Thu, 05 Jun 2008 15:57:56 -0700
6711316: Open source the Garbage-First garbage collector
Summary: First mercurial integration of the code for the Garbage-First garbage collector.
Reviewed-by: apetrusenko, iveresov, jmasa, sgoldman, tonyp, ysr
duke@435 | 1 | /* |
duke@435 | 2 | * Copyright 2001-2007 Sun Microsystems, Inc. All Rights Reserved. |
duke@435 | 3 | * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. |
duke@435 | 4 | * |
duke@435 | 5 | * This code is free software; you can redistribute it and/or modify it |
duke@435 | 6 | * under the terms of the GNU General Public License version 2 only, as |
duke@435 | 7 | * published by the Free Software Foundation. |
duke@435 | 8 | * |
duke@435 | 9 | * This code is distributed in the hope that it will be useful, but WITHOUT |
duke@435 | 10 | * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or |
duke@435 | 11 | * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License |
duke@435 | 12 | * version 2 for more details (a copy is included in the LICENSE file that |
duke@435 | 13 | * accompanied this code). |
duke@435 | 14 | * |
duke@435 | 15 | * You should have received a copy of the GNU General Public License version |
duke@435 | 16 | * 2 along with this work; if not, write to the Free Software Foundation, |
duke@435 | 17 | * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. |
duke@435 | 18 | * |
duke@435 | 19 | * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara, |
duke@435 | 20 | * CA 95054 USA or visit www.sun.com if you need additional information or |
duke@435 | 21 | * have any questions. |
duke@435 | 22 | * |
duke@435 | 23 | */ |
duke@435 | 24 | |
duke@435 | 25 | // Inline allocation implementations. |
duke@435 | 26 | |
duke@435 | 27 | void CollectedHeap::post_allocation_setup_common(KlassHandle klass, |
duke@435 | 28 | HeapWord* obj, |
duke@435 | 29 | size_t size) { |
duke@435 | 30 | post_allocation_setup_no_klass_install(klass, obj, size); |
duke@435 | 31 | post_allocation_install_obj_klass(klass, oop(obj), (int) size); |
duke@435 | 32 | } |
duke@435 | 33 | |
duke@435 | 34 | void CollectedHeap::post_allocation_setup_no_klass_install(KlassHandle klass, |
duke@435 | 35 | HeapWord* objPtr, |
duke@435 | 36 | size_t size) { |
duke@435 | 37 | |
duke@435 | 38 | oop obj = (oop)objPtr; |
duke@435 | 39 | |
duke@435 | 40 | assert(obj != NULL, "NULL object pointer"); |
duke@435 | 41 | if (UseBiasedLocking && (klass() != NULL)) { |
duke@435 | 42 | obj->set_mark(klass->prototype_header()); |
duke@435 | 43 | } else { |
duke@435 | 44 | // May be bootstrapping |
duke@435 | 45 | obj->set_mark(markOopDesc::prototype()); |
duke@435 | 46 | } |
duke@435 | 47 | |
duke@435 | 48 | // support low memory notifications (no-op if not enabled) |
duke@435 | 49 | LowMemoryDetector::detect_low_memory_for_collected_pools(); |
duke@435 | 50 | } |
duke@435 | 51 | |
duke@435 | 52 | void CollectedHeap::post_allocation_install_obj_klass(KlassHandle klass, |
duke@435 | 53 | oop obj, |
duke@435 | 54 | int size) { |
duke@435 | 55 | // These asserts are kind of complicated because of klassKlass |
duke@435 | 56 | // and the beginning of the world. |
duke@435 | 57 | assert(klass() != NULL || !Universe::is_fully_initialized(), "NULL klass"); |
duke@435 | 58 | assert(klass() == NULL || klass()->is_klass(), "not a klass"); |
