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 #include "runtime/atomic.hpp"
  29 #if INCLUDE_JVMCI
  30 #include "jvmci/jvmci.hpp"
  31 #endif
  32 
  33 #if INCLUDE_JVMCI
  34 JVMCICleaningTask::JVMCICleaningTask() :
  35   _cleaning_claimed(0) {
  36 }
  37 
  38 bool JVMCICleaningTask::claim_cleaning_task() {
  39   if (_cleaning_claimed) {
  40     return false;
  41   }
  42 
  43   return Atomic::cmpxchg(&_cleaning_claimed, 0, 1) == 0;
  44 }
  45 
  46 void JVMCICleaningTask::work(bool unloading_occurred) {
  47   // One worker will clean JVMCI metadata handles.
  48   if (unloading_occurred && EnableJVMCI && claim_cleaning_task()) {
  49     JVMCI::do_unloading(unloading_occurred);
  50   }
  51 }
  52 #endif // INCLUDE_JVMCI
  53 
  54 G1ParallelCleaningTask::G1ParallelCleaningTask(BoolObjectClosure* is_alive,
  55                                                uint num_workers,
  56                                                bool unloading_occurred,
  57                                                bool resize_dedup_table) :
  58   AbstractGangTask("G1 Parallel Cleaning"),
  59   _unloading_occurred(unloading_occurred),
  60   _string_dedup_task(is_alive, NULL, resize_dedup_table),
  61   _code_cache_task(num_workers, is_alive, unloading_occurred),
  62   JVMCI_ONLY(_jvmci_cleaning_task() COMMA)
  63   _klass_cleaning_task() {
  64 }
  65 
  66 // The parallel work done by all worker threads.
  67 void G1ParallelCleaningTask::work(uint worker_id) {
  68   // Clean JVMCI metadata handles.
  69   // Execute this task first because it is serial task.
  70   JVMCI_ONLY(_jvmci_cleaning_task.work(_unloading_occurred);)
  71 
  72   // Do first pass of code cache cleaning.
  73   _code_cache_task.work(worker_id);
  74 
  75   // Clean the string dedup data structures.
  76   _string_dedup_task.work(worker_id);
  77 
  78   // Clean all klasses that were not unloaded.
  79   // The weak metadata in klass doesn't need to be
  80   // processed if there was no unloading.
  81   if (_unloading_occurred) {
  82     _klass_cleaning_task.work();
  83   }
  84 }