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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 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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 24 
 25 #ifndef SHARE_CODE_CODECACHE_HPP
 26 #define SHARE_CODE_CODECACHE_HPP
 27 
 28 #include "code/codeBlob.hpp"
 29 #include "code/nmethod.hpp"
 30 #include "gc/shared/gcBehaviours.hpp"
 31 #include "memory/allocation.hpp"
 32 #include "memory/heap.hpp"
 33 #include "oops/instanceKlass.hpp"
 34 #include "oops/oopsHierarchy.hpp"
 35 #include "runtime/mutexLocker.hpp"
 36 #include "utilities/numberSeq.hpp"
 37 
 38 // The CodeCache implements the code cache for various pieces of generated
 39 // code, e.g., compiled java methods, runtime stubs, transition frames, etc.
 40 // The entries in the CodeCache are all CodeBlob's.
 41 
 42 // -- Implementation --
 43 // The CodeCache consists of one or more CodeHeaps, each of which contains
 44 // CodeBlobs of a specific CodeBlobType. Currently heaps for the following
 45 // types are available:
 46 //  - Non-nmethods: Non-nmethods like Buffers, Adapters and Runtime Stubs
 47 //  - Profiled nmethods: nmethods that are profiled, i.e., those
 48 //    executed at level 2 or 3
 49 //  - Non-Profiled nmethods: nmethods that are not profiled, i.e., those
 50 //    executed at level 1 or 4 and native methods
 51 //  - All: Used for code of all types if code cache segmentation is disabled.
 52 //
 53 // In the rare case of the non-nmethod code heap getting full, non-nmethod code
 54 // will be stored in the non-profiled code heap as a fallback solution.
 55 //
 56 // Depending on the availability of compilers and compilation mode there
 57 // may be fewer heaps. The size of the code heaps depends on the values of
 58 // ReservedCodeCacheSize, NonProfiledCodeHeapSize and ProfiledCodeHeapSize
 59 // (see CodeCache::heap_available(..) and CodeCache::initialize_heaps(..)
 60 // for details).
 61 //
 62 // Code cache segmentation is controlled by the flag SegmentedCodeCache.
 63 // If turned off, all code types are stored in a single code heap. By default
 64 // code cache segmentation is turned on if tiered mode is enabled and
 65 // ReservedCodeCacheSize >= 240 MB.
 66 //
 67 // All methods of the CodeCache accepting a CodeBlobType only apply to
 68 // CodeBlobs of the given type. For example, iteration over the
 69 // CodeBlobs of a specific type can be done by using CodeCache::first_blob(..)
 70 // and CodeCache::next_blob(..) and providing the corresponding CodeBlobType.
 71 //
 72 // IMPORTANT: If you add new CodeHeaps to the code cache or change the
 73 // existing ones, make sure to adapt the dtrace scripts (jhelper.d) for
 74 // Solaris and BSD.
 75 
 76 class ExceptionCache;
 77 class KlassDepChange;
 78 class OopClosure;
 79 class ShenandoahParallelCodeHeapIterator;
 80 class NativePostCallNop;
 81 class DeoptimizationScope;
 82 
 83 class CodeCache : AllStatic {
 84   friend class VMStructs;
 85   friend class JVMCIVMStructs;
 86   template <class T, class Filter, bool is_compiled_method> friend class CodeBlobIterator;
 87   friend class WhiteBox;
 88   friend class CodeCacheLoader;
 89   friend class ShenandoahParallelCodeHeapIterator;
 90  private:
 91   // CodeHeaps of the cache
 92   static GrowableArray<CodeHeap*>* _heaps;
 93   static GrowableArray<CodeHeap*>* _compiled_heaps;
 94   static GrowableArray<CodeHeap*>* _nmethod_heaps;
 95   static GrowableArray<CodeHeap*>* _allocable_heaps;
 96 
 97   static address _low_bound;                                 // Lower bound of CodeHeap addresses
 98   static address _high_bound;                                // Upper bound of CodeHeap addresses
 99   static volatile int _number_of_nmethods_with_dependencies; // Total number of nmethods with dependencies
100 
101   static uint8_t           _unloading_cycle;          // Global state for recognizing old nmethods that need to be unloaded
102   static uint64_t          _gc_epoch;                 // Global state for tracking when nmethods were found to be on-stack
103   static uint64_t          _cold_gc_count;            // Global state for determining how many GCs are needed before an nmethod is cold
104   static size_t            _last_unloading_used;
105   static double            _last_unloading_time;
106   static TruncatedSeq      _unloading_gc_intervals;
107   static TruncatedSeq      _unloading_allocation_rates;
108   static volatile bool     _unloading_threshold_gc_requested;
109 
110   static ExceptionCache* volatile _exception_cache_purge_list;
111 
112   // CodeHeap management
113   static void initialize_heaps();                             // Initializes the CodeHeaps
114   // Check the code heap sizes set by the user via command line
115   static void check_heap_sizes(size_t non_nmethod_size, size_t profiled_size, size_t non_profiled_size, size_t cache_size, bool all_set);