duke@435 | 59 | assert(klass() == NULL || klass()->klass_part() != NULL, "not a klass"); |
duke@435 | 60 | assert(obj != NULL, "NULL object pointer"); |
duke@435 | 61 | obj->set_klass(klass()); |
duke@435 | 62 | assert(!Universe::is_fully_initialized() || obj->blueprint() != NULL, |
duke@435 | 63 | "missing blueprint"); |
coleenp@548 | 64 | } |
duke@435 | 65 | |
coleenp@548 | 66 | // Support for jvmti and dtrace |
coleenp@548 | 67 | inline void post_allocation_notify(KlassHandle klass, oop obj) { |
duke@435 | 68 | // support for JVMTI VMObjectAlloc event (no-op if not enabled) |
duke@435 | 69 | JvmtiExport::vm_object_alloc_event_collector(obj); |
duke@435 | 70 | |
duke@435 | 71 | if (DTraceAllocProbes) { |
duke@435 | 72 | // support for Dtrace object alloc event (no-op most of the time) |
duke@435 | 73 | if (klass() != NULL && klass()->klass_part()->name() != NULL) { |
duke@435 | 74 | SharedRuntime::dtrace_object_alloc(obj); |
duke@435 | 75 | } |
duke@435 | 76 | } |
duke@435 | 77 | } |
duke@435 | 78 | |
duke@435 | 79 | void CollectedHeap::post_allocation_setup_obj(KlassHandle klass, |
duke@435 | 80 | HeapWord* obj, |
duke@435 | 81 | size_t size) { |
duke@435 | 82 | post_allocation_setup_common(klass, obj, size); |
duke@435 | 83 | assert(Universe::is_bootstrapping() || |
duke@435 | 84 | !((oop)obj)->blueprint()->oop_is_array(), "must not be an array"); |
coleenp@548 | 85 | // notify jvmti and dtrace |
coleenp@548 | 86 | post_allocation_notify(klass, (oop)obj); |
duke@435 | 87 | } |
duke@435 | 88 | |
duke@435 | 89 | void CollectedHeap::post_allocation_setup_array(KlassHandle klass, |
duke@435 | 90 | HeapWord* obj, |
duke@435 | 91 | size_t size, |
duke@435 | 92 | int length) { |
duke@435 | 93 | assert(length >= 0, "length should be non-negative"); |
coleenp@548 | 94 | post_allocation_setup_common(klass, obj, size); |
coleenp@548 | 95 | // Must set length after installing klass as set_klass zeros the length |
coleenp@548 | 96 | // field in UseCompressedOops |
duke@435 | 97 | ((arrayOop)obj)->set_length(length); |
duke@435 | 98 | assert(((oop)obj)->blueprint()->oop_is_array(), "must be an array"); |
coleenp@548 | 99 | // notify jvmti and dtrace (must be after length is set for dtrace) |
coleenp@548 | 100 | post_allocation_notify(klass, (oop)obj); |
duke@435 | 101 | } |
duke@435 | 102 | |
duke@435 | 103 | HeapWord* CollectedHeap::common_mem_allocate_noinit(size_t size, bool is_noref, TRAPS) { |
duke@435 | 104 | |
duke@435 | 105 | // Clear unhandled oops for memory allocation. Memory allocation might |
duke@435 | 106 | // not take out a lock if from tlab, so clear here. |
duke@435 | 107 | CHECK_UNHANDLED_OOPS_ONLY(THREAD->clear_unhandled_oops();) |
duke@435 | 108 | |
duke@435 | 109 | if (HAS_PENDING_EXCEPTION) { |
duke@435 | 110 | NOT_PRODUCT(guarantee(false, "Should not allocate with exception pending")); |
duke@435 | 111 | return NULL; // caller does a CHECK_0 too |
duke@435 | 112 | } |
duke@435 | 113 | |
duke@435 | 114 | // We may want to update this, is_noref objects might not be allocated in TLABs. |
duke@435 | 115 | HeapWord* result = NULL; |
duke@435 | 116 | if (UseTLAB) { |
duke@435 | 117 | result = CollectedHeap::allocate_from_tlab(THREAD, size); |
duke@435 | 118 | if (result != NULL) { |
