jdk8-mips64-public/hotspot: src/share/vm/gc_implementation/parallelScavenge/psScavenge.cpp@8dbc025ff709 (annotated)

src/share/vm/gc_implementation/parallelScavenge/psScavenge.cpp@8dbc025ff709 (annotated)

src/share/vm/gc_implementation/parallelScavenge/psScavenge.cpp

Mon, 27 May 2013 12:58:42 +0200

author: stefank
date: Mon, 27 May 2013 12:58:42 +0200
changeset 5196: 8dbc025ff709
parent 5194: eda078b01c65
child 5202: 47bdfb3d010f
permissions: -rw-r--r--

8015422: Large performance hit when the StringTable is walked twice in Parallel Scavenge
Summary: Combine the calls to StringTable::unlink and StringTable::oops_do in Parallel Scavenge.
Reviewed-by: pliden, coleenp

 /*
  * Copyright (c) 2002, 2013, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
  * under the terms of the GNU General Public License version 2 only, as
  * published by the Free Software Foundation.
  *
  * This code is distributed in the hope that it will be useful, but WITHOUT
  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  * version 2 for more details (a copy is included in the LICENSE file that
  * accompanied this code).
  *
  * You should have received a copy of the GNU General Public License version
  * 2 along with this work; if not, write to the Free Software Foundation,
  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  *
  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  * or visit www.oracle.com if you need additional information or have any
  * questions.
  *
  */
 #include "precompiled.hpp"
 #include "classfile/symbolTable.hpp"
 #include "code/codeCache.hpp"
 #include "gc_implementation/parallelScavenge/cardTableExtension.hpp"
 #include "gc_implementation/parallelScavenge/gcTaskManager.hpp"
 #include "gc_implementation/parallelScavenge/generationSizer.hpp"
 #include "gc_implementation/parallelScavenge/parallelScavengeHeap.hpp"
 #include "gc_implementation/parallelScavenge/psAdaptiveSizePolicy.hpp"
 #include "gc_implementation/parallelScavenge/psMarkSweep.hpp"
 #include "gc_implementation/parallelScavenge/psParallelCompact.hpp"
 #include "gc_implementation/parallelScavenge/psScavenge.inline.hpp"
 #include "gc_implementation/parallelScavenge/psTasks.hpp"
 #include "gc_implementation/shared/isGCActiveMark.hpp"
 #include "gc_implementation/shared/spaceDecorator.hpp"
 #include "gc_interface/gcCause.hpp"
 #include "memory/collectorPolicy.hpp"
 #include "memory/gcLocker.inline.hpp"
 #include "memory/referencePolicy.hpp"
 #include "memory/referenceProcessor.hpp"
 #include "memory/resourceArea.hpp"
 #include "oops/oop.inline.hpp"
 #include "oops/oop.psgc.inline.hpp"
 #include "runtime/biasedLocking.hpp"
 #include "runtime/fprofiler.hpp"
 #include "runtime/handles.inline.hpp"
 #include "runtime/threadCritical.hpp"
 #include "runtime/vmThread.hpp"
 #include "runtime/vm_operations.hpp"
 #include "services/memoryService.hpp"
 #include "utilities/stack.inline.hpp"
 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;
 uint                       PSScavenge::_tenuring_threshold = 0;
 HeapWord*                  PSScavenge::_young_generation_boundary = NULL;
 elapsedTimer               PSScavenge::_accumulated_time;
 Stack<markOop, mtGC>       PSScavenge::_preserved_mark_stack;
 Stack<oop, mtGC>           PSScavenge::_preserved_oop_stack;
 CollectorCounters*         PSScavenge::_counters = NULL;
 bool                       PSScavenge::_promotion_failed = false;
 // Define before use
 class PSIsAliveClosure: public BoolObjectClosure {
 public:
   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");
   }
   template <class T> void do_oop_work(T* p) {
     assert (!oopDesc::is_null(*p), "expected non-null ref");
     assert ((oopDesc::load_decode_heap_oop_not_null(p))->is_oop(),
             "expected an oop while scanning weak refs");
     // Weak refs may be visited more than once.
     if (PSScavenge::should_scavenge(p, _to_space)) {
       PSScavenge::copy_and_push_safe_barrier<T, /*promote_immediately=*/false>(_promotion_manager, p);
     }
   }
   virtual void do_oop(oop* p)       { PSKeepAliveClosure::do_oop_work(p); }
   virtual void do_oop(narrowOop* p) { PSKeepAliveClosure::do_oop_work(p); }
 };
 class PSEvacuateFollowersClosure: public VoidClosure {
  private:
   PSPromotionManager* _promotion_manager;
  public:
   PSEvacuateFollowersClosure(PSPromotionManager* pm) : _promotion_manager(pm) {}
   virtual 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();
   GCTaskManager* manager = ParallelScavengeHeap::gc_task_manager();
   for(uint i=0; i < manager->active_workers(); i++) {
     q->enqueue(new PSRefProcTaskProxy(task, i));
   }
   ParallelTaskTerminator terminator(manager->active_workers(),
                  (TaskQueueSetSuper*) PSPromotionManager::stack_array_depth());
   if (task.marks_oops_alive() && manager->active_workers() > 1) {
     for (uint j = 0; j < manager->active_workers(); j++) {
       q->enqueue(new StealTask(&terminator));
     }
   }
   manager->execute_and_wait(q);
 }
 void PSRefProcTaskExecutor::execute(EnqueueTask& task)
 {
   GCTaskQueue* q = GCTaskQueue::create();
   GCTaskManager* manager = ParallelScavengeHeap::gc_task_manager();
   for(uint i=0; i < manager->active_workers(); i++) {