116   // Creates a new heap with the given name and size, containing CodeBlobs of the given type
117   static void add_heap(ReservedSpace rs, const char* name, CodeBlobType code_blob_type);
118   static CodeHeap* get_code_heap_containing(void* p);         // Returns the CodeHeap containing the given pointer, or nullptr
119   static CodeHeap* get_code_heap(const void* cb);             // Returns the CodeHeap for the given CodeBlob
120   static CodeHeap* get_code_heap(CodeBlobType code_blob_type);         // Returns the CodeHeap for the given CodeBlobType
121   // Returns the name of the VM option to set the size of the corresponding CodeHeap
122   static const char* get_code_heap_flag_name(CodeBlobType code_blob_type);
123   static ReservedCodeSpace reserve_heap_memory(size_t size, size_t rs_ps); // Reserves one continuous chunk of memory for the CodeHeaps
124 
125   // Iteration
126   static CodeBlob* first_blob(CodeHeap* heap);                // Returns the first CodeBlob on the given CodeHeap
127   static CodeBlob* first_blob(CodeBlobType code_blob_type);            // Returns the first CodeBlob of the given type
128   static CodeBlob* next_blob(CodeHeap* heap, CodeBlob* cb);   // Returns the next CodeBlob on the given CodeHeap
129 
130  private:
131   static size_t bytes_allocated_in_freelists();
132   static int    allocated_segments();
133   static size_t freelists_length();
134 
135   // Make private to prevent unsafe calls.  Not all CodeBlob*'s are embedded in a CodeHeap.
136   static bool contains(CodeBlob *p) { fatal("don't call me!"); return false; }
137 
138  public:
139   // Initialization
140   static void initialize();
141   static size_t page_size(bool aligned = true, size_t min_pages = 1); // Returns the page size used by the CodeCache
142 
143   static int code_heap_compare(CodeHeap* const &lhs, CodeHeap* const &rhs);
144 
145   static void add_heap(CodeHeap* heap);
146   static const GrowableArray<CodeHeap*>* heaps() { return _heaps; }
147   static const GrowableArray<CodeHeap*>* compiled_heaps() { return _compiled_heaps; }
148   static const GrowableArray<CodeHeap*>* nmethod_heaps() { return _nmethod_heaps; }
149 
150   // Allocation/administration
151   static CodeBlob* allocate(uint size, CodeBlobType code_blob_type, bool handle_alloc_failure = true, CodeBlobType orig_code_blob_type = CodeBlobType::All); // allocates a new CodeBlob
152   static void commit(CodeBlob* cb);                        // called when the allocated CodeBlob has been filled
153   static void free(CodeBlob* cb);                          // frees a CodeBlob
154   static void free_unused_tail(CodeBlob* cb, size_t used); // frees the unused tail of a CodeBlob (only used by TemplateInterpreter::initialize())
155   static bool contains(void *p);                           // returns whether p is included
156   static bool contains(nmethod* nm);                       // returns whether nm is included
157   static void blobs_do(void f(CodeBlob* cb));              // iterates over all CodeBlobs
158   static void blobs_do(CodeBlobClosure* f);                // iterates over all CodeBlobs
159   static void nmethods_do(void f(nmethod* nm));            // iterates over all nmethods
160   static void metadata_do(MetadataClosure* f);             // iterates over metadata in alive nmethods
161 
162   // Lookup
163   static CodeBlob* find_blob(void* start);              // Returns the CodeBlob containing the given address
164   static CodeBlob* find_blob_fast(void* start);         // Returns the CodeBlob containing the given address
165   static CodeBlob* find_blob_and_oopmap(void* start, int& slot);         // Returns the CodeBlob containing the given address
166   static int find_oopmap_slot_fast(void* start);        // Returns a fast oopmap slot if there is any; -1 otherwise
167   static nmethod*  find_nmethod(void* start);           // Returns the nmethod containing the given address
168   static CompiledMethod* find_compiled(void* start);
169 
170   static int       blob_count();                        // Returns the total number of CodeBlobs in the cache
171   static int       blob_count(CodeBlobType code_blob_type);
172   static int       adapter_count();                     // Returns the total number of Adapters in the cache
173   static int       adapter_count(CodeBlobType code_blob_type);
174   static int       nmethod_count();                     // Returns the total number of nmethods in the cache
175   static int       nmethod_count(CodeBlobType code_blob_type);
176 
177   // GC support
178   static void verify_oops();
179 
180   // Helper scope object managing code cache unlinking behavior, i.e. sets and
181   // restores the closure that determines which nmethods are going to be removed
182   // during the unlinking part of code cache unloading.
