1 /*
2 * Copyright (c) 1997, 2013, 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 "memory/allocation.hpp"
30 #include "memory/heap.hpp"
31 #include "oops/instanceKlass.hpp"
32 #include "oops/oopsHierarchy.hpp"
33 #include "runtime/mutexLocker.hpp"
34
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-methods: Non-methods 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 // Depending on the availability of compilers and TieredCompilation there
52 // may be fewer heaps. The size of the code heaps depends on the values of
53 // ReservedCodeCacheSize, NonProfiledCodeHeapSize and ProfiledCodeHeapSize
54 // (see CodeCache::heap_available(..) and CodeCache::initialize_heaps(..)
55 // for details).
56 //
57 // Code cache segmentation is controlled by the flag SegmentedCodeCache.
58 // If turned off, all code types are stored in a single code heap. By default
59 // code cache segmentation is turned on if TieredCompilation is enabled and
60 // ReservedCodeCacheSize >= 240 MB.
61 //
62 // All methods of the CodeCache accepting a CodeBlobType only apply to
63 // CodeBlobs of the given type. For example, iteration over the
64 // CodeBlobs of a specific type can be done by using CodeCache::first_blob(..)
65 // and CodeCache::next_blob(..) and providing the corresponding CodeBlobType.
66 //
67 // IMPORTANT: If you add new CodeHeaps to the code cache or change the
68 // existing ones, make sure to adapt the dtrace scripts (jhelper.d) for
69 // Solaris and BSD.
70
71 class OopClosure;
72 class DepChange;
73
74 class CodeCache : AllStatic {
75 friend class VMStructs;
76 private:
77 // CodeHeaps of the cache
78 static GrowableArray<CodeHeap*>* _heaps;
79
80 static address _low_bound; // Lower bound of CodeHeap addresses
81 static address _high_bound; // Upper bound of CodeHeap addresses
82 static int _number_of_blobs; // Total number of CodeBlobs in the cache
83 static int _number_of_adapters; // Total number of Adapters in the cache
84 static int _number_of_nmethods; // Total number of nmethods in the cache
85 static int _number_of_nmethods_with_dependencies; // Total number of nmethods with dependencies
86 static bool _needs_cache_clean; // True if inline caches of the nmethods needs to be flushed
87 static nmethod* _scavenge_root_nmethods; // linked via nm->scavenge_root_link()
88 static int _codemem_full_count; // Number of times a CodeHeap in the cache was full
89
90 static void mark_scavenge_root_nmethods() PRODUCT_RETURN;
91 static void verify_perm_nmethods(CodeBlobClosure* f_or_null) PRODUCT_RETURN;
92
93 // CodeHeap management
94 static void initialize_heaps(); // Initializes the CodeHeaps
95 // Creates a new heap with the given name and size, containing CodeBlobs of the given type
96 static void add_heap(ReservedSpace rs, const char* name, size_t size_initial, int code_blob_type);
97 static CodeHeap* get_code_heap(int code_blob_type); // Returns the CodeHeap for the given CodeBlobType
98 static bool heap_available(int code_blob_type); // Returns true if a CodeHeap for the given CodeBlobType is available
99 static ReservedCodeSpace reserve_heap_memory(size_t size); // Reserves one continuous chunk of memory for the CodeHeaps
100
101 // Iteration
102 static CodeBlob* first_blob(CodeHeap* heap); // Returns the first CodeBlob on the given CodeHeap
103 static CodeBlob* next_blob(CodeHeap* heap, CodeBlob* cb); // Returns the first alive CodeBlob on the given CodeHeap
104 static CodeBlob* first_alive_blob(CodeHeap* heap); // Returns the next CodeBlob on the given CodeHeap succeeding the given CodeBlob
105 static CodeBlob* next_alive_blob(CodeHeap* heap, CodeBlob* cb); // Returns the next alive CodeBlob on the given CodeHeap succeeding the given CodeBlob
