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/*
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* Copyright 2002-2007 Sun Microsystems, Inc. All Rights Reserved.
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* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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*
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* This code is free software; you can redistribute it and/or modify it
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* under the terms of the GNU General Public License version 2 only, as
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* published by the Free Software Foundation.
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*
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* This code is distributed in the hope that it will be useful, but WITHOUT
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* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
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* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
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* version 2 for more details (a copy is included in the LICENSE file that
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* accompanied this code).
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*
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* You should have received a copy of the GNU General Public License version
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* 2 along with this work; if not, write to the Free Software Foundation,
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* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
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*
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* Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
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* CA 95054 USA or visit www.sun.com if you need additional information or
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* have any questions.
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*
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*/
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# include "incls/_precompiled.incl"
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# include "incls/_psScavenge.cpp.incl"
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HeapWord* PSScavenge::_to_space_top_before_gc = NULL;
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int PSScavenge::_consecutive_skipped_scavenges = 0;
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ReferenceProcessor* PSScavenge::_ref_processor = NULL;
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CardTableExtension* PSScavenge::_card_table = NULL;
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bool PSScavenge::_survivor_overflow = false;
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int PSScavenge::_tenuring_threshold = 0;
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HeapWord* PSScavenge::_young_generation_boundary = NULL;
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elapsedTimer PSScavenge::_accumulated_time;
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GrowableArray<markOop>* PSScavenge::_preserved_mark_stack = NULL;
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GrowableArray<oop>* PSScavenge::_preserved_oop_stack = NULL;
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CollectorCounters* PSScavenge::_counters = NULL;
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// Define before use
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class PSIsAliveClosure: public BoolObjectClosure {
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public:
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void do_object(oop p) {
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assert(false, "Do not call.");
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}
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bool do_object_b(oop p) {
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return (!PSScavenge::is_obj_in_young((HeapWord*) p)) || p->is_forwarded();
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}
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};
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PSIsAliveClosure PSScavenge::_is_alive_closure;
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class PSKeepAliveClosure: public OopClosure {
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protected:
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MutableSpace* _to_space;
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PSPromotionManager* _promotion_manager;
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public:
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PSKeepAliveClosure(PSPromotionManager* pm) : _promotion_manager(pm) {
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ParallelScavengeHeap* heap = (ParallelScavengeHeap*)Universe::heap();
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assert(heap->kind() == CollectedHeap::ParallelScavengeHeap, "Sanity");
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_to_space = heap->young_gen()->to_space();
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assert(_promotion_manager != NULL, "Sanity");
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}
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void do_oop(oop* p) {
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assert (*p != NULL, "expected non-null ref");
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assert ((*p)->is_oop(), "expected an oop while scanning weak refs");
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oop obj = oop(*p);
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// Weak refs may be visited more than once.
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if (PSScavenge::should_scavenge(obj, _to_space)) {
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PSScavenge::copy_and_push_safe_barrier(_promotion_manager, p);
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}
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}
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};
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class PSEvacuateFollowersClosure: public VoidClosure {
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private:
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PSPromotionManager* _promotion_manager;
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public:
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PSEvacuateFollowersClosure(PSPromotionManager* pm) : _promotion_manager(pm) {}
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void do_void() {
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assert(_promotion_manager != NULL, "Sanity");
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_promotion_manager->drain_stacks(true);
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guarantee(_promotion_manager->stacks_empty(),
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"stacks should be empty at this point");
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}
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};
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class PSPromotionFailedClosure : public ObjectClosure {
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virtual void do_object(oop obj) {
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if (obj->is_forwarded()) {
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obj->init_mark();
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}
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}
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};
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class PSRefProcTaskProxy: public GCTask {
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typedef AbstractRefProcTaskExecutor::ProcessTask ProcessTask;
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ProcessTask & _rp_task;
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uint _work_id;
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public:
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PSRefProcTaskProxy(ProcessTask & rp_task, uint work_id)
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: _rp_task(rp_task),
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_work_id(work_id)
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{ }
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private:
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virtual char* name() { return (char *)"Process referents by policy in parallel"; }
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virtual void do_it(GCTaskManager* manager, uint which);
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};
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void PSRefProcTaskProxy::do_it(GCTaskManager* manager, uint which)
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{
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PSPromotionManager* promotion_manager =
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PSPromotionManager::gc_thread_promotion_manager(which);
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assert(promotion_manager != NULL, "sanity check");
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PSKeepAliveClosure keep_alive(promotion_manager);
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PSEvacuateFollowersClosure evac_followers(promotion_manager);
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PSIsAliveClosure is_alive;
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_rp_task.work(_work_id, is_alive, keep_alive, evac_followers);
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}
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class PSRefEnqueueTaskProxy: public GCTask {
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typedef AbstractRefProcTaskExecutor::EnqueueTask EnqueueTask;
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EnqueueTask& _enq_task;
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uint _work_id;
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public:
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PSRefEnqueueTaskProxy(EnqueueTask& enq_task, uint work_id)
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: _enq_task(enq_task),
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_work_id(work_id)
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{ }
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virtual char* name() { return (char *)"Enqueue reference objects in parallel"; }
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virtual void do_it(GCTaskManager* manager, uint which)
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{
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_enq_task.work(_work_id);
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}
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};
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class PSRefProcTaskExecutor: public AbstractRefProcTaskExecutor {
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virtual void execute(ProcessTask& task);
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virtual void execute(EnqueueTask& task);
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};
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void PSRefProcTaskExecutor::execute(ProcessTask& task)
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{
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GCTaskQueue* q = GCTaskQueue::create();
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for(uint i=0; i<ParallelGCThreads; i++) {
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q->enqueue(new PSRefProcTaskProxy(task, i));
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}
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ParallelTaskTerminator terminator(
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ParallelScavengeHeap::gc_task_manager()->workers(),
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UseDepthFirstScavengeOrder ?
