1 /*
2 * Copyright (c) 2014, 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.
22 *
23 */
24
25 #ifndef SHARE_SERVICES_MALLOCSITETABLE_HPP
26 #define SHARE_SERVICES_MALLOCSITETABLE_HPP
27
28 #if INCLUDE_NMT
29
30 #include "memory/allocation.hpp"
31 #include "runtime/atomic.hpp"
32 #include "services/allocationSite.hpp"
33 #include "services/mallocTracker.hpp"
34 #include "services/nmtCommon.hpp"
35 #include "utilities/nativeCallStack.hpp"
36
37 // MallocSite represents a code path that eventually calls
38 // os::malloc() to allocate memory
39 class MallocSite : public AllocationSite<MemoryCounter> {
40 public:
41 MallocSite() :
42 AllocationSite<MemoryCounter>(NativeCallStack::empty_stack(), mtNone) {}
43
44 MallocSite(const NativeCallStack& stack, MEMFLAGS flags) :
45 AllocationSite<MemoryCounter>(stack, flags) {}
46
47
48 void allocate(size_t size) { data()->allocate(size); }
49 void deallocate(size_t size) { data()->deallocate(size); }
50
51 // Memory allocated from this code path
52 size_t size() const { return peek()->size(); }
53 // The number of calls were made
54 size_t count() const { return peek()->count(); }
55 };
56
57 // Malloc site hashtable entry
58 class MallocSiteHashtableEntry : public CHeapObj<mtNMT> {
59 private:
60 MallocSite _malloc_site;
61 MallocSiteHashtableEntry* volatile _next;
62
63 public:
64 MallocSiteHashtableEntry() : _next(NULL) { }
65
66 MallocSiteHashtableEntry(NativeCallStack stack, MEMFLAGS flags):
67 _malloc_site(stack, flags), _next(NULL) {
68 assert(flags != mtNone, "Expect a real memory type");
69 }
70
71 inline const MallocSiteHashtableEntry* next() const {
72 return _next;
73 }
74
75 // Insert an entry atomically.
76 // Return true if the entry is inserted successfully.
77 // The operation can be failed due to contention from other thread.
78 bool atomic_insert(MallocSiteHashtableEntry* entry);
79
80 void set_callsite(const MallocSite& site) {
81 _malloc_site = site;
82 }
83
84 inline const MallocSite* peek() const { return &_malloc_site; }
85 inline MallocSite* data() { return &_malloc_site; }
86
87 inline long hash() const { return _malloc_site.hash(); }
88 inline bool equals(const NativeCallStack& stack) const {
89 return _malloc_site.equals(stack);
90 }
91 // Allocation/deallocation on this allocation site
92 inline void allocate(size_t size) { _malloc_site.allocate(size); }
93 inline void deallocate(size_t size) { _malloc_site.deallocate(size); }
94 // Memory counters
95 inline size_t size() const { return _malloc_site.size(); }
96 inline size_t count() const { return _malloc_site.count(); }
97 };
98
99 // The walker walks every entry on MallocSiteTable
100 class MallocSiteWalker : public StackObj {
101 public:
102 virtual bool do_malloc_site(const MallocSite* e) { return false; }
103 };
104
105 /*
106 * Native memory tracking call site table.
107 * The table is only needed when detail tracking is enabled.
108 */
109 class MallocSiteTable : AllStatic {
110 private:
111 // The number of hash bucket in this hashtable. The number should
112 // be tuned if malloc activities changed significantly.
113 // The statistics data can be obtained via Jcmd
114 // jcmd <pid> VM.native_memory statistics.
115
116 // Currently, (number of buckets / number of entires) ratio is
117 // about 1 / 6
118 enum {
119 table_base_size = 128, // The base size is calculated from statistics to give
120 // table ratio around 1:6
121 table_size = (table_base_size * NMT_TrackingStackDepth - 1)
122 };
123
124
125 // This is a very special lock, that allows multiple shared accesses (sharedLock), but
126 // once exclusive access (exclusiveLock) is requested, all shared accesses are
127 // rejected forever.
128 class AccessLock : public StackObj {
129 enum LockState {
130 NoLock,
131 SharedLock,
132 ExclusiveLock
133 };
134
135 private:
136 // A very large negative number. The only possibility to "overflow"
137 // this number is when there are more than -min_jint threads in
138 // this process, which is not going to happen in foreseeable future.
139 const static int _MAGIC_ = min_jint;
140
141 LockState _lock_state;
142 volatile int* _lock;
143 public:
144 AccessLock(volatile int* lock) :
145 _lock_state(NoLock), _lock(lock) {
146 }
147
148 ~AccessLock() {
149 if (_lock_state == SharedLock) {
150 Atomic::dec(_lock);
151 }
152 }
153 // Acquire shared lock.
