Mercurial > hg > graal-compiler
annotate src/share/vm/memory/sharedHeap.hpp @ 1833:8b10f48633dc
6984287: Regularize how GC parallel workers are specified.
Summary: Associate number of GC workers with the workgang as opposed to the task.
Reviewed-by: johnc, ysr
| author | jmasa |
|---|---|
| date | Mon, 20 Sep 2010 14:38:38 -0700 |
| parents | c18cbe5936b8 |
| children | f95d63e2154a |
| rev | line source |
|---|---|
| 0 | 1 /* |
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2 * Copyright (c) 2000, 2010, Oracle and/or its affiliates. All rights reserved. |
| 0 | 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 * | |
|
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19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA |
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20 * or visit www.oracle.com if you need additional information or have any |
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21 * questions. |
| 0 | 22 * |
| 23 */ | |
| 24 | |
| 25 // A "SharedHeap" is an implementation of a java heap for HotSpot. This | |
| 26 // is an abstract class: there may be many different kinds of heaps. This | |
| 27 // class defines the functions that a heap must implement, and contains | |
| 28 // infrastructure common to all heaps. | |
| 29 | |
| 30 class PermGen; | |
| 31 class Generation; | |
| 32 class BarrierSet; | |
| 33 class GenRemSet; | |
| 34 class Space; | |
| 35 class SpaceClosure; | |
| 36 class OopClosure; | |
| 37 class OopsInGenClosure; | |
| 38 class ObjectClosure; | |
| 39 class SubTasksDone; | |
| 40 class WorkGang; | |
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41 class FlexibleWorkGang; |
| 0 | 42 class CollectorPolicy; |
| 43 class KlassHandle; | |
| 44 | |
| 45 class SharedHeap : public CollectedHeap { | |
| 46 friend class VMStructs; | |
| 47 | |
| 342 | 48 friend class VM_GC_Operation; |
| 49 friend class VM_CGC_Operation; | |
| 50 | |
| 0 | 51 private: |
| 52 // For claiming strong_roots tasks. | |
| 53 SubTasksDone* _process_strong_tasks; | |
| 54 | |
| 55 protected: | |
| 56 // There should be only a single instance of "SharedHeap" in a program. | |
| 57 // This is enforced with the protected constructor below, which will also | |
| 58 // set the static pointer "_sh" to that instance. | |
| 59 static SharedHeap* _sh; | |
| 60 | |
| 61 // All heaps contain a "permanent generation." This is some ways | |
| 62 // similar to a generation in a generational system, in other ways not. | |
| 63 // See the "PermGen" class. | |
| 64 PermGen* _perm_gen; | |
| 65 | |
| 66 // and the Gen Remembered Set, at least one good enough to scan the perm | |
| 67 // gen. | |
| 68 GenRemSet* _rem_set; | |
| 69 | |
| 70 // A gc policy, controls global gc resource issues | |
| 71 CollectorPolicy *_collector_policy; | |
| 72 | |
| 73 // See the discussion below, in the specification of the reader function | |
| 74 // for this variable. | |
| 75 int _strong_roots_parity; | |
| 76 | |
| 77 // If we're doing parallel GC, use this gang of threads. | |
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78 FlexibleWorkGang* _workers; |
| 0 | 79 |
| 80 // Number of parallel threads currently working on GC tasks. | |
| 81 // O indicates use sequential code; 1 means use parallel code even with | |
| 82 // only one thread, for performance testing purposes. | |
| 83 int _n_par_threads; | |
| 84 | |
| 85 // Full initialization is done in a concrete subtype's "initialize" | |
| 86 // function. | |
| 87 SharedHeap(CollectorPolicy* policy_); | |
| 88 | |
| 342 | 89 // Returns true if the calling thread holds the heap lock, |
| 90 // or the calling thread is a par gc thread and the heap_lock is held | |
| 91 // by the vm thread doing a gc operation. | |
| 92 bool heap_lock_held_for_gc(); | |
| 93 // True if the heap_lock is held by the a non-gc thread invoking a gc | |
| 94 // operation. | |
| 95 bool _thread_holds_heap_lock_for_gc; | |
| 96 | |
| 0 | 97 public: |
| 98 static SharedHeap* heap() { return _sh; } | |
| 99 | |
| 100 CollectorPolicy *collector_policy() const { return _collector_policy; } | |
| 101 | |
| 102 void set_barrier_set(BarrierSet* bs); | |
| 103 | |
| 104 // Does operations required after initialization has been done. | |
| 105 virtual void post_initialize(); | |
| 106 | |
| 107 // Initialization of ("weak") reference processing support | |
| 108 virtual void ref_processing_init(); | |
| 109 | |
