gcCause.hpp revision 9056:dc9930a04ab0 
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24
25#ifndef SHARE_VM_GC_SHARED_GCCAUSE_HPP
26#define SHARE_VM_GC_SHARED_GCCAUSE_HPP
27
28#include "memory/allocation.hpp"
29
30//
31// This class exposes implementation details of the various
32// collector(s), and we need to be very careful with it. If
33// use of this class grows, we should split it into public
34// and implementation-private "causes".
35//
36
37class GCCause : public AllStatic {
38 public:
39  enum Cause {
40    /* public */
41    _java_lang_system_gc,
42    _full_gc_alot,
43    _scavenge_alot,
44    _allocation_profiler,
45    _jvmti_force_gc,
46    _gc_locker,
47    _heap_inspection,
48    _heap_dump,
49    _wb_young_gc,
50    _wb_conc_mark,
51    _update_allocation_context_stats_inc,
52    _update_allocation_context_stats_full,
53
54    /* implementation independent, but reserved for GC use */
55    _no_gc,
56    _no_cause_specified,
57    _allocation_failure,
58
59    /* implementation specific */
60
61    _tenured_generation_full,
62    _metadata_GC_threshold,
63
64    _cms_generation_full,
65    _cms_initial_mark,
66    _cms_final_remark,
67    _cms_concurrent_mark,
68
69    _old_generation_expanded_on_last_scavenge,
70    _old_generation_too_full_to_scavenge,
71    _adaptive_size_policy,
72
73    _g1_inc_collection_pause,
74    _g1_humongous_allocation,
75
76    _last_ditch_collection,
77
78    _dcmd_gc_run,
79
80    _last_gc_cause
81  };
82
83  inline static bool is_user_requested_gc(GCCause::Cause cause) {
84    return (cause == GCCause::_java_lang_system_gc ||
85            cause == GCCause::_dcmd_gc_run);
86  }
87
88  inline static bool is_serviceability_requested_gc(GCCause::Cause
89                                                             cause) {
90    return (cause == GCCause::_jvmti_force_gc ||
91            cause == GCCause::_heap_inspection ||
92            cause == GCCause::_heap_dump);
93  }
94
95  // Causes for collection of the tenured gernation
96  inline static bool is_tenured_allocation_failure_gc(GCCause::Cause cause) {
97    assert(cause != GCCause::_old_generation_too_full_to_scavenge &&
98           cause != GCCause::_old_generation_expanded_on_last_scavenge,
99           "This GCCause may be correct but is not expected yet: %s",
100           to_string(cause));
101    // _tenured_generation_full or _cms_generation_full for full tenured generations
102    // _adaptive_size_policy for a full collection after a young GC
103    // _allocation_failure is the generic cause a collection which could result
104    // in the collection of the tenured generation if there is not enough space
105    // in the tenured generation to support a young GC.
106    // _last_ditch_collection is a collection done to include SoftReferences.
107    return (cause == GCCause::_tenured_generation_full ||
108            cause == GCCause::_cms_generation_full ||
109            cause == GCCause::_adaptive_size_policy ||
110            cause == GCCause::_allocation_failure ||
111            cause == GCCause::_last_ditch_collection);
112  }
113
114  // Causes for collection of the young generation
115  inline static bool is_allocation_failure_gc(GCCause::Cause cause) {
116    // _allocation_failure is the generic cause a collection for allocation failure
117    // _adaptive_size_policy is for a collecton done before a full GC
118    // _last_ditch_collection is a collection done to include SoftReferences.
119    return (cause == GCCause::_allocation_failure ||
120            cause == GCCause::_adaptive_size_policy ||
121            cause == GCCause::_last_ditch_collection);
122  }
123
124  // Return a string describing the GCCause.
125  static const char* to_string(GCCause::Cause cause);
126};
127
128// Helper class for doing logging that includes the GC Cause
129// as a string.
130class GCCauseString : StackObj {
131 private:
132   static const int _length = 128;
133   char _buffer[_length];
134   int _position;
135
136 public:
137   GCCauseString(const char* prefix, GCCause::Cause cause) {
138     if (PrintGCCause) {
139      _position = jio_snprintf(_buffer, _length, "%s (%s) ", prefix, GCCause::to_string(cause));
140     } else {
141      _position = jio_snprintf(_buffer, _length, "%s ", prefix);
142     }
143     assert(_position >= 0 && _position <= _length,
144            "Need to increase the buffer size in GCCauseString? %d", _position);
145   }
146
147   GCCauseString& append(const char* str) {
148     int res = jio_snprintf(_buffer + _position, _length - _position, "%s", str);
149     _position += res;
150     assert(res >= 0 && _position <= _length,
151            "Need to increase the buffer size in GCCauseString? %d", res);
152     return *this;
153   }
154
155   operator const char*() {
156     return _buffer;
157   }
158};
159
160#endif // SHARE_VM_GC_SHARED_GCCAUSE_HPP
161