability(bool retire_tlabs) { - CollectedHeap::ensure_parsability(retire_tlabs); - GenEnsureParsabilityClosure ep_cl; - generation_iterate(&ep_cl, false); -} - -oop GenCollectedHeap::handle_failed_promotion(Generation* old_gen, - oop obj, - size_t obj_size) { - guarantee(old_gen->level() == 1, "We only get here with an old generation"); - assert(obj_size == (size_t)obj->size(), "bad obj_size passed in"); - HeapWord* result = NULL; - - result = old_gen->expand_and_allocate(obj_size, false); - - if (result != NULL) { - Copy::aligned_disjoint_words((HeapWord*)obj, result, obj_size); - } - return oop(result); -} - -class GenTimeOfLastGCClosure: public GenCollectedHeap::GenClosure { - jlong _time; // in ms - jlong _now; // in ms - - public: - GenTimeOfLastGCClosure(jlong now) : _time(now), _now(now) { } - - jlong time() { return _time; } - - void do_generation(Generation* gen) { - _time = MIN2(_time, gen->time_of_last_gc(_now)); - } -}; - -jlong GenCollectedHeap::millis_since_last_gc() { - // We need a monotonically non-decreasing time in ms but - // os::javaTimeMillis() does not guarantee monotonicity. - jlong now = os::javaTimeNanos() / NANOSECS_PER_MILLISEC; - GenTimeOfLastGCClosure tolgc_cl(now); - // iterate over generations getting the oldest - // time that a generation was collected - generation_iterate(&tolgc_cl, false); - - // javaTimeNanos() is guaranteed to be monotonically non-decreasing - // provided the underlying platform provides such a time source - // (and it is bug free). So we still have to guard against getting - // back a time later than 'now'. - jlong retVal = now - tolgc_cl.time(); - if (retVal < 0) { - NOT_PRODUCT(warning("time warp: " JLONG_FORMAT, retVal);) - return 0; - } - return retVal; -} --- /dev/null 2015-03-18 17:10:38.111854831 +0100 +++ new/src/share/vm/gc/shared/genCollectedHeap.cpp 2015-05-12 11:41:58.569513333 +0200 @@ -0,0 +1,1336 @@ +/* + * Copyright (c) 2000, 2015, 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/symbolTable.hpp" +#include "classfile/systemDictionary.hpp" +#include "classfile/vmSymbols.hpp" +#include "code/codeCache.hpp" +#include "code/icBuffer.hpp" +#include "gc/shared/collectedHeap.inline.hpp" +#include "gc/shared/collectorCounters.hpp" +#include "gc/shared/gcLocker.inline.hpp" +#include "gc/shared/gcTrace.hpp" +#include "gc/shared/gcTraceTime.hpp" +#include "gc/shared/genCollectedHeap.hpp" +#include "gc/shared/genOopClosures.inline.hpp" +#include "gc/shared/generationSpec.hpp" +#include "gc/shared/space.hpp" +#include "gc/shared/strongRootsScope.hpp" +#include "gc/shared/vmGCOperations.hpp" +#include "gc/shared/workgroup.hpp" +#include "memory/filemap.hpp" +#include "memory/resourceArea.hpp" +#include "oops/oop.inline.hpp" +#include "runtime/biasedLocking.hpp" +#include "runtime/fprofiler.hpp" +#include "runtime/handles.hpp" +#include "runtime/handles.inline.hpp" +#include "runtime/java.hpp" +#include "runtime/vmThread.hpp" +#include "services/management.hpp" +#include "services/memoryService.hpp" +#include "utilities/macros.hpp" +#include "utilities/stack.inline.hpp" +#include "utilities/vmError.hpp" +#if INCLUDE_ALL_GCS +#include "gc/cms/concurrentMarkSweepThread.hpp" +#include "gc/cms/vmCMSOperations.hpp" +#endif // INCLUDE_ALL_GCS + +NOT_PRODUCT(size_t GenCollectedHeap::_skip_header_HeapWords = 0;) + +// The set of potentially parallel tasks in root scanning. +enum GCH_strong_roots_tasks { + GCH_PS_Universe_oops_do, + GCH_PS_JNIHandles_oops_do, + GCH_PS_ObjectSynchronizer_oops_do, + GCH_PS_FlatProfiler_oops_do, + GCH_PS_Management_oops_do, + GCH_PS_SystemDictionary_oops_do, + GCH_PS_ClassLoaderDataGraph_oops_do, + GCH_PS_jvmti_oops_do, + GCH_PS_CodeCache_oops_do, + GCH_PS_younger_gens, + // Leave this one last. + GCH_PS_NumElements +}; + +GenCollectedHeap::GenCollectedHeap(GenCollectorPolicy *policy) : + CollectedHeap(), + _rem_set(NULL), + _gen_policy(policy), + _process_strong_tasks(new SubTasksDone(GCH_PS_NumElements)), + _full_collections_completed(0) +{ + assert(policy != NULL, "Sanity check"); + if (UseConcMarkSweepGC) { + _workers = new FlexibleWorkGang("GC Thread", ParallelGCThreads, + /* are_GC_task_threads */true, + /* are_ConcurrentGC_threads */false); + _workers->initialize_workers(); + } else { + // Serial GC does not use workers. + _workers = NULL; + } +} + +jint GenCollectedHeap::initialize() { + CollectedHeap::pre_initialize(); + + // While there are no constraints in the GC code that HeapWordSize + // be any particular value, there are multiple other areas in the + // system which believe this to be true (e.g. oop->object_size in some + // cases incorrectly returns the size in wordSize units rather than + // HeapWordSize). + guarantee(HeapWordSize == wordSize, "HeapWordSize must equal wordSize"); + + // Allocate space for the heap. + + char* heap_address; + ReservedSpace heap_rs; + + size_t heap_alignment = collector_policy()->heap_alignment(); + + heap_address = allocate(heap_alignment, &heap_rs); + + if (!heap_rs.is_reserved()) { + vm_shutdown_during_initialization( + "Could not reserve enough space for object heap"); + return JNI_ENOMEM; + } + + initialize_reserved_region((HeapWord*)heap_rs.base(), (HeapWord*)(heap_rs.base() + heap_rs.size())); + + _rem_set = collector_policy()->create_rem_set(reserved_region()); + set_barrier_set(rem_set()->bs()); + + ReservedSpace young_rs = heap_rs.first_part(gen_policy()->young_gen_spec()->max_size(), false, false); + _young_gen = gen_policy()->young_gen_spec()->init(young_rs, 0, rem_set()); + heap_rs = heap_rs.last_part(gen_policy()->young_gen_spec()->max_size()); + + ReservedSpace