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(TaskQueueSetSuper*) PSPromotionManager::stack_array_depth()
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: (TaskQueueSetSuper*) PSPromotionManager::stack_array_breadth());
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if (task.marks_oops_alive() && ParallelGCThreads > 1) {
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for (uint j=0; j<ParallelGCThreads; j++) {
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q->enqueue(new StealTask(&terminator));
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}
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}
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ParallelScavengeHeap::gc_task_manager()->execute_and_wait(q);
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}
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void PSRefProcTaskExecutor::execute(EnqueueTask& task)
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{
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GCTaskQueue* q = GCTaskQueue::create();
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for(uint i=0; i<ParallelGCThreads; i++) {
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q->enqueue(new PSRefEnqueueTaskProxy(task, i));
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}
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ParallelScavengeHeap::gc_task_manager()->execute_and_wait(q);
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}
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// This method contains all heap specific policy for invoking scavenge.
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// PSScavenge::invoke_no_policy() will do nothing but attempt to
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// scavenge. It will not clean up after failed promotions, bail out if
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// we've exceeded policy time limits, or any other special behavior.
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// All such policy should be placed here.
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//
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// Note that this method should only be called from the vm_thread while
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// at a safepoint!
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void PSScavenge::invoke()
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{
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assert(SafepointSynchronize::is_at_safepoint(), "should be at safepoint");
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assert(Thread::current() == (Thread*)VMThread::vm_thread(), "should be in vm thread");
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assert(!Universe::heap()->is_gc_active(), "not reentrant");
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ParallelScavengeHeap* heap = (ParallelScavengeHeap*)Universe::heap();
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assert(heap->kind() == CollectedHeap::ParallelScavengeHeap, "Sanity");
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PSAdaptiveSizePolicy* policy = heap->size_policy();
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// Before each allocation/collection attempt, find out from the
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// policy object if GCs are, on the whole, taking too long. If so,
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// bail out without attempting a collection.
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if (!policy->gc_time_limit_exceeded()) {
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IsGCActiveMark mark;
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bool scavenge_was_done = PSScavenge::invoke_no_policy();
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PSGCAdaptivePolicyCounters* counters = heap->gc_policy_counters();
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if (UsePerfData)
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counters->update_full_follows_scavenge(0);
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if (!scavenge_was_done ||
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policy->should_full_GC(heap->old_gen()->free_in_bytes())) {
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if (UsePerfData)
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counters->update_full_follows_scavenge(full_follows_scavenge);
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GCCauseSetter gccs(heap, GCCause::_adaptive_size_policy);
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if (UseParallelOldGC) {
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PSParallelCompact::invoke_no_policy(false);
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} else {
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PSMarkSweep::invoke_no_policy(false);
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}
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}
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}
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}
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// This method contains no policy. You should probably
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// be calling invoke() instead.
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bool PSScavenge::invoke_no_policy() {
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assert(SafepointSynchronize::is_at_safepoint(), "should be at safepoint");
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assert(Thread::current() == (Thread*)VMThread::vm_thread(), "should be in vm thread");
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TimeStamp scavenge_entry;
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TimeStamp scavenge_midpoint;
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TimeStamp scavenge_exit;
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scavenge_entry.update();
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if (GC_locker::check_active_before_gc()) {
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return false;
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}
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ParallelScavengeHeap* heap = (ParallelScavengeHeap*)Universe::heap();
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GCCause::Cause gc_cause = heap->gc_cause();
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assert(heap->kind() == CollectedHeap::ParallelScavengeHeap, "Sanity");
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// Check for potential problems.
