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.
4 *
5 * This code is free software; you can redistribute it and/or modify it
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7 * published by the Free Software Foundation.
8 *
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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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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,
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23 */
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 friend class WhiteBox;
81 private:
82 // CodeHeaps of the cache
83 static GrowableArray<CodeHeap*>* _heaps;
84
85 static address _low_bound; // Lower bound of CodeHeap addresses
86 static address _high_bound; // Upper bound of CodeHeap addresses
87 static int _number_of_blobs; // Total number of CodeBlobs in the cache
88 static int _number_of_adapters; // Total number of Adapters in the cache
89 static int _number_of_nmethods; // Total number of nmethods in the cache
90 static int _number_of_nmethods_with_dependencies; // Total number of nmethods with dependencies
91 static bool _needs_cache_clean; // True if inline caches of the nmethods needs to be flushed
92 static nmethod* _scavenge_root_nmethods; // linked via nm->scavenge_root_link()
93 static int _codemem_full_count; // Number of times a CodeHeap in the cache was full
94
95 static void mark_scavenge_root_nmethods() PRODUCT_RETURN;
96 static void verify_perm_nmethods(CodeBlobClosure* f_or_null) PRODUCT_RETURN;
97
98 // CodeHeap management
99 static void initialize_heaps(); // Initializes the CodeHeaps
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 bool heap_available(int code_blob_type); // Returns true if an own CodeHeap for the given CodeBlobType is available
107 static size_t heap_alignment(); // Returns the alignment of the CodeHeaps in bytes
108 static ReservedCodeSpace reserve_heap_memory(size_t size); // Reserves one continuous chunk of memory for the CodeHeaps
109
110 // Iteration
111 static CodeBlob* first_blob(CodeHeap* heap); // Returns the first CodeBlob on the given CodeHeap
112 static CodeBlob* first_blob(int code_blob_type); // Returns the first CodeBlob of the given type
113 static CodeBlob* next_blob(CodeHeap* heap, CodeBlob* cb); // Returns the first alive CodeBlob on the given CodeHeap
114 static CodeBlob* next_blob(CodeBlob* cb); // Returns the next CodeBlob of the given type succeeding the given CodeBlob
115
116 static size_t bytes_allocated_in_freelists();
117 static int allocated_segments();
118 static size_t freelists_length();
119
120 public:
121 // Initialization
122 static void initialize();
123
124 // Allocation/administration
125 static CodeBlob* allocate(int size, int code_blob_type, bool strict = false); // allocates a new CodeBlob
126 static void commit(CodeBlob* cb); // called when the allocated CodeBlob has been filled
127 static int alignment_unit(); // guaranteed alignment of all CodeBlobs
128 static int alignment_offset(); // guaranteed offset of first CodeBlob byte within alignment unit (i.e., allocation header)
129 static void free(CodeBlob* cb); // frees a CodeBlob
130 static bool contains(void *p); // returns whether p is included
131 static void blobs_do(void f(CodeBlob* cb)); // iterates over all CodeBlobs
132 static void blobs_do(CodeBlobClosure* f); // iterates over all CodeBlobs
133 static void nmethods_do(void f(nmethod* nm)); // iterates over all nmethods
134 static void alive_nmethods_do(void f(nmethod* nm)); // iterates over all alive nmethods
135
136 // Lookup
137 static CodeBlob* find_blob(void* start); // Returns the CodeBlob containing the given address
138 static CodeBlob* find_blob_unsafe(void* start); // Same as find_blob but does not fail if looking up a zombie method
139 static nmethod* find_nmethod(void* start); // Returns the nmethod containing the given address
140
141 static int nof_blobs() { return _number_of_blobs; } // Returns the total number of CodeBlobs in the cache
142 static int nof_adapters() { return _number_of_adapters; } // Returns the total number of Adapters in the cache
143 static int nof_nmethods() { return _number_of_nmethods; } // Returns the total number of nmethods in the cache
144
145 // GC support
146 static void gc_epilogue();
147 static void gc_prologue();
148 static void verify_oops();
149 // If "unloading_occurred" is true, then unloads (i.e., breaks root links
150 // to) any unmarked codeBlobs in the cache. Sets "marked_for_unloading"
151 // to "true" iff some code got unloaded.
