1 /*
 2  * Copyright (c) 2014, 2020, 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_JFR_LEAKPROFILER_SAMPLING_OBJECTSAMPLER_HPP
26 #define SHARE_JFR_LEAKPROFILER_SAMPLING_OBJECTSAMPLER_HPP
27 
28 #include "jfr/utilities/jfrBlob.hpp"
29 #include "memory/allocation.hpp"
30 
31 typedef u8 traceid;
32 
33 class JavaThread;
34 class OopStorage;
35 class ObjectSample;
36 class SampleList;
37 class SamplePriorityQueue;
38 
39 // Class reponsible for holding samples and
40 // making sure the samples are evenly distributed as
41 // new entries are added and removed.
42 class ObjectSampler : public CHeapObj<mtTracing> {
43   friend class JfrRecorder;
44   friend class LeakProfiler;
45   friend class ObjectSample;
46   friend class StartOperation;
47   friend class StopOperation;
48  private:
49   SamplePriorityQueue* _priority_queue;
50   SampleList* _list;
51   size_t _total_allocated;
52   size_t _threshold;
53   size_t _size;
54 
55   // Lifecycle
56   explicit ObjectSampler(size_t size);
57   ~ObjectSampler();
58   static bool create(size_t size);
59   static bool is_created();
60   static void destroy();
61 
62   // Sampling
63   static void sample(HeapWord* object, size_t size, JavaThread* thread);
64   void add(HeapWord* object, size_t size, traceid thread_id, bool virtual_thread, const JfrBlobHandle& bh, JavaThread* thread);
65   void scavenge();
66   void remove_dead(ObjectSample* sample);
67 
68   const ObjectSample* item_at(int index) const;
69   ObjectSample* item_at(int index);
70   int item_count() const;
71 
72   // OopStorage
73   static bool create_oop_storage();
74   static OopStorage* oop_storage();
75   // Invoked by the GC post oop storage processing.
76   static void oop_storage_gc_notification(size_t num_dead);
77 
78  public:
79   static ObjectSampler* sampler();
80   // For operations that require exclusive access (non-safepoint)
81   static ObjectSampler* acquire();
82   static void release();
83   static int64_t last_sweep();
84   const ObjectSample* first() const;
85   ObjectSample* last() const;
86   const ObjectSample* last_resolved() const;
87   void set_last_resolved(const ObjectSample* sample);
88 };
89 
90 #endif // SHARE_JFR_LEAKPROFILER_SAMPLING_OBJECTSAMPLER_HPP