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if (!should_attempt_scavenge()) {
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return false;
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}
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bool promotion_failure_occurred = false;
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PSYoungGen* young_gen = heap->young_gen();
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PSOldGen* old_gen = heap->old_gen();
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PSPermGen* perm_gen = heap->perm_gen();
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PSAdaptiveSizePolicy* size_policy = heap->size_policy();
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heap->increment_total_collections();
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AdaptiveSizePolicyOutput(size_policy, heap->total_collections());
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if ((gc_cause != GCCause::_java_lang_system_gc) ||
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UseAdaptiveSizePolicyWithSystemGC) {
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// Gather the feedback data for eden occupancy.
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young_gen->eden_space()->accumulate_statistics();
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}
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if (PrintHeapAtGC) {
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Universe::print_heap_before_gc();
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}
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assert(!NeverTenure || _tenuring_threshold == markOopDesc::max_age + 1, "Sanity");
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assert(!AlwaysTenure || _tenuring_threshold == 0, "Sanity");
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size_t prev_used = heap->used();
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assert(promotion_failed() == false, "Sanity");
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// Fill in TLABs
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heap->accumulate_statistics_all_tlabs();
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heap->ensure_parsability(true); // retire TLABs
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if (VerifyBeforeGC && heap->total_collections() >= VerifyGCStartAt) {
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HandleMark hm; // Discard invalid handles created during verification
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gclog_or_tty->print(" VerifyBeforeGC:");
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Universe::verify(true);
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}
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{
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ResourceMark rm;
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HandleMark hm;
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gclog_or_tty->date_stamp(PrintGC && PrintGCDateStamps);
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TraceCPUTime tcpu(PrintGCDetails, true, gclog_or_tty);
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TraceTime t1("GC", PrintGC, !PrintGCDetails, gclog_or_tty);
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TraceCollectorStats tcs(counters());
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TraceMemoryManagerStats tms(false /* not full GC */);
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if (TraceGen0Time) accumulated_time()->start();
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// Let the size policy know we're starting
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size_policy->minor_collection_begin();
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// Verify the object start arrays.
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if (VerifyObjectStartArray &&
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VerifyBeforeGC) {
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old_gen->verify_object_start_array();
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perm_gen->verify_object_start_array();
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}
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// Verify no unmarked old->young roots
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if (VerifyRememberedSets) {
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CardTableExtension::verify_all_young_refs_imprecise();
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}
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if (!ScavengeWithObjectsInToSpace) {
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assert(young_gen->to_space()->is_empty(),
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"Attempt to scavenge with live objects in to_space");
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young_gen->to_space()->clear();
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} else if (ZapUnusedHeapArea) {
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young_gen->to_space()->mangle_unused_area();
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}
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save_to_space_top_before_gc();
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NOT_PRODUCT(reference_processor()->verify_no_references_recorded());
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COMPILER2_PRESENT(DerivedPointerTable::clear());
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reference_processor()->enable_discovery();
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// We track how much was promoted to the next generation for
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// the AdaptiveSizePolicy.
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size_t old_gen_used_before = old_gen->used_in_bytes();
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// For PrintGCDetails
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size_t young_gen_used_before = young_gen->used_in_bytes();
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// Reset our survivor overflow.
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set_survivor_overflow(false);
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// We need to save the old/perm top values before
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// creating the promotion_manager. We pass the top
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// values to the card_table, to prevent it from
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// straying into the promotion labs.
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HeapWord* old_top = old_gen->object_space()->top();
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HeapWord* perm_top = perm_gen->object_space()->top();
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// Release all previously held resources
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gc_task_manager()->release_all_resources();
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PSPromotionManager::pre_scavenge();
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// We'll use the promotion manager again later.
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PSPromotionManager* promotion_manager = PSPromotionManager::vm_thread_promotion_manager();
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{
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// TraceTime("Roots");
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GCTaskQueue* q = GCTaskQueue::create();
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for(uint i=0; i<ParallelGCThreads; i++) {
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q->enqueue(new OldToYoungRootsTask(old_gen, old_top, i));
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}
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q->enqueue(new SerialOldToYoungRootsTask(perm_gen, perm_top));
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q->enqueue(new ScavengeRootsTask(ScavengeRootsTask::universe));
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q->enqueue(new ScavengeRootsTask(ScavengeRootsTask::jni_handles));
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// We scan the thread roots in parallel
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Threads::create_thread_roots_tasks(q);
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q->enqueue(new ScavengeRootsTask(ScavengeRootsTask::object_synchronizer));
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q->enqueue(new ScavengeRootsTask(ScavengeRootsTask::flat_profiler));
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q->enqueue(new ScavengeRootsTask(ScavengeRootsTask::management));
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q->enqueue(new ScavengeRootsTask(ScavengeRootsTask::system_dictionary));
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q->enqueue(new ScavengeRootsTask(ScavengeRootsTask::jvmti));
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ParallelTaskTerminator terminator(
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gc_task_manager()->workers(),
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promotion_manager->depth_first() ?