     q->enqueue(new PSRefEnqueueTaskProxy(task, i));
   }
   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!
 bool 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* const heap = (ParallelScavengeHeap*)Universe::heap();
   assert(heap->kind() == CollectedHeap::ParallelScavengeHeap, "Sanity");
   PSAdaptiveSizePolicy* policy = heap->size_policy();
   IsGCActiveMark mark;
   const bool scavenge_done = PSScavenge::invoke_no_policy();
   const bool need_full_gc = !scavenge_done ||
     policy->should_full_GC(heap->old_gen()->free_in_bytes());
   bool full_gc_done = false;
   if (UsePerfData) {
     PSGCAdaptivePolicyCounters* const counters = heap->gc_policy_counters();
     const int ffs_val = need_full_gc ? full_follows_scavenge : not_skipped;
     counters->update_full_follows_scavenge(ffs_val);
   }
   if (need_full_gc) {
     GCCauseSetter gccs(heap, GCCause::_adaptive_size_policy);
     CollectorPolicy* cp = heap->collector_policy();
     const bool clear_all_softrefs = cp->should_clear_all_soft_refs();
     if (UseParallelOldGC) {
       full_gc_done = PSParallelCompact::invoke_no_policy(clear_all_softrefs);
     } else {
       full_gc_done = PSMarkSweep::invoke_no_policy(clear_all_softrefs);
     }
   }
   return full_gc_done;
 }
 // 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");
   assert(_preserved_mark_stack.is_empty(), "should be empty");
   assert(_preserved_oop_stack.is_empty(), "should be empty");
   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();
   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 (ZapUnusedHeapArea) {
     // Save information needed to minimize mangling
     heap->record_gen_tops_before_GC();
   }
   heap->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
     Universe::verify(" VerifyBeforeGC:");
   }
   {
     ResourceMark rm;
     HandleMark hm;
     gclog_or_tty->date_stamp(PrintGC && PrintGCDateStamps);
     TraceCPUTime tcpu(PrintGCDetails, true, gclog_or_tty);
     TraceTime t1(GCCauseString("GC", gc_cause), PrintGC, !PrintGCDetails, gclog_or_tty);
     TraceCollectorStats tcs(counters());
     TraceMemoryManagerStats tms(false /* not full GC */,gc_cause);
     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();
     }
     // 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(SpaceDecorator::Mangle);
     } else if (ZapUnusedHeapArea) {
       young_gen->to_space()->mangle_unused_area();
     }
     save_to_space_top_before_gc();
     COMPILER2_PRESENT(DerivedPointerTable::clear());
     reference_processor()->enable_discovery(true /*verify_disabled*/, true /*verify_no_refs*/);
     reference_processor()->setup_policy(false);
     // 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 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();
     // Release all previously held resources
     gc_task_manager()->release_all_resources();
     // Set the number of GC threads to be used in this collection
     gc_task_manager()->set_active_gang();
     gc_task_manager()->task_idle_workers();
     // Get the active number of workers here and use that value
     // throughout the methods.
     uint active_workers = gc_task_manager()->active_workers();
     heap->set_par_threads(active_workers);
     PSPromotionManager::pre_scavenge();
     // We'll use the promotion manager again later.
     PSPromotionManager* promotion_manager = PSPromotionManager::vm_thread_promotion_manager();
     {
       // TraceTime("Roots");
       ParallelScavengeHeap::ParStrongRootsScope psrs;
       GCTaskQueue* q = GCTaskQueue::create();
       if (!old_gen->object_space()->is_empty()) {
         // There are only old-to-young pointers if there are objects
         // in the old gen.
         uint stripe_total = active_workers;
         for(uint i=0; i < stripe_total; i++) {
           q->enqueue(new OldToYoungRootsTask(old_gen, old_top, i, stripe_total));
         }
       }
       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::class_loader_data));
       q->enqueue(new ScavengeRootsTask(ScavengeRootsTask::jvmti));
       q->enqueue(new ScavengeRootsTask(ScavengeRootsTask::code_cache));
       ParallelTaskTerminator terminator(
         active_workers,
                   (TaskQueueSetSuper*) promotion_manager->stack_array_depth());
       if (active_workers > 1) {
         for (uint j = 0; j < active_workers; j++) {
           q->enqueue(new StealTask(&terminator));
         }
       }
       gc_task_manager()->execute_and_wait(q);
     }
     scavenge_midpoint.update();
     // Process reference objects discovered during scavenge
     {
       reference_processor()->setup_policy(false); // not always_clear
       reference_processor()->set_active_mt_degree(active_workers);
       PSKeepAliveClosure keep_alive(promotion_manager);
       PSEvacuateFollowersClosure evac_followers(promotion_manager);
       if (reference_processor()->processing_is_mt()) {
         PSRefProcTaskExecutor task_executor;
         reference_processor()->process_discovered_references(
           &_is_alive_closure, &keep_alive, &evac_followers, &task_executor);
       } else {
         reference_processor()->process_discovered_references(
           &_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);
