Mercurial > hg > truffle
diff src/share/vm/gc_implementation/parallelScavenge/psMarkSweep.cpp @ 0:a61af66fc99e jdk7-b24
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author | duke |
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date | Sat, 01 Dec 2007 00:00:00 +0000 |
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children | 12eea04c8b06 |
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--- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/src/share/vm/gc_implementation/parallelScavenge/psMarkSweep.cpp Sat Dec 01 00:00:00 2007 +0000 @@ -0,0 +1,670 @@ +/* + * Copyright 2001-2007 Sun Microsystems, Inc. All Rights Reserved. + * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. + * + * This code is free software; you can redistribute it and/or modify it + * under the terms of the GNU General Public License version 2 only, as + * published by the Free Software Foundation. + * + * This code is distributed in the hope that it will be useful, but WITHOUT + * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or + * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License + * version 2 for more details (a copy is included in the LICENSE file that + * accompanied this code). + * + * You should have received a copy of the GNU General Public License version + * 2 along with this work; if not, write to the Free Software Foundation, + * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. + * + * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara, + * CA 95054 USA or visit www.sun.com if you need additional information or + * have any questions. + * + */ + +#include "incls/_precompiled.incl" +#include "incls/_psMarkSweep.cpp.incl" + +elapsedTimer PSMarkSweep::_accumulated_time; +unsigned int PSMarkSweep::_total_invocations = 0; +jlong PSMarkSweep::_time_of_last_gc = 0; +CollectorCounters* PSMarkSweep::_counters = NULL; + +void PSMarkSweep::initialize() { + MemRegion mr = Universe::heap()->reserved_region(); + _ref_processor = new ReferenceProcessor(mr, + true, // atomic_discovery + false); // mt_discovery + if (!UseParallelOldGC || !VerifyParallelOldWithMarkSweep) { + _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! +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(!Universe::heap()->is_gc_active(), "not reentrant"); + + ParallelScavengeHeap* heap = (ParallelScavengeHeap*)Universe::heap(); + GCCause::Cause gc_cause = heap->gc_cause(); + PSAdaptiveSizePolicy* policy = heap->size_policy(); + + // Before each allocation/collection attempt, find out from the + // policy object if GCs are, on the whole, taking too long. If so, + // bail out without attempting a collection. The exceptions are + // for explicitly requested GC's. + if (!policy->gc_time_limit_exceeded() || + GCCause::is_user_requested_gc(gc_cause) || + GCCause::is_serviceability_requested_gc(gc_cause)) { + IsGCActiveMark mark; + + if (ScavengeBeforeFullGC) { + PSScavenge::invoke_no_policy(); + } + + int count = (maximum_heap_compaction)?1:MarkSweepAlwaysCompactCount; + IntFlagSetting flag_setting(MarkSweepAlwaysCompactCount, count); + PSMarkSweep::invoke_no_policy(maximum_heap_compaction); + } +} + +// This method contains no policy. You should probably +// be calling invoke() instead. +void 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; + } + + ParallelScavengeHeap* heap = (ParallelScavengeHeap*)Universe::heap(); + GCCause::Cause gc_cause = heap->gc_cause(); + assert(heap->kind() == CollectedHeap::ParallelScavengeHeap, "Sanity"); + PSAdaptiveSizePolicy* size_policy = heap->size_policy(); + + PSYoungGen* young_gen = heap->young_gen(); + PSOldGen* old_gen = heap->old_gen(); + PSPermGen* perm_gen = heap->perm_gen(); + + // Increment the invocation count + heap->increment_total_collections(true /* full */); + + // We need to track unique mark sweep invocations as well. + _total_invocations++; + + AdaptiveSizePolicyOutput(size_policy, heap->total_collections()); + + if (PrintHeapAtGC) { + Universe::print_heap_before_gc(); + } + + // 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 + gclog_or_tty->print(" VerifyBeforeGC:"); + Universe::verify(true); + } + + // Verify object start arrays + if (VerifyObjectStartArray && + VerifyBeforeGC) { + old_gen->verify_object_start_array(); + perm_gen->verify_object_start_array(); + } + + // 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; + const bool is_system_gc = gc_cause == GCCause::_java_lang_system_gc; + // This is useful for debugging but don't change the output the + // the customer sees. + const char* gc_cause_str = "Full GC"; + if (is_system_gc && PrintGCDetails) { + gc_cause_str = "Full GC (System)"; + } + gclog_or_tty->date_stamp(PrintGC && PrintGCDateStamps); + TraceCPUTime tcpu(PrintGCDetails, true, gclog_or_tty); + TraceTime t1(gc_cause_str, PrintGC, !PrintGCDetails, gclog_or_tty); + TraceCollectorStats tcs(counters()); + TraceMemoryManagerStats tms(true /* Full GC */); + + if (TraceGen1Time) accumulated_time()->start(); + + // Let the size policy know we're starting + size_policy->major_collection_begin(); + + // When collecting the permanent generation methodOops may be moving, + // so we either have to flush all bcp data or convert it into bci. + CodeCache::gc_prologue(); + Threads::gc_prologue(); + BiasedLocking::preserve_marks(); + + // Capture heap size before collection for printing. + size_t prev_used = heap->used(); + + // Capture perm gen size before collection for sizing. + size_t perm_gen_prev_used = perm_gen->used_in_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(); + + NOT_PRODUCT(ref_processor()->verify_no_references_recorded()); + COMPILER2_PRESENT(DerivedPointerTable::clear()); + + ref_processor()->enable_discovery(); + + 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(); + + 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; + + BarrierSet* bs = heap->barrier_set(); + if (bs->is_a(BarrierSet::ModRef)) { + ModRefBarrierSet* modBS = (ModRefBarrierSet*)bs; + MemRegion old_mr = heap->old_gen()->reserved(); + MemRegion perm_mr = heap->perm_gen()->reserved(); + assert(perm_mr.end() <= old_mr.start(), "Generations out of order"); + + if (young_gen_empty) { + modBS->clear(MemRegion(perm_mr.start(), old_mr.end())); + } else { + modBS->invalidate(MemRegion(perm_mr.start(), old_mr.end())); + } + } + + BiasedLocking::restore_marks(); + Threads::gc_epilogue(); + CodeCache::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: %d young_gen_capacity: %d" + " perm_gen_capacity: %d ", + old_gen->capacity_in_bytes(), young_gen->capacity_in_bytes(), + perm_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)) { + // 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 max_eden_size = young_gen->max_size() - + young_gen->from_space()->capacity_in_bytes() - + young_gen->to_space()->capacity_in_bytes(); + size_policy->compute_generation_free_space(young_gen->used_in_bytes(), + young_gen->eden_space()->used_in_bytes(), + old_gen->used_in_bytes(), + perm_gen->used_in_bytes(), + young_gen->eden_space()->capacity_in_bytes(), + old_gen->max_gen_size(), + max_eden_size, + true /* full gc*/, + gc_cause); + + heap->resize_old_gen(size_policy->calculated_old_free_size_in_bytes()); + + // Don't resize the young generation at an major collection. A + // desired young generation size may have been calculated but + // resizing the young generation complicates the code because the + // resizing of the old generation may have moved the boundary + // between the young generation and the old generation. Let the + // young generation resizing happen at the minor collections. + } + 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 perm gen, so we'll resize it here. + perm_gen->compute_new_size(perm_gen_prev_used); + + if (TraceGen1Time) 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); + // Do perm gen after heap becase prev_used does + // not include the perm gen (done this way in the other + // collectors). + if (PrintGCDetails) { + perm_gen->print_used_change(perm_gen_prev_used); + } + } + + // Track memory usage and detect low memory + MemoryService::track_memory_usage(); + heap->update_counters(); + + if (PrintGCDetails) { + if (size_policy->print_gc_time_limit_would_be_exceeded()) { + if (size_policy->gc_time_limit_exceeded()) { + gclog_or_tty->print_cr(" GC time is exceeding GCTimeLimit " + "of %d%%", GCTimeLimit); + } else { + gclog_or_tty->print_cr(" GC