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 G1GCPhaseTimes;
  36 class G1ParPushHeapRSClosure;
  37 class Monitor;
  38 class OopClosure;
  39 class SubTasksDone;
  40 
  41 // Scoped object to assist in applying oop, CLD and code blob closures to
  42 // root locations. Handles claiming of different root scanning tasks
  43 // and takes care of global state for root scanning via a StrongRootsScope.
  44 // In the parallel case there is a shared G1RootProcessor object where all
  45 // worker thread call the process_roots methods.
  46 class G1RootProcessor : public StackObj {
  47   G1CollectedHeap* _g1h;
  48   SubTasksDone* _process_strong_tasks;
  49   StrongRootsScope _srs;
  50 
  51   // Used to implement the Thread work barrier.
  52   Monitor _lock;
  53   volatile jint _n_workers_discovered_strong_classes;
  54 
  55   enum G1H_process_roots_tasks {
  56     G1RP_PS_Universe_oops_do,
  57     G1RP_PS_JNIHandles_oops_do,
  58     G1RP_PS_ObjectSynchronizer_oops_do,
  59     G1RP_PS_FlatProfiler_oops_do,
  60     G1RP_PS_Management_oops_do,
  61     G1RP_PS_SystemDictionary_oops_do,
  62     G1RP_PS_ClassLoaderDataGraph_oops_do,
  63     G1RP_PS_jvmti_oops_do,
  64     G1RP_PS_CodeCache_oops_do,
  65     G1RP_PS_filter_satb_buffers,
  66     G1RP_PS_refProcessor_oops_do,
  67     // Leave this one last.
  68     G1RP_PS_NumElements
  69   };
  70 
  71   void worker_has_discovered_all_strong_classes();
  72   void wait_until_all_strong_classes_discovered();
  73 
  74   void process_java_roots(OopClosure* scan_non_heap_roots,
  75                           CLDClosure* thread_stack_clds,
  76                           CLDClosure* scan_strong_clds,
  77                           CLDClosure* scan_weak_clds,
  78                           CodeBlobClosure* scan_strong_code,
  79                           G1GCPhaseTimes* phase_times,
  80                           uint worker_i);
  81 
  82   void process_vm_roots(OopClosure* scan_non_heap_roots,
  83                         OopClosure* scan_non_heap_weak_roots,
  84                         G1GCPhaseTimes* phase_times,
  85                         uint worker_i);
  86 
  87 public:
  88   G1RootProcessor(G1CollectedHeap* g1h, uint n_workers);
  89 
  90   // Apply closures to the strongly and weakly reachable roots in the system
  91   // in a single pass.
  92   // Record and report timing measurements for sub phases using the worker_i
  93   void evacuate_roots(OopClosure* scan_non_heap_roots,
  94                       OopClosure* scan_non_heap_weak_roots,
  95                       CLDClosure* scan_strong_clds,
  96                       CLDClosure* scan_weak_clds,
  97                       bool trace_metadata,
  98                       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 scan_rs to all locations in the union of the remembered sets for all
 111   // regions in the collection set
 112   // (having done "set_region" to indicate the region in which the root resides),
 113   void scan_remembered_sets(G1ParPushHeapRSClosure* scan_rs,
 114                             OopClosure* scan_non_heap_weak_roots,
 115                             uint worker_i);
 116 
 117   // Inform SubTaskDone about the number of worker threads.
 118   void set_num_workers(uint active_workers);
 119 
 120   // Number of worker threads used by the root processor.
 121   uint n_workers() const;
 122 };
 123 
 124 #endif // SHARE_VM_GC_G1_G1ROOTPROCESSOR_HPP