--- old/src/share/vm/gc_implementation/parallelScavenge/psMarkSweep.cpp 2015-05-12 11:40:41.938321665 +0200 +++ /dev/null 2015-03-18 17:10:38.111854831 +0100 @@ -1,667 +0,0 @@ -/* - * Copyright (c) 2001, 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/stringTable.hpp" -#include "classfile/systemDictionary.hpp" -#include "code/codeCache.hpp" -#include "gc_implementation/parallelScavenge/parallelScavengeHeap.hpp" -#include "gc_implementation/parallelScavenge/psAdaptiveSizePolicy.hpp" -#include "gc_implementation/parallelScavenge/psMarkSweep.hpp" -#include "gc_implementation/parallelScavenge/psMarkSweepDecorator.hpp" -#include "gc_implementation/parallelScavenge/psOldGen.hpp" -#include "gc_implementation/parallelScavenge/psScavenge.hpp" -#include "gc_implementation/parallelScavenge/psYoungGen.hpp" -#include "gc_implementation/shared/gcHeapSummary.hpp" -#include "gc_implementation/shared/gcTimer.hpp" -#include "gc_implementation/shared/gcTrace.hpp" -#include "gc_implementation/shared/gcTraceTime.hpp" -#include "gc_implementation/shared/isGCActiveMark.hpp" -#include "gc_implementation/shared/markSweep.hpp" -#include "gc_implementation/shared/spaceDecorator.hpp" -#include "gc_interface/gcCause.hpp" -#include "memory/gcLocker.inline.hpp" -#include "memory/referencePolicy.hpp" -#include "memory/referenceProcessor.hpp" -#include "oops/oop.inline.hpp" -#include "runtime/biasedLocking.hpp" -#include "runtime/fprofiler.hpp" -#include "runtime/safepoint.hpp" -#include "runtime/vmThread.hpp" -#include "services/management.hpp" -#include "services/memoryService.hpp" -#include "utilities/events.hpp" -#include "utilities/stack.inline.hpp" - -elapsedTimer PSMarkSweep::_accumulated_time; -jlong PSMarkSweep::_time_of_last_gc = 0; -CollectorCounters* PSMarkSweep::_counters = NULL; - -void PSMarkSweep::initialize() { - MemRegion mr = ParallelScavengeHeap::heap()->reserved_region(); - _ref_processor = new ReferenceProcessor(mr); // a vanilla ref proc - _counters = new CollectorCounters("PSMarkSweep", 1); -} - -// This method contains all heap specific policy for invoking mark sweep. -// PSMarkSweep::invoke_no_policy() will only attempt to mark-sweep-compact -// the heap. It will do nothing further. If we need to bail out for policy -// reasons, scavenge before full gc, or any other specialized behavior, it -// needs to be added here. -// -// Note that this method should only be called from the vm_thread while -// at a safepoint! -// -// Note that the all_soft_refs_clear flag in the collector policy -// may be true because this method can be called without intervening -// activity. For example when the heap space is tight and full measure -// are being taken to free space. - -void PSMarkSweep::invoke(bool maximum_heap_compaction) { - assert(SafepointSynchronize::is_at_safepoint(), "should be at safepoint"); - assert(Thread::current() == (Thread*)VMThread::vm_thread(), "should be in vm thread"); - assert(!ParallelScavengeHeap::heap()->is_gc_active(), "not reentrant"); - - ParallelScavengeHeap* heap = ParallelScavengeHeap::heap(); - GCCause::Cause gc_cause = heap->gc_cause(); - PSAdaptiveSizePolicy* policy = heap->size_policy(); - IsGCActiveMark mark; - - if (ScavengeBeforeFullGC) { - PSScavenge::invoke_no_policy(); - } - - const bool clear_all_soft_refs = - heap->collector_policy()->should_clear_all_soft_refs(); - - uint count = maximum_heap_compaction ? 1 : MarkSweepAlwaysCompactCount; - UIntFlagSetting flag_setting(MarkSweepAlwaysCompactCount, count); - PSMarkSweep::invoke_no_policy(clear_all_soft_refs || maximum_heap_compaction); -} - -// This method contains no policy. You should probably -// be calling invoke() instead. -bool PSMarkSweep::invoke_no_policy(bool clear_all_softrefs) { - assert(SafepointSynchronize::is_at_safepoint(), "must be at a safepoint"); - assert(ref_processor() != NULL, "Sanity"); - - if (GC_locker::check_active_before_gc()) { - return false; - } - - ParallelScavengeHeap* heap = ParallelScavengeHeap::heap(); - GCCause::Cause gc_cause = heap->gc_cause(); - - _gc_timer->register_gc_start(); - _gc_tracer->report_gc_start(gc_cause, _gc_timer->gc_start()); - - PSAdaptiveSizePolicy* size_policy = heap->size_policy(); - - // The scope of casr should end after code that can change - // CollectorPolicy::_should_clear_all_soft_refs. - ClearedAllSoftRefs casr(clear_all_softrefs, heap->collector_policy()); - - PSYoungGen* young_gen = heap->young_gen(); - PSOldGen* old_gen = heap->old_gen(); - - // Increment the invocation count - heap->increment_total_collections(true /* full */); - - // Save information needed to minimize mangling - heap->record_gen_tops_before_GC(); - - // We need to track unique mark sweep invocations as well. - _total_invocations++; - - AdaptiveSizePolicyOutput(size_policy, heap->total_collections()); - - heap->print_heap_before_gc(); - heap->trace_heap_before_gc(_gc_tracer); - - // Fill in TLABs - heap->accumulate_statistics_all_tlabs(); - heap->ensure_parsability(true); // retire TLABs - - if (VerifyBeforeGC && heap->total_collections() >= VerifyGCStartAt) { - HandleMark hm; // Discard invalid handles created during verification - Universe::verify(" VerifyBeforeGC:"); - } - - // Verify object start arrays - if (VerifyObjectStartArray && - VerifyBeforeGC) { - old_gen->verify_object_start_array(); - } - - heap->pre_full_gc_dump(_gc_timer); - - // Filled in below to track the state of the young gen after the collection. - bool eden_empty; - bool survivors_empty; - bool young_gen_empty; - - { - HandleMark hm; - - TraceCPUTime tcpu(PrintGCDetails, true, gclog_or_tty); - GCTraceTime t1(GCCauseString("Full