| /* |
| * Copyright 2002-2007 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/_psScavenge.cpp.incl" |
| |
| HeapWord* PSScavenge::_to_space_top_before_gc = NULL; |
| int PSScavenge::_consecutive_skipped_scavenges = 0; |
| ReferenceProcessor* PSScavenge::_ref_processor = NULL; |
| CardTableExtension* PSScavenge::_card_table = NULL; |
| bool PSScavenge::_survivor_overflow = false; |
| int PSScavenge::_tenuring_threshold = 0; |
| HeapWord* PSScavenge::_young_generation_boundary = NULL; |
| elapsedTimer PSScavenge::_accumulated_time; |
| GrowableArray<markOop>* PSScavenge::_preserved_mark_stack = NULL; |
| GrowableArray<oop>* PSScavenge::_preserved_oop_stack = NULL; |
| CollectorCounters* PSScavenge::_counters = NULL; |
| |
| // Define before use |
| class PSIsAliveClosure: public BoolObjectClosure { |
| public: |
| void do_object(oop p) { |
| assert(false, "Do not call."); |
| } |
| bool do_object_b(oop p) { |
| return (!PSScavenge::is_obj_in_young((HeapWord*) p)) || p->is_forwarded(); |
| } |
| }; |
| |
| PSIsAliveClosure PSScavenge::_is_alive_closure; |
| |
| class PSKeepAliveClosure: public OopClosure { |
| protected: |
| MutableSpace* _to_space; |
| PSPromotionManager* _promotion_manager; |
| |
| public: |
| PSKeepAliveClosure(PSPromotionManager* pm) : _promotion_manager(pm) { |
| ParallelScavengeHeap* heap = (ParallelScavengeHeap*)Universe::heap(); |
| assert(heap->kind() == CollectedHeap::ParallelScavengeHeap, "Sanity"); |
| _to_space = heap->young_gen()->to_space(); |
| |
| assert(_promotion_manager != NULL, "Sanity"); |
| } |
| |
| void do_oop(oop* p) { |
| assert (*p != NULL, "expected non-null ref"); |
| assert ((*p)->is_oop(), "expected an oop while scanning weak refs"); |
| |
| oop obj = oop(*p); |
| // Weak refs may be visited more than once. |
| if (PSScavenge::should_scavenge(obj, _to_space)) { |
| PSScavenge::copy_and_push_safe_barrier(_promotion_manager, p); |
| } |
| } |
| }; |
| |
| class PSEvacuateFollowersClosure: public VoidClosure { |
| private: |
| PSPromotionManager* _promotion_manager; |
| public: |
| PSEvacuateFollowersClosure(PSPromotionManager* pm) : _promotion_manager(pm) {} |
| |
| void do_void() { |
| assert(_promotion_manager != NULL, "Sanity"); |
| _promotion_manager->drain_stacks(true); |
| guarantee(_promotion_manager->stacks_empty(), |
| "stacks should be empty at this point"); |
| } |
| }; |
| |
| class PSPromotionFailedClosure : public ObjectClosure { |
| virtual void do_object(oop obj) { |
| if (obj->is_forwarded()) { |
| obj->init_mark(); |
| } |
| } |
| }; |
| |
| class PSRefProcTaskProxy: public GCTask { |
| typedef AbstractRefProcTaskExecutor::ProcessTask ProcessTask; |
| ProcessTask & _rp_task; |
| uint _work_id; |
| public: |
| PSRefProcTaskProxy(ProcessTask & rp_task, uint work_id) |
| : _rp_task(rp_task), |
| _work_id(work_id) |
| { } |
| |
| private: |
| virtual char* name() { return (char *)"Process referents by policy in parallel"; } |
| virtual void do_it(GCTaskManager* manager, uint which); |
| }; |
| |
| void PSRefProcTaskProxy::do_it(GCTaskManager* manager, uint which) |
| { |
| PSPromotionManager* promotion_manager = |
| PSPromotionManager::gc_thread_promotion_manager(which); |
| assert(promotion_manager != NULL, "sanity check"); |
| PSKeepAliveClosure keep_alive(promotion_manager); |
| PSEvacuateFollowersClosure evac_followers(promotion_manager); |
| PSIsAliveClosure is_alive; |
| _rp_task.work(_work_id, is_alive, keep_alive, evac_followers); |
| } |
| |
| class PSRefEnqueueTaskProxy: public GCTask { |
