1 /*
   2  * Copyright (c) 2000, 2014, Oracle and/or its affiliates. All rights reserved.
   3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   4  *
   5  * This code is free software; you can redistribute it and/or modify it
   6  * under the terms of the GNU General Public License version 2 only, as
   7  * published by the Free Software Foundation.
   8  *
   9  * This code is distributed in the hope that it will be useful, but WITHOUT
  10  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  11  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  12  * version 2 for more details (a copy is included in the LICENSE file that
  13  * accompanied this code).
  14  *
  15  * You should have received a copy of the GNU General Public License version
  16  * 2 along with this work; if not, write to the Free Software Foundation,
  17  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  18  *
  19  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  20  * or visit www.oracle.com if you need additional information or have any
  21  * questions.
  22  *
  23  */
  24 
  25 #include "precompiled.hpp"
  26 #include "classfile/symbolTable.hpp"
  27 #include "classfile/systemDictionary.hpp"
  28 #include "code/codeCache.hpp"
  29 #include "gc_interface/collectedHeap.inline.hpp"
  30 #include "memory/sharedHeap.hpp"
  31 #include "oops/oop.inline.hpp"
  32 #include "runtime/atomic.inline.hpp"
  33 #include "runtime/fprofiler.hpp"
  34 #include "runtime/java.hpp"
  35 #include "utilities/copy.hpp"
  36 #include "utilities/workgroup.hpp"
  37 
  38 PRAGMA_FORMAT_MUTE_WARNINGS_FOR_GCC
  39 
  40 SharedHeap* SharedHeap::_sh;
  41 
  42 SharedHeap::SharedHeap(CollectorPolicy* policy_) :
  43   CollectedHeap(),
  44   _collector_policy(policy_),
  45   _rem_set(NULL),
  46   _strong_roots_parity(0),
  47   _workers(NULL)
  48 {
  49   _sh = this;  // ch is static, should be set only once.
  50   if ((UseParNewGC ||
  51       (UseConcMarkSweepGC && (CMSParallelInitialMarkEnabled ||
  52                               CMSParallelRemarkEnabled)) ||
  53        UseG1GC) &&
  54       ParallelGCThreads > 0) {
  55     _workers = new FlexibleWorkGang("Parallel GC Threads", ParallelGCThreads,
  56                             /* are_GC_task_threads */true,
  57                             /* are_ConcurrentGC_threads */false);
  58     if (_workers == NULL) {
  59       vm_exit_during_initialization("Failed necessary allocation.");
  60     } else {
  61       _workers->initialize_workers();
  62     }
  63   }
  64 }
  65 
  66 bool SharedHeap::heap_lock_held_for_gc() {
  67   Thread* t = Thread::current();
  68   return    Heap_lock->owned_by_self()
  69          || (   (t->is_GC_task_thread() ||  t->is_VM_thread())
  70              && _thread_holds_heap_lock_for_gc);
  71 }
  72 
  73 void SharedHeap::set_par_threads(uint t) {
  74   assert(t == 0 || !UseSerialGC, "Cannot have parallel threads");
  75   _n_par_threads = t;
  76 }
  77 
  78 void SharedHeap::change_strong_roots_parity() {
  79   // Also set the new collection parity.
  80   assert(_strong_roots_parity >= 0 && _strong_roots_parity <= 2,
  81          "Not in range.");
  82   _strong_roots_parity++;
  83   if (_strong_roots_parity == 3) _strong_roots_parity = 1;
  84   assert(_strong_roots_parity >= 1 && _strong_roots_parity <= 2,
  85          "Not in range.");
  86 }
  87 
  88 SharedHeap::StrongRootsScope::StrongRootsScope(SharedHeap* heap, bool activate)
  89   : MarkScope(activate), _sh(heap)
  90 {
  91   if (_active) {
  92     _sh->change_strong_roots_parity();
  93     // Zero the claimed high water mark in the StringTable
  94     StringTable::clear_parallel_claimed_index();
  95   }
  96 }
  97 
  98 void SharedHeap::set_barrier_set(BarrierSet* bs) {
  99   _barrier_set = bs;
 100   // Cached barrier set for fast access in oops
 101   oopDesc::set_bs(bs);
 102 }
 103 
 104 void SharedHeap::post_initialize() {
 105   CollectedHeap::post_initialize();
 106   ref_processing_init();
 107 }
 108 
 109 void SharedHeap::ref_processing_init() {}
 110 
 111 // Some utilities.
 112 void SharedHeap::print_size_transition(outputStream* out,
 113                                        size_t bytes_before,
 114                                        size_t bytes_after,
 115                                        size_t capacity) {
 116   out->print(" %d%s->%d%s(%d%s)",
 117              byte_size_in_proper_unit(bytes_before),
 118              proper_unit_for_byte_size(bytes_before),
 119              byte_size_in_proper_unit(bytes_after),
 120              proper_unit_for_byte_size(bytes_after),
 121              byte_size_in_proper_unit(capacity),
 122              proper_unit_for_byte_size(capacity));
 123 }