GC", gc_cause), PrintGC, !PrintGCDetails, NULL, _gc_tracer->gc_id()); - TraceCollectorStats tcs(counters()); - TraceMemoryManagerStats tms(true /* Full GC */,gc_cause); - - if (TraceOldGenTime) accumulated_time()->start(); - - // Let the size policy know we're starting - size_policy->major_collection_begin(); - - CodeCache::gc_prologue(); - BiasedLocking::preserve_marks(); - - // Capture heap size before collection for printing. - size_t prev_used = heap->used(); - - // Capture metadata size before collection for sizing. - size_t metadata_prev_used = MetaspaceAux::used_bytes(); - - // For PrintGCDetails - size_t old_gen_prev_used = old_gen->used_in_bytes(); - size_t young_gen_prev_used = young_gen->used_in_bytes(); - - allocate_stacks(); - - COMPILER2_PRESENT(DerivedPointerTable::clear()); - - ref_processor()->enable_discovery(); - ref_processor()->setup_policy(clear_all_softrefs); - - mark_sweep_phase1(clear_all_softrefs); - - mark_sweep_phase2(); - - // Don't add any more derived pointers during phase3 - COMPILER2_PRESENT(assert(DerivedPointerTable::is_active(), "Sanity")); - COMPILER2_PRESENT(DerivedPointerTable::set_active(false)); - - mark_sweep_phase3(); - - mark_sweep_phase4(); - - restore_marks(); - - deallocate_stacks(); - - if (ZapUnusedHeapArea) { - // Do a complete mangle (top to end) because the usage for - // scratch does not maintain a top pointer. - young_gen->to_space()->mangle_unused_area_complete(); - } - - eden_empty = young_gen->eden_space()->is_empty(); - if (!eden_empty) { - eden_empty = absorb_live_data_from_eden(size_policy, young_gen, old_gen); - } - - // Update heap occupancy information which is used as - // input to soft ref clearing policy at the next gc. - Universe::update_heap_info_at_gc(); - - survivors_empty = young_gen->from_space()->is_empty() && - young_gen->to_space()->is_empty(); - young_gen_empty = eden_empty && survivors_empty; - - ModRefBarrierSet* modBS = barrier_set_cast(heap->barrier_set()); - MemRegion old_mr = heap->old_gen()->reserved(); - if (young_gen_empty) { - modBS->clear(MemRegion(old_mr.start(), old_mr.end())); - } else { - modBS->invalidate(MemRegion(old_mr.start(), old_mr.end())); - } - - // Delete metaspaces for unloaded class loaders and clean up loader_data graph - ClassLoaderDataGraph::purge(); - MetaspaceAux::verify_metrics(); - - BiasedLocking::restore_marks(); - CodeCache::gc_epilogue(); - JvmtiExport::gc_epilogue(); - - COMPILER2_PRESENT(DerivedPointerTable::update_pointers()); - - ref_processor()->enqueue_discovered_references(NULL); - - // Update time of last GC - reset_millis_since_last_gc(); - - // Let the size policy know we're done - size_policy->major_collection_end(old_gen->used_in_bytes(), gc_cause); - - if (UseAdaptiveSizePolicy) { - - if (PrintAdaptiveSizePolicy) { - gclog_or_tty->print("AdaptiveSizeStart: "); - gclog_or_tty->stamp(); - gclog_or_tty->print_cr(" collection: %d ", - heap->total_collections()); - if (Verbose) { - gclog_or_tty->print("old_gen_capacity: " SIZE_FORMAT - " young_gen_capacity: " SIZE_FORMAT, - old_gen->capacity_in_bytes(), young_gen->capacity_in_bytes()); - } - } - - // Don't check if the size_policy is ready here. Let - // the size_policy check that internally. - if (UseAdaptiveGenerationSizePolicyAtMajorCollection && - ((gc_cause != GCCause::_java_lang_system_gc) || - UseAdaptiveSizePolicyWithSystemGC)) { - // Swap the survivor spaces if from_space is empty. The - // resize_young_gen() called below is normally used after - // a successful young GC and swapping of survivor spaces; - // otherwise, it will fail to resize the young gen with - // the current implementation. - if (young_gen->from_space()->is_empty()) { - young_gen->from_space()->clear(SpaceDecorator::Mangle); - young_gen->swap_spaces(); - } - - // Calculate optimal free space amounts - assert(young_gen->max_size() > - young_gen->from_space()->capacity_in_bytes() + - young_gen->to_space()->capacity_in_bytes(), - "Sizes of space in young gen are out-of-bounds"); - - size_t young_live = young_gen->used_in_bytes(); - size_t eden_live = young_gen->eden_space()->used_in_bytes(); - size_t old_live = old_gen->used_in_bytes(); - size_t cur_eden = young_gen->eden_space()->capacity_in_bytes(); - size_t max_old_gen_size = old_gen->max_gen_size(); - size_t max_eden_size = young_gen->max_size() - - young_gen->from_space()->capacity_in_bytes() - - young_gen->to_space()->capacity_in_bytes(); - - // Used for diagnostics - size_policy->clear_generation_free_space_flags(); - - size_policy->compute_generations_free_space(young_live, - eden_live, - old_live, - cur_eden, - max_old_gen_size, - max_eden_size, - true /* full gc*/); - - size_policy->check_gc_overhead_limit(young_live, - eden_live, - max_old_gen_size, - max_eden_size, - true /* full gc*/, - gc_cause, - heap->collector_policy()); - - size_policy->decay_supplemental_growth(true /* full gc*/); - - heap->resize_old_gen(size_policy->calculated_old_free_size_in_bytes()); - - heap->resize_young_gen(size_policy->calculated_eden_size_in_bytes(), - size_policy->calculated_survivor_size_in_bytes()); - } - if (PrintAdaptiveSizePolicy) { - gclog_or_tty->print_cr("AdaptiveSizeStop: collection: %d ", - heap->total_collections()); - } - } - - if (UsePerfData) { - heap->gc_policy_counters()->update_counters(); - heap->gc_policy_counters()->update_old_capacity( - old_gen->capacity_in_bytes()); - heap->gc_policy_counters()->update_young_capacity( - young_gen->capacity_in_bytes()); - } - - heap->resize_all_tlabs(); - - // We collected the heap, recalculate the metaspace capacity - MetaspaceGC::compute_new_size(); - - if (TraceOldGenTime) accumulated_time()->stop(); - - if (PrintGC) { - if (PrintGCDetails) { - // Don't