1 /*
2 * Copyright (c) 1997, 2015, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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5 * This code is free software; you can redistribute it and/or modify it
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11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
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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 JVMCIVMStructs;
80 friend class NMethodIterator;
81 friend class WhiteBox;
82 friend class CodeCacheLoader;
83 private:
84 // CodeHeaps of the cache
85 static GrowableArray<CodeHeap*>* _heaps;
86
87 static address _low_bound; // Lower bound of CodeHeap addresses
88 static address _high_bound; // Upper bound of CodeHeap addresses
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
93 static void mark_scavenge_root_nmethods() PRODUCT_RETURN;
94 static void verify_perm_nmethods(CodeBlobClosure* f_or_null) PRODUCT_RETURN;
95
96 // CodeHeap management
97 static void initialize_heaps(); // Initializes the CodeHeaps
98 // Check the code heap sizes set by the user via command line
99 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);
100 // Creates a new heap with the given name and size, containing CodeBlobs of the given type
101 static void add_heap(ReservedSpace rs, const char* name, int code_blob_type);
102 static CodeHeap* get_code_heap(const CodeBlob* cb); // Returns the CodeHeap for the given CodeBlob
103 static CodeHeap* get_code_heap(int code_blob_type); // Returns the CodeHeap for the given CodeBlobType
104 // Returns the name of the VM option to set the size of the corresponding CodeHeap
105 static const char* get_code_heap_flag_name(int code_blob_type);
106 static size_t heap_alignment(); // Returns the alignment of the CodeHeaps in bytes
107 static ReservedCodeSpace reserve_heap_memory(size_t size); // Reserves one continuous chunk of memory for the CodeHeaps
108
109 // Iteration
110 static CodeBlob* first_blob(CodeHeap* heap); // Returns the first CodeBlob on the given CodeHeap
111 static CodeBlob* first_blob(int code_blob_type); // Returns the first CodeBlob of the given type
112 static CodeBlob* next_blob(CodeHeap* heap, CodeBlob* cb); // Returns the first alive CodeBlob on the given CodeHeap
113 static CodeBlob* next_blob(CodeBlob* cb); // Returns the next CodeBlob of the given type succeeding the given CodeBlob
114
115 static size_t bytes_allocated_in_freelists();
116 static int allocated_segments();
117 static size_t freelists_length();
118
119 public:
120 // Initialization
121 static void initialize();
122
123 // Allocation/administration
124 static CodeBlob* allocate(int size, int code_blob_type, bool strict = false); // allocates a new CodeBlob
125 static void commit(CodeBlob* cb); // called when the allocated CodeBlob has been filled
126 static int alignment_unit(); // guaranteed alignment of all CodeBlobs
127 static int alignment_offset(); // guaranteed offset of first CodeBlob byte within alignment unit (i.e., allocation header)
128 static void free(CodeBlob* cb); // frees a CodeBlob
129 static bool contains(void *p); // returns whether p is included
130 static void blobs_do(void f(CodeBlob* cb)); // iterates over all CodeBlobs
131 static void blobs_do(CodeBlobClosure* f); // iterates over all CodeBlobs
132 static void nmethods_do(void f(nmethod* nm)); // iterates over all nmethods
133 static void alive_nmethods_do(void f(nmethod* nm)); // iterates over all alive nmethods
134
135 // Lookup
136 static CodeBlob* find_blob(void* start); // Returns the CodeBlob containing the given address
137 static CodeBlob* find_blob_unsafe(void* start); // Same as find_blob but does not fail if looking up a zombie method
138 static nmethod* find_nmethod(void* start); // Returns the nmethod containing the given address
139
140 static int blob_count(); // Returns the total number of CodeBlobs in the cache
141 static int blob_count(int code_blob_type);
142 static int adapter_count(); // Returns the total number of Adapters in the cache
143 static int adapter_count(int code_blob_type);
144 static int nmethod_count(); // Returns the total number of nmethods in the cache
145 static int nmethod_count(int code_blob_type);
146
147 // GC support
148 static void gc_epilogue();
149 static void gc_prologue();
150 static void verify_oops();
151 // If "unloading_occurred" is true, then unloads (i.e., breaks root links
152 // to) any unmarked codeBlobs in the cache. Sets "marked_for_unloading"
153 // to "true" iff some code got unloaded.