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(TaskQueueSetSuper*) promotion_manager->stack_array_depth()
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: (TaskQueueSetSuper*) promotion_manager->stack_array_breadth());
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if (ParallelGCThreads>1) {
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for (uint j=0; j<ParallelGCThreads; j++) {
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q->enqueue(new StealTask(&terminator));
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}
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}
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gc_task_manager()->execute_and_wait(q);
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}
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|
386 |
scavenge_midpoint.update();
|
|
387 |
|
|
388 |
// Process reference objects discovered during scavenge
|
|
389 |
{
|
|
390 |
#ifdef COMPILER2
|
|
391 |
ReferencePolicy *soft_ref_policy = new LRUMaxHeapPolicy();
|
|
392 |
#else
|
|
393 |
ReferencePolicy *soft_ref_policy = new LRUCurrentHeapPolicy();
|
|
394 |
#endif // COMPILER2
|
|
395 |
|
|
396 |
PSKeepAliveClosure keep_alive(promotion_manager);
|
|
397 |
PSEvacuateFollowersClosure evac_followers(promotion_manager);
|
|
398 |
assert(soft_ref_policy != NULL,"No soft reference policy");
|
|
399 |
if (reference_processor()->processing_is_mt()) {
|
|
400 |
PSRefProcTaskExecutor task_executor;
|
|
401 |
reference_processor()->process_discovered_references(
|
|
402 |
soft_ref_policy, &_is_alive_closure, &keep_alive, &evac_followers,
|
|
403 |
&task_executor);
|
|
404 |
} else {
|
|
405 |
reference_processor()->process_discovered_references(
|
|
406 |
soft_ref_policy, &_is_alive_closure, &keep_alive, &evac_followers,
|
|
407 |
NULL);
|
|
408 |
}
|
|
409 |
}
|
|
410 |
|
|
411 |
// Enqueue reference objects discovered during scavenge.
|
|
412 |
if (reference_processor()->processing_is_mt()) {
|
|
413 |
PSRefProcTaskExecutor task_executor;
|
|
414 |
reference_processor()->enqueue_discovered_references(&task_executor);
|
|
415 |
} else {
|
|
416 |
reference_processor()->enqueue_discovered_references(NULL);
|
|
417 |
}
|
|
418 |
|
|
419 |
// Finally, flush the promotion_manager's labs, and deallocate its stacks.
|
|
420 |
assert(promotion_manager->claimed_stack_empty(), "Sanity");
|
|
421 |
PSPromotionManager::post_scavenge();
|
|
422 |
|
|
423 |
promotion_failure_occurred = promotion_failed();
|
|
424 |
if (promotion_failure_occurred) {
|
|
425 |
clean_up_failed_promotion();
|
|
426 |
if (PrintGC) {
|
|
427 |
gclog_or_tty->print("--");
|
|
428 |
}
|
|
429 |
}
|
|
430 |
|
|
431 |
// Let the size policy know we're done. Note that we count promotion
|
|
432 |
// failure cleanup time as part of the collection (otherwise, we're
|
|
433 |
// implicitly saying it's mutator time).
|
|
434 |
size_policy->minor_collection_end(gc_cause);
|
|
435 |
|
|
436 |
if (!promotion_failure_occurred) {
|
|
437 |
// Swap the survivor spaces.
