1 /*
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3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
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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_relaxed> 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*>* _nmethod_heaps;
94 static GrowableArray<CodeHeap*>* _allocable_heaps;
95
96 static address _low_bound; // Lower bound of CodeHeap addresses
97 static address _high_bound; // Upper bound of CodeHeap addresses
98 static volatile int _number_of_nmethods_with_dependencies; // Total number of nmethods with dependencies
99
100 static uint8_t _unloading_cycle; // Global state for recognizing old nmethods that need to be unloaded
101 static uint64_t _gc_epoch; // Global state for tracking when nmethods were found to be on-stack
102 static uint64_t _cold_gc_count; // Global state for determining how many GCs are needed before an nmethod is cold
103 static size_t _last_unloading_used;
104 static double _last_unloading_time;
105 static TruncatedSeq _unloading_gc_intervals;
106 static TruncatedSeq _unloading_allocation_rates;
107 static volatile bool _unloading_threshold_gc_requested;
108
109 static ExceptionCache* volatile _exception_cache_purge_list;
110
111 // CodeHeap management
112 static void initialize_heaps(); // Initializes the CodeHeaps
113
114 // Creates a new heap with the given name and size, containing CodeBlobs of the given type
115 static void add_heap(ReservedSpace rs, const char* name, CodeBlobType code_blob_type);
116 static CodeHeap* get_code_heap_containing(void* p); // Returns the CodeHeap containing the given pointer, or nullptr
117 static CodeHeap* get_code_heap(const void* cb); // Returns the CodeHeap for the given CodeBlob
118 static CodeHeap* get_code_heap(CodeBlobType code_blob_type); // Returns the CodeHeap for the given CodeBlobType
119 // Returns the name of the VM option to set the size of the corresponding CodeHeap
120 static const char* get_code_heap_flag_name(CodeBlobType code_blob_type);
121 static ReservedCodeSpace reserve_heap_memory(size_t size, size_t rs_ps); // Reserves one continuous chunk of memory for the CodeHeaps
122
123 // Iteration
124 static CodeBlob* first_blob(CodeHeap* heap); // Returns the first CodeBlob on the given CodeHeap
125 static CodeBlob* first_blob(CodeBlobType code_blob_type); // Returns the first CodeBlob of the given type
126 static CodeBlob* next_blob(CodeHeap* heap, CodeBlob* cb); // Returns the next CodeBlob on the given CodeHeap
127
128 private:
129 static size_t bytes_allocated_in_freelists();
130 static int allocated_segments();
131 static size_t freelists_length();
132
133 // Make private to prevent unsafe calls. Not all CodeBlob*'s are embedded in a CodeHeap.
134 static bool contains(CodeBlob *p) { fatal("don't call me!"); return false; }
135
136 public:
137 // Initialization
138 static void initialize();
139 static size_t page_size(bool aligned = true, size_t min_pages = 1); // Returns the page size used by the CodeCache
140
141 static int code_heap_compare(CodeHeap* const &lhs, CodeHeap* const &rhs);
142
143 static void add_heap(CodeHeap* heap);
144 static const GrowableArray<CodeHeap*>* heaps() { return _heaps; }
145 static const GrowableArray<CodeHeap*>* nmethod_heaps() { return _nmethod_heaps; }
146
147 // Allocation/administration
148 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
149 static void commit(CodeBlob* cb); // called when the allocated CodeBlob has been filled
150 static void free(CodeBlob* cb); // frees a CodeBlob
151 static void free_unused_tail(CodeBlob* cb, size_t used); // frees the unused tail of a CodeBlob (only used by TemplateInterpreter::initialize())
152 static bool contains(void *p); // returns whether p is included
153 static bool contains(nmethod* nm); // returns whether nm is included
154 static void blobs_do(void f(CodeBlob* cb)); // iterates over all CodeBlobs