183   class UnlinkingScope : StackObj {
184     ClosureIsUnloadingBehaviour _is_unloading_behaviour;
185     IsUnloadingBehaviour*       _saved_behaviour;
186 
187   public:
188     UnlinkingScope(BoolObjectClosure* is_alive);
189     ~UnlinkingScope();
190   };
191 
192   // Code cache unloading heuristics
193   static uint64_t cold_gc_count();
194   static void update_cold_gc_count();
195   static void gc_on_allocation();
196 
197   // The GC epoch and marking_cycle code below is there to support sweeping
198   // nmethods in loom stack chunks.
199   static uint64_t gc_epoch();
200   static bool is_gc_marking_cycle_active();
201   static uint64_t previous_completed_gc_marking_cycle();
202   static void on_gc_marking_cycle_start();
203   static void on_gc_marking_cycle_finish();
204   // Arm nmethods so that special actions are taken (nmethod_entry_barrier) for
205   // on-stack nmethods. It's used in two places:
206   // 1. Used before the start of concurrent marking so that oops inside
207   //    on-stack nmethods are visited.
208   // 2. Used at the end of (stw/concurrent) marking so that nmethod::_gc_epoch
209   //    is up-to-date, which provides more accurate estimate of
210   //    nmethod::is_cold.
211   static void arm_all_nmethods();
212 
213   static void maybe_restart_compiler(size_t freed_memory);
214   static void do_unloading(bool unloading_occurred);
215   static uint8_t unloading_cycle() { return _unloading_cycle; }
216 
217   static void increment_unloading_cycle();
218 
219   static void release_exception_cache(ExceptionCache* entry);
220   static void purge_exception_caches();
221 
222   // Printing/debugging
223   static void print();                           // prints summary
224   static void print_internals();
225   static void print_memory_overhead();
226   static void verify();                          // verifies the code cache
227   static void print_trace(const char* event, CodeBlob* cb, uint size = 0) PRODUCT_RETURN;
228   static void print_summary(outputStream* st, bool detailed = true); // Prints a summary of the code cache usage
229   static void log_state(outputStream* st);
230   LINUX_ONLY(static void write_perf_map(const char* filename = nullptr);)
231   static const char* get_code_heap_name(CodeBlobType code_blob_type)  { return (heap_available(code_blob_type) ? get_code_heap(code_blob_type)->name() : "Unused"); }
232   static void report_codemem_full(CodeBlobType code_blob_type, bool print);
233 
234   // Dcmd (Diagnostic commands)
235   static void print_codelist(outputStream* st);
236   static void print_layout(outputStream* st);
237 
238   // The full limits of the codeCache
239   static address low_bound()                          { return _low_bound; }
240   static address low_bound(CodeBlobType code_blob_type);
241   static address high_bound()                         { return _high_bound; }
242   static address high_bound(CodeBlobType code_blob_type);
243 
244   // Profiling
245   static size_t capacity();
246   static size_t unallocated_capacity(CodeBlobType code_blob_type);
247   static size_t unallocated_capacity();
248   static size_t max_capacity();
249 
250   static double reverse_free_ratio();
251 
252   static size_t max_distance_to_non_nmethod();
253   static bool is_non_nmethod(address addr);
254 
255   static void clear_inline_caches();                  // clear all inline caches
256   static void cleanup_inline_caches_whitebox();       // clean bad nmethods from inline caches
257 
258   // Returns true if an own CodeHeap for the given CodeBlobType is available
