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
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation.
8 *
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).
14 *
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,
17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
18 *
19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
20 * or visit www.oracle.com if you need additional information or have any
21 * questions.
22 *
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 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 static void set_scavenge_root_nmethods(nmethod* nm) { _scavenge_root_nmethods = nm; }
120 static void prune_scavenge_root_nmethods();
121 static void unlink_scavenge_root_nmethod(nmethod* nm, nmethod* prev);
122
123 public:
124 // Initialization
125 static void initialize();
126
127 // Allocation/administration
128 static CodeBlob* allocate(int size, int code_blob_type, bool strict = false); // allocates a new CodeBlob
129 static void commit(CodeBlob* cb); // called when the allocated CodeBlob has been filled
130 static int alignment_unit(); // guaranteed alignment of all CodeBlobs
131 static int alignment_offset(); // guaranteed offset of first CodeBlob byte within alignment unit (i.e., allocation header)
132 static void free(CodeBlob* cb); // frees a CodeBlob
133 static bool contains(void *p); // returns whether p is included
134 static void blobs_do(void f(CodeBlob* cb)); // iterates over all CodeBlobs
135 static void blobs_do(CodeBlobClosure* f); // iterates over all CodeBlobs
136 static void nmethods_do(void f(nmethod* nm)); // iterates over all nmethods
137 static void alive_nmethods_do(void f(nmethod* nm)); // iterates over all alive nmethods
138
139 // Lookup
140 static CodeBlob* find_blob(void* start); // Returns the CodeBlob containing the given address
141 static CodeBlob* find_blob_unsafe(void* start); // Same as find_blob but does not fail if looking up a zombie method
142 static nmethod* find_nmethod(void* start); // Returns the nmethod containing the given address
143
144 static int blob_count(); // Returns the total number of CodeBlobs in the cache
145 static int blob_count(int code_blob_type);
146 static int adapter_count(); // Returns the total number of Adapters in the cache
147 static int adapter_count(int code_blob_type);
148 static int nmethod_count(); // Returns the total number of nmethods in the cache
149 static int nmethod_count(int code_blob_type);
150
151 // GC support
152 static void gc_epilogue();
153 static void gc_prologue();
154 static void verify_oops();
155 // If "unloading_occurred" is true, then unloads (i.e., breaks root links
156 // to) any unmarked codeBlobs in the cache. Sets "marked_for_unloading"
157 // to "true" iff some code got unloaded.
158 static void do_unloading(BoolObjectClosure* is_alive, bool unloading_occurred);
159 static void asserted_non_scavengable_nmethods_do(CodeBlobClosure* f = NULL) PRODUCT_RETURN;
160
161 // Apply f to every live code blob in scavengable nmethods. Prune nmethods
162 // from the list of scavengable nmethods if f->fix_relocations() and a nmethod
163 // no longer has scavengable oops. If f->fix_relocations(), then f must copy
164 // objects to their new location immediately to avoid fixing nmethods on the
165 // basis of the old object locations.
166 static void scavenge_root_nmethods_do(CodeBlobToOopClosure* f);
167
168 static nmethod* scavenge_root_nmethods() { return _scavenge_root_nmethods; }
169 static void add_scavenge_root_nmethod(nmethod* nm);
170 static void drop_scavenge_root_nmethod(nmethod* nm);
171
172 // Printing/debugging
173 static void print(); // prints summary
174 static void print_internals();
175 static void print_memory_overhead();
176 static void verify(); // verifies the code cache
177 static void print_trace(const char* event, CodeBlob* cb, int size = 0) PRODUCT_RETURN;
178 static void print_summary(outputStream* st, bool detailed = true); // Prints a summary of the code cache usage
179 static void log_state(outputStream* st);
180 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"); }
181 static void report_codemem_full(int code_blob_type, bool print);
182
183 // Dcmd (Diagnostic commands)
184 static void print_codelist(outputStream* st);
185 static void print_layout(outputStream* st);
186
187 // The full limits of the codeCache
188 static address low_bound() { return _low_bound; }
189 static address low_bound(int code_blob_type);
190 static address high_bound() { return _high_bound; }
191 static address high_bound(int code_blob_type);
192
193 // Profiling
194 static size_t capacity();
