1 /*
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   3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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   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.
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  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  *
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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/oopStorageParState.hpp"
  29 #include "gc/shared/strongRootsScope.hpp"
  30 #include "memory/allocation.hpp"
  31 #include "runtime/mutex.hpp"
  32 
  33 class CLDClosure;
  34 class CodeBlobClosure;
  35 class G1CollectedHeap;
  36 class G1EvacuationRootClosures;
  37 class G1GCPhaseTimes;
  38 class G1ParScanThreadState;
  39 class G1RootClosures;
  40 class Monitor;
  41 class OopClosure;
  42 class SubTasksDone;
  43 
  44 // Scoped object to assist in applying oop, CLD and code blob closures to
  45 // root locations. Handles claiming of different root scanning tasks
  46 // and takes care of global state for root scanning via a StrongRootsScope.
  47 // In the parallel case there is a shared G1RootProcessor object where all
  48 // worker thread call the process_roots methods.
  49 class G1RootProcessor : public StackObj {
  50   G1CollectedHeap* _g1h;
  51   SubTasksDone _process_strong_tasks;
  52   StrongRootsScope _srs;
  53   OopStorage::ParState<false, false> _par_state_string;
  54 
  55   // Used to implement the Thread work barrier.
  56   Monitor _lock;
  57   volatile jint _n_workers_discovered_strong_classes;
  58 
  59   enum G1H_process_roots_tasks {
  60     G1RP_PS_Universe_oops_do,
  61     G1RP_PS_JNIHandles_oops_do,
  62     G1RP_PS_ObjectSynchronizer_oops_do,
  63     G1RP_PS_Management_oops_do,
  64     G1RP_PS_SystemDictionary_oops_do,
  65     G1RP_PS_ClassLoaderDataGraph_oops_do,
  66     G1RP_PS_jvmti_oops_do,
  67     G1RP_PS_CodeCache_oops_do,
  68     G1RP_PS_aot_oops_do,
  69     G1RP_PS_filter_satb_buffers,
  70     G1RP_PS_refProcessor_oops_do,
  71     G1RP_PS_weakProcessor_oops_do,
  72     // Leave this one last.
  73     G1RP_PS_NumElements
  74   };
  75 
  76   void worker_has_discovered_all_strong_classes();
  77   void wait_until_all_strong_classes_discovered();
  78 
  79   void process_all_roots(OopClosure* oops,
  80                          CLDClosure* clds,
  81                          CodeBlobClosure* blobs,
  82                          bool process_string_table);
  83 
  84   void process_java_roots(G1RootClosures* closures,
  85                           G1GCPhaseTimes* phase_times,
  86                           uint worker_i);
  87 
  88   void process_vm_roots(G1RootClosures* closures,
  89                         G1GCPhaseTimes* phase_times,
  90                         uint worker_i);
  91 
  92   void process_string_table_roots(G1RootClosures* closures,
  93                                   G1GCPhaseTimes* phase_times,
  94                                   uint worker_i);
  95 
  96   void process_code_cache_roots(CodeBlobClosure* code_closure,
  97                                 G1GCPhaseTimes* phase_times,
  98                                 uint worker_i);
  99 
 100 public:
 101   G1RootProcessor(G1CollectedHeap* g1h, uint n_workers);
 102 
 103   // Apply correct closures from pss to the strongly and weakly reachable roots in the system
 104   // in a single pass.
 105   // Record and report timing measurements for sub phases using the worker_i
 106   void evacuate_roots(G1ParScanThreadState* pss, uint worker_id);
 107 
 108   // Apply oops, clds and blobs to all strongly reachable roots in the system
 109   void process_strong_roots(OopClosure* oops,
 110                             CLDClosure* clds,
 111                             CodeBlobClosure* blobs);
 112 
 113   // Apply oops, clds and blobs to strongly and weakly reachable roots in the system
 114   void process_all_roots(OopClosure* oops,
 115                          CLDClosure* clds,
 116                          CodeBlobClosure* blobs);
 117 
 118   // Apply oops, clds and blobs to strongly and weakly reachable roots in the system,
 119   // the only thing different from process_all_roots is that we skip the string table
 120   // to avoid keeping every string live when doing class unloading.
 121   void process_all_roots_no_string_table(OopClosure* oops,
 122                                          CLDClosure* clds,
 123                                          CodeBlobClosure* blobs);
 124 
 125   // Apply closure to weak roots in the system. Used during the adjust phase
 126   // for the Full GC.
 127   void process_full_gc_weak_roots(OopClosure* oops);
 128 
 129   // Number of worker threads used by the root processor.
 130   uint n_workers() const;
 131 };
 132 
 133 #endif // SHARE_VM_GC_G1_G1ROOTPROCESSOR_HPP