1 /*
   2  * Copyright (c) 2019, 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 
  27 #include "gc/g1/g1ParallelCleaning.hpp"
  28 #if INCLUDE_JVMCI
  29 #include "jvmci/jvmci.hpp"
  30 #endif
  31 
  32 #if INCLUDE_JVMCI
  33 JVMCICleaningTask::JVMCICleaningTask() :
  34   _cleaning_claimed(0) {
  35 }
  36 
  37 bool JVMCICleaningTask::claim_cleaning_task() {
  38   if (_cleaning_claimed) {
  39     return false;
  40   }
  41 
  42   return Atomic::cmpxchg(1, &_cleaning_claimed, 0) == 0;
  43 }
  44 
  45 void JVMCICleaningTask::work(bool unloading_occurred) {
  46   // One worker will clean JVMCI metadata handles.
  47   if (unloading_occurred && EnableJVMCI && claim_cleaning_task()) {
  48     JVMCI::do_unloading(unloading_occurred);
  49   }
  50 }
  51 #endif // INCLUDE_JVMCI
  52 
  53 G1ParallelCleaningTask::G1ParallelCleaningTask(BoolObjectClosure* is_alive,
  54                                                uint num_workers,
  55                                                bool unloading_occurred,
  56                                                bool resize_dedup_table) :
  57   AbstractGangTask("G1 Parallel Cleaning"),
  58   _unloading_occurred(unloading_occurred),
  59   _string_dedup_task(is_alive, NULL, resize_dedup_table),
  60   _code_cache_task(num_workers, is_alive, unloading_occurred),
  61   JVMCI_ONLY(_jvmci_cleaning_task() COMMA)
  62   _klass_cleaning_task() {
  63 }
  64 
  65 // The parallel work done by all worker threads.
  66 void G1ParallelCleaningTask::work(uint worker_id) {
  67   // Clean JVMCI metadata handles.
  68   // Execute this task first because it is serial task.
  69   JVMCI_ONLY(_jvmci_cleaning_task.work(_unloading_occurred);)
  70 
  71   // Do first pass of code cache cleaning.
  72   _code_cache_task.work(worker_id);
  73 
  74   // Clean the string dedup data structures.
  75   _string_dedup_task.work(worker_id);
  76 
  77   // Clean all klasses that were not unloaded.
  78   // The weak metadata in klass doesn't need to be
  79   // processed if there was no unloading.
  80   if (_unloading_occurred) {
  81     _klass_cleaning_task.work();
  82   }
  83 }