155 static void nmethods_do(void f(nmethod* nm)); // iterates over all nmethods
156 static void nmethods_do(NMethodClosure* cl); // iterates over all nmethods
157 static void metadata_do(MetadataClosure* f); // iterates over metadata in alive nmethods
158
159 // Lookup
160 static CodeBlob* find_blob(void* start); // Returns the CodeBlob containing the given address
161 static CodeBlob* find_blob_fast(void* start); // Returns the CodeBlob containing the given address
162 static CodeBlob* find_blob_and_oopmap(void* start, int& slot); // Returns the CodeBlob containing the given address
163 static int find_oopmap_slot_fast(void* start); // Returns a fast oopmap slot if there is any; -1 otherwise
164 static nmethod* find_nmethod(void* start); // Returns the nmethod containing the given address
165
166 static int blob_count(); // Returns the total number of CodeBlobs in the cache
167 static int blob_count(CodeBlobType code_blob_type);
168 static int adapter_count(); // Returns the total number of Adapters in the cache
169 static int adapter_count(CodeBlobType code_blob_type);
170 static int nmethod_count(); // Returns the total number of nmethods in the cache
171 static int nmethod_count(CodeBlobType code_blob_type);
172
173 // GC support
174 static void verify_oops();
175
176 // Helper scope object managing code cache unlinking behavior, i.e. sets and
177 // restores the closure that determines which nmethods are going to be removed
178 // during the unlinking part of code cache unloading.
179 class UnlinkingScope : StackObj {
180 ClosureIsUnloadingBehaviour _is_unloading_behaviour;
181 IsUnloadingBehaviour* _saved_behaviour;
182
183 public:
184 UnlinkingScope(BoolObjectClosure* is_alive);
185 ~UnlinkingScope();
186 };
187
188 // Code cache unloading heuristics
189 static uint64_t cold_gc_count();
190 static void update_cold_gc_count();
191 static void gc_on_allocation();
192
193 // The GC epoch and marking_cycle code below is there to support sweeping
194 // nmethods in loom stack chunks.
195 static uint64_t gc_epoch();
196 static bool is_gc_marking_cycle_active();
197 static uint64_t previous_completed_gc_marking_cycle();
198 static void on_gc_marking_cycle_start();
199 static void on_gc_marking_cycle_finish();
200 // Arm nmethods so that special actions are taken (nmethod_entry_barrier) for
201 // on-stack nmethods. It's used in two places:
202 // 1. Used before the start of concurrent marking so that oops inside
203 // on-stack nmethods are visited.
204 // 2. Used at the end of (stw/concurrent) marking so that nmethod::_gc_epoch
205 // is up-to-date, which provides more accurate estimate of
206 // nmethod::is_cold.
207 static void arm_all_nmethods();
208
209 static void maybe_restart_compiler(size_t freed_memory);
210 static void do_unloading(bool unloading_occurred);
211 static uint8_t unloading_cycle() { return _unloading_cycle; }
212
213 static void increment_unloading_cycle();
214
215 static void release_exception_cache(ExceptionCache* entry);
216 static void purge_exception_caches();
217
218 // Printing/debugging
219 static void print(); // prints summary
220 static void print_internals();
221 static void print_memory_overhead();
222 static void verify(); // verifies the code cache
223 static void print_trace(const char* event, CodeBlob* cb, uint size = 0) PRODUCT_RETURN;
224 static void print_summary(outputStream* st, bool detailed = true); // Prints a summary of the code cache usage
225 static void log_state(outputStream* st);
226 LINUX_ONLY(static void write_perf_map(const char* filename = nullptr);)
227 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"); }
228 static void report_codemem_full(CodeBlobType code_blob_type, bool print);
229
230 // Dcmd (Diagnostic commands)
231 static void print_codelist(outputStream* st);
232 static void print_layout(outputStream* st);
233
234 // The full limits of the codeCache
