1 /*
   2  * Copyright (c) 2014, 2018, 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
  21  * questions.
  22  *
  23  */
  24 
  25 #ifndef SHARE_VM_LEAKPROFILER_SAMPLING_OBJECTSAMPLER_HPP
  26 #define SHARE_VM_LEAKPROFILER_SAMPLING_OBJECTSAMPLER_HPP
  27 
  28 #include "memory/allocation.hpp"
  29 #include "jfr/utilities/jfrTime.hpp"
  30 
  31 typedef u8 traceid;
  32 
  33 class BoolObjectClosure;
  34 class JfrStackTrace;
  35 class OopClosure;
  36 class ObjectSample;
  37 class ObjectSampler;
  38 class SampleList;
  39 class SamplePriorityQueue;
  40 class Thread;
  41 
  42 // Class reponsible for holding samples and
  43 // making sure the samples are evenly distributed as
  44 // new entries are added and removed.
  45 class ObjectSampler : public CHeapObj<mtTracing> {
  46   friend class EventEmitter;
  47   friend class JfrRecorderService;
  48   friend class LeakProfiler;
  49   friend class StartOperation;
  50   friend class StopOperation;
  51   friend class ObjectSampleCheckpoint;
  52   friend class WriteObjectSampleStacktrace;
  53  private:
  54   SamplePriorityQueue* _priority_queue;
  55   SampleList* _list;
  56   JfrTicks _last_sweep;
  57   size_t _total_allocated;
  58   size_t _threshold;
  59   size_t _size;
  60   bool _dead_samples;
  61 
  62   // Lifecycle
  63   explicit ObjectSampler(size_t size);
  64   ~ObjectSampler();
  65   static bool create(size_t size);
  66   static bool is_created();
  67   static ObjectSampler* sampler();
  68   static void destroy();
  69 
  70   // For operations that require exclusive access (non-safepoint)
  71   static ObjectSampler* acquire();
  72   static void release();
  73 
  74   // Stacktrace
  75   static void fill_stacktrace(JfrStackTrace* stacktrace, JavaThread* thread);
  76   traceid stacktrace_id(const JfrStackTrace* stacktrace, JavaThread* thread);
  77 
  78   // Sampling
  79   static void sample(HeapWord* object, size_t size, JavaThread* thread);
  80   void add(HeapWord* object, size_t size, traceid thread_id/*, JfrStackTrace* stacktrace*/, JavaThread* thread);
  81   void scavenge();
  82   void remove_dead(ObjectSample* sample);
  83 
  84   // Called by GC
  85   static void oops_do(BoolObjectClosure* is_alive, OopClosure* f);
  86 
  87   const ObjectSample* item_at(int index) const;
  88   ObjectSample* item_at(int index);
  89   int item_count() const;
  90   const ObjectSample* first() const;
  91   const ObjectSample* last() const;
  92   const ObjectSample* last_resolved() const;
  93   void set_last_resolved(const ObjectSample* sample);
  94   const JfrTicks& last_sweep() const;
  95 };
  96 
  97 #endif // SHARE_VM_LEAKPROFILER_SAMPLING_OBJECTSAMPLER_HPP