old_rs = heap_rs.first_part(gen_policy()->old_gen_spec()->max_size(), false, false); + _old_gen = gen_policy()->old_gen_spec()->init(old_rs, 1, rem_set()); + clear_incremental_collection_failed(); + +#if INCLUDE_ALL_GCS + // If we are running CMS, create the collector responsible + // for collecting the CMS generations. + if (collector_policy()->is_concurrent_mark_sweep_policy()) { + bool success = create_cms_collector(); + if (!success) return JNI_ENOMEM; + } +#endif // INCLUDE_ALL_GCS + + return JNI_OK; +} + +char* GenCollectedHeap::allocate(size_t alignment, + ReservedSpace* heap_rs){ + // Now figure out the total size. + const size_t pageSize = UseLargePages ? os::large_page_size() : os::vm_page_size(); + assert(alignment % pageSize == 0, "Must be"); + + GenerationSpec* young_spec = gen_policy()->young_gen_spec(); + GenerationSpec* old_spec = gen_policy()->old_gen_spec(); + + // Check for overflow. + size_t total_reserved = young_spec->max_size() + old_spec->max_size(); + if (total_reserved < young_spec->max_size()) { + vm_exit_during_initialization("The size of the object heap + VM data exceeds " + "the maximum representable size"); + } + assert(total_reserved % alignment == 0, + err_msg("Gen size; total_reserved=" SIZE_FORMAT ", alignment=" + SIZE_FORMAT, total_reserved, alignment)); + + *heap_rs = Universe::reserve_heap(total_reserved, alignment); + return heap_rs->base(); +} + +void GenCollectedHeap::post_initialize() { + CollectedHeap::post_initialize(); + ref_processing_init(); + GenCollectorPolicy *policy = (GenCollectorPolicy *)collector_policy(); + guarantee(policy->is_generation_policy(), "Illegal policy type"); + assert((_young_gen->kind() == Generation::DefNew) || + (_young_gen->kind() == Generation::ParNew), + "Wrong youngest generation type"); + DefNewGeneration* def_new_gen = (DefNewGeneration*)_young_gen; + + assert(_old_gen->kind() == Generation::ConcurrentMarkSweep || + _old_gen->kind() == Generation::MarkSweepCompact, + "Wrong generation kind"); + + policy->initialize_size_policy(def_new_gen->eden()->capacity(), + _old_gen->capacity(), + def_new_gen->from()->capacity()); + policy->initialize_gc_policy_counters(); +} + +void GenCollectedHeap::ref_processing_init() { + _young_gen->ref_processor_init(); + _old_gen->ref_processor_init(); +} + +size_t GenCollectedHeap::capacity() const { + return _young_gen->capacity() + _old_gen->capacity(); +} + +size_t GenCollectedHeap::used() const { + return _young_gen->used() + _old_gen->used(); +} + +// Save the "used_region" for generations level and lower. +void GenCollectedHeap::save_used_regions(int level) { + assert(level == 0 || level == 1, "Illegal level parameter"); + if (level == 1) { + _old_gen->save_used_region(); + } + _young_gen->save_used_region(); +} + +size_t GenCollectedHeap::max_capacity() const { + return _young_gen->max_capacity() + _old_gen->max_capacity(); +} + +// Update the _full_collections_completed counter +// at the end of a stop-world full GC. +unsigned int GenCollectedHeap::update_full_collections_completed() { + MonitorLockerEx ml(FullGCCount_lock, Mutex::_no_safepoint_check_flag); + assert(_full_collections_completed <= _total_full_collections, + "Can't complete more collections than were started"); + _full_collections_completed = _total_full_collections; + ml.notify_all(); + return _full_collections_completed; +} + +// Update the _full_collections_completed counter, as appropriate, +// at the end of a concurrent GC cycle. Note the conditional update +// below to allow this method to be called by a concurrent collector +// without synchronizing in any manner with the VM thread (which +// may already have initiated a STW full collection "concurrently"). +unsigned int GenCollectedHeap::update_full_collections_completed(unsigned int count) { + MonitorLockerEx ml(FullGCCount_lock, Mutex::_no_safepoint_check_flag); + assert((_full_collections_completed <= _total_full_collections) && + (count <= _total_full_collections), + "Can't complete more collections than were started"); + if (count > _full_collections_completed) { + _full_collections_completed = count; + ml.notify_all(); + } + return _full_collections_completed; +} + + +#ifndef PRODUCT +// Override of memory state checking method in CollectedHeap: +// Some collectors (CMS for example) can't have badHeapWordVal written +// in the first two words of an object. (For instance , in the case of +// CMS these words hold state used to synchronize between certain +// (concurrent) GC steps and direct allocating mutators.) +// The skip_header_HeapWords() method below, allows us to skip +// over the requisite number of HeapWord's. Note that (for +// generational collectors) this means that those many words are +// skipped in each object, irrespective of the generation in which +// that object lives. The resultant loss of precision seems to be +// harmless and the pain of avoiding that imprecision appears somewhat +// higher than we are prepared to pay for such rudimentary debugging +// support. +void GenCollectedHeap::check_for_non_bad_heap_word_value(HeapWord* addr, + size_t size) { + if (CheckMemoryInitialization && ZapUnusedHeapArea) { + // We are asked to check a size in HeapWords, + // but the memory is mangled in juint words. + juint* start = (juint*) (addr + skip_header_HeapWords()); + juint* end = (juint*) (addr + size); + for (juint* slot = start; slot < end; slot += 1) { + assert(*slot == badHeapWordVal, + "Found non badHeapWordValue in pre-allocation check"); + } + } +} +#endif + +HeapWord* GenCollectedHeap::attempt_allocation(size_t size, + bool