print a GC timestamp here. This is after the GC so - // would be confusing. - young_gen->print_used_change(young_gen_prev_used); - old_gen->print_used_change(old_gen_prev_used); - } - heap->print_heap_change(prev_used); - if (PrintGCDetails) { - MetaspaceAux::print_metaspace_change(metadata_prev_used); - } - } - - // Track memory usage and detect low memory - MemoryService::track_memory_usage(); - heap->update_counters(); - } - - if (VerifyAfterGC && heap->total_collections() >= VerifyGCStartAt) { - HandleMark hm; // Discard invalid handles created during verification - Universe::verify(" VerifyAfterGC:"); - } - - // Re-verify object start arrays - if (VerifyObjectStartArray && - VerifyAfterGC) { - old_gen->verify_object_start_array(); - } - - if (ZapUnusedHeapArea) { - old_gen->object_space()->check_mangled_unused_area_complete(); - } - - NOT_PRODUCT(ref_processor()->verify_no_references_recorded()); - - heap->print_heap_after_gc(); - heap->trace_heap_after_gc(_gc_tracer); - - heap->post_full_gc_dump(_gc_timer); - -#ifdef TRACESPINNING - ParallelTaskTerminator::print_termination_counts(); -#endif - - _gc_timer->register_gc_end(); - - _gc_tracer->report_gc_end(_gc_timer->gc_end(), _gc_timer->time_partitions()); - - return true; -} - -bool PSMarkSweep::absorb_live_data_from_eden(PSAdaptiveSizePolicy* size_policy, - PSYoungGen* young_gen, - PSOldGen* old_gen) { - MutableSpace* const eden_space = young_gen->eden_space(); - assert(!eden_space->is_empty(), "eden must be non-empty"); - assert(young_gen->virtual_space()->alignment() == - old_gen->virtual_space()->alignment(), "alignments do not match"); - - if (!(UseAdaptiveSizePolicy && UseAdaptiveGCBoundary)) { - return false; - } - - // Both generations must be completely committed. - if (young_gen->virtual_space()->uncommitted_size() != 0) { - return false; - } - if (old_gen->virtual_space()->uncommitted_size() != 0) { - return false; - } - - // Figure out how much to take from eden. Include the average amount promoted - // in the total; otherwise the next young gen GC will simply bail out to a - // full GC. - const size_t alignment = old_gen->virtual_space()->alignment(); - const size_t eden_used = eden_space->used_in_bytes(); - const size_t promoted = (size_t)size_policy->avg_promoted()->padded_average(); - const size_t absorb_size = align_size_up(eden_used + promoted, alignment); - const size_t eden_capacity = eden_space->capacity_in_bytes(); - - if (absorb_size >= eden_capacity) { - return false; // Must leave some space in eden. - } - - const size_t new_young_size = young_gen->capacity_in_bytes() - absorb_size; - if (new_young_size < young_gen->min_gen_size()) { - return false; // Respect young gen minimum size. - } - - if (TraceAdaptiveGCBoundary && Verbose) { - gclog_or_tty->print(" absorbing " SIZE_FORMAT "K: " - "eden " SIZE_FORMAT "K->" SIZE_FORMAT "K " - "from " SIZE_FORMAT "K, to " SIZE_FORMAT "K " - "young_gen " SIZE_FORMAT "K->" SIZE_FORMAT "K ", - absorb_size / K, - eden_capacity / K, (eden_capacity - absorb_size) / K, - young_gen->from_space()->used_in_bytes() / K, - young_gen->to_space()->used_in_bytes() / K, - young_gen->capacity_in_bytes() / K, new_young_size / K); - } - - // Fill the unused part of the old gen. - MutableSpace* const old_space = old_gen->object_space(); - HeapWord* const unused_start = old_space->top(); - size_t const unused_words = pointer_delta(old_space->end(), unused_start); - - if (unused_words > 0) { - if (unused_words < CollectedHeap::min_fill_size()) { - return false; // If the old gen cannot be filled, must give up. - } - CollectedHeap::fill_with_objects(unused_start, unused_words); - } - - // Take the live data from eden and set both top and end in the old gen to - // eden top. (Need to set end because reset_after_change() mangles the region - // from end to virtual_space->high() in debug builds). - HeapWord* const new_top = eden_space->top(); - old_gen->virtual_space()->expand_into(young_gen->virtual_space(), - absorb_size); - young_gen->reset_after_change(); - old_space->set_top(new_top); - old_space->set_end(new_top); - old_gen->reset_after_change(); - - // Update the object start array for the filler object and the data from eden. - ObjectStartArray* const start_array = old_gen->start_array(); - for (HeapWord* p = unused_start; p < new_top; p += oop(p)->size()) { - start_array->allocate_block(p); - } - - // Could update the promoted average here, but it is not typically updated at - // full GCs and the value to use is unclear. Something like - // - // cur_promoted_avg + absorb_size / number_of_scavenges_since_last_full_gc. - - size_policy->set_bytes_absorbed_from_eden(absorb_size); - return true; -} - -void PSMarkSweep::allocate_stacks() { - ParallelScavengeHeap* heap = ParallelScavengeHeap::heap(); - PSYoungGen* young_gen = heap->young_gen(); - - MutableSpace* to_space = young_gen->to_space(); - _preserved_marks = (PreservedMark*)to_space->top(); - _preserved_count = 0; - - // We want to calculate the size in bytes first. - _preserved_count_max = pointer_delta(to_space->end(), to_space->top(), sizeof(jbyte)); - // Now divide by the size of a PreservedMark - _preserved_count_max /= sizeof(PreservedMark); -} - - -void PSMarkSweep::deallocate_stacks() { - _preserved_mark_stack.clear(true); - _preserved_oop_stack.clear(true); - _marking_stack.clear(); - _objarray_stack.clear(true); -} - -void PSMarkSweep::mark_sweep_phase1(bool clear_all_softrefs) { - // Recursively traverse all live objects and mark them - GCTraceTime tm("phase 1", PrintGCDetails && Verbose, true, _gc_timer, _gc_tracer->gc_id()); - - ParallelScavengeHeap* heap = ParallelScavengeHeap::heap(); - - // Need