235 static address low_bound() { return _low_bound; }
236 static address low_bound(CodeBlobType code_blob_type);
237 static address high_bound() { return _high_bound; }
238 static address high_bound(CodeBlobType code_blob_type);
239
240 // Profiling
241 static size_t capacity();
242 static size_t unallocated_capacity(CodeBlobType code_blob_type);
243 static size_t unallocated_capacity();
244 static size_t max_capacity();
245
246 static double reverse_free_ratio();
247
248 static size_t max_distance_to_non_nmethod();
249 static bool is_non_nmethod(address addr);
250
251 static void clear_inline_caches(); // clear all inline caches
252 static void cleanup_inline_caches_whitebox(); // clean bad nmethods from inline caches
253
254 // Returns true if an own CodeHeap for the given CodeBlobType is available
255 static bool heap_available(CodeBlobType code_blob_type);
256
257 // Returns the CodeBlobType for the given nmethod
258 static CodeBlobType get_code_blob_type(nmethod* nm) {
259 return get_code_heap(nm)->code_blob_type();
260 }
261
262 static bool code_blob_type_accepts_nmethod(CodeBlobType type) {
263 return type == CodeBlobType::All || type <= CodeBlobType::MethodProfiled;
264 }
265
266 static bool code_blob_type_accepts_allocable(CodeBlobType type) {
267 return type <= CodeBlobType::All;
268 }
269
270
271 // Returns the CodeBlobType for the given compilation level
272 static CodeBlobType get_code_blob_type(int comp_level) {
273 if (comp_level == CompLevel_none ||
274 comp_level == CompLevel_simple ||
275 comp_level == CompLevel_full_optimization) {
276 // Non profiled methods
277 return CodeBlobType::MethodNonProfiled;
278 } else if (comp_level == CompLevel_limited_profile ||
279 comp_level == CompLevel_full_profile) {
280 // Profiled methods
281 return CodeBlobType::MethodProfiled;
282 }
283 ShouldNotReachHere();
284 return static_cast<CodeBlobType>(0);
285 }
286
287 static void verify_clean_inline_caches();
288
289 // Deoptimization
290 private:
291 static void mark_for_deoptimization(DeoptimizationScope* deopt_scope, KlassDepChange& changes);
292
293 public:
294 static void mark_all_nmethods_for_deoptimization(DeoptimizationScope* deopt_scope);
295 static void mark_for_deoptimization(DeoptimizationScope* deopt_scope, Method* dependee);
296 static void make_marked_nmethods_deoptimized();
297
298 // Marks dependents during classloading
299 static void mark_dependents_on(DeoptimizationScope* deopt_scope, InstanceKlass* dependee);
300
301 // RedefineClasses support
302 // Marks in case of evolution
303 static void mark_dependents_for_evol_deoptimization(DeoptimizationScope* deopt_scope);
304 static void mark_all_nmethods_for_evol_deoptimization(DeoptimizationScope* deopt_scope);
305 static void old_nmethods_do(MetadataClosure* f) NOT_JVMTI_RETURN;
306 static void unregister_old_nmethod(nmethod* c) NOT_JVMTI_RETURN;
307
308 // Support for fullspeed debugging
309 static void mark_dependents_on_method_for_breakpoint(const methodHandle& dependee);
310
311 // tells if there are nmethods with dependencies
312 static bool has_nmethods_with_dependencies();
313
314 static int get_codemem_full_count(CodeBlobType code_blob_type) {
315 CodeHeap* heap = get_code_heap(code_blob_type);
316 return (heap != nullptr) ? heap->full_count() : 0;
317 }
318
319 // CodeHeap State Analytics.
320 // interface methods for CodeHeap printing, called by CompileBroker
321 static void aggregate(outputStream *out, size_t granularity);
322 static void discard(outputStream *out);
323 static void print_usedSpace(outputStream *out);
324 static void print_freeSpace(outputStream *out);
325 static void print_count(outputStream *out);
326 static void print_space(outputStream *out);
327 static void print_age(outputStream *out);
328 static void print_names(outputStream *out);
329 };
330
331
332 // Iterator to iterate over code blobs in the CodeCache.