is_tlab, + bool first_only) { + HeapWord* res = NULL; + + if (_young_gen->should_allocate(size, is_tlab)) { + res = _young_gen->allocate(size, is_tlab); + if (res != NULL || first_only) { + return res; + } + } + + if (_old_gen->should_allocate(size, is_tlab)) { + res = _old_gen->allocate(size, is_tlab); + } + + return res; +} + +HeapWord* GenCollectedHeap::mem_allocate(size_t size, + bool* gc_overhead_limit_was_exceeded) { + return collector_policy()->mem_allocate_work(size, + false /* is_tlab */, + gc_overhead_limit_was_exceeded); +} + +bool GenCollectedHeap::must_clear_all_soft_refs() { + return _gc_cause == GCCause::_last_ditch_collection; +} + +bool GenCollectedHeap::should_do_concurrent_full_gc(GCCause::Cause cause) { + return UseConcMarkSweepGC && + ((cause == GCCause::_gc_locker && GCLockerInvokesConcurrent) || + (cause == GCCause::_java_lang_system_gc && ExplicitGCInvokesConcurrent)); +} + +void GenCollectedHeap::collect_generation(Generation* gen, bool full, size_t size, + bool is_tlab, bool run_verification, bool clear_soft_refs, + bool restore_marks_for_biased_locking) { + // Timer for individual generations. Last argument is false: no CR + // FIXME: We should try to start the timing earlier to cover more of the GC pause + // The PrintGCDetails logging starts before we have incremented the GC id. We will do that later + // so we can assume here that the next GC id is what we want. + GCTraceTime t1(gen->short_name(), PrintGCDetails, false, NULL, GCId::peek()); + TraceCollectorStats tcs(gen->counters()); + TraceMemoryManagerStats tmms(gen->kind(),gc_cause()); + + size_t prev_used = gen->used(); + gen->stat_record()->invocations++; + gen->stat_record()->accumulated_time.start(); + + // Must be done anew before each collection because + // a previous collection will do mangling and will + // change top of some spaces. + record_gen_tops_before_GC(); + + if (PrintGC && Verbose) { + gclog_or_tty->print("level=%d invoke=%d size=" SIZE_FORMAT, + gen->level(), + gen->stat_record()->invocations, + size * HeapWordSize); + } + + if (run_verification && VerifyBeforeGC) { + HandleMark hm; // Discard invalid handles created during verification + Universe::verify(" VerifyBeforeGC:"); + } + COMPILER2_PRESENT(DerivedPointerTable::clear()); + + if (restore_marks_for_biased_locking) { + // We perform this mark word preservation work lazily + // because it's only at this point that we know whether we + // absolutely have to do it; we want to avoid doing it for + // scavenge-only collections where it's unnecessary + BiasedLocking::preserve_marks(); + } + + // Do collection work + { + // Note on ref discovery: For what appear to be historical reasons, + // GCH enables and disabled (by enqueing) refs discovery. + // In the future this should be moved into the generation's + // collect method so that ref discovery and enqueueing concerns + // are local to a generation. The collect method could return + // an appropriate indication in the case that notification on + // the ref lock was needed. This will make the treatment of + // weak refs more uniform (and indeed remove such concerns + // from GCH). XXX + + HandleMark hm; // Discard invalid handles created during gc + save_marks(); // save marks for all gens + // We want to discover references, but not process them yet. + // This mode is disabled in process_discovered_references if the + // generation does some collection work, or in + // enqueue_discovered_references if the generation returns + // without doing any work. + ReferenceProcessor* rp = gen->ref_processor(); + // If the discovery of ("weak") refs in this generation is + // atomic wrt other collectors in this configuration, we + // are guaranteed to have empty discovered ref lists. + if (rp->discovery_is_atomic()) { + rp->enable_discovery(); + rp->setup_policy(clear_soft_refs); + } else { + // collect() below will enable discovery as appropriate + } + gen->collect(full, clear_soft_refs, size, is_tlab); + if (!rp->enqueuing_is_done()) { + rp->enqueue_discovered_references(); + } else { + rp->set_enqueuing_is_done(false); + } + rp->verify_no_references_recorded(); + } + + COMPILER2_PRESENT(DerivedPointerTable::update_pointers()); + + gen->stat_record()->accumulated_time.stop(); + + update_gc_stats(gen->level(), full); + + if (run_verification && VerifyAfterGC) { + HandleMark hm; // Discard invalid handles created during verification + Universe::verify(" VerifyAfterGC:"); + } + + if (PrintGCDetails) { + gclog_or_tty->print(":"); + gen->print_heap_change(prev_used); + } +} + +void GenCollectedHeap::do_collection(bool full, + bool clear_all_soft_refs, + size_t size, + bool is_tlab, + int max_level) { + ResourceMark rm; + DEBUG_ONLY(Thread* my_thread = Thread::current();) + + assert(SafepointSynchronize::is_at_safepoint(), "should be at safepoint"); + assert(my_thread->is_VM_thread() || + my_thread->is_ConcurrentGC_thread(), + "incorrect thread type capability"); + assert(Heap_lock->is_locked(), + "the requesting thread should have the Heap_lock"); + guarantee(!is_gc_active(), "collection is not reentrant"); + + if (GC_locker::check_active_before_gc()) { + return; // GC is disabled (e.g. JNI GetXXXCritical operation) + } + + const bool do_clear_all_soft_refs = clear_all_soft_refs || + collector_policy()->should_clear_all_soft_refs(); + + ClearedAllSoftRefs casr(do_clear_all_soft_refs, collector_policy()); + + const size_t metadata_prev_used = MetaspaceAux::used_bytes(); + + print_heap_before_gc(); + + { + FlagSetting fl(_is_gc_active, true); + + bool complete = full && (max_level == 1 /* old */); + const