to clear claim bits before the tracing starts. - ClassLoaderDataGraph::clear_claimed_marks(); - - // General strong roots. - { - ParallelScavengeHeap::ParStrongRootsScope psrs; - Universe::oops_do(mark_and_push_closure()); - JNIHandles::oops_do(mark_and_push_closure()); // Global (strong) JNI handles - CLDToOopClosure mark_and_push_from_cld(mark_and_push_closure()); - MarkingCodeBlobClosure each_active_code_blob(mark_and_push_closure(), !CodeBlobToOopClosure::FixRelocations); - Threads::oops_do(mark_and_push_closure(), &mark_and_push_from_cld, &each_active_code_blob); - ObjectSynchronizer::oops_do(mark_and_push_closure()); - FlatProfiler::oops_do(mark_and_push_closure()); - Management::oops_do(mark_and_push_closure()); - JvmtiExport::oops_do(mark_and_push_closure()); - SystemDictionary::always_strong_oops_do(mark_and_push_closure()); - ClassLoaderDataGraph::always_strong_cld_do(follow_cld_closure()); - // Do not treat nmethods as strong roots for mark/sweep, since we can unload them. - //CodeCache::scavenge_root_nmethods_do(CodeBlobToOopClosure(mark_and_push_closure())); - } - - // Flush marking stack. - follow_stack(); - - // Process reference objects found during marking - { - ref_processor()->setup_policy(clear_all_softrefs); - const ReferenceProcessorStats& stats = - ref_processor()->process_discovered_references( - is_alive_closure(), mark_and_push_closure(), follow_stack_closure(), NULL, _gc_timer, _gc_tracer->gc_id()); - gc_tracer()->report_gc_reference_stats(stats); - } - - // This is the point where the entire marking should have completed. - assert(_marking_stack.is_empty(), "Marking should have completed"); - - // Unload classes and purge the SystemDictionary. - bool purged_class = SystemDictionary::do_unloading(is_alive_closure()); - - // Unload nmethods. - CodeCache::do_unloading(is_alive_closure(), purged_class); - - // Prune dead klasses from subklass/sibling/implementor lists. - Klass::clean_weak_klass_links(is_alive_closure()); - - // Delete entries for dead interned strings. - StringTable::unlink(is_alive_closure()); - - // Clean up unreferenced symbols in symbol table. - SymbolTable::unlink(); - _gc_tracer->report_object_count_after_gc(is_alive_closure()); -} - - -void PSMarkSweep::mark_sweep_phase2() { - GCTraceTime tm("phase 2", PrintGCDetails && Verbose, true, _gc_timer, _gc_tracer->gc_id()); - - // Now all live objects are marked, compute the new object addresses. - - // It is not required that we traverse spaces in the same order in - // phase2, phase3 and phase4, but the ValidateMarkSweep live oops - // tracking expects us to do so. See comment under phase4. - - ParallelScavengeHeap* heap = ParallelScavengeHeap::heap(); - PSOldGen* old_gen = heap->old_gen(); - - // Begin compacting into the old gen - PSMarkSweepDecorator::set_destination_decorator_tenured(); - - // This will also compact the young gen spaces. - old_gen->precompact(); -} - -// This should be moved to the shared markSweep code! -class PSAlwaysTrueClosure: public BoolObjectClosure { -public: - bool do_object_b(oop p) { return true; } -}; -static PSAlwaysTrueClosure always_true; - -void PSMarkSweep::mark_sweep_phase3() { - // Adjust the pointers to reflect the new locations - GCTraceTime tm("phase 3", PrintGCDetails && Verbose, true, _gc_timer, _gc_tracer->gc_id()); - - ParallelScavengeHeap* heap = ParallelScavengeHeap::heap(); - PSYoungGen* young_gen = heap->young_gen(); - PSOldGen* old_gen = heap->old_gen(); - - // Need to clear claim bits before the tracing starts. - ClassLoaderDataGraph::clear_claimed_marks(); - - // General strong roots. - Universe::oops_do(adjust_pointer_closure()); - JNIHandles::oops_do(adjust_pointer_closure()); // Global (strong) JNI handles - CLDToOopClosure adjust_from_cld(adjust_pointer_closure()); - Threads::oops_do(adjust_pointer_closure(), &adjust_from_cld, NULL); - ObjectSynchronizer::oops_do(adjust_pointer_closure()); - FlatProfiler::oops_do(adjust_pointer_closure()); - Management::oops_do(adjust_pointer_closure()); - JvmtiExport::oops_do(adjust_pointer_closure()); - SystemDictionary::oops_do(adjust_pointer_closure()); - ClassLoaderDataGraph::cld_do(adjust_cld_closure()); - - // Now adjust pointers in remaining weak roots. (All of which should - // have been cleared if they pointed to non-surviving objects.) - // Global (weak) JNI handles - JNIHandles::weak_oops_do(&always_true, adjust_pointer_closure()); - - CodeBlobToOopClosure adjust_from_blobs(adjust_pointer_closure(), CodeBlobToOopClosure::FixRelocations); - CodeCache::blobs_do(&adjust_from_blobs); - StringTable::oops_do(adjust_pointer_closure()); - ref_processor()->weak_oops_do(adjust_pointer_closure()); - PSScavenge::reference_processor()->weak_oops_do(adjust_pointer_closure()); - - adjust_marks(); - - young_gen->adjust_pointers(); - old_gen->adjust_pointers(); -} - -void PSMarkSweep::mark_sweep_phase4() { - EventMark m("4 compact heap"); - GCTraceTime tm("phase 4", PrintGCDetails && Verbose, true, _gc_timer, _gc_tracer->gc_id()); - - // All pointers are now adjusted, move objects accordingly - - ParallelScavengeHeap* heap = ParallelScavengeHeap::heap(); - PSYoungGen* young_gen = heap->young_gen(); - PSOldGen* old_gen = heap->old_gen(); - - old_gen->compact(); - young_gen->compact(); -} - -jlong PSMarkSweep::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; - jlong ret_val = now - _time_of_last_gc; - // XXX See note in genCollectedHeap::millis_since_last_gc(). - if (ret_val < 0) { - NOT_PRODUCT(warning("time warp: " JLONG_FORMAT, ret_val);) - return 0; - } - return ret_val; -} - -void PSMarkSweep::reset_millis_since_last_gc() { - // We need a monotonically non-decreasing