| typedef AbstractRefProcTaskExecutor::EnqueueTask EnqueueTask; |
| EnqueueTask& _enq_task; |
| uint _work_id; |
| |
| public: |
| PSRefEnqueueTaskProxy(EnqueueTask& enq_task, uint work_id) |
| : _enq_task(enq_task), |
| _work_id(work_id) |
| { } |
| |
| virtual char* name() { return (char *)"Enqueue reference objects in parallel"; } |
| virtual void do_it(GCTaskManager* manager, uint which) |
| { |
| _enq_task.work(_work_id); |
| } |
| }; |
| |
| class PSRefProcTaskExecutor: public AbstractRefProcTaskExecutor { |
| virtual void execute(ProcessTask& task); |
| virtual void execute(EnqueueTask& task); |
| }; |
| |
| void PSRefProcTaskExecutor::execute(ProcessTask& task) |
| { |
| GCTaskQueue* q = GCTaskQueue::create(); |
| for(uint i=0; i<ParallelGCThreads; i++) { |
| q->enqueue(new PSRefProcTaskProxy(task, i)); |
| } |
| ParallelTaskTerminator terminator( |
| ParallelScavengeHeap::gc_task_manager()->workers(), |
| UseDepthFirstScavengeOrder ? |
| (TaskQueueSetSuper*) PSPromotionManager::stack_array_depth() |
| : (TaskQueueSetSuper*) PSPromotionManager::stack_array_breadth()); |
| if (task.marks_oops_alive() && ParallelGCThreads > 1) { |
| for (uint j=0; j<ParallelGCThreads; j++) { |
| q->enqueue(new StealTask(&terminator)); |
| } |
| } |
| ParallelScavengeHeap::gc_task_manager()->execute_and_wait(q); |
| } |
| |
| |
| void PSRefProcTaskExecutor::execute(EnqueueTask& task) |
| { |
| GCTaskQueue* q = GCTaskQueue::create(); |
| for(uint i=0; i<ParallelGCThreads; i++) { |
| q->enqueue(new PSRefEnqueueTaskProxy(task, i)); |
| } |
| ParallelScavengeHeap::gc_task_manager()->execute_and_wait(q); |
| } |
| |
| // This method contains all heap specific policy for invoking scavenge. |
| // PSScavenge::invoke_no_policy() will do nothing but attempt to |
| // scavenge. It will not clean up after failed promotions, bail out if |
| // we've exceeded policy time limits, or any other special behavior. |
| // All such policy should be placed here. |
| // |
| // Note that this method should only be called from the vm_thread while |
| // at a safepoint! |
| void PSScavenge::invoke() |
| { |
| 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(); |
| assert(heap->kind() == CollectedHeap::ParallelScavengeHeap, "Sanity"); |
| |
| 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. |
| if (!policy->gc_time_limit_exceeded()) { |
| IsGCActiveMark mark; |
| |
| bool scavenge_was_done = PSScavenge::invoke_no_policy(); |
| |
| PSGCAdaptivePolicyCounters* counters = heap->gc_policy_counters(); |
| if (UsePerfData) |
| counters->update_full_follows_scavenge(0); |
| if (!scavenge_was_done || |
| policy->should_full_GC(heap->old_gen()->free_in_bytes())) { |
| if (UsePerfData) |
| counters->update_full_follows_scavenge(full_follows_scavenge); |
| |
| GCCauseSetter gccs(heap, GCCause::_adaptive_size_policy); |
| if (UseParallelOldGC) { |
| PSParallelCompact::invoke_no_policy(false); |
| } else { |
| PSMarkSweep::invoke_no_policy(false); |
| } |
| } |
| } |
| } |
| |
| // This method contains no policy. You should probably |
| // be calling invoke() instead. |
| bool PSScavenge::invoke_no_policy() { |
| assert(SafepointSynchronize::is_at_safepoint(), "should be at safepoint"); |
| assert(Thread::current() == (Thread*)VMThread::vm_thread(), "should be in vm thread"); |
| |
| TimeStamp scavenge_entry; |
| TimeStamp scavenge_midpoint; |
| TimeStamp scavenge_exit; |
| |
| scavenge_entry.update(); |
| |
| if (GC_locker::check_active_before_gc()) { |
| return false; |
| } |
| |
