view src/share/vm/gc_implementation/g1/heapRegionSets.cpp @ 2152:0fa27f37d4d4

6977804: G1: remove the zero-filling thread Summary: This changeset removes the zero-filling thread from G1 and collapses the two free region lists we had before (the "free" and "unclean" lists) into one. The new free list uses the new heap region sets / lists abstractions that we'll ultimately use it to keep track of all regions in the heap. A heap region set was also introduced for the humongous regions. Finally, this change increases the concurrency between the thread that completes freeing regions (after a cleanup pause) and the rest of the system (before we'd have to wait for said thread to complete before allocating a new region). The changest also includes a lot of refactoring and code simplification. Reviewed-by: jcoomes, johnc
author tonyp
date Wed, 19 Jan 2011 19:30:42 -0500
parents
children 1216415d8e35
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/*
 * Copyright (c) 2011, 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 "gc_implementation/g1/heapRegionSets.hpp"

//////////////////// FreeRegionList ////////////////////

const char* FreeRegionList::verify_region_extra(HeapRegion* hr) {
  if (hr->is_young()) {
    return "the region should not be young";
  }
  // The superclass will check that the region is empty and
  // not-humongous.
  return HeapRegionLinkedList::verify_region_extra(hr);
}

//////////////////// MasterFreeRegionList ////////////////////

bool MasterFreeRegionList::check_mt_safety() {
  // Master Free List MT safety protocol:
  // (a) If we're at a safepoint, operations on the master free list
  // should be invoked by either the VM thread (which will serialize
  // them) or by the GC workers while holding the
  // FreeList_lock.
  // (b) If we're not at a safepoint, operations on the master free
  // list should be invoked while holding the Heap_lock.

  guarantee((SafepointSynchronize::is_at_safepoint() &&
               (Thread::current()->is_VM_thread() ||
                                            FreeList_lock->owned_by_self())) ||
            (!SafepointSynchronize::is_at_safepoint() &&
                                                Heap_lock->owned_by_self()),
            hrl_ext_msg(this, "master free list MT safety protocol"));

  return FreeRegionList::check_mt_safety();
}

//////////////////// SecondaryFreeRegionList ////////////////////

bool SecondaryFreeRegionList::check_mt_safety() {
  // Secondary Free List MT safety protocol:
  // Operations on the secondary free list should always be invoked
  // while holding the SecondaryFreeList_lock.

  guarantee(SecondaryFreeList_lock->owned_by_self(),
            hrl_ext_msg(this, "secondary free list MT safety protocol"));

  return FreeRegionList::check_mt_safety();
}

//////////////////// HumongousRegionSet ////////////////////

const char* HumongousRegionSet::verify_region_extra(HeapRegion* hr) {
  if (hr->is_young()) {
    return "the region should not be young";
  }
  // The superclass will check that the region is not empty and
  // humongous.
  return HeapRegionSet::verify_region_extra(hr);
}

//////////////////// HumongousRegionSet ////////////////////

bool MasterHumongousRegionSet::check_mt_safety() {
  // Master Humongous Set MT safety protocol:
  // (a) If we're at a safepoint, operations on the master humongous
  // set should be invoked by either the VM thread (which will
  // serialize them) or by the GC workers while holding the
  // OldSets_lock.
  // (b) If we're not at a safepoint, operations on the master
  // humongous set should be invoked while holding the Heap_lock.

  guarantee((SafepointSynchronize::is_at_safepoint() &&
               (Thread::current()->is_VM_thread() ||
                                             OldSets_lock->owned_by_self())) ||
            (!SafepointSynchronize::is_at_safepoint() &&
                                                 Heap_lock->owned_by_self()),
            hrl_ext_msg(this, "master humongous set MT safety protocol"));
  return HumongousRegionSet::check_mt_safety();
}