106
107 static size_t bytes_allocated_in_freelists();
108 static int allocated_segments();
109 static size_t freelists_length();
110
111 public:
112 // Initialization
113 static void initialize();
114
115 // Allocation/administration
116 static CodeBlob* allocate(int size, int code_blob_type, bool is_critical = false); // allocates a new CodeBlob
117 static void commit(CodeBlob* cb); // called when the allocated CodeBlob has been filled
118 static int alignment_unit(); // guaranteed alignment of all CodeBlobs
119 static int alignment_offset(); // guaranteed offset of first CodeBlob byte within alignment unit (i.e., allocation header)
120 static void free(CodeBlob* cb, int code_blob_type); // frees a CodeBlob
121 static bool contains(void *p); // returns whether p is included
122 static void blobs_do(void f(CodeBlob* cb)); // iterates over all CodeBlobs
123 static void blobs_do(CodeBlobClosure* f); // iterates over all CodeBlobs
124 static void nmethods_do(void f(nmethod* nm)); // iterates over all nmethods
125 static void alive_nmethods_do(void f(nmethod* nm)); // iterates over all alive nmethods
126
127 // Lookup
128 static CodeBlob* find_blob(void* start); // Returns the CodeBlob containing the given address
129 static CodeBlob* find_blob_unsafe(void* start); // Same as find_blob but does not fail if looking up a zombie method
130 static nmethod* find_nmethod(void* start); // Returns the nmethod containing the given address
131
132 // Iteration
133 // Returns the first CodeBlob of the given type
134 static CodeBlob* first_blob(int code_blob_type) { return first_blob(get_code_heap(code_blob_type)); }
135 // Returns the next CodeBlob of the given type succeeding the given CodeBlob
136 static CodeBlob* next_blob(CodeBlob* cb, int code_blob_type) { return next_blob(get_code_heap(code_blob_type), cb); }
137
138 static int nof_blobs() { return _number_of_blobs; } // Returns the total number of CodeBlobs in the cache
139 static int nof_adapters() { return _number_of_adapters; } // Returns the total number of Adapters in the cache
140 static int nof_nmethods() { return _number_of_nmethods; } // Returns the total number of nmethods in the cache
141
142 // GC support
143 static void gc_epilogue();
144 static void gc_prologue();
145 static void verify_oops();
146 // If "unloading_occurred" is true, then unloads (i.e., breaks root links
147 // to) any unmarked codeBlobs in the cache. Sets "marked_for_unloading"
148 // to "true" iff some code got unloaded.
149 static void do_unloading(BoolObjectClosure* is_alive, bool unloading_occurred);
150 static void oops_do(OopClosure* f) {
151 CodeBlobToOopClosure oopc(f, /*do_marking=*/ false);
152 blobs_do(&oopc);
153 }
154 static void asserted_non_scavengable_nmethods_do(CodeBlobClosure* f = NULL) PRODUCT_RETURN;
155 static void scavenge_root_nmethods_do(CodeBlobClosure* f);
156
157 static nmethod* scavenge_root_nmethods() { return _scavenge_root_nmethods; }
158 static void set_scavenge_root_nmethods(nmethod* nm) { _scavenge_root_nmethods = nm; }
159 static void add_scavenge_root_nmethod(nmethod* nm);
160 static void drop_scavenge_root_nmethod(nmethod* nm);
161 static void prune_scavenge_root_nmethods();
162
163 // Printing/debugging
164 static void print(); // prints summary
165 static void print_internals();
166 static void print_memory_overhead();
167 static void verify(); // verifies the code cache
168 static void print_trace(const char* event, CodeBlob* cb, int size = 0) PRODUCT_RETURN;
169 static void print_summary(outputStream* st, bool detailed = true); // Prints a summary of the code cache usage