154 static void do_unloading(BoolObjectClosure* is_alive, bool unloading_occurred);
155 static void asserted_non_scavengable_nmethods_do(CodeBlobClosure* f = NULL) PRODUCT_RETURN;
156 static void scavenge_root_nmethods_do(CodeBlobClosure* f);
157
158 static nmethod* scavenge_root_nmethods() { return _scavenge_root_nmethods; }
159 static void set_scavenge_root_nmethods(nmethod* nm) { _scavenge_root_nmethods = nm; }
160 static void add_scavenge_root_nmethod(nmethod* nm);
161 static void drop_scavenge_root_nmethod(nmethod* nm);
162 static void prune_scavenge_root_nmethods();
163
164 // Printing/debugging
165 static void print(); // prints summary
166 static void print_internals();
167 static void print_memory_overhead();
168 static void verify(); // verifies the code cache
169 static void print_trace(const char* event, CodeBlob* cb, int size = 0) PRODUCT_RETURN;
170 static void print_summary(outputStream* st, bool detailed = true); // Prints a summary of the code cache usage
171 static void log_state(outputStream* st);
172 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"); }
173 static void report_codemem_full(int code_blob_type, bool print);
174
175 // Dcmd (Diagnostic commands)
176 static void print_codelist(outputStream* st);
177 static void print_layout(outputStream* st);
178
179 // The full limits of the codeCache
180 static address low_bound() { return _low_bound; }
181 static address low_bound(int code_blob_type);
182 static address high_bound() { return _high_bound; }
183 static address high_bound(int code_blob_type);
184
185 // Profiling
186 static size_t capacity();
187 static size_t unallocated_capacity(int code_blob_type);
188 static size_t unallocated_capacity();
189 static size_t max_capacity();
190
191 static double reverse_free_ratio(int code_blob_type);
192
193 static bool needs_cache_clean() { return _needs_cache_clean; }
194 static void set_needs_cache_clean(bool v) { _needs_cache_clean = v; }
195 static void clear_inline_caches(); // clear all inline caches
196
197 // Returns true if an own CodeHeap for the given CodeBlobType is available
198 static bool heap_available(int code_blob_type);
199
200 // Returns the CodeBlobType for the given nmethod
201 static int get_code_blob_type(nmethod* nm) {
202 return get_code_heap(nm)->code_blob_type();
203 }
204
205 // Returns the CodeBlobType for the given compilation level
206 static int get_code_blob_type(int comp_level) {
207 if (comp_level == CompLevel_none ||
208 comp_level == CompLevel_simple ||
209 comp_level == CompLevel_full_optimization) {
210 // Non profiled methods
211 return CodeBlobType::MethodNonProfiled;
212 } else if (comp_level == CompLevel_limited_profile ||
213 comp_level == CompLevel_full_profile) {
214 // Profiled methods
215 return CodeBlobType::MethodProfiled;
216 }
217 ShouldNotReachHere();
218 return 0;
219 }
220
221 static void verify_clean_inline_caches();
222 static void verify_icholder_relocations();
223
224 // Deoptimization
225 private:
226 static int mark_for_deoptimization(DepChange& changes);
227 #ifdef HOTSWAP
228 static int mark_for_evol_deoptimization(instanceKlassHandle dependee);
229 #endif // HOTSWAP
230
231 public:
232 static void mark_all_nmethods_for_deoptimization();
233 static int mark_for_deoptimization(Method* dependee);
234 static void make_marked_nmethods_not_entrant();
235
236 // Flushing and deoptimization
237 static void flush_dependents_on(instanceKlassHandle dependee);
238 #ifdef HOTSWAP
239 // Flushing and deoptimization in case of evolution
240 static void flush_evol_dependents_on(instanceKlassHandle dependee);
241 #endif // HOTSWAP
242 // Support for fullspeed debugging
243 static void flush_dependents_on_method(methodHandle dependee);
244
245 // tells how many nmethods have dependencies
246 static int number_of_nmethods_with_dependencies();
247
248 static int get_codemem_full_count(int code_blob_type) {
249 CodeHeap* heap = get_code_heap(code_blob_type);
250 return (heap != NULL) ? heap->full_count() : 0;
251 }
252 };
253
254
255 // Iterator to iterate over nmethods in the CodeCache.
256 class NMethodIterator : public StackObj {
257 private:
258 CodeBlob* _code_blob; // Current CodeBlob
259 int _code_blob_type; // Refers to current CodeHeap
260
261 public:
262 NMethodIterator() {
263 initialize(NULL); // Set to NULL, initialized by first call to next()
264 }
265
266 NMethodIterator(nmethod* nm) {
267 initialize(nm);
268 }
269
270 // Advance iterator to next nmethod
271 bool next() {
272 assert_locked_or_safepoint(CodeCache_lock);
273 assert(_code_blob_type < CodeBlobType::NumTypes, "end reached");
274
275 bool result = next_nmethod();
276 while (!result && (_code_blob_type < CodeBlobType::MethodProfiled)) {
277 // Advance to next code heap if segmented code cache
278 _code_blob_type++;
279 result = next_nmethod();
280 }
281 return result;
282 }
283
284 // Advance iterator to next alive nmethod
285 bool next_alive() {
286 bool result = next();
287 while(result && !_code_blob->is_alive()) {
288 result = next();
289 }
290 return result;
291 }
292
293 bool end() const { return _code_blob == NULL; }
294 nmethod* method() const { return (nmethod*)_code_blob; }
295
296 private:
297 // Initialize iterator to given nmethod
298 void initialize(nmethod* nm) {
299 _code_blob = (CodeBlob*)nm;
300 if (!SegmentedCodeCache) {
301 // Iterate over all CodeBlobs
302 _code_blob_type = CodeBlobType::All;
303 } else if (nm != NULL) {
304 _code_blob_type = CodeCache::get_code_blob_type(nm);
305 } else {
306 // Only iterate over method code heaps, starting with non-profiled
307 _code_blob_type = CodeBlobType::MethodNonProfiled;
308 }
309 }
310
311 // Advance iterator to the next nmethod in the current code heap
312 bool next_nmethod() {
313 // Get first method CodeBlob
314 if (_code_blob == NULL) {
315 _code_blob = CodeCache::first_blob(_code_blob_type);
316 if (_code_blob == NULL) {
317 return false;
318 } else if (_code_blob->is_nmethod()) {
319 return true;
320 }
321 }
322 // Search for next method CodeBlob
323 _code_blob = CodeCache::next_blob(_code_blob);
324 while (_code_blob != NULL && !_code_blob->is_nmethod()) {
325 _code_blob = CodeCache::next_blob(_code_blob);
326 }
327 return _code_blob != NULL;
328 }
329 };
330
331 #endif // SHARE_VM_CODE_CODECACHE_HPP