view src/share/vm/gc_implementation/parallelScavenge/pcTasks.cpp @ 453:c96030fff130

6684579: SoftReference processing can be made more efficient Summary: For current soft-ref clearing policies, we can decide at marking time if a soft-reference will definitely not be cleared, postponing the decision of whether it will definitely be cleared to the final reference processing phase. This can be especially beneficial in the case of concurrent collectors where the marking is usually concurrent but reference processing is usually not. Reviewed-by: jmasa
author ysr
date Thu, 20 Nov 2008 16:56:09 -0800
parents 81cd571500b0
children 8b46c4d82093 148e5441d916
line wrap: on
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/*
 * Copyright 2005-2008 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/_pcTasks.cpp.incl"

//
// ThreadRootsMarkingTask
//

void ThreadRootsMarkingTask::do_it(GCTaskManager* manager, uint which) {
  assert(Universe::heap()->is_gc_active(), "called outside gc");

  ResourceMark rm;

  NOT_PRODUCT(TraceTime tm("ThreadRootsMarkingTask",
    PrintGCDetails && TraceParallelOldGCTasks, true, gclog_or_tty));
  ParCompactionManager* cm =
    ParCompactionManager::gc_thread_compaction_manager(which);
  PSParallelCompact::MarkAndPushClosure mark_and_push_closure(cm);

  if (_java_thread != NULL)
    _java_thread->oops_do(&mark_and_push_closure);

  if (_vm_thread != NULL)
    _vm_thread->oops_do(&mark_and_push_closure);

  // Do the real work
  cm->drain_marking_stacks(&mark_and_push_closure);
}


void MarkFromRootsTask::do_it(GCTaskManager* manager, uint which) {
  assert(Universe::heap()->is_gc_active(), "called outside gc");

  NOT_PRODUCT(TraceTime tm("MarkFromRootsTask",
    PrintGCDetails && TraceParallelOldGCTasks, true, gclog_or_tty));
  ParCompactionManager* cm =
    ParCompactionManager::gc_thread_compaction_manager(which);
  // cm->allocate_stacks();
  assert(cm->stacks_have_been_allocated(),
    "Stack space has not been allocated");
  PSParallelCompact::MarkAndPushClosure mark_and_push_closure(cm);

  switch (_root_type) {
    case universe:
      Universe::oops_do(&mark_and_push_closure);
      break;

    case reference_processing:
      ReferenceProcessor::oops_do(&mark_and_push_closure);
      break;

    case jni_handles:
      JNIHandles::oops_do(&mark_and_push_closure);
      break;

    case threads:
    {
      ResourceMark rm;
      Threads::oops_do(&mark_and_push_closure);
    }
    break;

    case object_synchronizer:
      ObjectSynchronizer::oops_do(&mark_and_push_closure);
      break;

    case flat_profiler:
      FlatProfiler::oops_do(&mark_and_push_closure);
      break;

    case management:
      Management::oops_do(&mark_and_push_closure);
      break;

    case jvmti:
      JvmtiExport::oops_do(&mark_and_push_closure);
      break;

    case system_dictionary:
      SystemDictionary::always_strong_oops_do(&mark_and_push_closure);
      break;

    case vm_symbols:
      vmSymbols::oops_do(&mark_and_push_closure);
      break;

    default:
      fatal("Unknown root type");
  }

  // Do the real work
  cm->drain_marking_stacks(&mark_and_push_closure);
  // cm->deallocate_stacks();
}


//
// RefProcTaskProxy
//

void RefProcTaskProxy::do_it(GCTaskManager* manager, uint which)
{
  assert(Universe::heap()->is_gc_active(), "called outside gc");

  NOT_PRODUCT(TraceTime tm("RefProcTask",
    PrintGCDetails && TraceParallelOldGCTasks, true, gclog_or_tty));
  ParCompactionManager* cm =
    ParCompactionManager::gc_thread_compaction_manager(which);
  // cm->allocate_stacks();
  assert(cm->stacks_have_been_allocated(),
    "Stack space has not been allocated");
  PSParallelCompact::MarkAndPushClosure mark_and_push_closure(cm);
  PSParallelCompact::FollowStackClosure follow_stack_closure(cm);
  _rp_task.work(_work_id, *PSParallelCompact::is_alive_closure(),
                mark_and_push_closure, follow_stack_closure);
}

