1/*
2 * Copyright (c) 2017, 2018, Red Hat, Inc. All rights reserved.
3 *
4 * This code is free software; you can redistribute it and/or modify it
5 * under the terms of the GNU General Public License version 2 only, as
6 * published by the Free Software Foundation.
7 *
8 * This code is distributed in the hope that it will be useful, but WITHOUT
9 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
10 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
11 * version 2 for more details (a copy is included in the LICENSE file that
12 * accompanied this code).
13 *
14 * You should have received a copy of the GNU General Public License version
15 * 2 along with this work; if not, write to the Free Software Foundation,
16 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
17 *
18 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
19 * or visit www.oracle.com if you need additional information or have any
20 * questions.
21 *
22 */
23
24#ifndef SHARE_GC_EPSILON_EPSILONHEAP_HPP
25#define SHARE_GC_EPSILON_EPSILONHEAP_HPP
26
27#include "gc/shared/collectedHeap.hpp"
28#include "gc/shared/softRefPolicy.hpp"
29#include "gc/shared/space.hpp"
30#include "gc/epsilon/epsilonMonitoringSupport.hpp"
31#include "gc/epsilon/epsilonBarrierSet.hpp"
32#include "services/memoryManager.hpp"
33
34class EpsilonHeap : public CollectedHeap {
35 friend class VMStructs;
36private:
37 SoftRefPolicy _soft_ref_policy;
38 EpsilonMonitoringSupport* _monitoring_support;
39 MemoryPool* _pool;
40 GCMemoryManager _memory_manager;
41 ContiguousSpace* _space;
42 VirtualSpace _virtual_space;
43 size_t _max_tlab_size;
44 size_t _step_counter_update;
45 size_t _step_heap_print;
46 int64_t _decay_time_ns;
47 volatile size_t _last_counter_update;
48 volatile size_t _last_heap_print;
49
50public:
51 static EpsilonHeap* heap();
52
53 EpsilonHeap() :
54 _memory_manager("Epsilon Heap", "") {};
55
56 virtual Name kind() const {
57 return CollectedHeap::Epsilon;
58 }
59
60 virtual const char* name() const {
61 return "Epsilon";
62 }
63
64 virtual SoftRefPolicy* soft_ref_policy() {
65 return &_soft_ref_policy;
66 }
67
68 virtual jint initialize();
69 virtual void post_initialize();
70 virtual void initialize_serviceability();
71
72 virtual GrowableArray<GCMemoryManager*> memory_managers();
73 virtual GrowableArray<MemoryPool*> memory_pools();
74
75 virtual size_t max_capacity() const { return _virtual_space.reserved_size(); }
76 virtual size_t capacity() const { return _virtual_space.committed_size(); }
77 virtual size_t used() const { return _space->used(); }
78
79 virtual bool is_in(const void* p) const {
80 return _space->is_in(p);
81 }
82
83 virtual bool is_maximal_no_gc() const {
84 // No GC is going to happen. Return "we are at max", when we are about to fail.
85 return used() == capacity();
86 }
87
88 // Allocation
89 HeapWord* allocate_work(size_t size);
90 virtual HeapWord* mem_allocate(size_t size, bool* gc_overhead_limit_was_exceeded);
91 virtual HeapWord* allocate_new_tlab(size_t min_size,
92 size_t requested_size,
93 size_t* actual_size);
94
95 // TLAB allocation
96 virtual bool supports_tlab_allocation() const { return true; }
97 virtual size_t tlab_capacity(Thread* thr) const { return capacity(); }
98 virtual size_t tlab_used(Thread* thr) const { return used(); }
99 virtual size_t max_tlab_size() const { return _max_tlab_size; }
100 virtual size_t unsafe_max_tlab_alloc(Thread* thr) const;
101
102 virtual void collect(GCCause::Cause cause);
103 virtual void do_full_collection(bool clear_all_soft_refs);
104
105 // Heap walking support
106 virtual void safe_object_iterate(ObjectClosure* cl);
107 virtual void object_iterate(ObjectClosure* cl) {
108 safe_object_iterate(cl);
109 }
110
111 // Object pinning support: every object is implicitly pinned
112 virtual bool supports_object_pinning() const { return true; }
113 virtual oop pin_object(JavaThread* thread, oop obj) { return obj; }
114 virtual void unpin_object(JavaThread* thread, oop obj) { }
115
116 // No support for block parsing.
117 virtual HeapWord* block_start(const void* addr) const { return NULL; }
118 virtual bool block_is_obj(const HeapWord* addr) const { return false; }
119
120 // No GC threads
121 virtual void print_gc_threads_on(outputStream* st) const {}
122 virtual void gc_threads_do(ThreadClosure* tc) const {}
123
124 // No nmethod handling
125 virtual void register_nmethod(nmethod* nm) {}
126 virtual void unregister_nmethod(nmethod* nm) {}
127 virtual void flush_nmethod(nmethod* nm) {}
128 virtual void verify_nmethod(nmethod* nm) {}
129
130 // No heap verification
131 virtual void prepare_for_verify() {}
132 virtual void verify(VerifyOption option) {}
133
134 virtual jlong millis_since_last_gc() {
135 // Report time since the VM start
136 return os::elapsed_counter() / NANOSECS_PER_MILLISEC;
137 }
138
139 virtual void print_on(outputStream* st) const;
140 virtual void print_tracing_info() const;
141
142private:
143 void print_heap_info(size_t used) const;
144 void print_metaspace_info() const;
145
146};
147
148#endif // SHARE_GC_EPSILON_EPSILONHEAP_HPP
149