259   static bool heap_available(CodeBlobType code_blob_type);
260 
261   // Returns the CodeBlobType for the given CompiledMethod
262   static CodeBlobType get_code_blob_type(CompiledMethod* cm) {
263     return get_code_heap(cm)->code_blob_type();
264   }
265 
266   static bool code_blob_type_accepts_compiled(CodeBlobType code_blob_type) {
267     bool result = code_blob_type == CodeBlobType::All || code_blob_type <= CodeBlobType::MethodProfiled;
268     return result;
269   }
270 
271   static bool code_blob_type_accepts_nmethod(CodeBlobType type) {
272     return type == CodeBlobType::All || type <= CodeBlobType::MethodProfiled;
273   }
274 
275   static bool code_blob_type_accepts_allocable(CodeBlobType type) {
276     return type <= CodeBlobType::All;
277   }
278 
279 
280   // Returns the CodeBlobType for the given compilation level
281   static CodeBlobType get_code_blob_type(int comp_level) {
282     if (comp_level == CompLevel_none ||
283         comp_level == CompLevel_simple ||
284         comp_level == CompLevel_full_optimization) {
285       // Non profiled methods
286       return CodeBlobType::MethodNonProfiled;
287     } else if (comp_level == CompLevel_limited_profile ||
288                comp_level == CompLevel_full_profile) {
289       // Profiled methods
290       return CodeBlobType::MethodProfiled;
291     }
292     ShouldNotReachHere();
293     return static_cast<CodeBlobType>(0);
294   }
295 
296   static void verify_clean_inline_caches();
297   static void verify_icholder_relocations();
298 
299   // Deoptimization
300  private:
301   static void mark_for_deoptimization(DeoptimizationScope* deopt_scope, KlassDepChange& changes);
302 
303  public:
304   static void mark_all_nmethods_for_deoptimization(DeoptimizationScope* deopt_scope);
305   static void mark_for_deoptimization(DeoptimizationScope* deopt_scope, Method* dependee);
306   static void make_marked_nmethods_deoptimized();
307 
308   // Marks dependents during classloading
309   static void mark_dependents_on(DeoptimizationScope* deopt_scope, InstanceKlass* dependee);
310 
311   // RedefineClasses support
312   // Marks in case of evolution
313   static void mark_dependents_for_evol_deoptimization(DeoptimizationScope* deopt_scope);
314   static void mark_all_nmethods_for_evol_deoptimization(DeoptimizationScope* deopt_scope);
315   static void old_nmethods_do(MetadataClosure* f) NOT_JVMTI_RETURN;
316   static void unregister_old_nmethod(CompiledMethod* c) NOT_JVMTI_RETURN;
317 
318   // Support for fullspeed debugging
319   static void mark_dependents_on_method_for_breakpoint(const methodHandle& dependee);
320 
321   // tells if there are nmethods with dependencies
322   static bool has_nmethods_with_dependencies();
323 
324   static int get_codemem_full_count(CodeBlobType code_blob_type) {
325     CodeHeap* heap = get_code_heap(code_blob_type);
326     return (heap != nullptr) ? heap->full_count() : 0;
327   }
328 
329   // CodeHeap State Analytics.
330   // interface methods for CodeHeap printing, called by CompileBroker
331   static void aggregate(outputStream *out, size_t granularity);
332   static void discard(outputStream *out);
333   static void print_usedSpace(outputStream *out);
334   static void print_freeSpace(outputStream *out);
335   static void print_count(outputStream *out);
336   static void print_space(outputStream *out);
337   static void print_age(outputStream *out);
338   static void print_names(outputStream *out);
339 };
340 
341 
342 // Iterator to iterate over code blobs in the CodeCache.
