1 /*
   2  * Copyright (c) 2014, 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_GC_IMPLEMENTATION_G1_G1CODECACHEREMSET_HPP
  26 #define SHARE_VM_GC_IMPLEMENTATION_G1_G1CODECACHEREMSET_HPP
  27 
  28 #include "memory/allocation.hpp"
  29 #include "memory/freeList.hpp"
  30 #include "runtime/globals.hpp"
  31 
  32 class CodeBlobClosure;
  33 
  34 class G1CodeRootChunk : public CHeapObj<mtGC> {
  35  private:
  36   static const int NUM_ENTRIES = 32;
  37  public:
  38   G1CodeRootChunk*     _next;
  39   G1CodeRootChunk*     _prev;
  40 
  41   nmethod** _top;
  42 
  43   nmethod* _data[NUM_ENTRIES];
  44 
  45   nmethod** bottom() const {
  46     return (nmethod**) &(_data[0]);
  47   }
  48 
  49   nmethod** end() const {
  50     return (nmethod**) &(_data[NUM_ENTRIES]);
  51   }
  52 
  53  public:
  54   G1CodeRootChunk();
  55   ~G1CodeRootChunk() {}
  56 
  57   static size_t word_size() { return (size_t)(align_size_up_(sizeof(G1CodeRootChunk), HeapWordSize) / HeapWordSize); }
  58 
  59   // FreeList "interface" methods
  60 
  61   G1CodeRootChunk* next() const         { return _next; }
  62   G1CodeRootChunk* prev() const         { return _prev; }
  63   void set_next(G1CodeRootChunk* v)     { _next = v; assert(v != this, "Boom");}
  64   void set_prev(G1CodeRootChunk* v)     { _prev = v; assert(v != this, "Boom");}
  65   void clear_next()       { set_next(NULL); }
  66   void clear_prev()       { set_prev(NULL); }
  67 
  68   size_t size() const { return word_size(); }
  69 
  70   void link_next(G1CodeRootChunk* ptr)  { set_next(ptr); }
  71   void link_prev(G1CodeRootChunk* ptr)  { set_prev(ptr); }
  72   void link_after(G1CodeRootChunk* ptr) {
  73     link_next(ptr);
  74     if (ptr != NULL) ptr->link_prev((G1CodeRootChunk*)this);
  75   }
  76 
  77   bool is_free()                 { return true; }
  78 
  79   // New G1CodeRootChunk routines
  80 
  81   void reset();
  82 
  83   bool is_empty() const {
  84     return _top == bottom();
  85   }
  86 
  87   bool is_full() const {
  88     return _top == (nmethod**)end();
  89   }
  90 
  91   bool contains(nmethod* method) {
  92     nmethod** cur = bottom();
  93     while (cur != _top) {
  94       if (*cur == method) return true;
  95       cur++;
  96     }
  97     return false;
  98   }
  99 
 100   bool add(nmethod* method) {
 101     if (is_full()) return false;
 102     *_top = method;
 103     _top++;
 104     return true;
 105   }
 106 
 107   bool remove(nmethod* method) {
 108     nmethod** cur = bottom();
 109     while (cur != _top) {
 110       if (*cur == method) {
 111         memmove(cur, cur + 1, (_top - (cur + 1)) * sizeof(nmethod**));
 112         _top--;
 113         return true;
 114       }
 115       cur++;
 116     }
 117     return false;
 118   }
 119 
 120   void nmethods_do(CodeBlobClosure* blk);
 121 
 122   nmethod* pop() {
 123     if (is_empty()) {
 124       return NULL;
 125     }
 126     _top--;
 127     return *_top;
 128   }
 129 };
 130 
 131 // Manages free chunks.
 132 class G1CodeRootChunkManager VALUE_OBJ_CLASS_SPEC {
 133  private:
 134   // Global free chunk list management
 135   FreeList<G1CodeRootChunk> _free_list;
 136   // Total number of chunks handed out
 137   size_t _num_chunks_handed_out;
 138 
 139  public:
 140   G1CodeRootChunkManager();
 141 
 142   G1CodeRootChunk* new_chunk();
 143   void free_chunk(G1CodeRootChunk* chunk);
 144   // Free all elements of the given list.
 145   void free_all_chunks(FreeList<G1CodeRootChunk>* list);
 146 
 147   void initialize();
 148   void purge_chunks(size_t keep_ratio);
 149 
 150   size_t static_mem_size();
 151   size_t fl_mem_size();
 152 
 153 #ifndef PRODUCT
 154   size_t num_chunks_handed_out() const;
 155   size_t num_free_chunks() const;
 156 #endif
 157 };
 158 
 159 // Implements storage for a set of code roots.
 160 // All methods that modify the set are not thread-safe except if otherwise noted.
 161 class G1CodeRootSet VALUE_OBJ_CLASS_SPEC {
 162  private:
 163   // Global default free chunk manager instance.
 164   static G1CodeRootChunkManager _default_chunk_manager;
 165 
 166   G1CodeRootChunk* new_chunk() { return _manager->new_chunk(); }
 167   void free_chunk(G1CodeRootChunk* chunk) { _manager->free_chunk(chunk); }
 168   // Free all elements of the given list.
 169   void free_all_chunks(FreeList<G1CodeRootChunk>* list) { _manager->free_all_chunks(list); }
 170 
 171   // Return the chunk that contains the given nmethod, NULL otherwise.
 172   // Scans the list of chunks backwards, as this method is used to add new
 173   // entries, which are typically added in bulk for a single nmethod.
 174   G1CodeRootChunk* find(nmethod* method);
 175   void free(G1CodeRootChunk* chunk);
 176 
 177   size_t _length;
 178   FreeList<G1CodeRootChunk> _list;
 179   G1CodeRootChunkManager* _manager;
 180 
 181  public:
 182   // If an instance is initialized with a chunk manager of NULL, use the global
 183   // default one.
 184   G1CodeRootSet(G1CodeRootChunkManager* manager = NULL);
 185   ~G1CodeRootSet();
 186 
 187   static void purge_chunks(size_t keep_ratio);
 188 
 189   static size_t static_mem_size();
 190   static size_t free_chunks_mem_size();
 191 
 192   // Search for the code blob from the recently allocated ones to find duplicates more quickly, as this
 193   // method is likely to be repeatedly called with the same nmethod.
 194   void add(nmethod* method);
 195 
 196   void remove(nmethod* method);
 197   nmethod* pop();
 198 
 199   bool contains(nmethod* method);
 200 
 201   void clear();
 202 
 203   void nmethods_do(CodeBlobClosure* blk) const;
 204 
 205   bool is_empty() { return length() == 0; }
 206 
 207   // Length in elements
 208   size_t length() const { return _length; }
 209 
 210   // Memory size in bytes taken by this set.
 211   size_t mem_size();
 212 
 213   static void test() PRODUCT_RETURN;
 214 };
 215 
 216 #endif // SHARE_VM_GC_IMPLEMENTATION_G1_G1CODECACHEREMSET_HPP