|
|
438 |
young_gen->eden_space()->clear();
|
|
439 |
young_gen->from_space()->clear();
|
|
440 |
young_gen->swap_spaces();
|
|
441 |
|
|
442 |
size_t survived = young_gen->from_space()->used_in_bytes();
|
|
443 |
size_t promoted = old_gen->used_in_bytes() - old_gen_used_before;
|
|
444 |
size_policy->update_averages(_survivor_overflow, survived, promoted);
|
|
445 |
|
|
446 |
if (UseAdaptiveSizePolicy) {
|
|
447 |
// Calculate the new survivor size and tenuring threshold
|
|
448 |
|
|
449 |
if (PrintAdaptiveSizePolicy) {
|
|
450 |
gclog_or_tty->print("AdaptiveSizeStart: ");
|
|
451 |
gclog_or_tty->stamp();
|
|
452 |
gclog_or_tty->print_cr(" collection: %d ",
|
|
453 |
heap->total_collections());
|
|
454 |
|
|
455 |
if (Verbose) {
|
|
456 |
gclog_or_tty->print("old_gen_capacity: %d young_gen_capacity: %d"
|
|
457 |
" perm_gen_capacity: %d ",
|
|
458 |
old_gen->capacity_in_bytes(), young_gen->capacity_in_bytes(),
|
|
459 |
perm_gen->capacity_in_bytes());
|
|
460 |
}
|
|
461 |
}
|
|
462 |
|
|
463 |
|
|
464 |
if (UsePerfData) {
|
|
465 |
PSGCAdaptivePolicyCounters* counters = heap->gc_policy_counters();
|
|
466 |
counters->update_old_eden_size(
|
|
467 |
size_policy->calculated_eden_size_in_bytes());
|
|
468 |
counters->update_old_promo_size(
|
|
469 |
size_policy->calculated_promo_size_in_bytes());
|
|
470 |
counters->update_old_capacity(old_gen->capacity_in_bytes());
|
|
471 |
counters->update_young_capacity(young_gen->capacity_in_bytes());
|
|
472 |
counters->update_survived(survived);
|
|
473 |
counters->update_promoted(promoted);
|
|
474 |
counters->update_survivor_overflowed(_survivor_overflow);
|
|
475 |
}
|
|
476 |
|
|
477 |
size_t survivor_limit =
|
|
478 |
size_policy->max_survivor_size(young_gen->max_size());
|
|
479 |
_tenuring_threshold =
|
|
480 |
size_policy->compute_survivor_space_size_and_threshold(
|
|
481 |
_survivor_overflow,
|
|
482 |
_tenuring_threshold,
|
|
483 |
survivor_limit);
|
|
484 |
|
|
485 |
if (PrintTenuringDistribution) {
|
|
486 |
gclog_or_tty->cr();
|
|
487 |
gclog_or_tty->print_cr("Desired survivor size %ld bytes, new threshold %d (max %d)",
|
|
488 |
size_policy->calculated_survivor_size_in_bytes(),
|
|
489 |
_tenuring_threshold, MaxTenuringThreshold);
|
|
490 |
}
|
|
491 |
|
|
492 |
if (UsePerfData) {
|
|
493 |
PSGCAdaptivePolicyCounters* counters = heap->gc_policy_counters();
|
|
494 |
counters->update_tenuring_threshold(_tenuring_threshold);
|
|
495 |
counters->update_survivor_size_counters();
|
|
496 |
}
|
|
497 |
|
|
498 |
// Do call at minor collections?
|
|
499 |
// Don't check if the size_policy is ready at this
|
|
500 |
// level. Let the size_policy check that internally.
|
|
501 |
if (UseAdaptiveSizePolicy &&
|
|
502 |
UseAdaptiveGenerationSizePolicyAtMinorCollection &&
|
|
503 |
((gc_cause != GCCause::_java_lang_system_gc) ||
|
|
504 |
UseAdaptiveSizePolicyWithSystemGC)) {
|
|
505 |
|
|
506 |
// Calculate optimial free space amounts
|
|
507 |
assert(young_gen->max_size() >
|
|
508 |
young_gen->from_space()->capacity_in_bytes() +
|
|
509 |
young_gen->to_space()->capacity_in_bytes(),
|
|
510 |
"Sizes of space in young gen are out-of-bounds");
|
|
511 |
size_t max_eden_size = young_gen->max_size() -
|
|
512 |
young_gen->from_space()->capacity_in_bytes() -
|
|
513 |
young_gen->to_space()->capacity_in_bytes();
|
|
514 |
size_policy->compute_generation_free_space(young_gen->used_in_bytes(),
|
|
515 |
young_gen->eden_space()->used_in_bytes(),
|
|
516 |
old_gen->used_in_bytes(),
|
|
517 |
perm_gen->used_in_bytes(),
|
|
518 |
young_gen->eden_space()->capacity_in_bytes(),
|
|
519 |
old_gen->max_gen_size(),
|
|
520 |
max_eden_size,
|
|
521 |
false /* full gc*/,
|
|
522 |
gc_cause);
|
|
523 |
|
|
524 |
}
|
|
525 |
// Resize the young generation at every collection
|
|
526 |
// even if new sizes have not been calculated. This is
|
|
527 |
// to allow resizes that may have been inhibited by the
|
|
528 |
// relative location of the "to" and "from" spaces.
|
|
529 |
|
|
530 |
// Resizing the old gen at minor collects can cause increases
|
|
531 |
// that don't feed back to the generation sizing policy until
|
|
532 |
// a major collection. Don't resize the old gen here.