| ParallelScavengeHeap* heap = (ParallelScavengeHeap*)Universe::heap(); |
| GCCause::Cause gc_cause = heap->gc_cause(); |
| assert(heap->kind() == CollectedHeap::ParallelScavengeHeap, "Sanity"); |
| |
| // Check for potential problems. |
| if (!should_attempt_scavenge()) { |
| return false; |
| } |
| |
| bool promotion_failure_occurred = false; |
| |
| PSYoungGen* young_gen = heap->young_gen(); |
| PSOldGen* old_gen = heap->old_gen(); |
| PSPermGen* perm_gen = heap->perm_gen(); |
| PSAdaptiveSizePolicy* size_policy = heap->size_policy(); |
| heap->increment_total_collections(); |
| |
| AdaptiveSizePolicyOutput(size_policy, heap->total_collections()); |
| |
| if ((gc_cause != GCCause::_java_lang_system_gc) || |
| UseAdaptiveSizePolicyWithSystemGC) { |
| // Gather the feedback data for eden occupancy. |
| young_gen->eden_space()->accumulate_statistics(); |
| } |
| |
| if (PrintHeapAtGC) { |
| Universe::print_heap_before_gc(); |
| } |
| |
| assert(!NeverTenure || _tenuring_threshold == markOopDesc::max_age + 1, "Sanity"); |
| assert(!AlwaysTenure || _tenuring_threshold == 0, "Sanity"); |
| |
| size_t prev_used = heap->used(); |
| assert(promotion_failed() == false, "Sanity"); |
| |
| // 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); |
| } |
| |
| { |
| ResourceMark rm; |
| HandleMark hm; |
| |
| gclog_or_tty->date_stamp(PrintGC && PrintGCDateStamps); |
| TraceCPUTime tcpu(PrintGCDetails, true, gclog_or_tty); |
| TraceTime t1("GC", PrintGC, !PrintGCDetails, gclog_or_tty); |
| TraceCollectorStats tcs(counters()); |
| TraceMemoryManagerStats tms(false /* not full GC */); |
| |
| if (TraceGen0Time) accumulated_time()->start(); |
| |
| // Let the size policy know we're starting |
| size_policy->minor_collection_begin(); |
| |
| // Verify the object start arrays. |
| if (VerifyObjectStartArray && |
| VerifyBeforeGC) { |
| old_gen->verify_object_start_array(); |
| perm_gen->verify_object_start_array(); |
| } |
| |
| // Verify no unmarked old->young roots |
| if (VerifyRememberedSets) { |
| CardTableExtension::verify_all_young_refs_imprecise(); |
| } |
| |
| if (!ScavengeWithObjectsInToSpace) { |
| assert(young_gen->to_space()->is_empty(), |
| "Attempt to scavenge with live objects in to_space"); |
| young_gen->to_space()->clear(); |
| } else if (ZapUnusedHeapArea) { |
| young_gen->to_space()->mangle_unused_area(); |
| } |
| save_to_space_top_before_gc(); |
| |
| NOT_PRODUCT(reference_processor()->verify_no_references_recorded()); |
| COMPILER2_PRESENT(DerivedPointerTable::clear()); |
| |
| reference_processor()->enable_discovery(); |
| |
| // We track how much was promoted to the next generation for |
| // the AdaptiveSizePolicy. |
| size_t old_gen_used_before = old_gen->used_in_bytes(); |
| |
| // For PrintGCDetails |
| size_t young_gen_used_before = young_gen->used_in_bytes(); |
| |
| // Reset our survivor overflow. |
| set_survivor_overflow(false); |
| |
| // We need to save the old/perm top values before |
| // creating the promotion_manager. We pass the top |
| // values to the card_table, to prevent it from |
| // straying into the promotion labs. |
| HeapWord* old_top = old_gen->object_space()->top(); |
| HeapWord* perm_top = perm_gen->object_space()->top(); |
| |
| // Release all previously held resources |
| gc_task_manager()->release_all_resources(); |
| |
| PSPromotionManager::pre_scavenge(); |
| |
| // We'll use the promotion manager again later. |
| PSPromotionManager* promotion_manager = PSPromotionManager::vm_thread_promotion_manager(); |
| { |
| // TraceTime("Roots"); |
| |