195 static size_t unallocated_capacity(int code_blob_type);
196 static size_t unallocated_capacity();
197 static size_t max_capacity();
198
199 static double reverse_free_ratio(int code_blob_type);
200
201 static bool needs_cache_clean() { return _needs_cache_clean; }
202 static void set_needs_cache_clean(bool v) { _needs_cache_clean = v; }
203 static void clear_inline_caches(); // clear all inline caches
204
205 // Returns true if an own CodeHeap for the given CodeBlobType is available
206 static bool heap_available(int code_blob_type);
207
208 // Returns the CodeBlobType for the given nmethod
209 static int get_code_blob_type(nmethod* nm) {
210 return get_code_heap(nm)->code_blob_type();
211 }
212
213 // Returns the CodeBlobType for the given compilation level
214 static int get_code_blob_type(int comp_level) {
215 if (comp_level == CompLevel_none ||
216 comp_level == CompLevel_simple ||
217 comp_level == CompLevel_full_optimization) {
218 // Non profiled methods
219 return CodeBlobType::MethodNonProfiled;
220 } else if (comp_level == CompLevel_limited_profile ||
221 comp_level == CompLevel_full_profile) {
222 // Profiled methods
223 return CodeBlobType::MethodProfiled;
224 }
225 ShouldNotReachHere();
226 return 0;
227 }
228
229 static void verify_clean_inline_caches();
230 static void verify_icholder_relocations();
231
232 // Deoptimization
233 private:
234 static int mark_for_deoptimization(DepChange& changes);
235 #ifdef HOTSWAP
236 static int mark_for_evol_deoptimization(instanceKlassHandle dependee);
237 #endif // HOTSWAP
238
239 public:
240 static void mark_all_nmethods_for_deoptimization();
241 static int mark_for_deoptimization(Method* dependee);
242 static void make_marked_nmethods_not_entrant();
243
244 // Flushing and deoptimization
245 static void flush_dependents_on(instanceKlassHandle dependee);
246 #ifdef HOTSWAP
247 // Flushing and deoptimization in case of evolution
248 static void flush_evol_dependents_on(instanceKlassHandle dependee);
249 #endif // HOTSWAP
250 // Support for fullspeed debugging
251 static void flush_dependents_on_method(methodHandle dependee);
252
253 // tells how many nmethods have dependencies
254 static int number_of_nmethods_with_dependencies();
255
256 static int get_codemem_full_count(int code_blob_type) {
257 CodeHeap* heap = get_code_heap(code_blob_type);
258 return (heap != NULL) ? heap->full_count() : 0;
259 }
260 };
261
262
263 // Iterator to iterate over nmethods in the CodeCache.
264 class NMethodIterator : public StackObj {
265 private:
266 CodeBlob* _code_blob; // Current CodeBlob
267 int _code_blob_type; // Refers to current CodeHeap
268
269 public:
270 NMethodIterator() {
271 initialize(NULL); // Set to NULL, initialized by first call to next()
272 }
273
274 NMethodIterator(nmethod* nm) {
275 initialize(nm);
276 }
277
278 // Advance iterator to next nmethod
279 bool next() {
280 assert_locked_or_safepoint(CodeCache_lock);
281 assert(_code_blob_type < CodeBlobType::NumTypes, "end reached");
282
283 bool result = next_nmethod();
284 while (!result && (_code_blob_type < CodeBlobType::MethodProfiled)) {
285 // Advance to next code heap if segmented code cache
286 _code_blob_type++;
287 result = next_nmethod();
288 }
289 return result;
290 }
291
292 // Advance iterator to next alive nmethod
293 bool next_alive() {
294 bool result = next();
295 while(result && !_code_blob->is_alive()) {
296 result = next();
297 }
298 return result;
299 }
300
301 bool end() const { return _code_blob == NULL; }
302 nmethod* method() const { return (nmethod*)_code_blob; }
303
304 private:
305 // Initialize iterator to given nmethod
306 void initialize(nmethod* nm) {
307 _code_blob = (CodeBlob*)nm;
308 if (!SegmentedCodeCache) {
309 // Iterate over all CodeBlobs
310 _code_blob_type = CodeBlobType::All;
311 } else if (nm != NULL) {
312 _code_blob_type = CodeCache::get_code_blob_type(nm);
313 } else {
314 // Only iterate over method code heaps, starting with non-profiled
315 _code_blob_type = CodeBlobType::MethodNonProfiled;
316 }
317 }
318
319 // Advance iterator to the next nmethod in the current code heap
320 bool next_nmethod() {
321 // Get first method CodeBlob
322 if (_code_blob == NULL) {
323 _code_blob = CodeCache::first_blob(_code_blob_type);
324 if (_code_blob == NULL) {
325 return false;
326 } else if (_code_blob->is_nmethod()) {
327 return true;
328 }
329 }
330 // Search for next method CodeBlob
331 _code_blob = CodeCache::next_blob(_code_blob);
332 while (_code_blob != NULL && !_code_blob->is_nmethod()) {
333 _code_blob = CodeCache::next_blob(_code_blob);
334 }
335 return _code_blob != NULL;
336 }
337 };
338
339 #endif // SHARE_VM_CODE_CODECACHE_HPP