time in ms but - // os::javaTimeMillis() does not guarantee monotonicity. - _time_of_last_gc = os::javaTimeNanos() / NANOSECS_PER_MILLISEC; -} --- /dev/null 2015-03-18 17:10:38.111854831 +0100 +++ new/src/share/vm/gc/parallel/psMarkSweep.cpp 2015-05-12 11:40:41.759314209 +0200 @@ -0,0 +1,667 @@ +/* + * Copyright (c) 2001, 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/stringTable.hpp" +#include "classfile/systemDictionary.hpp" +#include "code/codeCache.hpp" +#include "gc/parallel/parallelScavengeHeap.hpp" +#include "gc/parallel/psAdaptiveSizePolicy.hpp" +#include "gc/parallel/psMarkSweep.hpp" +#include "gc/parallel/psMarkSweepDecorator.hpp" +#include "gc/parallel/psOldGen.hpp" +#include "gc/parallel/psScavenge.hpp" +#include "gc/parallel/psYoungGen.hpp" +#include "gc/serial/markSweep.hpp" +#include "gc/shared/gcCause.hpp" +#include "gc/shared/gcHeapSummary.hpp" +#include "gc/shared/gcLocker.inline.hpp" +#include "gc/shared/gcTimer.hpp" +#include "gc/shared/gcTrace.hpp" +#include "gc/shared/gcTraceTime.hpp" +#include "gc/shared/isGCActiveMark.hpp" +#include "gc/shared/referencePolicy.hpp" +#include "gc/shared/referenceProcessor.hpp" +#include "gc/shared/spaceDecorator.hpp" +#include "oops/oop.inline.hpp" +#include "runtime/biasedLocking.hpp" +#include "runtime/fprofiler.hpp" +#include "runtime/safepoint.hpp" +#include "runtime/vmThread.hpp" +#include "services/management.hpp" +#include "services/memoryService.hpp" +#include "utilities/events.hpp" +#include "utilities/stack.inline.hpp" + +elapsedTimer PSMarkSweep::_accumulated_time; +jlong PSMarkSweep::_time_of_last_gc = 0; +CollectorCounters* PSMarkSweep::_counters = NULL; + +void PSMarkSweep::initialize() { + MemRegion mr = ParallelScavengeHeap::heap()->reserved_region(); + _ref_processor = new ReferenceProcessor(mr); // a vanilla ref proc + _counters = new CollectorCounters("PSMarkSweep", 1); +} + +// This method contains all heap specific policy for invoking mark sweep. +// PSMarkSweep::invoke_no_policy() will only attempt to mark-sweep-compact +// the heap. It will do nothing further. If we need to bail out for policy +// reasons, scavenge before full gc, or any other specialized behavior, it +// needs to be added here. +// +// Note that this method should only be called from the vm_thread while +// at a safepoint! +// +// Note that the all_soft_refs_clear flag in the collector policy +// may be true because this method can be called without intervening +// activity. For example when the heap space is tight and full measure +// are being taken to free space. + +void PSMarkSweep::invoke(bool maximum_heap_compaction) { + assert(SafepointSynchronize::is_at_safepoint(), "should be at safepoint"); + assert(Thread::current() == (Thread*)VMThread::vm_thread(), "should be in vm thread"); + assert(!ParallelScavengeHeap::heap()->is_gc_active(), "not reentrant"); + + ParallelScavengeHeap* heap = ParallelScavengeHeap::heap(); + GCCause::Cause gc_cause = heap->gc_cause(); + PSAdaptiveSizePolicy* policy = heap->size_policy(); + IsGCActiveMark mark; + + if (ScavengeBeforeFullGC) { + PSScavenge::invoke_no_policy(); + } + + const bool clear_all_soft_refs = + heap->collector_policy()->should_clear_all_soft_refs(); + + uint count = maximum_heap_compaction ? 1 : MarkSweepAlwaysCompactCount; + UIntFlagSetting flag_setting(MarkSweepAlwaysCompactCount, count); + PSMarkSweep::invoke_no_policy(clear_all_soft_refs || maximum_heap_compaction); +} + +// This method contains no policy. You should probably +// be calling invoke() instead. +bool PSMarkSweep::invoke_no_policy(bool clear_all_softrefs) { + assert(SafepointSynchronize::is_at_safepoint(), "must be at a safepoint"); + assert(ref_processor() != NULL, "Sanity"); + + if (GC_locker::check_active_before_gc()) { + return false; + } + + ParallelScavengeHeap* heap = ParallelScavengeHeap::heap(); + GCCause::Cause gc_cause = heap->gc_cause(); + + _gc_timer->register_gc_start(); + _gc_tracer->report_gc_start(gc_cause, _gc_timer->gc_start()); + + PSAdaptiveSizePolicy* size_policy = heap->size_policy(); + + // The scope of casr should end after code that can change + // CollectorPolicy::_should_clear_all_soft_refs. + ClearedAllSoftRefs casr(clear_all_softrefs, heap->collector_policy()); + + PSYoungGen* young_gen = heap->young_gen(); + PSOldGen* old_gen = heap->old_gen(); + + // Increment the invocation count + heap->increment_total_collections(true /* full */); + + // Save information needed to minimize mangling + heap->record_gen_tops_before_GC(); + + // We need to track unique mark sweep invocations as well. + _total_invocations++; + + AdaptiveSizePolicyOutput(size_policy, heap->total_collections()); + + heap->print_heap_before_gc(); + heap->trace_heap_before_gc(_gc_tracer); + + // Fill in TLABs + heap->accumulate_statistics_all_tlabs(); + heap->ensure_parsability(true); // retire TLABs + + if (VerifyBeforeGC && heap->total_collections() >= VerifyGCStartAt) { + HandleMark hm; // Discard invalid handles created during verification + Universe::verify(" VerifyBeforeGC:"); + } + + // Verify object start arrays + if (VerifyObjectStartArray && + VerifyBeforeGC) { + old_gen->verify_object_start_array(); + } + + heap->pre_full_gc_dump(_gc_timer); + + // Filled in below to track the state of the young gen after the collection. + bool eden_empty; + bool survivors_empty; + bool young_gen_empty; + + { + HandleMark hm; + + TraceCPUTime tcpu(PrintGCDetails, true, gclog_or_tty); + GCTraceTime t1(GCCauseString("Full GC", gc_cause), PrintGC, !PrintGCDetails, NULL, _gc_tracer->gc_id()); + TraceCollectorStats tcs(counters()); + TraceMemoryManagerStats tms(true /* Full GC */,gc_cause); + + if (TraceOldGenTime) accumulated_time()->start(); + + // Let the size policy know we're starting + size_policy->major_collection_begin(); + + CodeCache::gc_prologue(); + BiasedLocking::preserve_marks(); + + // Capture heap size before collection for printing. + size_t prev_used = heap->used(); + + // Capture metadata size before collection for sizing. + size_t metadata_prev_used = MetaspaceAux::used_bytes(); + + // For PrintGCDetails + size_t old_gen_prev_used = old_gen->used_in_bytes(); + size_t young_gen_prev_used = young_gen->used_in_bytes(); + + allocate_stacks(); + + COMPILER2_PRESENT(DerivedPointerTable::clear()); + + ref_processor()->enable_discovery(); + ref_processor()->setup_policy(clear_all_softrefs); + + mark_sweep_phase1(clear_all_softrefs); + + mark_sweep_phase2(); + + // Don't add any more derived pointers during phase3 + COMPILER2_PRESENT(assert(DerivedPointerTable::is_active(), "Sanity")); + COMPILER2_PRESENT(DerivedPointerTable::set_active(false)); + + mark_sweep_phase3(); + + mark_sweep_phase4(); + + restore_marks(); + + deallocate_stacks(); + + if (ZapUnusedHeapArea) { + // Do a complete mangle (top to end) because the usage for + // scratch does not maintain a top pointer. + young_gen->to_space()->mangle_unused_area_complete(); + } + + eden_empty = young_gen->eden_space()->is_empty(); + if (!eden_empty) { + eden_empty = absorb_live_data_from_eden(size_policy, young_gen, old_gen); + } + + // Update heap occupancy information which is used as + // input to soft ref clearing policy at the next gc. + Universe::update_heap_info_at_gc(); + + survivors_empty = young_gen->from_space()->is_empty() && + young_gen->to_space()->is_empty(); + young_gen_empty = eden_empty && survivors_empty; + + ModRefBarrierSet* modBS = barrier_set_cast(heap->barrier_set()); + MemRegion old_mr = heap->old_gen()->reserved(); + if (young_gen_empty) { + modBS->clear(MemRegion(old_mr.start(), old_mr.end())); + } else { + modBS->invalidate(MemRegion(old_mr.start(), old_mr.end())); + } + + // Delete metaspaces for unloaded class loaders and clean up loader_data graph + ClassLoaderDataGraph::purge(); + MetaspaceAux::verify_metrics(); + + BiasedLocking::restore_marks(); + CodeCache::gc_epilogue(); + JvmtiExport::gc_epilogue(); + + COMPILER2_PRESENT(DerivedPointerTable::update_pointers()); + + ref_processor()->enqueue_discovered_references(NULL); + + // Update time of last GC + reset_millis_since_last_gc(); + + // Let the size policy know we're done + size_policy->major_collection_end(old_gen->used_in_bytes(), gc_cause); + + if (UseAdaptiveSizePolicy) { + + if (PrintAdaptiveSizePolicy) { + gclog_or_tty->print("AdaptiveSizeStart: "); + gclog_or_tty->stamp(); + gclog_or_tty->print_cr(" collection: %d ", + heap->total_collections()); + if (Verbose) { + gclog_or_tty->print("old_gen_capacity: " SIZE_FORMAT + " young_gen_capacity: " SIZE_FORMAT, + old_gen->capacity_in_bytes(), young_gen->capacity_in_bytes()); + } + } + + // Don't check if the size_policy is ready here. Let + // the size_policy check that internally. + if (UseAdaptiveGenerationSizePolicyAtMajorCollection && + ((gc_cause != GCCause::_java_lang_system_gc) || + UseAdaptiveSizePolicyWithSystemGC)) { + // Swap the survivor spaces if from_space is empty. The + // resize_young_gen() called below is normally used after + // a successful young GC and swapping of survivor spaces; + // otherwise, it will fail to resize the young gen with + // the current implementation. + if (young_gen->from_space()->is_empty()) { + young_gen->from_space()->clear(SpaceDecorator::Mangle); + young_gen->swap_spaces(); + } + + // Calculate optimal free space amounts + assert(young_gen->max_size() > + young_gen->from_space()->capacity_in_bytes() + + young_gen->to_space()->capacity_in_bytes(), + "Sizes of space in young gen are out-of-bounds"); + + size_t young_live = young_gen->used_in_bytes(); + size_t eden_live = young_gen->eden_space()->used_in_bytes(); + size_t old_live = old_gen->used_in_bytes(); + size_t cur_eden = young_gen->eden_space()->capacity_in_bytes(); + size_t max_old_gen_size = old_gen->max_gen_size(); + size_t max_eden_size = young_gen->max_size() - + young_gen->from_space()->capacity_in_bytes() - + young_gen->to_space()->capacity_in_bytes(); + + // Used for diagnostics + size_policy->clear_generation_free_space_flags(); + + size_policy->compute_generations_free_space(young_live, + eden_live, + old_live, + cur_eden, + max_old_gen_size, + max_eden_size, + true /* full gc*/); + + size_policy->check_gc_overhead_limit(young_live, + eden_live, + max_old_gen_size, + max_eden_size, + true /* full gc*/, + gc_cause, + heap->collector_policy()); + + size_policy->decay_supplemental_growth(true /* full gc*/); + + heap->resize_old_gen(size_policy->calculated_old_free_size_in_bytes()); + + heap->resize_young_gen(size_policy->calculated_eden_size_in_bytes(), + size_policy->calculated_survivor_size_in_bytes()); + } + if (PrintAdaptiveSizePolicy) { + gclog_or_tty->print_cr("AdaptiveSizeStop: collection: %d ", + heap->total_collections()); + } + } + + if (UsePerfData) { + heap->gc_policy_counters()->update_counters(); + heap->gc_policy_counters()->update_old_capacity( + old_gen->capacity_in_bytes()); + heap->gc_policy_counters()->update_young_capacity( + young_gen->capacity_in_bytes()); + } + + heap->resize_all_tlabs(); + + // We collected the heap, recalculate the metaspace capacity + MetaspaceGC::compute_new_size(); + + if (TraceOldGenTime) accumulated_time()->stop(); + + if (PrintGC) { + if (PrintGCDetails) { + // Don't print a GC timestamp here. This is after the GC so + // would be