170 static void log_state(outputStream* st);
171 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"); }
172 static void report_codemem_full(int code_blob_type, bool print);
173
174 // The full limits of the codeCache
175 static address low_bound() { return _low_bound; }
176 static address high_bound() { return _high_bound; }
177
178 // Profiling
179 static size_t capacity(int code_blob_type) { return heap_available(code_blob_type) ? get_code_heap(code_blob_type)->capacity() : 0; }
180 static size_t capacity();
181 static size_t unallocated_capacity(int code_blob_type) { return heap_available(code_blob_type) ? get_code_heap(code_blob_type)->unallocated_capacity() : 0; }
182 static size_t unallocated_capacity();
183 static size_t max_capacity(int code_blob_type) { return heap_available(code_blob_type) ? get_code_heap(code_blob_type)->max_capacity() : 0; }
184 static size_t max_capacity();
185
186 static bool is_full(int* code_blob_type);
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 // Deoptimization
210 static int mark_for_deoptimization(DepChange& changes);
211 #ifdef HOTSWAP
212 static int mark_for_evol_deoptimization(instanceKlassHandle dependee);
213 #endif // HOTSWAP
214
215 static void mark_all_nmethods_for_deoptimization();
216 static int mark_for_deoptimization(Method* dependee);
217 static void make_marked_nmethods_zombies();
218 static void make_marked_nmethods_not_entrant();
219
220 // tells how many nmethods have dependencies
221 static int number_of_nmethods_with_dependencies();
222
223 static int get_codemem_full_count() { return _codemem_full_count; }
224 };
225
226
227 // Iterator to iterate over nmethods in the CodeCache.
228 class NMethodIterator : public StackObj {
229 private:
230 int _code_blob_type; // Refers to current CodeHeap
231 CodeBlob* _code_blob; // Current CodeBlob
232
233 public:
234 NMethodIterator() {
235 if (SegmentedCodeCache) {
236 // Only iterate over method code heaps
237 _code_blob_type = CodeBlobType::MethodNonProfiled;
238 } else {
239 // Iterate over all CodeBlobs
240 _code_blob_type = CodeBlobType::All;
241 }
242 // Initialize to NULL, first call to next() sets _code_blob
243 _code_blob = NULL;
244 }
245
246 // Advance iterator to next nmethod
247 bool next() {
248 assert_locked_or_safepoint(CodeCache_lock);
249 assert(_code_blob_type < CodeBlobType::NumTypes, "end reached");
250
251 if (SegmentedCodeCache) {
252 // Code cache is segmented, iterate over all method heaps
253 // Get first CodeBlob
254 if (_code_blob == NULL) {
255 _code_blob = CodeCache::first_blob(_code_blob_type);
256 return _code_blob != NULL;
257 }
258 // Get next CodeBlob
259 _code_blob = CodeCache::next_blob(_code_blob, _code_blob_type);
260 while (_code_blob == NULL && _code_blob_type < CodeBlobType::MethodProfiled) {
261 // Advance to next CodeBlobType if CodeBlob is NULL
262 _code_blob_type++;
263 _code_blob = CodeCache::first_blob(_code_blob_type);
264 }
265 } else {
266 // Code cache is not segmented, search for method code blobs
267 // Get first method CodeBlob
268 if (_code_blob == NULL) {
269 _code_blob = CodeCache::first_blob(_code_blob_type);
270 if (_code_blob->is_nmethod()) {
271 return true;
272 }
273 }
274 // Search for next method CodeBlob
275 _code_blob = CodeCache::next_blob(_code_blob, _code_blob_type);
276 while (_code_blob != NULL && !_code_blob->is_nmethod()) {
277 _code_blob = CodeCache::next_blob(_code_blob, _code_blob_type);
278 }
279 }
280 // End reached?
281 return _code_blob != NULL;
282 }
283
284 bool end() const { return _code_blob == NULL; }
285 nmethod* method() const { return (nmethod*)_code_blob; }
286 };
287
288 #endif // SHARE_VM_CODE_CODECACHE_HPP