343 // The relaxed iterators only hold the CodeCache_lock across next calls
344 template <class T, class Filter, bool is_relaxed> class CodeBlobIterator : public StackObj {
345  public:
346   enum LivenessFilter { all_blobs, only_not_unloading };
347 
348  private:
349   CodeBlob* _code_blob;   // Current CodeBlob
350   GrowableArrayIterator<CodeHeap*> _heap;
351   GrowableArrayIterator<CodeHeap*> _end;
352   bool _only_not_unloading;
353 
354   void initialize_iteration(T* nm) {
355   }
356 
357   bool next_impl() {
358     for (;;) {
359       // Walk through heaps as required
360       if (!next_blob()) {
361         if (_heap == _end) {
362           return false;
363         }
364         ++_heap;
365         continue;
366       }
367 
368       // Filter is_unloading as required
369       if (_only_not_unloading) {
370         CompiledMethod* cm = _code_blob->as_compiled_method_or_null();
371         if (cm != nullptr && cm->is_unloading()) {
372           continue;
373         }
374       }
375 
376       return true;
377     }
378   }
379 
380  public:
381   CodeBlobIterator(LivenessFilter filter, T* nm = nullptr)
382     : _only_not_unloading(filter == only_not_unloading)
383   {
384     if (Filter::heaps() == nullptr) {
385       // The iterator is supposed to shortcut since we have
386       // _heap == _end, but make sure we do not have garbage
387       // in other fields as well.
388       _code_blob = nullptr;
389       return;
390     }
391     _heap = Filter::heaps()->begin();
392     _end = Filter::heaps()->end();
393     // If set to nullptr, initialized by first call to next()
394     _code_blob = nm;
395     if (nm != nullptr) {
396       while(!(*_heap)->contains(_code_blob)) {
397         ++_heap;
398       }
399       assert((*_heap)->contains(_code_blob), "match not found");
400     }
401   }
402 
403   // Advance iterator to next blob
404   bool next() {
405     if (is_relaxed) {
406       MutexLocker ml(CodeCache_lock, Mutex::_no_safepoint_check_flag);
407       return next_impl();
408     } else {
409       assert_locked_or_safepoint(CodeCache_lock);
410       return next_impl();
411     }
412   }
413 
414   bool end()  const { return _code_blob == nullptr; }
415   T* method() const { return (T*)_code_blob; }
416 
417 private:
418 
419   // Advance iterator to the next blob in the current code heap
420   bool next_blob() {
421     if (_heap == _end) {
422       return false;
423     }
424     CodeHeap *heap = *_heap;
425     // Get first method CodeBlob
426     if (_code_blob == nullptr) {
427       _code_blob = CodeCache::first_blob(heap);
428       if (_code_blob == nullptr) {
429         return false;
430       } else if (Filter::apply(_code_blob)) {
431         return true;
432       }
433     }
434     // Search for next method CodeBlob
435     _code_blob = CodeCache::next_blob(heap, _code_blob);
436     while (_code_blob != nullptr && !Filter::apply(_code_blob)) {
437       _code_blob = CodeCache::next_blob(heap, _code_blob);
438     }
439     return _code_blob != nullptr;
440   }
441 };
442 
443 struct CompiledMethodFilter {
444   static bool apply(CodeBlob* cb) { return cb->is_compiled(); }
445   static const GrowableArray<CodeHeap*>* heaps() { return CodeCache::compiled_heaps(); }
446 };
447 
448 
449 struct NMethodFilter {
450   static bool apply(CodeBlob* cb) { return cb->is_nmethod(); }
451   static const GrowableArray<CodeHeap*>* heaps() { return CodeCache::nmethod_heaps(); }
452 };
453 
454 struct AllCodeBlobsFilter {
455   static bool apply(CodeBlob* cb) { return true; }
456   static const GrowableArray<CodeHeap*>* heaps() { return CodeCache::heaps(); }
457 };
458 
459 typedef CodeBlobIterator<CompiledMethod, CompiledMethodFilter, false /* is_relaxed */> CompiledMethodIterator;
460 typedef CodeBlobIterator<CompiledMethod, CompiledMethodFilter, true /* is_relaxed */> RelaxedCompiledMethodIterator;
461 typedef CodeBlobIterator<nmethod, NMethodFilter, false /* is_relaxed */> NMethodIterator;
462 typedef CodeBlobIterator<CodeBlob, AllCodeBlobsFilter, false /* is_relaxed */> AllCodeBlobsIterator;
463 
464 #endif // SHARE_CODE_CODECACHE_HPP