|
|
533 |
|
|
534 |
heap->resize_young_gen(size_policy->calculated_eden_size_in_bytes(),
|
|
535 |
size_policy->calculated_survivor_size_in_bytes());
|
|
536 |
|
|
537 |
if (PrintAdaptiveSizePolicy) {
|
|
538 |
gclog_or_tty->print_cr("AdaptiveSizeStop: collection: %d ",
|
|
539 |
heap->total_collections());
|
|
540 |
}
|
|
541 |
}
|
|
542 |
|
|
543 |
// Update the structure of the eden. With NUMA-eden CPU hotplugging or offlining can
|
|
544 |
// cause the change of the heap layout. Make sure eden is reshaped if that's the case.
|
|
545 |
// Also update() will case adaptive NUMA chunk resizing.
|
|
546 |
assert(young_gen->eden_space()->is_empty(), "eden space should be empty now");
|
|
547 |
young_gen->eden_space()->update();
|
|
548 |
|
|
549 |
heap->gc_policy_counters()->update_counters();
|
|
550 |
|
|
551 |
heap->resize_all_tlabs();
|
|
552 |
|
|
553 |
assert(young_gen->to_space()->is_empty(), "to space should be empty now");
|
|
554 |
}
|
|
555 |
|
|
556 |
COMPILER2_PRESENT(DerivedPointerTable::update_pointers());
|
|
557 |
|
|
558 |
NOT_PRODUCT(reference_processor()->verify_no_references_recorded());
|
|
559 |
|
|
560 |
// Re-verify object start arrays
|
|
561 |
if (VerifyObjectStartArray &&
|
|
562 |
VerifyAfterGC) {
|
|
563 |
old_gen->verify_object_start_array();
|
|
564 |
perm_gen->verify_object_start_array();
|
|
565 |
}
|
|
566 |
|
|
567 |
// Verify all old -> young cards are now precise
|
|
568 |
if (VerifyRememberedSets) {
|
|
569 |
// Precise verification will give false positives. Until this is fixed,
|
|
570 |
// use imprecise verification.
|
|
571 |
// CardTableExtension::verify_all_young_refs_precise();
|
|
572 |
CardTableExtension::verify_all_young_refs_imprecise();
|
|
573 |
}
|
|
574 |
|
|
575 |
if (TraceGen0Time) accumulated_time()->stop();
|
|
576 |
|
|
577 |
if (PrintGC) {
|
|
578 |
if (PrintGCDetails) {
|
|
579 |
// Don't print a GC timestamp here. This is after the GC so
|
|
580 |
// would be confusing.
|
|
581 |
young_gen->print_used_change(young_gen_used_before);
|
|
582 |
}
|
|
583 |
heap->print_heap_change(prev_used);
|
|
584 |
}
|
|
585 |
|
|
586 |
// Track memory usage and detect low memory
|
|
587 |
MemoryService::track_memory_usage();
|
|
588 |
heap->update_counters();
|
|
589 |
}
|
|
590 |
|
|
591 |
if (VerifyAfterGC && heap->total_collections() >= VerifyGCStartAt) {
|
|
592 |
HandleMark hm; // Discard invalid handles created during verification
|
|
593 |
gclog_or_tty->print(" VerifyAfterGC:");
|
|
594 |
Universe::verify(false);
|
|
595 |
}
|
|
596 |
|
|
597 |
if (PrintHeapAtGC) {
|
|
598 |
Universe::print_heap_after_gc();
|
|
599 |
}
|
|
600 |
|
|
601 |
scavenge_exit.update();
|
|
602 |
|
|
603 |
if (PrintGCTaskTimeStamps) {
|
|
604 |
tty->print_cr("VM-Thread " INT64_FORMAT " " INT64_FORMAT " " INT64_FORMAT,
|
|
605 |
scavenge_entry.ticks(), scavenge_midpoint.ticks(),
|
|
606 |
scavenge_exit.ticks());
|
|
607 |
gc_task_manager()->print_task_time_stamps();
|
|
608 |
}
|
|
609 |
|
|
610 |
return !promotion_failure_occurred;
|
|
611 |
}
|
|
612 |
|
|
613 |
// This method iterates over all objects in the young generation,
|
|
614 |
// unforwarding markOops. It then restores any preserved mark oops,
|
|
615 |
// and clears the _preserved_mark_stack.
|
|
616 |
void PSScavenge::clean_up_failed_promotion() {
|
|
617 |
ParallelScavengeHeap* heap = (ParallelScavengeHeap*)Universe::heap();
|
|
618 |
assert(heap->kind() == CollectedHeap::ParallelScavengeHeap, "Sanity");
|
|
619 |
assert(promotion_failed(), "Sanity");
|
|
620 |
|
|
621 |
PSYoungGen* young_gen = heap->young_gen();
|
|
622 |
|
|
623 |
{
|
|
624 |
ResourceMark rm;
|
|
625 |
|
|
626 |
// Unforward all pointers in the young gen.