152 static void do_unloading(BoolObjectClosure* is_alive, bool unloading_occurred);
153 static void asserted_non_scavengable_nmethods_do(CodeBlobClosure* f = NULL) PRODUCT_RETURN;
154 static void scavenge_root_nmethods_do(CodeBlobClosure* f);
155
156 static nmethod* scavenge_root_nmethods() { return _scavenge_root_nmethods; }
157 static void set_scavenge_root_nmethods(nmethod* nm) { _scavenge_root_nmethods = nm; }
158 static void add_scavenge_root_nmethod(nmethod* nm);
159 static void drop_scavenge_root_nmethod(nmethod* nm);
160 static void prune_scavenge_root_nmethods();
161
162 // Printing/debugging
163 static void print(); // prints summary
164 static void print_internals();
165 static void print_memory_overhead();
166 static void verify(); // verifies the code cache
167 static void print_trace(const char* event, CodeBlob* cb, int size = 0) PRODUCT_RETURN;
168 static void print_summary(outputStream* st, bool detailed = true); // Prints a summary of the code cache usage
169 static void log_state(outputStream* st);
170 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"); }
171 static void report_codemem_full(int code_blob_type, bool print);
172
173 // Dcmd (Diagnostic commands)
174 static void print_codelist(outputStream* st);
175 static void print_layout(outputStream* st);
176
177 // The full limits of the codeCache
178 static address low_bound() { return _low_bound; }
179 static address high_bound() { return _high_bound; }
180
181 // Profiling
182 static size_t capacity();
183 static size_t unallocated_capacity(int code_blob_type);
184 static size_t unallocated_capacity();
185 static size_t max_capacity();
186
187 static double reverse_free_ratio(int code_blob_type);
188
189 static bool needs_cache_clean() { return _needs_cache_clean; }
190 static void set_needs_cache_clean(bool v) { _needs_cache_clean = v; }
191 static void clear_inline_caches(); // clear all inline caches
192
193 // Returns the CodeBlobType for nmethods of the given compilation level
194 static int get_code_blob_type(int comp_level) {
195 if (comp_level == CompLevel_none ||
196 comp_level == CompLevel_simple ||
197 comp_level == CompLevel_full_optimization) {
198 // Non profiled methods
199 return CodeBlobType::MethodNonProfiled;
200 } else if (comp_level == CompLevel_limited_profile ||
201 comp_level == CompLevel_full_profile) {
202 // Profiled methods
203 return CodeBlobType::MethodProfiled;
204 }
205 ShouldNotReachHere();
206 return 0;
207 }
208
209 static void verify_clean_inline_caches();
210 static void verify_icholder_relocations();
211
212 // Deoptimization
213 private:
214 static int mark_for_deoptimization(DepChange& changes);
215 #ifdef HOTSWAP
216 static int mark_for_evol_deoptimization(instanceKlassHandle dependee);
217 #endif // HOTSWAP
218
219 public:
220 static void mark_all_nmethods_for_deoptimization();
221 static int mark_for_deoptimization(Method* dependee);
222 static void make_marked_nmethods_zombies();
223 static void make_marked_nmethods_not_entrant();
224
225 // Flushing and deoptimization
226 static void flush_dependents_on(instanceKlassHandle dependee);
227 static void flush_dependents_on(Handle call_site, Handle method_handle);
228 #ifdef HOTSWAP
229 // Flushing and deoptimization in case of evolution
230 static void flush_evol_dependents_on(instanceKlassHandle dependee);
231 #endif // HOTSWAP
232 // Support for fullspeed debugging
233 static void flush_dependents_on_method(methodHandle dependee);
234
235 // tells how many nmethods have dependencies
236 static int number_of_nmethods_with_dependencies();
237
238 static int get_codemem_full_count() { return _codemem_full_count; }
239 };
240
241
242 // Iterator to iterate over nmethods in the CodeCache.
243 class NMethodIterator : public StackObj {
244 private:
245 CodeBlob* _code_blob; // Current CodeBlob
246 int _code_blob_type; // Refers to current CodeHeap
247
248 public:
249 NMethodIterator() {
250 initialize(NULL); // Set to NULL, initialized by first call to next()
251 }
252
253 NMethodIterator(nmethod* nm) {
254 initialize(nm);
255 }
256
257 // Advance iterator to next nmethod
258 bool next() {
259 assert_locked_or_safepoint(CodeCache_lock);
260 assert(_code_blob_type < CodeBlobType::NumTypes, "end reached");
261
262 bool result = next_nmethod();
263 while (!result && (_code_blob_type < CodeBlobType::MethodProfiled)) {
264 // Advance to next code heap if segmented code cache
265 _code_blob_type++;
266 result = next_nmethod();
267 }
268 return result;
269 }
270
271 // Advance iterator to next alive nmethod
272 bool next_alive() {
273 bool result = next();
274 while(result && !_code_blob->is_alive()) {
275 result = next();
276 }
277 return result;
278 }
279
280 bool end() const { return _code_blob == NULL; }
281 nmethod* method() const { return (nmethod*)_code_blob; }
282
283 private:
284 // Initialize iterator to given nmethod
285 void initialize(nmethod* nm) {
286 _code_blob = (CodeBlob*)nm;
287 if (!SegmentedCodeCache) {
288 // Iterate over all CodeBlobs
289 _code_blob_type = CodeBlobType::All;
290 } else if (nm != NULL) {
291 _code_blob_type = CodeCache::get_code_blob_type(nm->comp_level());
292 } else {
293 // Only iterate over method code heaps, starting with non-profiled
294 _code_blob_type = CodeBlobType::MethodNonProfiled;
295 }
296 }
297
298 // Advance iterator to the next nmethod in the current code heap
299 bool next_nmethod() {
300 // Get first method CodeBlob
301 if (_code_blob == NULL) {
302 _code_blob = CodeCache::first_blob(_code_blob_type);
303 if (_code_blob == NULL) {
304 return false;
305 } else if (_code_blob->is_nmethod()) {
306 return true;
307 }
308 }
309 // Search for next method CodeBlob
310 _code_blob = CodeCache::next_blob(_code_blob);
311 while (_code_blob != NULL && !_code_blob->is_nmethod()) {
312 _code_blob = CodeCache::next_blob(_code_blob);
313 }
314 return _code_blob != NULL;
315 }
316 };
317
318 #endif // SHARE_VM_CODE_CODECACHE_HPP