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