69 void G1YoungRemSetSamplingThread::stop_service() { |
69 void G1YoungRemSetSamplingThread::stop_service() { |
70 MutexLockerEx x(&_monitor, Mutex::_no_safepoint_check_flag); |
70 MutexLockerEx x(&_monitor, Mutex::_no_safepoint_check_flag); |
71 _monitor.notify(); |
71 _monitor.notify(); |
72 } |
72 } |
73 |
73 |
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74 class G1YoungRemSetSamplingClosure : public HeapRegionClosure { |
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75 SuspendibleThreadSetJoiner* _sts; |
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76 size_t _regions_visited; |
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77 size_t _sampled_rs_lengths; |
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78 public: |
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79 G1YoungRemSetSamplingClosure(SuspendibleThreadSetJoiner* sts) : |
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80 HeapRegionClosure(), _sts(sts), _regions_visited(0), _sampled_rs_lengths(0) { } |
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81 |
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82 virtual bool doHeapRegion(HeapRegion* r) { |
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83 size_t rs_length = r->rem_set()->occupied(); |
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84 _sampled_rs_lengths += rs_length; |
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85 |
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86 // Update the collection set policy information for this region |
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87 G1CollectedHeap::heap()->collection_set()->update_young_region_prediction(r, rs_length); |
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88 |
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89 _regions_visited++; |
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90 |
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91 if (_regions_visited == 10) { |
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92 if (_sts->should_yield()) { |
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93 _sts->yield(); |
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94 // A gc may have occurred and our sampling data is stale and further |
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95 // traversal of the collection set is unsafe |
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96 return true; |
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97 } |
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98 _regions_visited = 0; |
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99 } |
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100 return false; |
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101 } |
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102 |
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103 size_t sampled_rs_lengths() const { return _sampled_rs_lengths; } |
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104 }; |
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105 |
74 void G1YoungRemSetSamplingThread::sample_young_list_rs_lengths() { |
106 void G1YoungRemSetSamplingThread::sample_young_list_rs_lengths() { |
75 SuspendibleThreadSetJoiner sts; |
107 SuspendibleThreadSetJoiner sts; |
76 G1CollectedHeap* g1h = G1CollectedHeap::heap(); |
108 G1CollectedHeap* g1h = G1CollectedHeap::heap(); |
77 G1Policy* g1p = g1h->g1_policy(); |
109 G1Policy* g1p = g1h->g1_policy(); |
78 G1CollectionSet* g1cs = g1h->collection_set(); |
110 |
79 if (g1p->adaptive_young_list_length()) { |
111 if (g1p->adaptive_young_list_length()) { |
80 int regions_visited = 0; |
112 G1YoungRemSetSamplingClosure cl(&sts); |
81 HeapRegion* hr = g1cs->inc_head(); |
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82 size_t sampled_rs_lengths = 0; |
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83 |
113 |
84 while (hr != NULL) { |
114 G1CollectionSet* g1cs = g1h->collection_set(); |
85 size_t rs_length = hr->rem_set()->occupied(); |
115 g1cs->iterate(&cl); |
86 sampled_rs_lengths += rs_length; |
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87 |
116 |
88 // Update the collection set policy information for this region |
117 if (cl.complete()) { |
89 g1cs->update_young_region_prediction(hr, rs_length); |
118 g1p->revise_young_list_target_length_if_necessary(cl.sampled_rs_lengths()); |
90 |
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91 ++regions_visited; |
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92 |
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93 // we try to yield every time we visit 10 regions |
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94 if (regions_visited == 10) { |
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95 if (sts.should_yield()) { |
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96 sts.yield(); |
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97 // A gc may have occurred and our sampling data is stale and further |
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98 // traversal of the collection set is unsafe |
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99 return; |
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100 } |
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101 regions_visited = 0; |
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102 } |
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103 assert(hr == g1cs->inc_tail() || hr->next_in_collection_set() != NULL, "next should only be null at tail of icset"); |
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104 hr = hr->next_in_collection_set(); |
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105 } |
119 } |
106 g1p->revise_young_list_target_length_if_necessary(sampled_rs_lengths); |
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107 } |
120 } |
108 } |
121 } |