time would exceed GCTimeLimit " + "of %d%%", GCTimeLimit); + } + } + size_policy->set_print_gc_time_limit_would_be_exceeded(false); + } + } + + if (VerifyAfterGC && heap->total_collections() >= VerifyGCStartAt) { + HandleMark hm; // Discard invalid handles created during verification + gclog_or_tty->print(" VerifyAfterGC:"); + Universe::verify(false); + } + + // Re-verify object start arrays + if (VerifyObjectStartArray && + VerifyAfterGC) { + old_gen->verify_object_start_array(); + perm_gen->verify_object_start_array(); + } + + NOT_PRODUCT(ref_processor()->verify_no_references_recorded()); + + if (PrintHeapAtGC) { + Universe::print_heap_after_gc(); + } +} + +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(); + MemRegion old_gen_unused(old_space->top(), old_space->end()); + + // If the unused part of the old gen cannot be filled, skip + // absorbing eden. + if (old_gen_unused.word_size() < SharedHeap::min_fill_size()) { + return false; + } + + if (!old_gen_unused.is_empty()) { + SharedHeap::fill_region_with_object(old_gen_unused); + } + + // 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(); + HeapWord* const start = old_gen_unused.start(); + for (HeapWord* addr = start; addr < new_top; addr += oop(addr)->size()) { + start_array->allocate_block(addr); + } + + // 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*)Universe::heap(); + assert(heap->kind() == CollectedHeap::ParallelScavengeHeap, "Sanity"); + + 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); + + _preserved_mark_stack = NULL; + _preserved_oop_stack = NULL; + + _marking_stack = new (ResourceObj::C_HEAP) GrowableArray<oop>(4000, true); + + int size = SystemDictionary::number_of_classes() * 2; + _revisit_klass_stack = new (ResourceObj::C_HEAP) GrowableArray<Klass*>(size, true); +} + + +void PSMarkSweep::deallocate_stacks() { + if (_preserved_oop_stack) { + delete _preserved_mark_stack; + _preserved_mark_stack = NULL; + delete _preserved_oop_stack; + _preserved_oop_stack = NULL; + } + + delete _marking_stack; + delete _revisit_klass_stack; +} + +void PSMarkSweep::mark_sweep_phase1(bool clear_all_softrefs) { + // Recursively traverse all live objects and mark them + EventMark m("1 mark object"); + TraceTime tm("phase 1", PrintGCDetails && Verbose, true, gclog_or_tty); + trace(" 1"); + + ParallelScavengeHeap* heap = (ParallelScavengeHeap*)Universe::heap(); + assert(heap->kind() == CollectedHeap::ParallelScavengeHeap, "Sanity"); + + // General strong roots. + Universe::oops_do(mark_and_push_closure()); + ReferenceProcessor::oops_do(mark_and_push_closure()); + JNIHandles::oops_do(mark_and_push_closure()); // Global (strong) JNI handles + Threads::oops_do(mark_and_push_closure()); + 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()); + vmSymbols::oops_do(mark_and_push_closure()); + + // Flush marking stack. + follow_stack(); + + // Process reference objects found during marking + + // Skipping the reference processing for VerifyParallelOldWithMarkSweep + // affects the marking (makes it different). + { + ReferencePolicy *soft_ref_policy; + if (clear_all_softrefs) { + soft_ref_policy = new AlwaysClearPolicy(); + } else { +#ifdef COMPILER2 + soft_ref_policy = new LRUMaxHeapPolicy(); +#else + soft_ref_policy = new LRUCurrentHeapPolicy(); +#endif // COMPILER2 + } + assert(soft_ref_policy != NULL,"No soft reference policy"); + ref_processor()->process_discovered_references( + soft_ref_policy, is_alive_closure(), mark_and_push_closure(), + follow_stack_closure(), NULL); + } + + // Follow system dictionary roots and unload classes + bool purged_class = SystemDictionary::do_unloading(is_alive_closure()); + + // Follow code cache roots + CodeCache::do_unloading(is_alive_closure(), mark_and_push_closure(), + purged_class); + follow_stack(); // Flush marking stack + + // Update subklass/sibling/implementor links of live klasses + follow_weak_klass_links(); + assert(_marking_stack->is_empty(), "just drained"); + + // Visit symbol and interned string tables and delete unmarked oops + SymbolTable::unlink(is_alive_closure()); + StringTable::unlink(is_alive_closure()); + + assert(_marking_stack->is_empty(), "stack should be empty by