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
--- EOF ---