333 // The relaxed iterators only hold the CodeCache_lock across next calls
334 template <class T, class Filter, bool is_relaxed> class CodeBlobIterator : public StackObj {
335 public:
336 enum LivenessFilter { all, not_unloading };
337
338 private:
339 CodeBlob* _code_blob; // Current CodeBlob
340 GrowableArrayIterator<CodeHeap*> _heap;
341 GrowableArrayIterator<CodeHeap*> _end;
342 bool _not_unloading; // Those nmethods that are not unloading
343
344 void initialize_iteration(T* nm) {
345 }
346
347 bool next_impl() {
348 for (;;) {
349 // Walk through heaps as required
350 if (!next_blob()) {
351 if (_heap == _end) {
352 return false;
353 }
354 ++_heap;
355 continue;
356 }
357
358 // Filter is_unloading as required
359 if (_not_unloading) {
360 nmethod* nm = _code_blob->as_nmethod_or_null();
361 if (nm != nullptr && nm->is_unloading()) {
362 continue;
363 }
364 }
365
366 return true;
367 }
368 }
369
370 public:
371 CodeBlobIterator(LivenessFilter filter, T* nm = nullptr)
372 : _not_unloading(filter == not_unloading)
373 {
374 if (Filter::heaps() == nullptr) {
375 // The iterator is supposed to shortcut since we have
376 // _heap == _end, but make sure we do not have garbage
377 // in other fields as well.
378 _code_blob = nullptr;
379 return;
380 }
381 _heap = Filter::heaps()->begin();
382 _end = Filter::heaps()->end();
383 // If set to nullptr, initialized by first call to next()
384 _code_blob = nm;
385 if (nm != nullptr) {
386 while(!(*_heap)->contains(_code_blob)) {
387 ++_heap;
388 }
389 assert((*_heap)->contains(_code_blob), "match not found");
390 }
391 }
392
393 // Advance iterator to next blob
394 bool next() {
395 if (is_relaxed) {
396 MutexLocker ml(CodeCache_lock, Mutex::_no_safepoint_check_flag);
397 return next_impl();
398 } else {
399 assert_locked_or_safepoint(CodeCache_lock);
400 return next_impl();
401 }
402 }
403
404 bool end() const { return _code_blob == nullptr; }
405 T* method() const { return (T*)_code_blob; }
406
407 private:
408
409 // Advance iterator to the next blob in the current code heap
410 bool next_blob() {
411 if (_heap == _end) {
412 return false;
413 }
414 CodeHeap *heap = *_heap;
415 // Get first method CodeBlob
416 if (_code_blob == nullptr) {
417 _code_blob = CodeCache::first_blob(heap);
418 if (_code_blob == nullptr) {
419 return false;
420 } else if (Filter::apply(_code_blob)) {
421 return true;
422 }
423 }
424 // Search for next method CodeBlob
425 _code_blob = CodeCache::next_blob(heap, _code_blob);
426 while (_code_blob != nullptr && !Filter::apply(_code_blob)) {
427 _code_blob = CodeCache::next_blob(heap, _code_blob);
428 }
429 return _code_blob != nullptr;
430 }
431 };
432
433 struct NMethodFilter {
434 static bool apply(CodeBlob* cb) { return cb->is_nmethod(); }
435 static const GrowableArray<CodeHeap*>* heaps() { return CodeCache::nmethod_heaps(); }
436 };
437
438 struct AllCodeBlobsFilter {
439 static bool apply(CodeBlob* cb) { return true; }
440 static const GrowableArray<CodeHeap*>* heaps() { return CodeCache::heaps(); }
441 };
442
443 typedef CodeBlobIterator<nmethod, NMethodFilter, false /* is_relaxed */> NMethodIterator;
444 typedef CodeBlobIterator<nmethod, NMethodFilter, true /* is_relaxed */> RelaxedNMethodIterator;
445 typedef CodeBlobIterator<CodeBlob, AllCodeBlobsFilter, false /* is_relaxed */> AllCodeBlobsIterator;
446
447 #endif // SHARE_CODE_CODECACHE_HPP