1 /*
2 * Copyright (c) 2014, 2017, 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_SERVICES_MALLOC_SITE_TABLE_HPP
26 #define SHARE_VM_SERVICES_MALLOC_SITE_TABLE_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 private:
41 MEMFLAGS _flags;
42
43 public:
44 MallocSite() :
45 AllocationSite<MemoryCounter>(NativeCallStack::EMPTY_STACK), _flags(mtNone) {}
46
47 MallocSite(const NativeCallStack& stack, MEMFLAGS flags) :
48 AllocationSite<MemoryCounter>(stack), _flags(flags) {}
49
50
51 void allocate(size_t size) { data()->allocate(size); }
52 void deallocate(size_t size) { data()->deallocate(size); }
53
54 // Memory allocated from this code path
55 size_t size() const { return peek()->size(); }
56 // The number of calls were made
57 size_t count() const { return peek()->count(); }
58 MEMFLAGS flags() const { return (MEMFLAGS)_flags; }
59 };
60
61 // Malloc site hashtable entry
62 class MallocSiteHashtableEntry : public CHeapObj<mtNMT> {
63 private:
64 MallocSite _malloc_site;
65 MallocSiteHashtableEntry* _next;
66
67 public:
68 MallocSiteHashtableEntry() : _next(NULL) { }
69
70 MallocSiteHashtableEntry(NativeCallStack stack, MEMFLAGS flags):
71 _malloc_site(stack, flags), _next(NULL) {
72 assert(flags != mtNone, "Expect a real memory type");
73 }
74
75 inline const MallocSiteHashtableEntry* next() const {
76 return _next;
77 }
78
79 // Insert an entry atomically.
80 // Return true if the entry is inserted successfully.
81 // The operation can be failed due to contention from other thread.
82 bool atomic_insert(const MallocSiteHashtableEntry* entry) {
83 return (Atomic::cmpxchg_ptr((void*)entry, (volatile void*)&_next,
84 NULL) == NULL);
85 }
86
87 void set_callsite(const MallocSite& site) {
88 _malloc_site = site;
89 }
90
91 inline const MallocSite* peek() const { return &_malloc_site; }
92 inline MallocSite* data() { return &_malloc_site; }
93
94 inline long hash() const { return _malloc_site.hash(); }
95 inline bool equals(const NativeCallStack& stack) const {
96 return _malloc_site.equals(stack);
97 }
98 // Allocation/deallocation on this allocation site
99 inline void allocate(size_t size) { _malloc_site.allocate(size); }
100 inline void deallocate(size_t size) { _malloc_site.deallocate(size); }
101 // Memory counters
102 inline size_t size() const { return _malloc_site.size(); }
103 inline size_t count() const { return _malloc_site.count(); }
104 };
105
106 // The walker walks every entry on MallocSiteTable
107 class MallocSiteWalker : public StackObj {
108 public:
109 virtual bool do_malloc_site(const MallocSite* e) { return false; }
110 };
111
112 /*
113 * Native memory tracking call site table.
114 * The table is only needed when detail tracking is enabled.
115 */
116 class MallocSiteTable : AllStatic {
117 private:
118 // The number of hash bucket in this hashtable. The number should
119 // be tuned if malloc activities changed significantly.
120 // The statistics data can be obtained via Jcmd
121 // jcmd <pid> VM.native_memory statistics.
122
123 // Currently, (number of buckets / number of entires) ratio is
124 // about 1 / 6
125 enum {
126 table_base_size = 128, // The base size is calculated from statistics to give
127 // table ratio around 1:6
128 table_size = (table_base_size * NMT_TrackingStackDepth - 1)
129 };
130
131
132 // This is a very special lock, that allows multiple shared accesses (sharedLock), but
133 // once exclusive access (exclusiveLock) is requested, all shared accesses are
134 // rejected forever.
135 class AccessLock : public StackObj {
136 enum LockState {
137 NoLock,
138 SharedLock,
139 ExclusiveLock
140 };
141
142 private:
143 // A very large negative number. The only possibility to "overflow"
144 // this number is when there are more than -min_jint threads in
145 // this process, which is not going to happen in foreseeable future.
146 const static int _MAGIC_ = min_jint;
147
148 LockState _lock_state;
149 volatile int* _lock;
150 public:
151 AccessLock(volatile int* lock) :
152 _lock(lock), _lock_state(NoLock) {
153 }
154
155 ~AccessLock() {
156 if (_lock_state == SharedLock) {
157 Atomic::dec((volatile jint*)_lock);
158 }
159 }
160 // Acquire shared lock.