confusing. + young_gen->print_used_change(young_gen_prev_used); + old_gen->print_used_change(old_gen_prev_used); + } + heap->print_heap_change(prev_used); + if (PrintGCDetails) { + MetaspaceAux::print_metaspace_change(metadata_prev_used); + } + } + + // Track memory usage and detect low memory + MemoryService::track_memory_usage(); + heap->update_counters(); + } + + if (VerifyAfterGC && heap->total_collections() >= VerifyGCStartAt) { + HandleMark hm; // Discard invalid handles created during verification + Universe::verify(" VerifyAfterGC:"); + } + + // Re-verify object start arrays + if (VerifyObjectStartArray && + VerifyAfterGC) { + old_gen->verify_object_start_array(); + } + + if (ZapUnusedHeapArea) { + old_gen->object_space()->check_mangled_unused_area_complete(); + } + + NOT_PRODUCT(ref_processor()->verify_no_references_recorded()); + + heap->print_heap_after_gc(); + heap->trace_heap_after_gc(_gc_tracer); + + heap->post_full_gc_dump(_gc_timer); + +#ifdef TRACESPINNING + ParallelTaskTerminator::print_termination_counts(); +#endif + + _gc_timer->register_gc_end(); + + _gc_tracer->report_gc_end(_gc_timer->gc_end(), _gc_timer->time_partitions()); + + return true; +} + +bool PSMarkSweep::absorb_live_data_from_eden(PSAdaptiveSizePolicy* size_policy, + PSYoungGen* young_gen, + PSOldGen* old_gen) { + MutableSpace* const eden_space = young_gen->eden_space(); + assert(!eden_space->is_empty(), "eden must be non-empty"); + assert(young_gen->virtual_space()->alignment() == + old_gen->virtual_space()->alignment(), "alignments do not match"); + + if (!(UseAdaptiveSizePolicy && UseAdaptiveGCBoundary)) { + return false; + } + + // Both generations must be completely committed. + if (young_gen->virtual_space()->uncommitted_size() != 0) { + return false; + } + if (old_gen->virtual_space()->uncommitted_size() != 0) { + return false; + } + + // Figure out how much to take from eden. Include the average amount promoted + // in the total; otherwise the next young gen GC will simply bail out to a + // full GC. + const size_t alignment = old_gen->virtual_space()->alignment(); + const size_t eden_used = eden_space->used_in_bytes(); + const size_t promoted = (size_t)size_policy->avg_promoted()->padded_average(); + const size_t absorb_size = align_size_up(eden_used + promoted, alignment); + const size_t eden_capacity = eden_space->capacity_in_bytes(); + + if (absorb_size >= eden_capacity) { + return false; // Must leave some space in eden. + } + + const size_t new_young_size = young_gen->capacity_in_bytes() - absorb_size; + if (new_young_size < young_gen->min_gen_size()) { + return false; // Respect young gen minimum size. + } + + if (TraceAdaptiveGCBoundary && Verbose) { + gclog_or_tty->print(" absorbing " SIZE_FORMAT "K: " + "eden " SIZE_FORMAT "K->" SIZE_FORMAT "K " + "from " SIZE_FORMAT "K, to " SIZE_FORMAT "K " + "young_gen " SIZE_FORMAT "K->" SIZE_FORMAT "K ", + absorb_size / K, + eden_capacity / K, (eden_capacity - absorb_size) / K, + young_gen->from_space()->used_in_bytes() / K, + young_gen->to_space()->used_in_bytes() / K, + young_gen->capacity_in_bytes() / K, new_young_size / K); + } + + // Fill the unused part of the old gen. + MutableSpace* const old_space = old_gen->object_space(); + HeapWord* const unused_start = old_space->top(); + size_t const unused_words = pointer_delta(old_space->end(), unused_start); + + if (unused_words > 0) { + if (unused_words < CollectedHeap::min_fill_size()) { + return false; // If the old gen cannot be filled, must give up. + } + CollectedHeap::fill_with_objects(unused_start, unused_words); + } + + // Take the live data from eden and set both top and end in the old gen to + // eden top. (Need to set end because reset_after_change() mangles the region + // from end to virtual_space->high() in debug builds). + HeapWord* const new_top = eden_space->top(); + old_gen->virtual_space()->expand_into(young_gen->virtual_space(), + absorb_size); + young_gen->reset_after_change(); + old_space->set_top(new_top); + old_space->set_end(new_top); + old_gen->reset_after_change(); + + // Update the object start array for the filler object and the data from eden. + ObjectStartArray* const start_array = old_gen->start_array(); + for (HeapWord* p = unused_start; p < new_top; p += oop(p)->size()) { + start_array->allocate_block(p); + } + + // Could update the promoted average here, but it is not typically updated at + // full GCs and the value to use is unclear. Something like + // + // cur_promoted_avg + absorb_size / number_of_scavenges_since_last_full_gc. + + size_policy->set_bytes_absorbed_from_eden(absorb_size); + return true; +} + +void PSMarkSweep::allocate_stacks() { + ParallelScavengeHeap* heap = ParallelScavengeHeap::heap(); + PSYoungGen* young_gen = heap->young_gen(); + + MutableSpace* to_space = young_gen->to_space(); + _preserved_marks = (PreservedMark*)to_space->top(); + _preserved_count = 0; + + // We want to calculate the size in bytes first. + _preserved_count_max = pointer_delta(to_space->end(), to_space->top(), sizeof(jbyte)); + // Now divide by the size of a PreservedMark + _preserved_count_max /= sizeof(PreservedMark); +} + + +void PSMarkSweep::deallocate_stacks() { + _preserved_mark_stack.clear(true); + _preserved_oop_stack.clear(true); + _marking_stack.clear(); + _objarray_stack.clear(true); +} + +void PSMarkSweep::mark_sweep_phase1(bool clear_all_softrefs) { + // Recursively traverse all live objects and mark them + GCTraceTime tm("phase 1", PrintGCDetails && Verbose, true, _gc_timer, _gc_tracer->gc_id()); + + ParallelScavengeHeap* heap = ParallelScavengeHeap::heap(); + + // Need to clear claim bits before the tracing starts. + ClassLoaderDataGraph::clear_claimed_marks(); + + // General strong