| GCTaskQueue* q = GCTaskQueue::create(); |
| |
| for(uint i=0; i<ParallelGCThreads; i++) { |
| q->enqueue(new OldToYoungRootsTask(old_gen, old_top, i)); |
| } |
| |
| q->enqueue(new SerialOldToYoungRootsTask(perm_gen, perm_top)); |
| |
| q->enqueue(new ScavengeRootsTask(ScavengeRootsTask::universe)); |
| q->enqueue(new ScavengeRootsTask(ScavengeRootsTask::jni_handles)); |
| // We scan the thread roots in parallel |
| Threads::create_thread_roots_tasks(q); |
| q->enqueue(new ScavengeRootsTask(ScavengeRootsTask::object_synchronizer)); |
| q->enqueue(new ScavengeRootsTask(ScavengeRootsTask::flat_profiler)); |
| q->enqueue(new ScavengeRootsTask(ScavengeRootsTask::management)); |
| q->enqueue(new ScavengeRootsTask(ScavengeRootsTask::system_dictionary)); |
| q->enqueue(new ScavengeRootsTask(ScavengeRootsTask::jvmti)); |
| |
| ParallelTaskTerminator terminator( |
| gc_task_manager()->workers(), |
| promotion_manager->depth_first() ? |
| (TaskQueueSetSuper*) promotion_manager->stack_array_depth() |
| : (TaskQueueSetSuper*) promotion_manager->stack_array_breadth()); |
| if (ParallelGCThreads>1) { |
| for (uint j=0; j<ParallelGCThreads; j++) { |
| q->enqueue(new StealTask(&terminator)); |
| } |
| } |
| |
| gc_task_manager()->execute_and_wait(q); |
| } |
| |
| scavenge_midpoint.update(); |
| |
| // Process reference objects discovered during scavenge |
| { |
| #ifdef COMPILER2 |
| ReferencePolicy *soft_ref_policy = new LRUMaxHeapPolicy(); |
| #else |
| ReferencePolicy *soft_ref_policy = new LRUCurrentHeapPolicy(); |
| #endif // COMPILER2 |
| |
| PSKeepAliveClosure keep_alive(promotion_manager); |
| PSEvacuateFollowersClosure evac_followers(promotion_manager); |
| assert(soft_ref_policy != NULL,"No soft reference policy"); |
| if (reference_processor()->processing_is_mt()) { |
| PSRefProcTaskExecutor task_executor; |
| reference_processor()->process_discovered_references( |
| soft_ref_policy, &_is_alive_closure, &keep_alive, &evac_followers, |
| &task_executor); |
| } else { |
| reference_processor()->process_discovered_references( |
| soft_ref_policy, &_is_alive_closure, &keep_alive, &evac_followers, |
| NULL); |
| } |
| } |
| |
| // Enqueue reference objects discovered during scavenge. |
| if (reference_processor()->processing_is_mt()) { |
| PSRefProcTaskExecutor task_executor; |
| reference_processor()->enqueue_discovered_references(&task_executor); |
| } else { |
| reference_processor()->enqueue_discovered_references(NULL); |
| } |
| |
| // Finally, flush the promotion_manager's labs, and deallocate its stacks. |
| assert(promotion_manager->claimed_stack_empty(), "Sanity"); |
| PSPromotionManager::post_scavenge(); |
| |
| promotion_failure_occurred = promotion_failed(); |
| if (promotion_failure_occurred) { |
| clean_up_failed_promotion(); |
| if (PrintGC) { |
| gclog_or_tty->print("--"); |
| } |
| } |
| |
| // Let the size policy know we're done. Note that we count promotion |
| // failure cleanup time as part of the collection (otherwise, we're |
| // implicitly saying it's mutator time). |
| size_policy->minor_collection_end(gc_cause); |
| |
| if (!promotion_failure_occurred) { |
| // Swap the survivor spaces. |
| young_gen->eden_space()->clear(); |
| young_gen->from_space()->clear(); |
| young_gen->swap_spaces(); |
| |
| size_t survived = young_gen->from_space()->used_in_bytes(); |
| size_t promoted = old_gen->used_in_bytes() - old_gen_used_before; |
| size_policy->update_averages(_survivor_overflow, survived, promoted); |
| |
| if (UseAdaptiveSizePolicy) { |
