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