duke@435 | 119 | assert(!HAS_PENDING_EXCEPTION, |
duke@435 | 120 | "Unexpected exception, will result in uninitialized storage"); |
duke@435 | 121 | return result; |
duke@435 | 122 | } |
duke@435 | 123 | } |
ysr@777 | 124 | bool gc_overhead_limit_was_exceeded = false; |
duke@435 | 125 | result = Universe::heap()->mem_allocate(size, |
duke@435 | 126 | is_noref, |
duke@435 | 127 | false, |
duke@435 | 128 | &gc_overhead_limit_was_exceeded); |
duke@435 | 129 | if (result != NULL) { |
duke@435 | 130 | NOT_PRODUCT(Universe::heap()-> |
duke@435 | 131 | check_for_non_bad_heap_word_value(result, size)); |
duke@435 | 132 | assert(!HAS_PENDING_EXCEPTION, |
duke@435 | 133 | "Unexpected exception, will result in uninitialized storage"); |
duke@435 | 134 | return result; |
duke@435 | 135 | } |
duke@435 | 136 | |
duke@435 | 137 | |
duke@435 | 138 | if (!gc_overhead_limit_was_exceeded) { |
duke@435 | 139 | // -XX:+HeapDumpOnOutOfMemoryError and -XX:OnOutOfMemoryError support |
duke@435 | 140 | report_java_out_of_memory("Java heap space"); |
duke@435 | 141 | |
duke@435 | 142 | if (JvmtiExport::should_post_resource_exhausted()) { |
duke@435 | 143 | JvmtiExport::post_resource_exhausted( |
duke@435 | 144 | JVMTI_RESOURCE_EXHAUSTED_OOM_ERROR | JVMTI_RESOURCE_EXHAUSTED_JAVA_HEAP, |
duke@435 | 145 | "Java heap space"); |
duke@435 | 146 | } |
duke@435 | 147 | |
duke@435 | 148 | THROW_OOP_0(Universe::out_of_memory_error_java_heap()); |
duke@435 | 149 | } else { |
duke@435 | 150 | // -XX:+HeapDumpOnOutOfMemoryError and -XX:OnOutOfMemoryError support |
duke@435 | 151 | report_java_out_of_memory("GC overhead limit exceeded"); |
duke@435 | 152 | |
duke@435 | 153 | if (JvmtiExport::should_post_resource_exhausted()) { |
duke@435 | 154 | JvmtiExport::post_resource_exhausted( |
duke@435 | 155 | JVMTI_RESOURCE_EXHAUSTED_OOM_ERROR | JVMTI_RESOURCE_EXHAUSTED_JAVA_HEAP, |
duke@435 | 156 | "GC overhead limit exceeded"); |
duke@435 | 157 | } |
duke@435 | 158 | |
duke@435 | 159 | THROW_OOP_0(Universe::out_of_memory_error_gc_overhead_limit()); |
duke@435 | 160 | } |
duke@435 | 161 | } |
duke@435 | 162 | |
duke@435 | 163 | HeapWord* CollectedHeap::common_mem_allocate_init(size_t size, bool is_noref, TRAPS) { |
duke@435 | 164 | HeapWord* obj = common_mem_allocate_noinit(size, is_noref, CHECK_NULL); |
duke@435 | 165 | init_obj(obj, size); |
duke@435 | 166 | return obj; |
duke@435 | 167 | } |
duke@435 | 168 | |
duke@435 | 169 | // Need to investigate, do we really want to throw OOM exception here? |
duke@435 | 170 | HeapWord* CollectedHeap::common_permanent_mem_allocate_noinit(size_t size, TRAPS) { |
duke@435 | 171 | if (HAS_PENDING_EXCEPTION) { |
duke@435 | 172 | NOT_PRODUCT(guarantee(false, "Should not allocate with exception pending")); |
duke@435 | 173 | return NULL; // caller does a CHECK_NULL too |
duke@435 | 174 | } |
duke@435 | 175 | |
duke@435 | 176 | #ifdef ASSERT |
duke@435 | 177 | if (CIFireOOMAt > 0 && THREAD->is_Compiler_thread() && |
duke@435 | 178 | ++_fire_out_of_memory_count >= CIFireOOMAt) { |
duke@435 | 179 | // For testing of OOM handling in the CI throw an OOM and see how |
duke@435 | 180 | // it does. Historically improper handling of these has resulted |
duke@435 | 181 | // in crashes which we really don't want to have in the CI. |