|
|
627 |
PSPromotionFailedClosure unforward_closure;
|
|
628 |
young_gen->object_iterate(&unforward_closure);
|
|
629 |
|
|
630 |
if (PrintGC && Verbose) {
|
|
631 |
gclog_or_tty->print_cr("Restoring %d marks",
|
|
632 |
_preserved_oop_stack->length());
|
|
633 |
}
|
|
634 |
|
|
635 |
// Restore any saved marks.
|
|
636 |
for (int i=0; i < _preserved_oop_stack->length(); i++) {
|
|
637 |
oop obj = _preserved_oop_stack->at(i);
|
|
638 |
markOop mark = _preserved_mark_stack->at(i);
|
|
639 |
obj->set_mark(mark);
|
|
640 |
}
|
|
641 |
|
|
642 |
// Deallocate the preserved mark and oop stacks.
|
|
643 |
// The stacks were allocated as CHeap objects, so
|
|
644 |
// we must call delete to prevent mem leaks.
|
|
645 |
delete _preserved_mark_stack;
|
|
646 |
_preserved_mark_stack = NULL;
|
|
647 |
delete _preserved_oop_stack;
|
|
648 |
_preserved_oop_stack = NULL;
|
|
649 |
}
|
|
650 |
|
|
651 |
// Reset the PromotionFailureALot counters.
|
|
652 |
NOT_PRODUCT(Universe::heap()->reset_promotion_should_fail();)
|
|
653 |
}
|
|
654 |
|
|
655 |
// This method is called whenever an attempt to promote an object
|
|
656 |
// fails. Some markOops will need preserving, some will not. Note
|
|
657 |
// that the entire eden is traversed after a failed promotion, with
|
|
658 |
// all forwarded headers replaced by the default markOop. This means
|
|
659 |
// it is not neccessary to preserve most markOops.
|
|
660 |
void PSScavenge::oop_promotion_failed(oop obj, markOop obj_mark) {
|
|
661 |
if (_preserved_mark_stack == NULL) {
|
|
662 |
ThreadCritical tc; // Lock and retest
|
|
663 |
if (_preserved_mark_stack == NULL) {
|
|
664 |
assert(_preserved_oop_stack == NULL, "Sanity");
|
|
665 |
_preserved_mark_stack = new (ResourceObj::C_HEAP) GrowableArray<markOop>(40, true);
|
|
666 |
_preserved_oop_stack = new (ResourceObj::C_HEAP) GrowableArray<oop>(40, true);
|
|
667 |
}
|
|
668 |
}
|
|
669 |
|
|
670 |
// Because we must hold the ThreadCritical lock before using
|
|
671 |
// the stacks, we should be safe from observing partial allocations,
|
|
672 |
// which are also guarded by the ThreadCritical lock.
|
|
673 |
if (obj_mark->must_be_preserved_for_promotion_failure(obj)) {
|
|
674 |
ThreadCritical tc;
|
|
675 |
_preserved_oop_stack->push(obj);
|
|
676 |
_preserved_mark_stack->push(obj_mark);
|
|
677 |
}
|
|
678 |
}
|
|
679 |
|
|
680 |
bool PSScavenge::should_attempt_scavenge() {
|
|
681 |
ParallelScavengeHeap* heap = (ParallelScavengeHeap*)Universe::heap();
|
|
682 |
assert(heap->kind() == CollectedHeap::ParallelScavengeHeap, "Sanity");
|
|
683 |
PSGCAdaptivePolicyCounters* counters = heap->gc_policy_counters();
|
|
684 |
|
|
685 |
if (UsePerfData) {
|
|
686 |
counters->update_scavenge_skipped(not_skipped);
|
|
687 |
}
|
|
688 |
|
|
689 |
PSYoungGen* young_gen = heap->young_gen();
|
|
690 |
PSOldGen* old_gen = heap->old_gen();
|
|
691 |
|
|
692 |
if (!ScavengeWithObjectsInToSpace) {
|
|
693 |
// Do not attempt to promote unless to_space is empty
|
|
694 |
if (!young_gen->to_space()->is_empty()) {
|
|
695 |
_consecutive_skipped_scavenges++;
|
|
696 |
if (UsePerfData) {
|
|
697 |
counters->update_scavenge_skipped(to_space_not_empty);
|
|
698 |
}
|
|
699 |
return false;
|
|
700 |
}
|
|
701 |
}
|
|
702 |
|
|
703 |
// Test to see if the scavenge will likely fail.
|
|
704 |
PSAdaptiveSizePolicy* policy = heap->size_policy();
|
|
705 |
|
|
706 |
// A similar test is done in the policy's should_full_GC(). If this is
|
|
707 |
// changed, decide if that test should also be changed.