     }
     // Unlink any dead interned Strings and process the remaining live ones.
     PSScavengeRootsClosure root_closure(promotion_manager);
     StringTable::unlink_or_oops_do(&_is_alive_closure, &root_closure);
     // Finally, flush the promotion_manager's labs, and deallocate its stacks.
     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(SpaceDecorator::Mangle);
       young_gen->from_space()->clear(SpaceDecorator::Mangle);
       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);
       // A successful scavenge should restart the GC time limit count which is
       // for full GC's.
       size_policy->reset_gc_overhead_limit_count();
       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",
               old_gen->capacity_in_bytes(), young_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 " SIZE_FORMAT " bytes, new threshold %u (max %u)",
                                 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 young_live = young_gen->used_in_bytes();
           size_t eden_live = young_gen->eden_space()->used_in_bytes();
           size_t cur_eden = young_gen->eden_space()->capacity_in_bytes();
           size_t max_old_gen_size = old_gen->max_gen_size();
           size_t max_eden_size = young_gen->max_size() -
             young_gen->from_space()->capacity_in_bytes() -
             young_gen->to_space()->capacity_in_bytes();
           // Used for diagnostics
           size_policy->clear_generation_free_space_flags();
           size_policy->compute_eden_space_size(young_live,
                                                eden_live,
                                                cur_eden,
                                                max_eden_size,
                                                false /* not full gc*/);
           size_policy->check_gc_overhead_limit(young_live,
                                                eden_live,
                                                max_old_gen_size,
                                                max_eden_size,
                                                false /* not full gc*/,
                                                gc_cause,
                                                heap->collector_policy());
           size_policy->decay_supplemental_growth(false /* not full gc*/);
         }
         // 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());
     CodeCache::prune_scavenge_root_nmethods();
     // Re-verify object start arrays
     if (VerifyObjectStartArray &&
         VerifyAfterGC) {
       old_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();
     gc_task_manager()->release_idle_workers();
   }
   if (VerifyAfterGC && heap->total_collections() >= VerifyGCStartAt) {
     HandleMark hm;  // Discard invalid handles created during verification
     Universe::verify(" VerifyAfterGC:");
   }
   heap->print_heap_after_gc();
   if (ZapUnusedHeapArea) {
     young_gen->eden_space()->check_mangled_unused_area_complete();
     young_gen->from_space()->check_mangled_unused_area_complete();
     young_gen->to_space()->check_mangled_unused_area_complete();
   }
   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();
   }
 #ifdef TRACESPINNING
   ParallelTaskTerminator::print_termination_counts();
 #endif
   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.size());
     }
     // Restore any saved marks.
     while (!_preserved_oop_stack.is_empty()) {
       oop obj      = _preserved_oop_stack.pop();
       markOop mark = _preserved_mark_stack.pop();
       obj->set_mark(mark);
     }
     // Clear the preserved mark and oop stack caches.
     _preserved_mark_stack.clear(true);
     _preserved_oop_stack.clear(true);
     _promotion_failed = false;
   }
   // 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 preservation, 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) {
   _promotion_failed = true;
   if (obj_mark->must_be_preserved_for_promotion_failure(obj)) {
     // Should use per-worker private stakcs hetre rather than
     // locking a common pair of stacks.
     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();
   // Set boundary between young_gen and old_gen
   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 =
     new ReferenceProcessor(mr,                         // span
                            ParallelRefProcEnabled && (ParallelGCThreads > 1), // mt processing
                            (int) ParallelGCThreads,    // mt processing degree
                            true,                       // mt discovery
                            (int) ParallelGCThreads,    // mt discovery degree
                            true,                       // atomic_discovery
                            NULL,                       // header provides liveness info
                            false);                     // next field updates do not need write barrier
   // 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);
 }

Mercurial > jdk8-mips64-public > hotspot / annotate

src/share/vm/gc_implementation/parallelScavenge/psScavenge.cpp@8dbc025ff709 (annotated)

src/share/vm/gc_implementation/parallelScavenge/psScavenge.cpp