1 /*
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   3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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   6  * under the terms of the GNU General Public License version 2 only, as
   7  * published by the Free Software Foundation.
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   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).
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  17  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
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  20  * or visit www.oracle.com if you need additional information or have any
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  24 
  25 #ifndef SHARE_VM_CODE_CODECACHE_HPP
  26 #define SHARE_VM_CODE_CODECACHE_HPP
  27 
  28 #include "code/codeBlob.hpp"
  29 #include "code/nmethod.hpp"
  30 #include "memory/allocation.hpp"
  31 #include "memory/heap.hpp"
  32 #include "oops/instanceKlass.hpp"
  33 #include "oops/oopsHierarchy.hpp"
  34 #include "runtime/mutexLocker.hpp"
  35 
  36 // The CodeCache implements the code cache for various pieces of generated
  37 // code, e.g., compiled java methods, runtime stubs, transition frames, etc.
  38 // The entries in the CodeCache are all CodeBlob's.
  39 
  40 // -- Implementation --
  41 // The CodeCache consists of one or more CodeHeaps, each of which contains
  42 // CodeBlobs of a specific CodeBlobType. Currently heaps for the following
  43 // types are available:
  44 //  - Non-nmethods: Non-nmethods like Buffers, Adapters and Runtime Stubs
  45 //  - Profiled nmethods: nmethods that are profiled, i.e., those
  46 //    executed at level 2 or 3
  47 //  - Non-Profiled nmethods: nmethods that are not profiled, i.e., those
  48 //    executed at level 1 or 4 and native methods
  49 //  - All: Used for code of all types if code cache segmentation is disabled.
  50 //
  51 // In the rare case of the non-nmethod code heap getting full, non-nmethod code
  52 // will be stored in the non-profiled code heap as a fallback solution.
  53 //
  54 // Depending on the availability of compilers and TieredCompilation there
  55 // may be fewer heaps. The size of the code heaps depends on the values of
  56 // ReservedCodeCacheSize, NonProfiledCodeHeapSize and ProfiledCodeHeapSize
  57 // (see CodeCache::heap_available(..) and CodeCache::initialize_heaps(..)
  58 // for details).
  59 //
  60 // Code cache segmentation is controlled by the flag SegmentedCodeCache.
  61 // If turned off, all code types are stored in a single code heap. By default
  62 // code cache segmentation is turned on if TieredCompilation is enabled and
  63 // ReservedCodeCacheSize >= 240 MB.
  64 //
  65 // All methods of the CodeCache accepting a CodeBlobType only apply to
  66 // CodeBlobs of the given type. For example, iteration over the
  67 // CodeBlobs of a specific type can be done by using CodeCache::first_blob(..)
  68 // and CodeCache::next_blob(..) and providing the corresponding CodeBlobType.
  69 //
  70 // IMPORTANT: If you add new CodeHeaps to the code cache or change the
  71 // existing ones, make sure to adapt the dtrace scripts (jhelper.d) for
  72 // Solaris and BSD.
  73 
  74 class OopClosure;
  75 class DepChange;
  76 
  77 class CodeCache : AllStatic {
  78   friend class VMStructs;
  79   friend class NMethodIterator;
  80  private:
  81   // CodeHeaps of the cache
  82   static GrowableArray<CodeHeap*>* _heaps;
  83 
  84   static address _low_bound;                            // Lower bound of CodeHeap addresses
  85   static address _high_bound;                           // Upper bound of CodeHeap addresses
  86   static int _number_of_blobs;                          // Total number of CodeBlobs in the cache
  87   static int _number_of_adapters;                       // Total number of Adapters in the cache
  88   static int _number_of_nmethods;                       // Total number of nmethods in the cache
  89   static int _number_of_nmethods_with_dependencies;     // Total number of nmethods with dependencies
  90   static bool _needs_cache_clean;                       // True if inline caches of the nmethods needs to be flushed
  91   static nmethod* _scavenge_root_nmethods;              // linked via nm->scavenge_root_link()
  92   static int _codemem_full_count;                       // Number of times a CodeHeap in the cache was full
  93 
  94   static void mark_scavenge_root_nmethods() PRODUCT_RETURN;
  95   static void verify_perm_nmethods(CodeBlobClosure* f_or_null) PRODUCT_RETURN;
  96 
  97   // CodeHeap management
  98   static void initialize_heaps();                             // Initializes the CodeHeaps
  99   // Creates a new heap with the given name and size, containing CodeBlobs of the given type
 100   static void add_heap(ReservedSpace rs, const char* name, size_t size_initial, int code_blob_type);
 101   static CodeHeap* get_code_heap(CodeBlob* cb);               // Returns the CodeHeap for the given CodeBlob