duke@435 | 182 | THROW_OOP_0(Universe::out_of_memory_error_perm_gen()); |
duke@435 | 183 | } |
duke@435 | 184 | #endif |
duke@435 | 185 | |
duke@435 | 186 | HeapWord* result = Universe::heap()->permanent_mem_allocate(size); |
duke@435 | 187 | if (result != NULL) { |
duke@435 | 188 | NOT_PRODUCT(Universe::heap()-> |
duke@435 | 189 | check_for_non_bad_heap_word_value(result, size)); |
duke@435 | 190 | assert(!HAS_PENDING_EXCEPTION, |
duke@435 | 191 | "Unexpected exception, will result in uninitialized storage"); |
duke@435 | 192 | return result; |
duke@435 | 193 | } |
duke@435 | 194 | // -XX:+HeapDumpOnOutOfMemoryError and -XX:OnOutOfMemoryError support |
duke@435 | 195 | report_java_out_of_memory("PermGen space"); |
duke@435 | 196 | |
duke@435 | 197 | if (JvmtiExport::should_post_resource_exhausted()) { |
duke@435 | 198 | JvmtiExport::post_resource_exhausted( |
duke@435 | 199 | JVMTI_RESOURCE_EXHAUSTED_OOM_ERROR, |
duke@435 | 200 | "PermGen space"); |
duke@435 | 201 | } |
duke@435 | 202 | |
duke@435 | 203 | THROW_OOP_0(Universe::out_of_memory_error_perm_gen()); |
duke@435 | 204 | } |
duke@435 | 205 | |
duke@435 | 206 | HeapWord* CollectedHeap::common_permanent_mem_allocate_init(size_t size, TRAPS) { |
duke@435 | 207 | HeapWord* obj = common_permanent_mem_allocate_noinit(size, CHECK_NULL); |
duke@435 | 208 | init_obj(obj, size); |
duke@435 | 209 | return obj; |
duke@435 | 210 | } |
duke@435 | 211 | |
duke@435 | 212 | HeapWord* CollectedHeap::allocate_from_tlab(Thread* thread, size_t size) { |
duke@435 | 213 | assert(UseTLAB, "should use UseTLAB"); |
duke@435 | 214 | |
duke@435 | 215 | HeapWord* obj = thread->tlab().allocate(size); |
duke@435 | 216 | if (obj != NULL) { |
duke@435 | 217 | return obj; |
duke@435 | 218 | } |
duke@435 | 219 | // Otherwise... |
duke@435 | 220 | return allocate_from_tlab_slow(thread, size); |
duke@435 | 221 | } |
duke@435 | 222 | |
duke@435 | 223 | void CollectedHeap::init_obj(HeapWord* obj, size_t size) { |
duke@435 | 224 | assert(obj != NULL, "cannot initialize NULL object"); |
duke@435 | 225 | const size_t hs = oopDesc::header_size(); |
duke@435 | 226 | assert(size >= hs, "unexpected object size"); |
duke@435 | 227 | Copy::fill_to_aligned_words(obj + hs, size - hs); |
duke@435 | 228 | } |
duke@435 | 229 | |
duke@435 | 230 | oop CollectedHeap::obj_allocate(KlassHandle klass, int size, TRAPS) { |
duke@435 | 231 | debug_only(check_for_valid_allocation_state()); |
duke@435 | 232 | assert(!Universe::heap()->is_gc_active(), "Allocation during gc not allowed"); |
duke@435 | 233 | assert(size >= 0, "int won't convert to size_t"); |
duke@435 | 234 | HeapWord* obj = common_mem_allocate_init(size, false, CHECK_NULL); |
duke@435 | 235 | post_allocation_setup_obj(klass, obj, size); |
duke@435 | 236 | NOT_PRODUCT(Universe::heap()->check_for_bad_heap_word_value(obj, size)); |
duke@435 | 237 | return (oop)obj; |
duke@435 | 238 | } |
duke@435 | 239 | |
duke@435 | 240 | oop CollectedHeap::array_allocate(KlassHandle klass, |
duke@435 | 241 | int size, |
duke@435 | 242 | int length, |
duke@435 | 243 | TRAPS) { |
duke@435 | 244 | debug_only(check_for_valid_allocation_state()); |
duke@435 | 245 | assert(!Universe::heap()->is_gc_active(), "Allocation during gc not allowed"); |
duke@435 | 246 | assert(size >= 0, "int won't convert to size_t"); |