| // Calculate the new survivor size and tenuring threshold |
| |
| 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()); |
| } |
| } |
| |
| |
| if (UsePerfData) { |
| PSGCAdaptivePolicyCounters* counters = heap->gc_policy_counters(); |
| counters->update_old_eden_size( |
| size_policy->calculated_eden_size_in_bytes()); |
| counters->update_old_promo_size( |
| size_policy->calculated_promo_size_in_bytes()); |
| counters->update_old_capacity(old_gen->capacity_in_bytes()); |
| counters->update_young_capacity(young_gen->capacity_in_bytes()); |
| counters->update_survived(survived); |
| counters->update_promoted(promoted); |
| counters->update_survivor_overflowed(_survivor_overflow); |
| } |
| |
| size_t survivor_limit = |
| size_policy->max_survivor_size(young_gen->max_size()); |
| _tenuring_threshold = |
| size_policy->compute_survivor_space_size_and_threshold( |
| _survivor_overflow, |
| _tenuring_threshold, |
| survivor_limit); |
| |
| if (PrintTenuringDistribution) { |
| gclog_or_tty->cr(); |
| gclog_or_tty->print_cr("Desired survivor size %ld bytes, new threshold %d (max %d)", |
| size_policy->calculated_survivor_size_in_bytes(), |
| _tenuring_threshold, MaxTenuringThreshold); |
| } |
| |
| if (UsePerfData) { |
| PSGCAdaptivePolicyCounters* counters = heap->gc_policy_counters(); |
| counters->update_tenuring_threshold(_tenuring_threshold); |
| counters->update_survivor_size_counters(); |
| } |
| |
| // Do call at minor collections? |
| // Don't check if the size_policy is ready at this |
| // level. Let the size_policy check that internally. |
| if (UseAdaptiveSizePolicy && |
| UseAdaptiveGenerationSizePolicyAtMinorCollection && |
| ((gc_cause != GCCause::_java_lang_system_gc) || |
| UseAdaptiveSizePolicyWithSystemGC)) { |
| |
| // Calculate optimial 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, |
| false /* full gc*/, |
| gc_cause); |
| |
| } |
| // Resize the young generation at every collection |
| // even if new sizes have not been calculated. This is |
| // to allow resizes that may have been inhibited by the |
| // relative location of the "to" and "from" spaces. |
| |
| // Resizing the old gen at minor collects can cause increases |
| // that don't feed back to the generation sizing policy until |
| // a major collection. Don't resize the old gen here. |
| |
| 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()); |
| } |
| } |
| |
| // Update the structure of the eden. With NUMA-eden CPU hotplugging or offlining can |
| // cause the change of the heap layout. Make sure eden is reshaped if that's the case. |
| // Also update() will case adaptive NUMA chunk resizing. |
| assert(young_gen->eden_space()->is_empty(), "eden space should be empty now"); |
| young_gen->eden_space()->update(); |
| |
| heap->gc_policy_counters()->update_counters(); |
| |
| heap->resize_all_tlabs(); |
| |
| assert(young_gen->to_space()->is_empty(), "to space should be empty now"); |
| } |
| |
| COMPILER2_PRESENT(DerivedPointerTable::update_pointers()); |
| |
| NOT_PRODUCT(reference_processor()->verify_no_references_recorded()); |
| |
| // Re-verify object start arrays |
| if (VerifyObjectStartArray && |
| VerifyAfterGC) { |
| old_gen->verify_object_start_array(); |
| perm_gen->verify_object_start_array(); |
| } |
| |
| // Verify all old -> young cards are now precise |
| if (VerifyRememberedSets) { |
| // Precise verification will give false positives. Until this is fixed, |
| // use imprecise verification. |
| // CardTableExtension::verify_all_young_refs_precise(); |
