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(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
--- EOF ---