154 // Return true if shared access is granted.
155 inline bool sharedLock() {
156 jint res = Atomic::add(_lock, 1);
157 if (res < 0) {
158 Atomic::dec(_lock);
159 return false;
160 }
161 _lock_state = SharedLock;
162 return true;
163 }
164 // Acquire exclusive lock
165 void exclusiveLock();
166 };
167
168 public:
169 static bool initialize();
170 static void shutdown();
171
172 NOT_PRODUCT(static int access_peak_count() { return _peak_count; })
173
174 // Number of hash buckets
175 static inline int hash_buckets() { return (int)table_size; }
176
177 // Access and copy a call stack from this table. Shared lock should be
178 // acquired before access the entry.
179 static inline bool access_stack(NativeCallStack& stack, size_t bucket_idx,
180 size_t pos_idx) {
181 AccessLock locker(&_access_count);
182 if (locker.sharedLock()) {
183 NOT_PRODUCT(_peak_count = MAX2(_peak_count, _access_count);)
184 MallocSite* site = malloc_site(bucket_idx, pos_idx);
185 if (site != NULL) {
186 stack = *site->call_stack();
187 return true;
188 }
189 }
190 return false;
191 }
192
193 // Record a new allocation from specified call path.
194 // Return true if the allocation is recorded successfully, bucket_idx
195 // and pos_idx are also updated to indicate the entry where the allocation
196 // information was recorded.
197 // Return false only occurs under rare scenarios:
198 // 1. out of memory
199 // 2. overflow hash bucket
200 static inline bool allocation_at(const NativeCallStack& stack, size_t size,
201 size_t* bucket_idx, size_t* pos_idx, MEMFLAGS flags) {
202 AccessLock locker(&_access_count);
203 if (locker.sharedLock()) {
204 NOT_PRODUCT(_peak_count = MAX2(_peak_count, _access_count);)
205 MallocSite* site = lookup_or_add(stack, bucket_idx, pos_idx, flags);
206 if (site != NULL) site->allocate(size);
207 return site != NULL;
208 }
209 return false;
210 }
211
212 // Record memory deallocation. bucket_idx and pos_idx indicate where the allocation
213 // information was recorded.
214 static inline bool deallocation_at(size_t size, size_t bucket_idx, size_t pos_idx) {
215 AccessLock locker(&_access_count);
216 if (locker.sharedLock()) {
217 NOT_PRODUCT(_peak_count = MAX2(_peak_count, _access_count);)
218 MallocSite* site = malloc_site(bucket_idx, pos_idx);
219 if (site != NULL) {
220 site->deallocate(size);
221 return true;
222 }
223 }
224 return false;
225 }
226
227 // Walk this table.
228 static bool walk_malloc_site(MallocSiteWalker* walker);
229
230 private:
231 static MallocSiteHashtableEntry* new_entry(const NativeCallStack& key, MEMFLAGS flags);
232 static void reset();
233
234 // Delete a bucket linked list
235 static void delete_linked_list(MallocSiteHashtableEntry* head);
236
237 static MallocSite* lookup_or_add(const NativeCallStack& key, size_t* bucket_idx, size_t* pos_idx, MEMFLAGS flags);
238 static MallocSite* malloc_site(size_t bucket_idx, size_t pos_idx);
239 static bool walk(MallocSiteWalker* walker);
240
241 static inline unsigned int hash_to_index(unsigned int hash) {
242 return (hash % table_size);
243 }
244
245 static inline const NativeCallStack* hash_entry_allocation_stack() {
246 assert(_hash_entry_allocation_stack != NULL, "Must be set");
247 return _hash_entry_allocation_stack;
248 }
249
250 static inline const MallocSiteHashtableEntry* hash_entry_allocation_site() {
251 assert(_hash_entry_allocation_site != NULL, "Must be set");
252 return _hash_entry_allocation_site;
253 }
254
255 private:
256 // Counter for counting concurrent access
257 static volatile int _access_count;
258
259 // The callsite hashtable. It has to be a static table,
260 // since malloc call can come from C runtime linker.
261 static MallocSiteHashtableEntry* _table[table_size];
262 static const NativeCallStack* _hash_entry_allocation_stack;
263 static const MallocSiteHashtableEntry* _hash_entry_allocation_site;
264
265
266 NOT_PRODUCT(static int _peak_count;)
267 };
268
269 #endif // INCLUDE_NMT
270 #endif // SHARE_SERVICES_MALLOCSITETABLE_HPP