| 110 void set_perm(PermGen* perm_gen) { _perm_gen = perm_gen; } | |
| 111 | |
| 112 // This function returns the "GenRemSet" object that allows us to scan | |
| 113 // generations; at least the perm gen, possibly more in a fully | |
| 114 // generational heap. | |
| 115 GenRemSet* rem_set() { return _rem_set; } | |
| 116 | |
| 117 // These function return the "permanent" generation, in which | |
| 118 // reflective objects are allocated and stored. Two versions, the second | |
| 119 // of which returns the view of the perm gen as a generation. | |
| 120 PermGen* perm() const { return _perm_gen; } | |
| 121 Generation* perm_gen() const { return _perm_gen->as_gen(); } | |
| 122 | |
| 123 // Iteration functions. | |
| 124 void oop_iterate(OopClosure* cl) = 0; | |
| 125 | |
| 126 // Same as above, restricted to a memory region. | |
| 127 virtual void oop_iterate(MemRegion mr, OopClosure* cl) = 0; | |
| 128 | |
| 129 // Iterate over all objects allocated since the last collection, calling | |
| 130 // "cl->do_object" on each. The heap must have been initialized properly | |
| 131 // to support this function, or else this call will fail. | |
| 132 virtual void object_iterate_since_last_GC(ObjectClosure* cl) = 0; | |
| 133 | |
| 134 // Iterate over all spaces in use in the heap, in an undefined order. | |
| 135 virtual void space_iterate(SpaceClosure* cl) = 0; | |
| 136 | |
| 137 // A SharedHeap will contain some number of spaces. This finds the | |
| 138 // space whose reserved area contains the given address, or else returns | |
| 139 // NULL. | |
| 140 virtual Space* space_containing(const void* addr) const = 0; | |
| 141 | |
| 142 bool no_gc_in_progress() { return !is_gc_active(); } | |
| 143 | |
| 144 // Some collectors will perform "process_strong_roots" in parallel. | |
| 145 // Such a call will involve claiming some fine-grained tasks, such as | |
| 146 // scanning of threads. To make this process simpler, we provide the | |
| 147 // "strong_roots_parity()" method. Collectors that start parallel tasks | |
| 148 // whose threads invoke "process_strong_roots" must | |
| 149 // call "change_strong_roots_parity" in sequential code starting such a | |
| 150 // task. (This also means that a parallel thread may only call | |
| 151 // process_strong_roots once.) | |
| 152 // | |
| 153 // For calls to process_strong_roots by sequential code, the parity is | |
| 154 // updated automatically. | |
| 155 // | |
| 156 // The idea is that objects representing fine-grained tasks, such as | |
| 157 // threads, will contain a "parity" field. A task will is claimed in the | |
| 158 // current "process_strong_roots" call only if its parity field is the | |
| 159 // same as the "strong_roots_parity"; task claiming is accomplished by | |
| 160 // updating the parity field to the strong_roots_parity with a CAS. | |
| 161 // | |
| 162 // If the client meats this spec, then strong_roots_parity() will have | |
| 163 // the following properties: | |
| 164 // a) to return a different value than was returned before the last | |
| 165 // call to change_strong_roots_parity, and | |
| 166 // c) to never return a distinguished value (zero) with which such | |
| 167 // task-claiming variables may be initialized, to indicate "never | |
| 168 // claimed". | |
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169 private: |
| 0 | 170 void change_strong_roots_parity(); |
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171 public: |
| 0 | 172 int strong_roots_parity() { return _strong_roots_parity; } |
| 173 | |
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174 // Call these in sequential code around process_strong_roots. |
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175 // strong_roots_prologue calls change_strong_roots_parity, if |
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176 // parallel tasks are enabled. |
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177 class StrongRootsScope : public MarkingCodeBlobClosure::MarkScope { |
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178 public: |
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179 StrongRootsScope(SharedHeap* outer, bool activate = true); |
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180 ~StrongRootsScope(); |
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181 }; |
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182 friend class StrongRootsScope; |
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183 |