| CardTableExtension::verify_all_young_refs_imprecise(); |
| } |
| |
| if (TraceGen0Time) 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_used_before); |
| } |
| heap->print_heap_change(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 |
| gclog_or_tty->print(" VerifyAfterGC:"); |
| Universe::verify(false); |
| } |
| |
| if (PrintHeapAtGC) { |
| Universe::print_heap_after_gc(); |
| } |
| |
| scavenge_exit.update(); |
| |
| if (PrintGCTaskTimeStamps) { |
| tty->print_cr("VM-Thread " INT64_FORMAT " " INT64_FORMAT " " INT64_FORMAT, |
| scavenge_entry.ticks(), scavenge_midpoint.ticks(), |
| scavenge_exit.ticks()); |
| gc_task_manager()->print_task_time_stamps(); |
| } |
| |
| return !promotion_failure_occurred; |
| } |
| |
| // This method iterates over all objects in the young generation, |
| // unforwarding markOops. It then restores any preserved mark oops, |
| // and clears the _preserved_mark_stack. |
| void PSScavenge::clean_up_failed_promotion() { |
| ParallelScavengeHeap* heap = (ParallelScavengeHeap*)Universe::heap(); |
| assert(heap->kind() == CollectedHeap::ParallelScavengeHeap, "Sanity"); |
| assert(promotion_failed(), "Sanity"); |
| |
| PSYoungGen* young_gen = heap->young_gen(); |
| |
| { |
| ResourceMark rm; |
| |
| // Unforward all pointers in the young gen. |
| PSPromotionFailedClosure unforward_closure; |
| young_gen->object_iterate(&unforward_closure); |
| |
| if (PrintGC && Verbose) { |
| gclog_or_tty->print_cr("Restoring %d marks", |
| _preserved_oop_stack->length()); |
| } |
| |
| // Restore any saved marks. |
| for (int i=0; i < _preserved_oop_stack->length(); i++) { |
| oop obj = _preserved_oop_stack->at(i); |
| markOop mark = _preserved_mark_stack->at(i); |
| obj->set_mark(mark); |
| } |
| |
| // Deallocate the preserved mark and oop stacks. |
| // The stacks were allocated as CHeap objects, so |
| // we must call delete to prevent mem leaks. |
| delete _preserved_mark_stack; |
| _preserved_mark_stack = NULL; |
| delete _preserved_oop_stack; |
| _preserved_oop_stack = NULL; |
| } |
| |
| // Reset the PromotionFailureALot counters. |
| NOT_PRODUCT(Universe::heap()->reset_promotion_should_fail();) |
| } |
| |
| // This method is called whenever an attempt to promote an object |
| // fails. Some markOops will need preserving, some will not. Note |
| // that the entire eden is traversed after a failed promotion, with |
| // all forwarded headers replaced by the default markOop. This means |
| // it is not neccessary to preserve most markOops. |
| void PSScavenge::oop_promotion_failed(oop obj, markOop obj_mark) { |
| if (_preserved_mark_stack == NULL) { |
| ThreadCritical tc; // Lock and retest |
| if (_preserved_mark_stack == NULL) { |
| assert(_preserved_oop_stack == NULL, "Sanity"); |
| _preserved_mark_stack = new (ResourceObj::C_HEAP) GrowableArray<markOop>(40, true); |
| _preserved_oop_stack = new (ResourceObj::C_HEAP) GrowableArray<oop>(40, true); |
| } |
| } |
| |
| // Because we must hold the ThreadCritical lock before using |
| // the stacks, we should be safe from observing partial allocations, |
| // which are also guarded by the ThreadCritical lock. |
| if (obj_mark->must_be_preserved_for_promotion_failure(obj)) { |
| ThreadCritical tc; |
| _preserved_oop_stack->push(obj); |
| _preserved_mark_stack->push(obj_mark); |
| } |
| } |
| |
| bool PSScavenge::should_attempt_scavenge() { |
| ParallelScavengeHeap* heap = (ParallelScavengeHeap*)Universe::heap(); |
| assert(heap->kind() == CollectedHeap::ParallelScavengeHeap, "Sanity"); |