 102   static CodeHeap* get_code_heap(int code_blob_type);         // Returns the CodeHeap for the given CodeBlobType
 103   static bool heap_available(int code_blob_type);             // Returns true if a CodeHeap for the given CodeBlobType is available
 104   static ReservedCodeSpace reserve_heap_memory(size_t size);  // Reserves one continuous chunk of memory for the CodeHeaps
 105 
 106   // Iteration
 107   static CodeBlob* first_blob(CodeHeap* heap);                // Returns the first CodeBlob on the given CodeHeap
 108   static CodeBlob* first_blob(int code_blob_type);            // Returns the first CodeBlob of the given type
 109   static CodeBlob* next_blob(CodeHeap* heap, CodeBlob* cb);   // Returns the first alive CodeBlob on the given CodeHeap
 110   static CodeBlob* next_blob(CodeBlob* cb);                   // Returns the next CodeBlob of the given type succeeding the given CodeBlob
 111 
 112   static size_t bytes_allocated_in_freelists();
 113   static int    allocated_segments();
 114   static size_t freelists_length();
 115 
 116  public:
 117   // Initialization
 118   static void initialize();
 119 
 120   // Allocation/administration
 121   static CodeBlob* allocate(int size, int code_blob_type, bool is_critical = false); // allocates a new CodeBlob
 122   static void commit(CodeBlob* cb);                     // called when the allocated CodeBlob has been filled
 123   static int  alignment_unit();                         // guaranteed alignment of all CodeBlobs
 124   static int  alignment_offset();                       // guaranteed offset of first CodeBlob byte within alignment unit (i.e., allocation header)
 125   static void free(CodeBlob* cb);                       // frees a CodeBlob
 126   static bool contains(void *p);                        // returns whether p is included
 127   static void blobs_do(void f(CodeBlob* cb));           // iterates over all CodeBlobs
 128   static void blobs_do(CodeBlobClosure* f);             // iterates over all CodeBlobs
 129   static void nmethods_do(void f(nmethod* nm));         // iterates over all nmethods
 130   static void alive_nmethods_do(void f(nmethod* nm));   // iterates over all alive nmethods
 131 
 132   // Lookup
 133   static CodeBlob* find_blob(void* start);              // Returns the CodeBlob containing the given address
 134   static CodeBlob* find_blob_unsafe(void* start);       // Same as find_blob but does not fail if looking up a zombie method
 135   static nmethod*  find_nmethod(void* start);           // Returns the nmethod containing the given address
 136 
 137   static int       nof_blobs()      { return _number_of_blobs; }      // Returns the total number of CodeBlobs in the cache
 138   static int       nof_adapters()   { return _number_of_adapters; }   // Returns the total number of Adapters in the cache
 139   static int       nof_nmethods()   { return _number_of_nmethods; }   // Returns the total number of nmethods in the cache
 140 
 141   // GC support
 142   static void gc_epilogue();
 143   static void gc_prologue();
 144   static void verify_oops();
 145   // If "unloading_occurred" is true, then unloads (i.e., breaks root links
 146   // to) any unmarked codeBlobs in the cache.  Sets "marked_for_unloading"
 147   // to "true" iff some code got unloaded.
 148   static void do_unloading(BoolObjectClosure* is_alive, bool unloading_occurred);
 149   static void asserted_non_scavengable_nmethods_do(CodeBlobClosure* f = NULL) PRODUCT_RETURN;
 150   static void scavenge_root_nmethods_do(CodeBlobClosure* f);
 151 
 152   static nmethod* scavenge_root_nmethods()            { return _scavenge_root_nmethods; }
 153   static void set_scavenge_root_nmethods(nmethod* nm) { _scavenge_root_nmethods = nm; }
 154   static void add_scavenge_root_nmethod(nmethod* nm);
 155   static void drop_scavenge_root_nmethod(nmethod* nm);
 156   static void prune_scavenge_root_nmethods();
 157 
 158   // Printing/debugging
 159   static void print();                           // prints summary
 160   static void print_internals();
 161   static void print_memory_overhead();
 162   static void verify();                          // verifies the code cache
 163   static void print_trace(const char* event, CodeBlob* cb, int size = 0) PRODUCT_RETURN;
 164   static void print_summary(outputStream* st, bool detailed = true); // Prints a summary of the code cache usage
 165   static void log_state(outputStream* st);
 166   static const char* get_code_heap_name(int code_blob_type)  { return (heap_available(code_blob_type) ? get_code_heap(code_blob_type)->name() : "Unused"); }
 167   static void report_codemem_full(int code_blob_type, bool print);
 168 
 169   // Dcmd (Diagnostic commands)
 170   static void print_codelist(outputStream* st);
 171   static void print_layout(outputStream* st);
 172 
 173   // The full limits of the codeCache
 174   static address low_bound()                          { return _low_bound; }
 175   static address high_bound()                         { return _high_bound; }
