1 /*
2 * Copyright (c) 1999, 2019, 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.
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23 */
24
25 #ifndef SHARE_GC_SHARED_THREADLOCALALLOCBUFFER_HPP
26 #define SHARE_GC_SHARED_THREADLOCALALLOCBUFFER_HPP
27
28 #include "gc/shared/gcUtil.hpp"
29 #include "runtime/perfData.hpp"
30 #include "runtime/vm_version.hpp"
31
32 class ThreadLocalAllocStats;
33
34 // ThreadLocalAllocBuffer: a descriptor for thread-local storage used by
35 // the threads for allocation.
36 // It is thread-private at any time, but maybe multiplexed over
37 // time across multiple threads. The park()/unpark() pair is
38 // used to make it available for such multiplexing.
39 //
40 // Heap sampling is performed via the end and allocation_end
41 // fields.
42 // allocation_end contains the real end of the tlab allocation,
43 // whereas end can be set to an arbitrary spot in the tlab to
44 // trip the return and sample the allocation.
45 class ThreadLocalAllocBuffer: public CHeapObj<mtThread> {
46 friend class VMStructs;
47 friend class JVMCIVMStructs;
48 private:
49 HeapWord* _start; // address of TLAB
50 HeapWord* _top; // address after last allocation
51 HeapWord* _pf_top; // allocation prefetch watermark
52 HeapWord* _end; // allocation end (can be the sampling end point or _allocation_end)
53 HeapWord* _allocation_end; // end for allocations (actual TLAB end, excluding alignment_reserve)
54
55 size_t _desired_size; // desired size (including alignment_reserve)
56 size_t _refill_waste_limit; // hold onto tlab if free() is larger than this
57 size_t _allocated_before_last_gc; // total bytes allocated up until the last gc
58 size_t _bytes_since_last_sample_point; // bytes since last sample point.
59
60 static size_t _max_size; // maximum size of any TLAB
61 static int _reserve_for_allocation_prefetch; // Reserve at the end of the TLAB
62 static unsigned _target_refills; // expected number of refills between GCs
63
64 unsigned _number_of_refills;
65 unsigned _refill_waste;
66 unsigned _gc_waste;
67 unsigned _slow_allocations;
68 size_t _allocated_size;
69
70 AdaptiveWeightedAverage _allocation_fraction; // fraction of eden allocated in tlabs
71
72 void reset_statistics();
73
74 void set_start(HeapWord* start) { _start = start; }
75 void set_end(HeapWord* end) { _end = end; }
76 void set_allocation_end(HeapWord* ptr) { _allocation_end = ptr; }
77 void set_top(HeapWord* top) { _top = top; }
78 void set_pf_top(HeapWord* pf_top) { _pf_top = pf_top; }
79 void set_desired_size(size_t desired_size) { _desired_size = desired_size; }
80 void set_refill_waste_limit(size_t waste) { _refill_waste_limit = waste; }
81
82 size_t initial_refill_waste_limit() { return desired_size() / TLABRefillWasteFraction; }
83
84 static int target_refills() { return _target_refills; }
85 size_t initial_desired_size();
86
87 size_t remaining();
88
89 // Make parsable and release it.
90 void reset();
91
92 void invariants() const { assert(top() >= start() && top() <= end(), "invalid tlab"); }
93
94 void initialize(HeapWord* start, HeapWord* top, HeapWord* end);
95
96 void insert_filler();
97
98 void accumulate_and_reset_statistics(ThreadLocalAllocStats* stats);
99
100 void print_stats(const char* tag);
101
102 Thread* thread();
103 public:
104 ThreadLocalAllocBuffer() : _allocated_before_last_gc(0), _allocation_fraction(TLABAllocationWeight) {
105 // do nothing. tlabs must be inited by initialize() calls
106 }
107
108 static size_t min_size() { return align_object_size(MinTLABSize / HeapWordSize) + alignment_reserve(); }
109 static size_t max_size() { assert(_max_size != 0, "max_size not set up"); return _max_size; }
110 static size_t max_size_in_bytes() { return max_size() * BytesPerWord; }
111 static void set_max_size(size_t max_size) { _max_size = max_size; }
112
113 HeapWord* start() const { return _start; }
114 HeapWord* end() const { return _end; }
115 HeapWord* top() const { return _top; }
116 HeapWord* hard_end();
117 HeapWord* pf_top() const { return _pf_top; }
118 size_t desired_size() const { return _desired_size; }
119 size_t used() const { return pointer_delta(top(), start()); }
120 size_t used_bytes() const { return pointer_delta(top(), start(), 1); }
121 size_t free() const { return pointer_delta(end(), top()); }
122 // Don't discard tlab if remaining space is larger than this.