duke@435 | 247 | HeapWord* obj = common_mem_allocate_init(size, false, CHECK_NULL); |
duke@435 | 248 | post_allocation_setup_array(klass, obj, size, length); |
duke@435 | 249 | NOT_PRODUCT(Universe::heap()->check_for_bad_heap_word_value(obj, size)); |
duke@435 | 250 | return (oop)obj; |
duke@435 | 251 | } |
duke@435 | 252 | |
duke@435 | 253 | oop CollectedHeap::large_typearray_allocate(KlassHandle klass, |
duke@435 | 254 | int size, |
duke@435 | 255 | int length, |
duke@435 | 256 | TRAPS) { |
duke@435 | 257 | debug_only(check_for_valid_allocation_state()); |
duke@435 | 258 | assert(!Universe::heap()->is_gc_active(), "Allocation during gc not allowed"); |
duke@435 | 259 | assert(size >= 0, "int won't convert to size_t"); |
duke@435 | 260 | HeapWord* obj = common_mem_allocate_init(size, true, CHECK_NULL); |
duke@435 | 261 | post_allocation_setup_array(klass, obj, size, length); |
duke@435 | 262 | NOT_PRODUCT(Universe::heap()->check_for_bad_heap_word_value(obj, size)); |
duke@435 | 263 | return (oop)obj; |
duke@435 | 264 | } |
duke@435 | 265 | |
duke@435 | 266 | oop CollectedHeap::permanent_obj_allocate(KlassHandle klass, int size, TRAPS) { |
duke@435 | 267 | oop obj = permanent_obj_allocate_no_klass_install(klass, size, CHECK_NULL); |
duke@435 | 268 | post_allocation_install_obj_klass(klass, obj, size); |
duke@435 | 269 | NOT_PRODUCT(Universe::heap()->check_for_bad_heap_word_value((HeapWord*) obj, |
duke@435 | 270 | size)); |
duke@435 | 271 | return obj; |
duke@435 | 272 | } |
duke@435 | 273 | |
duke@435 | 274 | oop CollectedHeap::permanent_obj_allocate_no_klass_install(KlassHandle klass, |
duke@435 | 275 | int size, |
duke@435 | 276 | TRAPS) { |
duke@435 | 277 | debug_only(check_for_valid_allocation_state()); |
duke@435 | 278 | assert(!Universe::heap()->is_gc_active(), "Allocation during gc not allowed"); |
duke@435 | 279 | assert(size >= 0, "int won't convert to size_t"); |
duke@435 | 280 | HeapWord* obj = common_permanent_mem_allocate_init(size, CHECK_NULL); |
duke@435 | 281 | post_allocation_setup_no_klass_install(klass, obj, size); |
duke@435 | 282 | NOT_PRODUCT(Universe::heap()->check_for_bad_heap_word_value(obj, size)); |
duke@435 | 283 | return (oop)obj; |
duke@435 | 284 | } |
duke@435 | 285 | |
duke@435 | 286 | oop CollectedHeap::permanent_array_allocate(KlassHandle klass, |
duke@435 | 287 | int size, |
duke@435 | 288 | int length, |
duke@435 | 289 | TRAPS) { |
duke@435 | 290 | debug_only(check_for_valid_allocation_state()); |
duke@435 | 291 | assert(!Universe::heap()->is_gc_active(), "Allocation during gc not allowed"); |
duke@435 | 292 | assert(size >= 0, "int won't convert to size_t"); |
duke@435 | 293 | HeapWord* obj = common_permanent_mem_allocate_init(size, CHECK_NULL); |
duke@435 | 294 | post_allocation_setup_array(klass, obj, size, length); |
duke@435 | 295 | NOT_PRODUCT(Universe::heap()->check_for_bad_heap_word_value(obj, size)); |
duke@435 | 296 | return (oop)obj; |
duke@435 | 297 | } |
duke@435 | 298 | |
duke@435 | 299 | // Returns "TRUE" if "p" is a method oop in the |
duke@435 | 300 | // current heap with high probability. NOTE: The main |
duke@435 | 301 | // current consumers of this interface are Forte:: |
duke@435 | 302 | // and ThreadProfiler::. In these cases, the |
duke@435 | 303 | // interpreter frame from which "p" came, may be |
