1 /*
   2  * Copyright (c) 2015, 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
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  24 
  25 #ifndef SHARE_VM_GC_G1_G1ROOTPROCESSOR_HPP
  26 #define SHARE_VM_GC_G1_G1ROOTPROCESSOR_HPP
  27 
  28 #include "gc/shared/strongRootsScope.hpp"
  29 #include "memory/allocation.hpp"
  30 #include "runtime/mutex.hpp"
  31 
  32 class CLDClosure;
  33 class CodeBlobClosure;
  34 class G1CollectedHeap;
  35 class G1EvacuationRootClosures;
  36 class G1GCPhaseTimes;
  37 class G1ParPushHeapRSClosure;
  38 class G1RootClosures;
  39 class Monitor;
  40 class OopClosure;
  41 class SubTasksDone;
  42 
  43 // Scoped object to assist in applying oop, CLD and code blob closures to
  44 // root locations. Handles claiming of different root scanning tasks
  45 // and takes care of global state for root scanning via a StrongRootsScope.
  46 // In the parallel case there is a shared G1RootProcessor object where all
  47 // worker thread call the process_roots methods.
  48 class G1RootProcessor : public StackObj {
  49   G1CollectedHeap* _g1h;
  50   SubTasksDone _process_strong_tasks;
  51   StrongRootsScope _srs;
  52 
  53   // Used to implement the Thread work barrier.
  54   Monitor _lock;
  55   volatile jint _n_workers_discovered_strong_classes;
  56 
  57   enum G1H_process_roots_tasks {
  58     G1RP_PS_Universe_oops_do,
  59     G1RP_PS_JNIHandles_oops_do,
  60     G1RP_PS_ObjectSynchronizer_oops_do,
  61     G1RP_PS_FlatProfiler_oops_do,
  62     G1RP_PS_Management_oops_do,
  63     G1RP_PS_SystemDictionary_oops_do,
  64     G1RP_PS_ClassLoaderDataGraph_oops_do,
  65     G1RP_PS_jvmti_oops_do,
  66     G1RP_PS_CodeCache_oops_do,
  67     G1RP_PS_filter_satb_buffers,
  68     G1RP_PS_refProcessor_oops_do,
  69     // Leave this one last.
  70     G1RP_PS_NumElements
  71   };
  72 
  73   void worker_has_discovered_all_strong_classes();
  74   void wait_until_all_strong_classes_discovered();
  75 
  76   void process_java_roots(G1RootClosures* closures,
  77                           G1GCPhaseTimes* phase_times,
  78                           uint worker_i);
  79 
  80   void process_vm_roots(G1RootClosures* closures,
  81                         G1GCPhaseTimes* phase_times,
  82                         uint worker_i);
  83 
  84   void process_string_table_roots(G1RootClosures* closures,
  85                                   G1GCPhaseTimes* phase_times,
  86                                   uint worker_i);
  87 
  88   void process_code_cache_roots(CodeBlobClosure* code_closure,
  89                                 G1GCPhaseTimes* phase_times,
  90                                 uint worker_i);
  91 
  92 public:
  93   G1RootProcessor(G1CollectedHeap* g1h, uint n_workers);
  94 
  95   // Apply closures to the strongly and weakly reachable roots in the system
  96   // in a single pass.
  97   // Record and report timing measurements for sub phases using the worker_i
  98   void evacuate_roots(G1EvacuationRootClosures* closures, uint worker_i);
  99 
 100   // Apply oops, clds and blobs to all strongly reachable roots in the system
 101   void process_strong_roots(OopClosure* oops,
 102                             CLDClosure* clds,
 103                             CodeBlobClosure* blobs);
 104 
 105   // Apply oops, clds and blobs to strongly and weakly reachable roots in the system
 106   void process_all_roots(OopClosure* oops,
 107                          CLDClosure* clds,
 108                          CodeBlobClosure* blobs);
 109 
 110   // Apply oops, clds and blobs to strongly and weakly reachable roots in the system,
 111   // the only thing different from process_all_roots is that we skip the string table
 112   // to avoid keeping every string live when doing class unloading.
 113   void process_all_roots_no_string_table(OopClosure* oops,
 114                                          CLDClosure* clds,
 115                                          CodeBlobClosure* blobs);
 116 
 117   // Number of worker threads used by the root processor.
 118   uint n_workers() const;
 119 };
 120 
 121 #endif // SHARE_VM_GC_G1_G1ROOTPROCESSOR_HPP