char* gc_cause_prefix = complete ? "Full GC" : "GC"; + TraceCPUTime tcpu(PrintGCDetails, true, gclog_or_tty); + // The PrintGCDetails logging starts before we have incremented the GC id. We will do that later + // so we can assume here that the next GC id is what we want. + GCTraceTime t(GCCauseString(gc_cause_prefix, gc_cause()), PrintGCDetails, false, NULL, GCId::peek()); + + gc_prologue(complete); + increment_total_collections(complete); + + size_t gch_prev_used = used(); + bool run_verification = total_collections() >= VerifyGCStartAt; + + bool prepared_for_verification = false; + int max_level_collected = 0; + bool old_collects_young = (max_level == 1) && + full && + _old_gen->full_collects_younger_generations(); + if (!old_collects_young && + _young_gen->should_collect(full, size, is_tlab)) { + if (run_verification && VerifyGCLevel <= 0 && VerifyBeforeGC) { + prepare_for_verify(); + prepared_for_verification = true; + } + + assert(!_young_gen->performs_in_place_marking(), "No young generation do in place marking"); + collect_generation(_young_gen, + full, + size, + is_tlab, + run_verification && VerifyGCLevel <= 0, + do_clear_all_soft_refs, + false); + + if (size > 0 && (!is_tlab || _young_gen->supports_tlab_allocation()) && + size * HeapWordSize <= _young_gen->unsafe_max_alloc_nogc()) { + // Allocation request was met by young GC. + size = 0; + } + } + + bool must_restore_marks_for_biased_locking = false; + + if (max_level == 1 && _old_gen->should_collect(full, size, is_tlab)) { + if (!complete) { + // The full_collections increment was missed above. + increment_total_full_collections(); + } + + pre_full_gc_dump(NULL); // do any pre full gc dumps + + if (!prepared_for_verification && run_verification && + VerifyGCLevel <= 1 && VerifyBeforeGC) { + prepare_for_verify(); + } + + assert(_old_gen->performs_in_place_marking(), "All old generations do in place marking"); + collect_generation(_old_gen, + full, + size, + is_tlab, + run_verification && VerifyGCLevel <= 1, + do_clear_all_soft_refs, + true); + + must_restore_marks_for_biased_locking = true; + max_level_collected = 1; + } + + // Update "complete" boolean wrt what actually transpired -- + // for instance, a promotion failure could have led to + // a whole heap collection. + complete = complete || (max_level_collected == 1 /* old */); + + if (complete) { // We did a "major" collection + // FIXME: See comment at pre_full_gc_dump call + post_full_gc_dump(NULL); // do any post full gc dumps + } + + if (PrintGCDetails) { + print_heap_change(gch_prev_used); + + // Print metaspace info for full GC with PrintGCDetails flag. + if (complete) { + MetaspaceAux::print_metaspace_change(metadata_prev_used); + } + } + + // Adjust generation sizes. + if (max_level_collected == 1 /* old */) { + _old_gen->compute_new_size(); + } + _young_gen->compute_new_size(); + + if (complete) { + // Delete metaspaces for unloaded class loaders and clean up loader_data graph + ClassLoaderDataGraph::purge(); + MetaspaceAux::verify_metrics(); + // Resize the metaspace capacity after full collections + MetaspaceGC::compute_new_size(); + update_full_collections_completed(); + } + + // Track memory usage and detect low memory after GC finishes + MemoryService::track_memory_usage(); + + gc_epilogue(complete); + + if (must_restore_marks_for_biased_locking) { + BiasedLocking::restore_marks(); + } + } + + print_heap_after_gc(); + +#ifdef TRACESPINNING + ParallelTaskTerminator::print_termination_counts(); +#endif +} + +HeapWord* GenCollectedHeap::satisfy_failed_allocation(size_t size, bool is_tlab) { + return collector_policy()->satisfy_failed_allocation(size, is_tlab); +} + +void GenCollectedHeap::set_par_threads(uint t) { + assert(t == 0 || !UseSerialGC, "Cannot have parallel threads"); + CollectedHeap::set_par_threads(t); + set_n_termination(t); +} + +void GenCollectedHeap::set_n_termination(uint t) { + _process_strong_tasks->set_n_threads(t); +} + +#ifdef ASSERT +class AssertNonScavengableClosure: public OopClosure { +public: + virtual void do_oop(oop* p) { + assert(!GenCollectedHeap::heap()->is_in_partial_collection(*p), + "Referent should not be scavengable."); } + virtual void do_oop(narrowOop* p) { ShouldNotReachHere(); } +}; +static AssertNonScavengableClosure assert_is_non_scavengable_closure; +#endif + +void GenCollectedHeap::process_roots(bool activate_scope, + ScanningOption so, + OopClosure* strong_roots, + OopClosure* weak_roots, + CLDClosure* strong_cld_closure, + CLDClosure* weak_cld_closure, + CodeBlobClosure* code_roots) { + StrongRootsScope srs(activate_scope); + + // General roots. + assert(Threads::thread_claim_parity() != 0, "must have called prologue code"); + assert(code_roots != NULL, "code root closure should always be set"); + // _n_termination for _process_strong_tasks should be set up stream + // in a method not running in a GC worker. Otherwise the GC worker + // could be trying to change the termination condition while the task + // is executing in another GC worker. + + if (!_process_strong_tasks->is_task_claimed(GCH_PS_ClassLoaderDataGraph_oops_do)) { + ClassLoaderDataGraph::roots_cld_do(strong_cld_closure, weak_cld_closure); + } + + // Some CLDs contained in the thread frames should be considered strong. + // Don't process them if they will be processed during the ClassLoaderDataGraph phase. + CLDClosure* roots_from_clds_p = (strong_cld_closure != weak_cld_closure) ? strong_cld_closure : NULL; + // Only process code roots from thread stacks if we aren't visiting the entire CodeCache anyway + CodeBlobClosure* roots_from_code_p = (so & SO_AllCodeCache) ? NULL : code_roots; + + bool is_par = n_par_threads() > 0; + Threads::possibly_parallel_oops_do(is_par, strong_roots, roots_from_clds_p, roots_from_code_p); + + if (!