 176 
 177   // Profiling
 178   static size_t capacity(int code_blob_type)             { return heap_available(code_blob_type) ? get_code_heap(code_blob_type)->capacity() : 0; }
 179   static size_t capacity();
 180   static size_t unallocated_capacity(int code_blob_type) { return heap_available(code_blob_type) ? get_code_heap(code_blob_type)->unallocated_capacity() : 0; }
 181   static size_t unallocated_capacity();
 182   static size_t max_capacity(int code_blob_type)         { return heap_available(code_blob_type) ? get_code_heap(code_blob_type)->max_capacity() : 0; }
 183   static size_t max_capacity();
 184 
 185   static bool   is_full(int* code_blob_type);
 186   static double reverse_free_ratio(int code_blob_type);
 187 
 188   static bool needs_cache_clean()                     { return _needs_cache_clean; }
 189   static void set_needs_cache_clean(bool v)           { _needs_cache_clean = v;    }
 190   static void clear_inline_caches();                  // clear all inline caches
 191 
 192   // Returns the CodeBlobType for nmethods of the given compilation level
 193   static int get_code_blob_type(int comp_level) {
 194     if (comp_level == CompLevel_none ||
 195         comp_level == CompLevel_simple ||
 196         comp_level == CompLevel_full_optimization) {
 197       // Non profiled methods
 198       return CodeBlobType::MethodNonProfiled;
 199     } else if (comp_level == CompLevel_limited_profile ||
 200                comp_level == CompLevel_full_profile) {
 201       // Profiled methods
 202       return CodeBlobType::MethodProfiled;
 203     }
 204     ShouldNotReachHere();
 205     return 0;
 206   }
 207 
 208   static void verify_clean_inline_caches();
 209   static void verify_icholder_relocations();
 210 
 211   // Deoptimization
 212   static int  mark_for_deoptimization(DepChange& changes);
 213 #ifdef HOTSWAP
 214   static int  mark_for_evol_deoptimization(instanceKlassHandle dependee);
 215 #endif // HOTSWAP
 216 
 217   static void mark_all_nmethods_for_deoptimization();
 218   static int  mark_for_deoptimization(Method* dependee);
 219   static void make_marked_nmethods_zombies();
 220   static void make_marked_nmethods_not_entrant();
 221 
 222   // tells how many nmethods have dependencies
 223   static int number_of_nmethods_with_dependencies();
 224 
 225   static int get_codemem_full_count() { return _codemem_full_count; }
 226 };
 227 
 228 
 229 // Iterator to iterate over nmethods in the CodeCache.
 230 class NMethodIterator : public StackObj {
 231  private:
 232   CodeBlob* _code_blob;   // Current CodeBlob
 233   int _code_blob_type;    // Refers to current CodeHeap
 234 
 235  public:
 236   NMethodIterator() {
 237     initialize(NULL); // Set to NULL, initialized by first call to next()
 238   }
 239 
 240   NMethodIterator(nmethod* nm) {
 241     initialize(nm);
 242   }
 243 
 244   // Advance iterator to next nmethod
 245   bool next() {
 246     assert_locked_or_safepoint(CodeCache_lock);
 247     assert(_code_blob_type < CodeBlobType::NumTypes, "end reached");
 248 
 249     bool result = next_nmethod();
 250     while (!result && (_code_blob_type < CodeBlobType::MethodProfiled)) {
 251       // Advance to next code heap if segmented code cache
 252       _code_blob_type++;
 253       result = next_nmethod();
 254     }
 255     return result;
 256   }
 257 
 258   // Advance iterator to next alive nmethod
 259   bool next_alive() {
 260     bool result = next();
 261     while(result && !_code_blob->is_alive()) {
 262       result = next();
 263     }
 264     return result;
 265   }
 266 
 267   bool end()        const   { return _code_blob == NULL; }
 268   nmethod* method() const   { return (nmethod*)_code_blob; }
 269 
 270 private:
 271   // Initialize iterator to given nmethod
 272   void initialize(nmethod* nm) {
 273     _code_blob = (CodeBlob*)nm;
 274     if (!SegmentedCodeCache) {
 275       // Iterate over all CodeBlobs
 276       _code_blob_type = CodeBlobType::All;
 277     } else if (nm != NULL) {
 278       _code_blob_type = CodeCache::get_code_blob_type(nm->comp_level());
 279     } else {
 280       // Only iterate over method code heaps, starting with non-profiled
 281       _code_blob_type = CodeBlobType::MethodNonProfiled;
 282     }
 283   }
 284 
 285   // Advance iterator to the next nmethod in the current code heap
 286   bool next_nmethod() {
 287     // Get first method CodeBlob
 288     if (_code_blob == NULL) {
 289       _code_blob = CodeCache::first_blob(_code_blob_type);
 290       if (_code_blob == NULL) {
 291         return false;
 292       } else if (_code_blob->is_nmethod()) {
 293         return true;
 294       }
 295     }
 296     // Search for next method CodeBlob
 297     _code_blob = CodeCache::next_blob(_code_blob);
 298     while (_code_blob != NULL && !_code_blob->is_nmethod()) {
 299       _code_blob = CodeCache::next_blob(_code_blob);
 300     }
 301     return _code_blob != NULL;
 302   }
 303 };
 304 
 305 #endif // SHARE_VM_CODE_CODECACHE_HPP