| PSGCAdaptivePolicyCounters* counters = heap->gc_policy_counters(); |
| |
| if (UsePerfData) { |
| counters->update_scavenge_skipped(not_skipped); |
| } |
| |
| PSYoungGen* young_gen = heap->young_gen(); |
| PSOldGen* old_gen = heap->old_gen(); |
| |
| if (!ScavengeWithObjectsInToSpace) { |
| // Do not attempt to promote unless to_space is empty |
| if (!young_gen->to_space()->is_empty()) { |
| _consecutive_skipped_scavenges++; |
| if (UsePerfData) { |
| counters->update_scavenge_skipped(to_space_not_empty); |
| } |
| return false; |
| } |
| } |
| |
| // Test to see if the scavenge will likely fail. |
| PSAdaptiveSizePolicy* policy = heap->size_policy(); |
| |
| // A similar test is done in the policy's should_full_GC(). If this is |
| // changed, decide if that test should also be changed. |
| size_t avg_promoted = (size_t) policy->padded_average_promoted_in_bytes(); |
| size_t promotion_estimate = MIN2(avg_promoted, young_gen->used_in_bytes()); |
| bool result = promotion_estimate < old_gen->free_in_bytes(); |
| |
| if (PrintGCDetails && Verbose) { |
| gclog_or_tty->print(result ? " do scavenge: " : " skip scavenge: "); |
| gclog_or_tty->print_cr(" average_promoted " SIZE_FORMAT |
| " padded_average_promoted " SIZE_FORMAT |
| " free in old gen " SIZE_FORMAT, |
| (size_t) policy->average_promoted_in_bytes(), |
| (size_t) policy->padded_average_promoted_in_bytes(), |
| old_gen->free_in_bytes()); |
| if (young_gen->used_in_bytes() < |
| (size_t) policy->padded_average_promoted_in_bytes()) { |
| gclog_or_tty->print_cr(" padded_promoted_average is greater" |
| " than maximum promotion = " SIZE_FORMAT, young_gen->used_in_bytes()); |
| } |
| } |
| |
| if (result) { |
| _consecutive_skipped_scavenges = 0; |
| } else { |
| _consecutive_skipped_scavenges++; |
| if (UsePerfData) { |
| counters->update_scavenge_skipped(promoted_too_large); |
| } |
| } |
| return result; |
| } |
| |
| // Used to add tasks |
| GCTaskManager* const PSScavenge::gc_task_manager() { |
| assert(ParallelScavengeHeap::gc_task_manager() != NULL, |
| "shouldn't return NULL"); |
| return ParallelScavengeHeap::gc_task_manager(); |
| } |
| |
| void PSScavenge::initialize() { |
| // Arguments must have been parsed |
| |
| if (AlwaysTenure) { |
| _tenuring_threshold = 0; |
| } else if (NeverTenure) { |
| _tenuring_threshold = markOopDesc::max_age + 1; |
| } else { |
| // We want to smooth out our startup times for the AdaptiveSizePolicy |
| _tenuring_threshold = (UseAdaptiveSizePolicy) ? InitialTenuringThreshold : |
| MaxTenuringThreshold; |
| } |
| |
| 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(); |
| |
| // Set boundary between young_gen and old_gen |
| assert(perm_gen->reserved().end() <= old_gen->object_space()->bottom(), |
| "perm above old"); |
| assert(old_gen->reserved().end() <= young_gen->eden_space()->bottom(), |
| "old above young"); |
| _young_generation_boundary = young_gen->eden_space()->bottom(); |
| |
| // Initialize ref handling object for scavenging. |
| MemRegion mr = young_gen->reserved(); |
| _ref_processor = ReferenceProcessor::create_ref_processor( |
| mr, // span |
| true, // atomic_discovery |
| true, // mt_discovery |
| NULL, // is_alive_non_header |
| ParallelGCThreads, |
| ParallelRefProcEnabled); |
| |
| // Cache the cardtable |
| BarrierSet* bs = Universe::heap()->barrier_set(); |
| assert(bs->kind() == BarrierSet::CardTableModRef, "Wrong barrier set kind"); |
| _card_table = (CardTableExtension*)bs; |
| |
| _counters = new CollectorCounters("PSScavenge", 0); |
| } |