_process_strong_tasks->is_task_claimed(GCH_PS_Universe_oops_do)) { + Universe::oops_do(strong_roots); + } + // Global (strong) JNI handles + if (!_process_strong_tasks->is_task_claimed(GCH_PS_JNIHandles_oops_do)) { + JNIHandles::oops_do(strong_roots); + } + + if (!_process_strong_tasks->is_task_claimed(GCH_PS_ObjectSynchronizer_oops_do)) { + ObjectSynchronizer::oops_do(strong_roots); + } + if (!_process_strong_tasks->is_task_claimed(GCH_PS_FlatProfiler_oops_do)) { + FlatProfiler::oops_do(strong_roots); + } + if (!_process_strong_tasks->is_task_claimed(GCH_PS_Management_oops_do)) { + Management::oops_do(strong_roots); + } + if (!_process_strong_tasks->is_task_claimed(GCH_PS_jvmti_oops_do)) { + JvmtiExport::oops_do(strong_roots); + } + + if (!_process_strong_tasks->is_task_claimed(GCH_PS_SystemDictionary_oops_do)) { + SystemDictionary::roots_oops_do(strong_roots, weak_roots); + } + + // All threads execute the following. A specific chunk of buckets + // from the StringTable are the individual tasks. + if (weak_roots != NULL) { + if (is_par) { + StringTable::possibly_parallel_oops_do(weak_roots); + } else { + StringTable::oops_do(weak_roots); + } + } + + if (!_process_strong_tasks->is_task_claimed(GCH_PS_CodeCache_oops_do)) { + if (so & SO_ScavengeCodeCache) { + assert(code_roots != NULL, "must supply closure for code cache"); + + // We only visit parts of the CodeCache when scavenging. + CodeCache::scavenge_root_nmethods_do(code_roots); + } + if (so & SO_AllCodeCache) { + assert(code_roots != NULL, "must supply closure for code cache"); + + // CMSCollector uses this to do intermediate-strength collections. + // We scan the entire code cache, since CodeCache::do_unloading is not called. + CodeCache::blobs_do(code_roots); + } + // Verify that the code cache contents are not subject to + // movement by a scavenging collection. + DEBUG_ONLY(CodeBlobToOopClosure assert_code_is_non_scavengable(&assert_is_non_scavengable_closure, !CodeBlobToOopClosure::FixRelocations)); + DEBUG_ONLY(CodeCache::asserted_non_scavengable_nmethods_do(&assert_code_is_non_scavengable)); + } + +} + +void GenCollectedHeap::gen_process_roots(int level, + bool younger_gens_as_roots, + bool activate_scope, + ScanningOption so, + bool only_strong_roots, + OopsInGenClosure* not_older_gens, + OopsInGenClosure* older_gens, + CLDClosure* cld_closure) { + const bool is_adjust_phase = !only_strong_roots && !younger_gens_as_roots; + + bool is_moving_collection = false; + if (level == 0 || is_adjust_phase) { + // young collections are always moving + is_moving_collection = true; + } + + MarkingCodeBlobClosure mark_code_closure(not_older_gens, is_moving_collection); + OopsInGenClosure* weak_roots = only_strong_roots ? NULL : not_older_gens; + CLDClosure* weak_cld_closure = only_strong_roots ? NULL : cld_closure; + + process_roots(activate_scope, so, + not_older_gens, weak_roots, + cld_closure, weak_cld_closure, + &mark_code_closure); + + if (younger_gens_as_roots) { + if (!_process_strong_tasks->is_task_claimed(GCH_PS_younger_gens)) { + if (level == 1) { + not_older_gens->set_generation(_young_gen); + _young_gen->oop_iterate(not_older_gens); + } + not_older_gens->reset_generation(); + } + } + // When collection is parallel, all threads get to cooperate to do + // older-gen scanning. + if (level == 0) { + older_gens->set_generation(_old_gen); + rem_set()->younger_refs_iterate(_old_gen, older_gens); + older_gens->reset_generation(); + } + + _process_strong_tasks->all_tasks_completed(); +} + + +class AlwaysTrueClosure: public BoolObjectClosure { +public: + bool do_object_b(oop p) { return true; } +}; +static AlwaysTrueClosure always_true; + +void GenCollectedHeap::gen_process_weak_roots(OopClosure* root_closure) { + JNIHandles::weak_oops_do(&always_true, root_closure); + _young_gen->ref_processor()->weak_oops_do(root_closure); + _old_gen->ref_processor()->weak_oops_do(root_closure); +} + +#define GCH_SINCE_SAVE_MARKS_ITERATE_DEFN(OopClosureType, nv_suffix) \ +void GenCollectedHeap:: \ +oop_since_save_marks_iterate(int level, \ + OopClosureType* cur, \ + OopClosureType* older) { \ + if (level == 0) { \ + _young_gen->oop_since_save_marks_iterate##nv_suffix(cur); \ + _old_gen->oop_since_save_marks_iterate##nv_suffix(older); \ + } else { \ + _old_gen->oop_since_save_marks_iterate##nv_suffix(cur); \ + } \ +} + +ALL_SINCE_SAVE_MARKS_CLOSURES(GCH_SINCE_SAVE_MARKS_ITERATE_DEFN) + +#undef GCH_SINCE_SAVE_MARKS_ITERATE_DEFN + +bool GenCollectedHeap::no_allocs_since_save_marks(int level) { + if (level == 0 && !_young_gen->no_allocs_since_save_marks()) { + return false; + } + return _old_gen->no_allocs_since_save_marks(); +} + +bool GenCollectedHeap::supports_inline_contig_alloc() const { + return _young_gen->supports_inline_contig_alloc(); +} + +HeapWord** GenCollectedHeap::top_addr() const { + return _young_gen->top_addr(); +} + +HeapWord** GenCollectedHeap::end_addr() const { + return _young_gen->end_addr(); +} + +// public collection interfaces + +void GenCollectedHeap::collect(GCCause::Cause cause) { + if (should_do_concurrent_full_gc(cause)) { +#if INCLUDE_ALL_GCS + // mostly concurrent full collection + collect_mostly_concurrent(cause); +#else // INCLUDE_ALL_GCS + ShouldNotReachHere(); +#endif // INCLUDE_ALL_GCS + } else if (cause == GCCause::_wb_young_gc) { + // minor collection for WhiteBox API + collect(cause, 0 /* young */); + } else { +#ifdef ASSERT + if (cause == GCCause::_scavenge_alot) { + // minor collection only + collect(cause, 0 /* young */); + } else { + // Stop-the-world full collection + collect(cause, 1 /* old */); + } +#else + // Stop-the-world full collection + collect(cause, 1 /* old */); +#endif + } +} + +void GenCollectedHeap::collect(GCCause::Cause cause, int max_level) { + // The caller doesn't have the Heap_lock + assert(!Heap_lock->owned_by_self(), "this thread should not own the Heap_lock"); + MutexLocker ml(Heap_lock); + collect_locked(cause, max_level); +} + +void GenCollectedHeap::collect_locked(GCCause::Cause cause) { + // The caller has the Heap_lock + assert(Heap_lock->owned_by_self(), "this thread should own the Heap_lock"); + collect_locked(cause, 1 /* old */); +} + +// this is the private collection interface +// The Heap_lock is expected to be held on entry. + +void GenCollectedHeap::collect_locked(GCCause::Cause cause, int max_level) { + // Read the GC count while holding the Heap_lock + unsigned int gc_count_before = total_collections(); + unsigned int full_gc_count_before = total_full_collections(); + { + MutexUnlocker mu(Heap_lock); // give up heap lock, execute gets it back + VM_GenCollectFull op(gc_count_before, full_gc_count_before, + cause, max_level); + VMThread::execute(&op); + } +} + +#if INCLUDE_ALL_GCS +bool GenCollectedHeap::create_cms_collector() { + + assert(_old_gen->kind() == Generation::ConcurrentMarkSweep, + "Unexpected generation kinds"); + // Skip two header words in the block content verification + NOT_PRODUCT(_skip_header_HeapWords = CMSCollector::skip_header_HeapWords();) + CMSCollector* collector = new CMSCollector( + (ConcurrentMarkSweepGeneration*)_old_gen, + _rem_set->as_CardTableRS(), + (ConcurrentMarkSweepPolicy*) collector_policy()); + + if (collector == NULL || !collector->completed_initialization()) { + if (collector) { + delete collector; // Be nice in embedded situation + } + vm_shutdown_during_initialization("Could not create CMS collector"); + return false; + } + return true; // success +} + +void GenCollectedHeap::collect_mostly_concurrent(GCCause::Cause cause) { + assert(!Heap_lock->owned_by_self(), "Should not own Heap_lock"); + + MutexLocker ml(Heap_lock); + // Read the GC counts while holding the Heap_lock + unsigned int full_gc_count_before = total_full_collections(); + unsigned int gc_count_before = total_collections(); + { + MutexUnlocker mu(Heap_lock); + VM_GenCollectFullConcurrent op(gc_count_before, full_gc_count_before, cause); + VMThread::execute(&op); + } +} +#endif // INCLUDE_ALL_GCS + +void GenCollectedHeap::do_full_collection(bool clear_all_soft_refs) { + do_full_collection(clear_all_soft_refs, 1 /* old */); +} + +void GenCollectedHeap::do_full_collection(bool clear_all_soft_refs, + int max_level) { + int local_max_level; + if (!incremental_collection_will_fail(false /* don't consult_young */) && + gc_cause() == GCCause::_gc_locker) { + local_max_level = 0; + } else { + local_max_level = max_level; + } + + do_collection(true /* full */, + clear_all_soft_refs /* clear_all_soft_refs */, + 0 /* size */, + false /* is_tlab */, + local_max_level /* max_level */); + // Hack XXX FIX ME !!! + // A scavenge may not have been attempted, or may have + // been attempted and failed, because the old gen was too full + if (local_max_level == 0 && gc_cause() == GCCause::_gc_locker && + incremental_collection_will_fail(false /* don't consult_young */)) { + if (PrintGCDetails) { + gclog_or_tty->print_cr("GC locker: Trying a full collection " + "because scavenge failed"); + } + // This time allow the old gen to be collected as well + do_collection(true /* full */, + clear_all_soft_refs /* clear_all_soft_refs */, + 0 /* size */, + false /* is_tlab */, + 1 /* old */ /* max_level */); + } +} + +bool GenCollectedHeap::is_in_young(oop p) { + bool result = ((HeapWord*)p) < _old_gen->reserved().start(); + assert(result == _young_gen->is_in_reserved(p), + err_msg("incorrect test - result=%d, p=" INTPTR_FORMAT, result, p2i((void*)p))); + return result; +} + +// Returns "TRUE" iff "p" points into the committed areas of the heap. +bool GenCollectedHeap::is_in(const void* p) const { + return _young_gen->is_in(p) || _old_gen->is_in(p); +} + +#ifdef ASSERT +// Don't implement this by using is_in_young(). This method is used +// in some cases to check that is_in_young() is correct. +bool GenCollectedHeap::is_in_partial_collection(const void* p) { + assert(is_in_reserved(p) || p == NULL, + "Does not work if address is non-null and outside of the heap"); + return p < _young_gen->reserved().end() && p != NULL; +} +#endif + +void GenCollectedHeap::oop_iterate_no_header(OopClosure* cl) { + NoHeaderExtendedOopClosure no_header_cl(cl); + oop_iterate(&no_header_cl); +} + +void GenCollectedHeap::oop_iterate(ExtendedOopClosure* cl) { + _young_gen->oop_iterate(cl); + _old_gen->oop_iterate(cl); +} + +void GenCollectedHeap::object_iterate(ObjectClosure* cl) { + _young_gen->object_iterate(cl); + _old_gen->object_iterate(cl); +} + +void GenCollectedHeap::safe_object_iterate(ObjectClosure* cl) { + _young_gen->safe_object_iterate(cl); + _old_gen->safe_object_iterate(cl); +} + +Space* GenCollectedHeap::space_containing(const void* addr) const { + Space* res = _young_gen->space_containing(addr); + if (res != NULL) { + return res; + } + res = _old_gen->space_containing(addr); + assert(res != NULL, "Could not find containing space"); + return res; +} + +HeapWord* GenCollectedHeap::block_start(const void* addr) const { + assert(is_in_reserved(addr), "block_start of address outside of heap"); + if (_young_gen->is_in_reserved(addr)) { + assert(_young_gen->is_in(addr), "addr should be in allocated part of generation"); + return _young_gen->block_start(addr); + } + + assert(_old_gen->is_in_reserved(addr), "Some generation should contain the address"); + assert(_old_gen->is_in(addr), "addr should be in allocated part of generation"); + return _old_gen->block_start(addr); +} + +size_t GenCollectedHeap::block_size(const HeapWord* addr) const { + assert(is_in_reserved(addr), "block_size of address outside of heap"); + if (_young_gen->is_in_reserved(addr)) { + assert(_young_gen->is_in(addr), "addr should be in allocated part of generation"); + return _young_gen->block_size(addr); + } + + assert(_old_gen->is_in_reserved(addr), "Some generation should contain the address"); + assert(_old_gen->is_in(addr), "addr should be in allocated part of generation"); + return _old_gen->block_size(addr); +} + +bool GenCollectedHeap::block_is_obj(const HeapWord* addr) const { + assert(is_in_reserved(addr), "block_is_obj of address outside of heap"); + assert(block_start(addr) == addr, "addr must be a block start"); + if (_young_gen->is_in_reserved(addr)) { + return _young_gen->block_is_obj(addr); + } + + assert(_old_gen->is_in_reserved(addr), "Some generation should contain the address"); + return _old_gen->block_is_obj(addr); +} + +bool GenCollectedHeap::supports_tlab_allocation() const { + assert(!_old_gen->supports_tlab_allocation(), "Old gen supports TLAB allocation?!"); + return _young_gen->supports_tlab_allocation(); +} + +size_t GenCollectedHeap::tlab_capacity(Thread* thr) const { + assert(!_old_gen->supports_tlab_allocation(), "Old gen supports TLAB allocation?!"); + if (_young_gen->supports_tlab_allocation()) { + return _young_gen->tlab_capacity(); + } + return 0; +} + +size_t GenCollectedHeap::tlab_used(Thread* thr) const { + assert(!_old_gen->supports_tlab_allocation(), "Old gen supports TLAB allocation?!"); + if (_young_gen->supports_tlab_allocation()) { + return _young_gen->tlab_used(); + } + return 0; +} + +size_t GenCollectedHeap::unsafe_max_tlab_alloc(Thread* thr) const { + assert(!_old_gen->supports_tlab_allocation(), "Old gen supports TLAB allocation?!"); + if (_young_gen->supports_tlab_allocation()) { + return _young_gen->unsafe_max_tlab_alloc(); + } + return 0; +} + +HeapWord* GenCollectedHeap::allocate_new_tlab(size_t size) { + bool gc_overhead_limit_was_exceeded; + return collector_policy()->mem_allocate_work(size /* size */, + true /* is_tlab */, + &gc_overhead_limit_was_exceeded); +} + +// Requires "*prev_ptr" to be non-NULL. Deletes and a block of minimal size +// from the list headed by "*prev_ptr". +static ScratchBlock *removeSmallestScratch(ScratchBlock **prev_ptr) { + bool first = true; + size_t min_size = 0; // "first" makes this conceptually infinite. + ScratchBlock **smallest_ptr, *smallest; + ScratchBlock *cur = *prev_ptr; + while (cur) { + assert(*prev_ptr == cur, "just checking"); + if (first || cur->num_words < min_size) { + smallest_ptr = prev_ptr; + smallest = cur; + min_size = smallest->num_words; + first = false; + } + prev_ptr = &cur->next; + cur = cur->next; + } + smallest = *smallest_ptr; + *smallest_ptr = smallest->next; + return smallest; +} + +// Sort the scratch block list headed by res into decreasing size order, +// and set "res" to the result. +static void sort_scratch_list(ScratchBlock*& list) { + ScratchBlock* sorted = NULL; + ScratchBlock* unsorted = list; + while (unsorted) { + ScratchBlock *smallest = removeSmallestScratch(&unsorted); + smallest->next = sorted; + sorted = smallest; + } + list = sorted; +} + +ScratchBlock* GenCollectedHeap::gather_scratch(Generation* requestor, + size_t max_alloc_words) { + ScratchBlock* res = NULL; + _young_gen->contribute_scratch(res, requestor, max_alloc_words); + _old_gen->contribute_scratch(res, requestor, max_alloc_words); + sort_scratch_list(res); + return res; +} + +void GenCollectedHeap::release_scratch() { + _young_gen->reset_scratch(); + _old_gen->reset_scratch(); +} + +class GenPrepareForVerifyClosure: public GenCollectedHeap::GenClosure { + void do_generation(Generation* gen) { + gen->prepare_for_verify(); + } +}; + +void GenCollectedHeap::prepare_for_verify() { + ensure_parsability(false); // no need to retire TLABs + GenPrepareForVerifyClosure blk; + generation_iterate(&blk, false); +} + +void GenCollectedHeap::generation_iterate(GenClosure* cl, + bool old_to_young) { + if (old_to_young) { + cl->do_generation(_old_gen); + cl->do_generation(_young_gen); + } else { + cl->do_generation(_young_gen); + cl->do_generation(_old_gen); + } +} + +bool GenCollectedHeap::is_maximal_no_gc() const { + return _young_gen->is_maximal_no_gc() && _old_gen->is_maximal_no_gc(); +} + +void GenCollectedHeap::save_marks() { + _young_gen->save_marks(); + _old_gen->save_marks(); +} + +GenCollectedHeap* GenCollectedHeap::heap() { + CollectedHeap* heap = Universe::heap(); + assert(heap != NULL, "Uninitialized access to GenCollectedHeap::heap()"); + assert(heap->kind() == CollectedHeap::GenCollectedHeap, "Not a GenCollectedHeap"); + return (GenCollectedHeap*)heap; +} + +void GenCollectedHeap::prepare_for_compaction() { + // Start by compacting into same gen. + CompactPoint cp(_old_gen); + _old_gen->prepare_for_compaction(&cp); + _young_gen->prepare_for_compaction(&cp); +} + +GCStats* GenCollectedHeap::gc_stats(int level) const { + if (level == 0) { + return _young_gen->gc_stats(); + } else { + return _old_gen->gc_stats(); + } +} + +void GenCollectedHeap::verify(bool silent, VerifyOption option /* ignored */) { + if (!silent) { + gclog_or_tty->print("%s", _old_gen->name()); + gclog_or_tty->print(" "); + } + _old_gen->verify(); + + if (!silent) { + gclog_or_tty->print("%s", _young_gen->name()); + gclog_or_tty->print(" "); + } + _young_gen->verify(); + + if (!silent) { + gclog_or_tty->print("remset "); + } + rem_set()->verify(); +} + +void GenCollectedHeap::print_on(outputStream* st) const { + _young_gen->print_on(st); + _old_gen->print_on(st); + MetaspaceAux::print_on(st); +} + +void GenCollectedHeap::gc_threads_do(ThreadClosure* tc) const { + if (workers() != NULL) { + workers()->threads_do(tc); + } +#if INCLUDE_ALL_GCS + if (UseConcMarkSweepGC) { + ConcurrentMarkSweepThread::threads_do(tc); + } +#endif // INCLUDE_ALL_GCS +} + +void GenCollectedHeap::print_gc_threads_on(outputStream* st) const { +#if INCLUDE_ALL_GCS + if (UseConcMarkSweepGC) { + workers()->print_worker_threads_on(st); + ConcurrentMarkSweepThread::print_all_on(st); + } +#endif // INCLUDE_ALL_GCS +} + +void GenCollectedHeap::print_on_error(outputStream* st) const { + this->CollectedHeap::print_on_error(st); + +#if INCLUDE_ALL_GCS + if (UseConcMarkSweepGC) { + st->cr(); + CMSCollector::print_on_error(st); + } +#endif // INCLUDE_ALL_GCS +} + +void GenCollectedHeap::print_tracing_info() const { + if (TraceYoungGenTime) { + _young_gen->print_summary_info(); + } + if (TraceOldGenTime) { + _old_gen->print_summary_info(); + } +} + +void GenCollectedHeap::print_heap_change(size_t prev_used) const { + if (PrintGCDetails && Verbose) { + gclog_or_tty->print(" " SIZE_FORMAT + "->" SIZE_FORMAT + "(" SIZE_FORMAT ")", + prev_used, used(), capacity()); + } else { + gclog_or_tty->print(" " SIZE_FORMAT "K" + "->" SIZE_FORMAT "K" + "(" SIZE_FORMAT "K)", + prev_used / K, used() / K, capacity() / K); + } +} + +class GenGCPrologueClosure: public GenCollectedHeap::GenClosure { + private: + bool _full; + public: + void do_generation(Generation* gen) { + gen->gc_prologue(_full); + } + GenGCPrologueClosure(bool full) : _full(full) {}; +}; + +void GenCollectedHeap::gc_prologue(bool full) { + assert(InlineCacheBuffer::is_empty(), "should have cleaned up ICBuffer"); + + always_do_update_barrier = false; + // Fill TLAB's and such + CollectedHeap::accumulate_statistics_all_tlabs(); + ensure_parsability(true); // retire TLABs + + // Walk generations + GenGCPrologueClosure blk(full); + generation_iterate(&blk, false); // not old-to-young. +}; + +class GenGCEpilogueClosure: public GenCollectedHeap::GenClosure { + private: + bool _full; + public: + void do_generation(Generation* gen) { + gen->gc_epilogue(_full); + } + GenGCEpilogueClosure(bool full) : _full(full) {}; +}; + +void GenCollectedHeap::gc_epilogue(bool full) { +#ifdef COMPILER2 + assert(DerivedPointerTable::is_empty(), "derived pointer present"); + size_t actual_gap = pointer_delta((HeapWord*) (max_uintx-3), *(end_addr())); + guarantee(actual_gap > (size_t)FastAllocateSizeLimit, "inline allocation wraps"); +#endif /* COMPILER2 */ + + resize_all_tlabs(); + + GenGCEpilogueClosure blk(full); + generation_iterate(&blk, false); // not old-to-young. + + if (!CleanChunkPoolAsync) { + Chunk::clean_chunk_pool(); + } + + MetaspaceCounters::update_performance_counters(); + CompressedClassSpaceCounters::update_performance_counters(); + + always_do_update_barrier = UseConcMarkSweepGC; +}; + +#ifndef PRODUCT +class GenGCSaveTopsBeforeGCClosure: public GenCollectedHeap::GenClosure { + private: + public: + void do_generation(Generation* gen) { + gen->record_spaces_top(); + } +}; + +void GenCollectedHeap::record_gen_tops_before_GC() { + if (ZapUnusedHeapArea) { + GenGCSaveTopsBeforeGCClosure blk; + generation_iterate(&blk, false); // not old-to-young. + } +} +#endif // not PRODUCT + +class GenEnsureParsabilityClosure: public GenCollectedHeap::GenClosure { + public: + void do_generation(Generation* gen) { + gen->ensure_parsability(); + } +}; + +void GenCollectedHeap::ensure_parsability(bool retire_tlabs) { + CollectedHeap::ensure_parsability(retire_tlabs); + GenEnsureParsabilityClosure ep_cl; + generation_iterate(&ep_cl, false); +} + +oop GenCollectedHeap::handle_failed_promotion(Generation* old_gen, + oop obj, + size_t obj_size) { + guarantee(old_gen->level() == 1, "We only get here with an old generation"); + assert(obj_size == (size_t)obj->size(), "bad obj_size passed in"); + HeapWord* result = NULL; + + result = old_gen->expand_and_allocate(obj_size, false); + + if (result != NULL) { + Copy::aligned_disjoint_words((HeapWord*)obj, result, obj_size); + } + return oop(result); +} + +class GenTimeOfLastGCClosure: public GenCollectedHeap::GenClosure { + jlong _time; // in ms + jlong _now; // in ms + + public: + GenTimeOfLastGCClosure(jlong now) : _time(now), _now(now) { } + + jlong time() { return _time; } + + void do_generation(Generation* gen) { + _time = MIN2(_time, gen->time_of_last_gc(_now)); + } +}; + +jlong GenCollectedHeap::millis_since_last_gc() { + // We need a monotonically non-decreasing time in ms but + // os::javaTimeMillis() does not guarantee monotonicity. + jlong now = os::javaTimeNanos() / NANOSECS_PER_MILLISEC; + GenTimeOfLastGCClosure tolgc_cl(now); + // iterate over generations getting the oldest + // time that a generation was collected + generation_iterate(&tolgc_cl, false); + + // javaTimeNanos() is guaranteed to be monotonically non-decreasing + // provided the underlying platform provides such a time source + // (and it is bug free). So we still have to guard against getting + // back a time later than 'now'. + jlong retVal = now - tolgc_cl.time(); + if (retVal < 0) { + NOT_PRODUCT(warning("time warp: " JLONG_FORMAT, retVal);) + return 0; + } + return retVal; +}