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