161 // Return true if shared access is granted.
162 inline bool sharedLock() {
163 jint res = Atomic::add(1, _lock);
164 if (res < 0) {
165 Atomic::add(-1, _lock);
166 return false;
167 }
168 _lock_state = SharedLock;
169 return true;
170 }
171 // Acquire exclusive lock
172 void exclusiveLock();
173 };
174
175 public:
176 static bool initialize();
177 static void shutdown();
178
179 NOT_PRODUCT(static int access_peak_count() { return _peak_count; })
180
181 // Number of hash buckets
182 static inline int hash_buckets() { return (int)table_size; }
183
184 // Access and copy a call stack from this table. Shared lock should be
185 // acquired before access the entry.
186 static inline bool access_stack(NativeCallStack& stack, size_t bucket_idx,
187 size_t pos_idx) {
188 AccessLock locker(&_access_count);
189 if (locker.sharedLock()) {
190 NOT_PRODUCT(_peak_count = MAX2(_peak_count, _access_count);)
191 MallocSite* site = malloc_site(bucket_idx, pos_idx);
192 if (site != NULL) {
193 stack = *site->call_stack();
194 return true;
195 }
196 }
197 return false;
198 }
199
200 // Record a new allocation from specified call path.
201 // Return true if the allocation is recorded successfully, bucket_idx
202 // and pos_idx are also updated to indicate the entry where the allocation
203 // information was recorded.
204 // Return false only occurs under rare scenarios:
205 // 1. out of memory
206 // 2. overflow hash bucket
207 static inline bool allocation_at(const NativeCallStack& stack, size_t size,
208 size_t* bucket_idx, size_t* pos_idx, MEMFLAGS flags) {
209 AccessLock locker(&_access_count);
210 if (locker.sharedLock()) {
211 NOT_PRODUCT(_peak_count = MAX2(_peak_count, _access_count);)
212 MallocSite* site = lookup_or_add(stack, bucket_idx, pos_idx, flags);
213 if (site != NULL) site->allocate(size);
214 return site != NULL;
215 }
216 return false;
217 }
218
219 // Record memory deallocation. bucket_idx and pos_idx indicate where the allocation
220 // information was recorded.
221 static inline bool deallocation_at(size_t size, size_t bucket_idx, size_t pos_idx) {
222 AccessLock locker(&_access_count);
223 if (locker.sharedLock()) {
224 NOT_PRODUCT(_peak_count = MAX2(_peak_count, _access_count);)
225 MallocSite* site = malloc_site(bucket_idx, pos_idx);
226 if (site != NULL) {
227 site->deallocate(size);
228 return true;
229 }
230 }
231 return false;
232 }
233
234 // Walk this table.
235 static bool walk_malloc_site(MallocSiteWalker* walker);
236
237 private:
238 static MallocSiteHashtableEntry* new_entry(const NativeCallStack& key, MEMFLAGS flags);
239 static void reset();
240
241 // Delete a bucket linked list
242 static void delete_linked_list(MallocSiteHashtableEntry* head);
243
244 static MallocSite* lookup_or_add(const NativeCallStack& key, size_t* bucket_idx, size_t* pos_idx, MEMFLAGS flags);
245 static MallocSite* malloc_site(size_t bucket_idx, size_t pos_idx);
246 static bool walk(MallocSiteWalker* walker);
247
248 static inline unsigned int hash_to_index(unsigned int hash) {
249 return (hash % table_size);
250 }
251
252 static inline const NativeCallStack* hash_entry_allocation_stack() {
253 return (NativeCallStack*)_hash_entry_allocation_stack;
254 }
255
256 private:
257 // Counter for counting concurrent access
258 static volatile int _access_count;
259
260 // The callsite hashtable. It has to be a static table,
261 // since malloc call can come from C runtime linker.
262 static MallocSiteHashtableEntry* _table[table_size];
263
264
265 // Reserve enough memory for placing the objects
266
267 // The memory for hashtable entry allocation stack object
268 static size_t _hash_entry_allocation_stack[CALC_OBJ_SIZE_IN_TYPE(NativeCallStack, size_t)];
269 // The memory for hashtable entry allocation callsite object
270 static size_t _hash_entry_allocation_site[CALC_OBJ_SIZE_IN_TYPE(MallocSiteHashtableEntry, size_t)];
271 NOT_PRODUCT(static int _peak_count;)
272 };
273
274 #endif // INCLUDE_NMT
275 #endif // SHARE_VM_SERVICES_MALLOC_SITE_TABLE_HPP