//
// RefProcTaskExecutor
//

void RefProcTaskExecutor::execute(ProcessTask& task)
{
  ParallelScavengeHeap* heap = PSParallelCompact::gc_heap();
  uint parallel_gc_threads = heap->gc_task_manager()->workers();
  RegionTaskQueueSet* qset = ParCompactionManager::region_array();
  ParallelTaskTerminator terminator(parallel_gc_threads, qset);
  GCTaskQueue* q = GCTaskQueue::create();
  for(uint i=0; i<parallel_gc_threads; i++) {
    q->enqueue(new RefProcTaskProxy(task, i));
  }
  if (task.marks_oops_alive()) {
    if (parallel_gc_threads>1) {
      for (uint j=0; j<parallel_gc_threads; j++) {
        q->enqueue(new StealMarkingTask(&terminator));
      }
    }
  }
  PSParallelCompact::gc_task_manager()->execute_and_wait(q);
}

void RefProcTaskExecutor::execute(EnqueueTask& task)
{
  ParallelScavengeHeap* heap = PSParallelCompact::gc_heap();
  uint parallel_gc_threads = heap->gc_task_manager()->workers();
  GCTaskQueue* q = GCTaskQueue::create();
  for(uint i=0; i<parallel_gc_threads; i++) {
    q->enqueue(new RefEnqueueTaskProxy(task, i));
  }
  PSParallelCompact::gc_task_manager()->execute_and_wait(q);
}

//
// StealMarkingTask
//

StealMarkingTask::StealMarkingTask(ParallelTaskTerminator* t) :
  _terminator(t) {}

void StealMarkingTask::do_it(GCTaskManager* manager, uint which) {
  assert(Universe::heap()->is_gc_active(), "called outside gc");

  NOT_PRODUCT(TraceTime tm("StealMarkingTask",
    PrintGCDetails && TraceParallelOldGCTasks, true, gclog_or_tty));

  ParCompactionManager* cm =
    ParCompactionManager::gc_thread_compaction_manager(which);
  PSParallelCompact::MarkAndPushClosure mark_and_push_closure(cm);

  oop obj = NULL;
  int random_seed = 17;
  while(true) {
    if (ParCompactionManager::steal(which, &random_seed, obj)) {
      obj->follow_contents(cm);
      cm->drain_marking_stacks(&mark_and_push_closure);
    } else {
      if (terminator()->offer_termination()) {
        break;
      }
    }
  }
}

//
// StealRegionCompactionTask
//


StealRegionCompactionTask::StealRegionCompactionTask(ParallelTaskTerminator* t):
  _terminator(t) {}

void StealRegionCompactionTask::do_it(GCTaskManager* manager, uint which) {
  assert(Universe::heap()->is_gc_active(), "called outside gc");

  NOT_PRODUCT(TraceTime tm("StealRegionCompactionTask",
    PrintGCDetails && TraceParallelOldGCTasks, true, gclog_or_tty));

  ParCompactionManager* cm =
    ParCompactionManager::gc_thread_compaction_manager(which);

  // Has to drain stacks first because there may be regions on
  // preloaded onto the stack and this thread may never have
  // done a draining task.  Are the draining tasks needed?

  cm->drain_region_stacks();

  size_t region_index = 0;
  int random_seed = 17;

  // If we're the termination task, try 10 rounds of stealing before
  // setting the termination flag

  while(true) {
    if (ParCompactionManager::steal(which, &random_seed, region_index)) {
      PSParallelCompact::fill_and_update_region(cm, region_index);
      cm->drain_region_stacks();
    } else {
      if (terminator()->offer_termination()) {
        break;
      }
      // Go around again.
    }
  }
  return;
}

UpdateDensePrefixTask::UpdateDensePrefixTask(
                                   PSParallelCompact::SpaceId space_id,
                                   size_t region_index_start,
                                   size_t region_index_end) :
  _space_id(space_id), _region_index_start(region_index_start),
  _region_index_end(region_index_end) {}

void UpdateDensePrefixTask::do_it(GCTaskManager* manager, uint which) {

  NOT_PRODUCT(TraceTime tm("UpdateDensePrefixTask",
    PrintGCDetails && TraceParallelOldGCTasks, true, gclog_or_tty));

  ParCompactionManager* cm =
    ParCompactionManager::gc_thread_compaction_manager(which);

  PSParallelCompact::update_and_deadwood_in_dense_prefix(cm,
                                                         _space_id,
                                                         _region_index_start,
                                                         _region_index_end);
}

void DrainStacksCompactionTask::do_it(GCTaskManager* manager, uint which) {
  assert(Universe::heap()->is_gc_active(), "called outside gc");

  NOT_PRODUCT(TraceTime tm("DrainStacksCompactionTask",
    PrintGCDetails && TraceParallelOldGCTasks, true, gclog_or_tty));

  ParCompactionManager* cm =
    ParCompactionManager::gc_thread_compaction_manager(which);

  // Process any regions already in the compaction managers stacks.
  cm->drain_region_stacks();
}