duke@435 | 304 | // under construction when sampled asynchronously, so |
duke@435 | 305 | // the clients want to check that it represents a |
duke@435 | 306 | // valid method before using it. Nonetheless since |
duke@435 | 307 | // the clients do not typically lock out GC, the |
duke@435 | 308 | // predicate is_valid_method() is not stable, so |
duke@435 | 309 | // it is possible that by the time "p" is used, it |
duke@435 | 310 | // is no longer valid. |
duke@435 | 311 | inline bool CollectedHeap::is_valid_method(oop p) const { |
duke@435 | 312 | return |
duke@435 | 313 | p != NULL && |
duke@435 | 314 | |
duke@435 | 315 | // Check whether it is aligned at a HeapWord boundary. |
duke@435 | 316 | Space::is_aligned(p) && |
duke@435 | 317 | |
duke@435 | 318 | // Check whether "method" is in the allocated part of the |
duke@435 | 319 | // permanent generation -- this needs to be checked before |
duke@435 | 320 | // p->klass() below to avoid a SEGV (but see below |
duke@435 | 321 | // for a potential window of vulnerability). |
duke@435 | 322 | is_permanent((void*)p) && |
duke@435 | 323 | |
duke@435 | 324 | // See if GC is active; however, there is still an |
duke@435 | 325 | // apparently unavoidable window after this call |
duke@435 | 326 | // and before the client of this interface uses "p". |
duke@435 | 327 | // If the client chooses not to lock out GC, then |
duke@435 | 328 | // it's a risk the client must accept. |
duke@435 | 329 | !is_gc_active() && |
duke@435 | 330 | |
duke@435 | 331 | // Check that p is a methodOop. |
duke@435 | 332 | p->klass() == Universe::methodKlassObj(); |
duke@435 | 333 | } |
duke@435 | 334 | |
duke@435 | 335 | |
duke@435 | 336 | #ifndef PRODUCT |
duke@435 | 337 | |
duke@435 | 338 | inline bool |
duke@435 | 339 | CollectedHeap::promotion_should_fail(volatile size_t* count) { |
duke@435 | 340 | // Access to count is not atomic; the value does not have to be exact. |
duke@435 | 341 | if (PromotionFailureALot) { |
duke@435 | 342 | const size_t gc_num = total_collections(); |
duke@435 | 343 | const size_t elapsed_gcs = gc_num - _promotion_failure_alot_gc_number; |
duke@435 | 344 | if (elapsed_gcs >= PromotionFailureALotInterval) { |
duke@435 | 345 | // Test for unsigned arithmetic wrap-around. |
duke@435 | 346 | if (++*count >= PromotionFailureALotCount) { |
duke@435 | 347 | *count = 0; |
duke@435 | 348 | return true; |
duke@435 | 349 | } |
duke@435 | 350 | } |
duke@435 | 351 | } |
duke@435 | 352 | return false; |
duke@435 | 353 | } |
duke@435 | 354 | |
duke@435 | 355 | inline bool CollectedHeap::promotion_should_fail() { |
duke@435 | 356 | return promotion_should_fail(&_promotion_failure_alot_count); |
duke@435 | 357 | } |
duke@435 | 358 | |
duke@435 | 359 | inline void CollectedHeap::reset_promotion_should_fail(volatile size_t* count) { |
duke@435 | 360 | if (PromotionFailureALot) { |
duke@435 | 361 | _promotion_failure_alot_gc_number = total_collections(); |
duke@435 | 362 | *count = 0; |
duke@435 | 363 | } |
duke@435 | 364 | } |
duke@435 | 365 | |
duke@435 | 366 | inline void CollectedHeap::reset_promotion_should_fail() { |
duke@435 | 367 | reset_promotion_should_fail(&_promotion_failure_alot_count); |
duke@435 | 368 | } |
duke@435 | 369 | #endif // #ifndef PRODUCT |