|
|
708 |
size_t avg_promoted = (size_t) policy->padded_average_promoted_in_bytes();
|
|
709 |
size_t promotion_estimate = MIN2(avg_promoted, young_gen->used_in_bytes());
|
|
710 |
bool result = promotion_estimate < old_gen->free_in_bytes();
|
|
711 |
|
|
712 |
if (PrintGCDetails && Verbose) {
|
|
713 |
gclog_or_tty->print(result ? " do scavenge: " : " skip scavenge: ");
|
|
714 |
gclog_or_tty->print_cr(" average_promoted " SIZE_FORMAT
|
|
715 |
" padded_average_promoted " SIZE_FORMAT
|
|
716 |
" free in old gen " SIZE_FORMAT,
|
|
717 |
(size_t) policy->average_promoted_in_bytes(),
|
|
718 |
(size_t) policy->padded_average_promoted_in_bytes(),
|
|
719 |
old_gen->free_in_bytes());
|
|
720 |
if (young_gen->used_in_bytes() <
|
|
721 |
(size_t) policy->padded_average_promoted_in_bytes()) {
|
|
722 |
gclog_or_tty->print_cr(" padded_promoted_average is greater"
|
|
723 |
" than maximum promotion = " SIZE_FORMAT, young_gen->used_in_bytes());
|
|
724 |
}
|
|
725 |
}
|
|
726 |
|
|
727 |
if (result) {
|
|
728 |
_consecutive_skipped_scavenges = 0;
|
|
729 |
} else {
|
|
730 |
_consecutive_skipped_scavenges++;
|
|
731 |
if (UsePerfData) {
|
|
732 |
counters->update_scavenge_skipped(promoted_too_large);
|
|
733 |
}
|
|
734 |
}
|
|
735 |
return result;
|
|
736 |
}
|
|
737 |
|
|
738 |
// Used to add tasks
|
|
739 |
GCTaskManager* const PSScavenge::gc_task_manager() {
|
|
740 |
assert(ParallelScavengeHeap::gc_task_manager() != NULL,
|
|
741 |
"shouldn't return NULL");
|
|
742 |
return ParallelScavengeHeap::gc_task_manager();
|
|
743 |
}
|
|
744 |
|
|
745 |
void PSScavenge::initialize() {
|
|
746 |
// Arguments must have been parsed
|
|
747 |
|
|
748 |
if (AlwaysTenure) {
|
|
749 |
_tenuring_threshold = 0;
|
|
750 |
} else if (NeverTenure) {
|
|
751 |
_tenuring_threshold = markOopDesc::max_age + 1;
|
|
752 |
} else {
|
|
753 |
// We want to smooth out our startup times for the AdaptiveSizePolicy
|
|
754 |
_tenuring_threshold = (UseAdaptiveSizePolicy) ? InitialTenuringThreshold :
|
|
755 |
MaxTenuringThreshold;
|
|
756 |
}
|
|
757 |
|
|
758 |
ParallelScavengeHeap* heap = (ParallelScavengeHeap*)Universe::heap();
|
|
759 |
assert(heap->kind() == CollectedHeap::ParallelScavengeHeap, "Sanity");
|
|
760 |
|
|
761 |
PSYoungGen* young_gen = heap->young_gen();
|
|
762 |
PSOldGen* old_gen = heap->old_gen();
|
|
763 |
PSPermGen* perm_gen = heap->perm_gen();
|
|
764 |
|
|
765 |
// Set boundary between young_gen and old_gen
|
|
766 |
assert(perm_gen->reserved().end() <= old_gen->object_space()->bottom(),
|
|
767 |
"perm above old");
|
|
768 |
assert(old_gen->reserved().end() <= young_gen->eden_space()->bottom(),
|
|
769 |
"old above young");
|
|
770 |
_young_generation_boundary = young_gen->eden_space()->bottom();
|
|
771 |
|
|
772 |
// Initialize ref handling object for scavenging.
|
|
773 |
MemRegion mr = young_gen->reserved();
|
|
774 |
_ref_processor = ReferenceProcessor::create_ref_processor(
|
|
775 |
mr, // span
|
|
776 |
true, // atomic_discovery
|
|
777 |
true, // mt_discovery
|
|
778 |
NULL, // is_alive_non_header
|
|
779 |
ParallelGCThreads,
|
|
780 |
ParallelRefProcEnabled);
|
|
781 |
|
|
782 |
// Cache the cardtable
|
|
783 |
BarrierSet* bs = Universe::heap()->barrier_set();
|
|
784 |
assert(bs->kind() == BarrierSet::CardTableModRef, "Wrong barrier set kind");
|
|
785 |
_card_table = (CardTableExtension*)bs;
|
|
786 |
|
|
787 |
_counters = new CollectorCounters("PSScavenge", 0);
|
|
788 |
}
|