| 0 | 184 enum ScanningOption { |
| 185 SO_None = 0x0, | |
| 186 SO_AllClasses = 0x1, | |
| 187 SO_SystemClasses = 0x2, | |
| 188 SO_Symbols = 0x4, | |
| 189 SO_Strings = 0x8, | |
| 190 SO_CodeCache = 0x10 | |
| 191 }; | |
| 192 | |
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193 FlexibleWorkGang* workers() const { return _workers; } |
| 0 | 194 |
| 195 // Sets the number of parallel threads that will be doing tasks | |
| 196 // (such as process strong roots) subsequently. | |
| 197 virtual void set_par_threads(int t); | |
| 198 | |
| 199 // Number of threads currently working on GC tasks. | |
| 200 int n_par_threads() { return _n_par_threads; } | |
| 201 | |
| 202 // Invoke the "do_oop" method the closure "roots" on all root locations. | |
| 203 // If "collecting_perm_gen" is false, then roots that may only contain | |
| 204 // references to permGen objects are not scanned. If true, the | |
| 205 // "perm_gen" closure is applied to all older-to-younger refs in the | |
| 206 // permanent generation. The "so" argument determines which of roots | |
| 207 // the closure is applied to: | |
| 208 // "SO_None" does none; | |
| 209 // "SO_AllClasses" applies the closure to all entries in the SystemDictionary; | |
| 210 // "SO_SystemClasses" to all the "system" classes and loaders; | |
| 211 // "SO_Symbols" applies the closure to all entries in SymbolsTable; | |
| 212 // "SO_Strings" applies the closure to all entries in StringTable; | |
| 213 // "SO_CodeCache" applies the closure to all elements of the CodeCache. | |
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214 void process_strong_roots(bool activate_scope, |
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215 bool collecting_perm_gen, |
| 0 | 216 ScanningOption so, |
| 217 OopClosure* roots, | |
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218 CodeBlobClosure* code_roots, |
| 0 | 219 OopsInGenClosure* perm_blk); |
| 220 | |
| 221 // Apply "blk" to all the weak roots of the system. These include | |
| 222 // JNI weak roots, the code cache, system dictionary, symbol table, | |
| 223 // string table. | |
| 224 void process_weak_roots(OopClosure* root_closure, | |
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225 CodeBlobClosure* code_roots, |
| 0 | 226 OopClosure* non_root_closure); |
| 227 | |
| 228 // The functions below are helper functions that a subclass of | |
| 229 // "SharedHeap" can use in the implementation of its virtual | |
| 230 // functions. | |
| 231 | |
| 342 | 232 public: |
| 0 | 233 |
| 234 // Do anything common to GC's. | |
| 235 virtual void gc_prologue(bool full) = 0; | |
| 236 virtual void gc_epilogue(bool full) = 0; | |
| 237 | |
| 238 // | |
| 239 // New methods from CollectedHeap | |
| 240 // | |
| 241 | |
| 242 size_t permanent_capacity() const { | |
| 243 assert(perm_gen(), "NULL perm gen"); | |
| 244 return perm_gen()->capacity(); | |
| 245 } | |
| 246 | |
| 247 size_t permanent_used() const { | |
| 248 assert(perm_gen(), "NULL perm gen"); | |
| 249 return perm_gen()->used(); | |
| 250 } | |
| 251 | |
| 252 bool is_in_permanent(const void *p) const { | |
| 253 assert(perm_gen(), "NULL perm gen"); | |
| 254 return perm_gen()->is_in_reserved(p); | |
| 255 } | |
| 256 | |
| 257 // Different from is_in_permanent in that is_in_permanent | |
| 258 // only checks if p is in the reserved area of the heap | |
| 259 // and this checks to see if it in the commited area. | |
| 260 // This is typically used by things like the forte stackwalker | |
| 261 // during verification of suspicious frame values. | |
| 262 bool is_permanent(const void *p) const { | |
| 263 assert(perm_gen(), "NULL perm gen"); | |
| 264 return perm_gen()->is_in(p); | |
| 265 } | |
| 266 | |
| 267 HeapWord* permanent_mem_allocate(size_t size) { | |
| 268 assert(perm_gen(), "NULL perm gen"); | |
| 269 return _perm_gen->mem_allocate(size); | |
| 270 } | |
| 271 | |
| 272 void permanent_oop_iterate(OopClosure* cl) { | |
| 273 assert(perm_gen(), "NULL perm gen"); | |
| 274 _perm_gen->oop_iterate(cl); | |
| 275 } | |
| 276 | |
| 277 void permanent_object_iterate(ObjectClosure* cl) { | |
| 278 assert(perm_gen(), "NULL perm gen"); | |
| 279 _perm_gen->object_iterate(cl); | |
| 280 } | |
| 281 | |
| 282 // Some utilities. | |
| 342 | 283 void print_size_transition(outputStream* out, |
| 284 size_t bytes_before, | |
| 0 | 285 size_t bytes_after, |
| 286 size_t capacity); | |
| 287 }; |