123 size_t refill_waste_limit() const { return _refill_waste_limit; }
124 size_t bytes_since_last_sample_point() const { return _bytes_since_last_sample_point; }
125
126 // Allocate size HeapWords. The memory is NOT initialized to zero.
127 inline HeapWord* allocate(size_t size);
128
129 // Reserve space at the end of TLAB
130 static size_t end_reserve();
131 static size_t alignment_reserve() { return align_object_size(end_reserve()); }
132 static size_t alignment_reserve_in_bytes() { return alignment_reserve() * HeapWordSize; }
133
134 // Return tlab size or remaining space in eden such that the
135 // space is large enough to hold obj_size and necessary fill space.
136 // Otherwise return 0;
137 inline size_t compute_size(size_t obj_size);
138
139 // Compute the minimal needed tlab size for the given object size.
140 static inline size_t compute_min_size(size_t obj_size);
141
142 // Record slow allocation
143 inline void record_slow_allocation(size_t obj_size);
144
145 // Initialization at startup
146 static void startup_initialization();
147
148 // Make an in-use tlab parsable.
149 void make_parsable();
150
151 // Retire an in-use tlab and optionally collect statistics.
152 void retire(ThreadLocalAllocStats* stats = NULL);
153
154 // Retire in-use tlab before allocation of a new tlab
155 void retire_before_allocation();
156
157 // Resize based on amount of allocation, etc.
158 void resize();
159
160 void fill(HeapWord* start, HeapWord* top, size_t new_size);
161 void initialize();
162
163 void set_back_allocation_end();
164 void set_sample_end();
165
166 static size_t refill_waste_limit_increment() { return TLABWasteIncrement; }
167
168 template <typename T> void addresses_do(T f) {
169 f(&_start);
170 f(&_top);
171 f(&_pf_top);
172 f(&_end);
173 f(&_allocation_end);
174 }
175
176 // Code generation support
177 static ByteSize start_offset() { return byte_offset_of(ThreadLocalAllocBuffer, _start); }
178 static ByteSize end_offset() { return byte_offset_of(ThreadLocalAllocBuffer, _end); }
179 static ByteSize top_offset() { return byte_offset_of(ThreadLocalAllocBuffer, _top); }
180 static ByteSize pf_top_offset() { return byte_offset_of(ThreadLocalAllocBuffer, _pf_top); }
181 };
182
183 class ThreadLocalAllocStats : public StackObj {
184 private:
185 static PerfVariable* _perf_allocating_threads;
186 static PerfVariable* _perf_total_refills;
187 static PerfVariable* _perf_max_refills;
188 static PerfVariable* _perf_total_allocations;
189 static PerfVariable* _perf_total_gc_waste;
190 static PerfVariable* _perf_max_gc_waste;
191 static PerfVariable* _perf_total_refill_waste;
192 static PerfVariable* _perf_max_refill_waste;
193 static PerfVariable* _perf_total_slow_allocations;
194 static PerfVariable* _perf_max_slow_allocations;
195
196 static AdaptiveWeightedAverage _allocating_threads_avg;
197
198 unsigned int _allocating_threads;
199 unsigned int _total_refills;
200 unsigned int _max_refills;
201 size_t _total_allocations;
202 size_t _total_gc_waste;
203 size_t _max_gc_waste;
204 size_t _total_refill_waste;
205 size_t _max_refill_waste;
206 unsigned int _total_slow_allocations;
207 unsigned int _max_slow_allocations;
208
209 public:
210 static void initialize();
211 static unsigned int allocating_threads_avg();
212
213 ThreadLocalAllocStats();
214
215 void update_fast_allocations(unsigned int refills,
216 size_t allocations,
217 size_t gc_waste,
218 size_t refill_waste);
219 void update_slow_allocations(unsigned int allocations);
220 void update(const ThreadLocalAllocStats& other);
221
222 void reset();
223 void publish();
224 };
225
226 #endif // SHARE_GC_SHARED_THREADLOCALALLOCBUFFER_HPP