1 /*
   2  * Copyright (c) 2002, 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_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 
  37 class 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.
 130 class 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