roots. + { + ParallelScavengeHeap::ParStrongRootsScope psrs; + Universe::oops_do(mark_and_push_closure()); + JNIHandles::oops_do(mark_and_push_closure()); // Global (strong) JNI handles + CLDToOopClosure mark_and_push_from_cld(mark_and_push_closure()); + MarkingCodeBlobClosure each_active_code_blob(mark_and_push_closure(), !CodeBlobToOopClosure::FixRelocations); + Threads::oops_do(mark_and_push_closure(), &mark_and_push_from_cld, &each_active_code_blob); + ObjectSynchronizer::oops_do(mark_and_push_closure()); + FlatProfiler::oops_do(mark_and_push_closure()); + Management::oops_do(mark_and_push_closure()); + JvmtiExport::oops_do(mark_and_push_closure()); + SystemDictionary::always_strong_oops_do(mark_and_push_closure()); + ClassLoaderDataGraph::always_strong_cld_do(follow_cld_closure()); + // Do not treat nmethods as strong roots for mark/sweep, since we can unload them. + //CodeCache::scavenge_root_nmethods_do(CodeBlobToOopClosure(mark_and_push_closure())); + } + + // Flush marking stack. + follow_stack(); + + // Process reference objects found during marking + { + ref_processor()->setup_policy(clear_all_softrefs); + const ReferenceProcessorStats& stats = + ref_processor()->process_discovered_references( + is_alive_closure(), mark_and_push_closure(), follow_stack_closure(), NULL, _gc_timer, _gc_tracer->gc_id()); + gc_tracer()->report_gc_reference_stats(stats); + } + + // This is the point where the entire marking should have completed. + assert(_marking_stack.is_empty(), "Marking should have completed"); + + // Unload classes and purge the SystemDictionary. + bool purged_class = SystemDictionary::do_unloading(is_alive_closure()); + + // Unload nmethods. + CodeCache::do_unloading(is_alive_closure(), purged_class); + + // Prune dead klasses from subklass/sibling/implementor lists. + Klass::clean_weak_klass_links(is_alive_closure()); + + // Delete entries for dead interned strings. + StringTable::unlink(is_alive_closure()); + + // Clean up unreferenced symbols in symbol table. + SymbolTable::unlink(); + _gc_tracer->report_object_count_after_gc(is_alive_closure()); +} + + +void PSMarkSweep::mark_sweep_phase2() { + GCTraceTime tm("phase 2", PrintGCDetails && Verbose, true, _gc_timer, _gc_tracer->gc_id()); + + // Now all live objects are marked, compute the new object addresses. + + // It is not required that we traverse spaces in the same order in + // phase2, phase3 and phase4, but the ValidateMarkSweep live oops + // tracking expects us to do so. See comment under phase4. + + ParallelScavengeHeap* heap = ParallelScavengeHeap::heap(); + PSOldGen* old_gen = heap->old_gen(); + + // Begin compacting into the old gen + PSMarkSweepDecorator::set_destination_decorator_tenured(); + + // This will also compact the young gen spaces. + old_gen->precompact(); +} + +// This should be moved to the shared markSweep code! +class PSAlwaysTrueClosure: public BoolObjectClosure { +public: + bool do_object_b(oop p) { return true; } +}; +static PSAlwaysTrueClosure always_true; + +void PSMarkSweep::mark_sweep_phase3() { + // Adjust the pointers to reflect the new locations + GCTraceTime tm("phase 3", PrintGCDetails && Verbose, true, _gc_timer, _gc_tracer->gc_id()); + + ParallelScavengeHeap* heap = ParallelScavengeHeap::heap(); + PSYoungGen* young_gen = heap->young_gen(); + PSOldGen* old_gen = heap->old_gen(); + + // Need to clear claim bits before the tracing starts. + ClassLoaderDataGraph::clear_claimed_marks(); + + // General strong roots. + Universe::oops_do(adjust_pointer_closure()); + JNIHandles::oops_do(adjust_pointer_closure()); // Global (strong) JNI handles + CLDToOopClosure adjust_from_cld(adjust_pointer_closure()); + Threads::oops_do(adjust_pointer_closure(), &adjust_from_cld, NULL); + ObjectSynchronizer::oops_do(adjust_pointer_closure()); + FlatProfiler::oops_do(adjust_pointer_closure()); + Management::oops_do(adjust_pointer_closure()); + JvmtiExport::oops_do(adjust_pointer_closure()); + SystemDictionary::oops_do(adjust_pointer_closure()); + ClassLoaderDataGraph::cld_do(adjust_cld_closure()); + + // Now adjust pointers in remaining weak roots. (All of which should + // have been cleared if they pointed to non-surviving objects.) + // Global (weak) JNI handles + JNIHandles::weak_oops_do(&always_true, adjust_pointer_closure()); + + CodeBlobToOopClosure adjust_from_blobs(adjust_pointer_closure(), CodeBlobToOopClosure::FixRelocations); + CodeCache::blobs_do(&adjust_from_blobs); + StringTable::oops_do(adjust_pointer_closure()); + ref_processor()->weak_oops_do(adjust_pointer_closure()); + PSScavenge::reference_processor()->weak_oops_do(adjust_pointer_closure()); + + adjust_marks(); + + young_gen->adjust_pointers(); + old_gen->adjust_pointers(); +} + +void PSMarkSweep::mark_sweep_phase4() { + EventMark m("4 compact heap"); + GCTraceTime tm("phase 4", PrintGCDetails && Verbose, true, _gc_timer, _gc_tracer->gc_id()); + + // All pointers are now adjusted, move objects accordingly + + ParallelScavengeHeap* heap = ParallelScavengeHeap::heap(); + PSYoungGen* young_gen = heap->young_gen(); + PSOldGen* old_gen = heap->old_gen(); + + old_gen->compact(); + young_gen->compact(); +} + +jlong PSMarkSweep::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; + jlong ret_val = now - _time_of_last_gc; + // XXX See note in genCollectedHeap::millis_since_last_gc(). + if (ret_val < 0) { + NOT_PRODUCT(warning("time warp: " JLONG_FORMAT, ret_val);) + return 0; + } + return ret_val; +} + +void PSMarkSweep::reset_millis_since_last_gc() { + // We need a monotonically non-decreasing time in ms but + // os::javaTimeMillis() does not guarantee monotonicity. + _time_of_last_gc = os::javaTimeNanos() / NANOSECS_PER_MILLISEC; +}