now"); +} + + +void PSMarkSweep::mark_sweep_phase2() { + EventMark m("2 compute new addresses"); + TraceTime tm("phase 2", PrintGCDetails && Verbose, true, gclog_or_tty); + trace("2"); + + // Now all live objects are marked, compute the new object addresses. + + // It is imperative that we traverse perm_gen LAST. If dead space is + // allowed a range of dead object may get overwritten by a dead int + // array. If perm_gen is not traversed last a klassOop may get + // overwritten. This is fine since it is dead, but if the class has dead + // instances we have to skip them, and in order to find their size we + // need the klassOop! + // + // 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*)Universe::heap(); + assert(heap->kind() == CollectedHeap::ParallelScavengeHeap, "Sanity"); + + PSOldGen* old_gen = heap->old_gen(); + PSPermGen* perm_gen = heap->perm_gen(); + + // Begin compacting into the old gen + PSMarkSweepDecorator::set_destination_decorator_tenured(); + + // This will also compact the young gen spaces. + old_gen->precompact(); + + // Compact the perm gen into the perm gen + PSMarkSweepDecorator::set_destination_decorator_perm_gen(); + + perm_gen->precompact(); +} + +// This should be moved to the shared markSweep code! +class PSAlwaysTrueClosure: public BoolObjectClosure { +public: + void do_object(oop p) { ShouldNotReachHere(); } + 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 + EventMark m("3 adjust pointers"); + TraceTime tm("phase 3", PrintGCDetails && Verbose, true, gclog_or_tty); + trace("3"); + + ParallelScavengeHeap* heap = (ParallelScavengeHeap*)Universe::heap(); + assert(heap->kind() == CollectedHeap::ParallelScavengeHeap, "Sanity"); + + PSYoungGen* young_gen = heap->young_gen(); + PSOldGen* old_gen = heap->old_gen(); + PSPermGen* perm_gen = heap->perm_gen(); + + // General strong roots. + Universe::oops_do(adjust_root_pointer_closure()); + ReferenceProcessor::oops_do(adjust_root_pointer_closure()); + JNIHandles::oops_do(adjust_root_pointer_closure()); // Global (strong) JNI handles + Threads::oops_do(adjust_root_pointer_closure()); + ObjectSynchronizer::oops_do(adjust_root_pointer_closure()); + FlatProfiler::oops_do(adjust_root_pointer_closure()); + Management::oops_do(adjust_root_pointer_closure()); + JvmtiExport::oops_do(adjust_root_pointer_closure()); + // SO_AllClasses + SystemDictionary::oops_do(adjust_root_pointer_closure()); + vmSymbols::oops_do(adjust_root_pointer_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_root_pointer_closure()); + + CodeCache::oops_do(adjust_pointer_closure()); + SymbolTable::oops_do(adjust_root_pointer_closure()); + StringTable::oops_do(adjust_root_pointer_closure()); + ref_processor()->weak_oops_do(adjust_root_pointer_closure()); + PSScavenge::reference_processor()->weak_oops_do(adjust_root_pointer_closure()); + + adjust_marks(); + + young_gen->adjust_pointers(); + old_gen->adjust_pointers(); + perm_gen->adjust_pointers(); +} + +void PSMarkSweep::mark_sweep_phase4() { + EventMark m("4 compact heap"); + TraceTime tm("phase 4", PrintGCDetails && Verbose, true, gclog_or_tty); + trace("4"); + + // All pointers are now adjusted, move objects accordingly + + // It is imperative that we traverse perm_gen first in phase4. All + // classes must be allocated earlier than their instances, and traversing + // perm_gen first makes sure that all klassOops have moved to their new + // location before any instance does a dispatch through it's klass! + ParallelScavengeHeap* heap = (ParallelScavengeHeap*)Universe::heap(); + assert(heap->kind() == CollectedHeap::ParallelScavengeHeap, "Sanity"); + + PSYoungGen* young_gen = heap->young_gen(); + PSOldGen* old_gen = heap->old_gen(); + PSPermGen* perm_gen = heap->perm_gen(); + + perm_gen->compact(); + old_gen->compact(); + young_gen->compact(); +} + +jlong PSMarkSweep::millis_since_last_gc() { + jlong ret_val = os::javaTimeMillis() - _time_of_last_gc; + // XXX See note in genCollectedHeap::millis_since_last_gc(). + if (ret_val < 0) { + NOT_PRODUCT(warning("time warp: %d", ret_val);) + return 0; + } + return ret_val; +} + +void PSMarkSweep::reset_millis_since_last_gc() { + _time_of_last_gc = os::javaTimeMillis(); +}