1.1 --- /dev/null Thu Jan 01 00:00:00 1970 +0000
1.2 +++ b/src/share/vm/gc_implementation/g1/g1CollectedHeap.hpp Wed Apr 27 01:25:04 2016 +0800
1.3 @@ -0,0 +1,1979 @@
1.4 +/*
1.5 + * Copyright (c) 2001, 2014, Oracle and/or its affiliates. All rights reserved.
1.6 + * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
1.7 + *
1.8 + * This code is free software; you can redistribute it and/or modify it
1.9 + * under the terms of the GNU General Public License version 2 only, as
1.10 + * published by the Free Software Foundation.
1.11 + *
1.12 + * This code is distributed in the hope that it will be useful, but WITHOUT
1.13 + * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
1.14 + * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
1.15 + * version 2 for more details (a copy is included in the LICENSE file that
1.16 + * accompanied this code).
1.17 + *
1.18 + * You should have received a copy of the GNU General Public License version
1.19 + * 2 along with this work; if not, write to the Free Software Foundation,
1.20 + * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
1.21 + *
1.22 + * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
1.23 + * or visit www.oracle.com if you need additional information or have any
1.24 + * questions.
1.25 + *
1.26 + */
1.27 +
1.28 +#ifndef SHARE_VM_GC_IMPLEMENTATION_G1_G1COLLECTEDHEAP_HPP
1.29 +#define SHARE_VM_GC_IMPLEMENTATION_G1_G1COLLECTEDHEAP_HPP
1.30 +
1.31 +#include "gc_implementation/g1/concurrentMark.hpp"
1.32 +#include "gc_implementation/g1/evacuationInfo.hpp"
1.33 +#include "gc_implementation/g1/g1AllocRegion.hpp"
1.34 +#include "gc_implementation/g1/g1HRPrinter.hpp"
1.35 +#include "gc_implementation/g1/g1MonitoringSupport.hpp"
1.36 +#include "gc_implementation/g1/g1RemSet.hpp"
1.37 +#include "gc_implementation/g1/g1SATBCardTableModRefBS.hpp"
1.38 +#include "gc_implementation/g1/g1YCTypes.hpp"
1.39 +#include "gc_implementation/g1/heapRegionSeq.hpp"
1.40 +#include "gc_implementation/g1/heapRegionSet.hpp"
1.41 +#include "gc_implementation/shared/hSpaceCounters.hpp"
1.42 +#include "gc_implementation/shared/parGCAllocBuffer.hpp"
1.43 +#include "memory/barrierSet.hpp"
1.44 +#include "memory/memRegion.hpp"
1.45 +#include "memory/sharedHeap.hpp"
1.46 +#include "utilities/stack.hpp"
1.47 +
1.48 +// A "G1CollectedHeap" is an implementation of a java heap for HotSpot.
1.49 +// It uses the "Garbage First" heap organization and algorithm, which
1.50 +// may combine concurrent marking with parallel, incremental compaction of
1.51 +// heap subsets that will yield large amounts of garbage.
1.52 +
1.53 +// Forward declarations
1.54 +class HeapRegion;
1.55 +class HRRSCleanupTask;
1.56 +class GenerationSpec;
1.57 +class OopsInHeapRegionClosure;
1.58 +class G1KlassScanClosure;
1.59 +class G1ScanHeapEvacClosure;
1.60 +class ObjectClosure;
1.61 +class SpaceClosure;
1.62 +class CompactibleSpaceClosure;
1.63 +class Space;
1.64 +class G1CollectorPolicy;
1.65 +class GenRemSet;
1.66 +class G1RemSet;
1.67 +class HeapRegionRemSetIterator;
1.68 +class ConcurrentMark;
1.69 +class ConcurrentMarkThread;
1.70 +class ConcurrentG1Refine;
1.71 +class ConcurrentGCTimer;
1.72 +class GenerationCounters;
1.73 +class STWGCTimer;
1.74 +class G1NewTracer;
1.75 +class G1OldTracer;
1.76 +class EvacuationFailedInfo;
1.77 +class nmethod;
1.78 +class Ticks;
1.79 +
1.80 +typedef OverflowTaskQueue<StarTask, mtGC> RefToScanQueue;
1.81 +typedef GenericTaskQueueSet<RefToScanQueue, mtGC> RefToScanQueueSet;
1.82 +
1.83 +typedef int RegionIdx_t; // needs to hold [ 0..max_regions() )
1.84 +typedef int CardIdx_t; // needs to hold [ 0..CardsPerRegion )
1.85 +
1.86 +enum GCAllocPurpose {
1.87 + GCAllocForTenured,
1.88 + GCAllocForSurvived,
1.89 + GCAllocPurposeCount
1.90 +};
1.91 +
1.92 +class YoungList : public CHeapObj<mtGC> {
1.93 +private:
1.94 + G1CollectedHeap* _g1h;
1.95 +
1.96 + HeapRegion* _head;
1.97 +
1.98 + HeapRegion* _survivor_head;
1.99 + HeapRegion* _survivor_tail;
1.100 +
1.101 + HeapRegion* _curr;
1.102 +
1.103 + uint _length;
1.104 + uint _survivor_length;
1.105 +
1.106 + size_t _last_sampled_rs_lengths;
1.107 + size_t _sampled_rs_lengths;
1.108 +
1.109 + void empty_list(HeapRegion* list);
1.110 +
1.111 +public:
1.112 + YoungList(G1CollectedHeap* g1h);
1.113 +
1.114 + void push_region(HeapRegion* hr);
1.115 + void add_survivor_region(HeapRegion* hr);
1.116 +
1.117 + void empty_list();
1.118 + bool is_empty() { return _length == 0; }
1.119 + uint length() { return _length; }
1.120 + uint survivor_length() { return _survivor_length; }
1.121 +
1.122 + // Currently we do not keep track of the used byte sum for the
1.123 + // young list and the survivors and it'd be quite a lot of work to
1.124 + // do so. When we'll eventually replace the young list with
1.125 + // instances of HeapRegionLinkedList we'll get that for free. So,
1.126 + // we'll report the more accurate information then.
1.127 + size_t eden_used_bytes() {
1.128 + assert(length() >= survivor_length(), "invariant");
1.129 + return (size_t) (length() - survivor_length()) * HeapRegion::GrainBytes;
1.130 + }
1.131 + size_t survivor_used_bytes() {
1.132 + return (size_t) survivor_length() * HeapRegion::GrainBytes;
1.133 + }
1.134 +
1.135 + void rs_length_sampling_init();
1.136 + bool rs_length_sampling_more();
1.137 + void rs_length_sampling_next();
1.138 +
1.139 + void reset_sampled_info() {
1.140 + _last_sampled_rs_lengths = 0;
1.141 + }
1.142 + size_t sampled_rs_lengths() { return _last_sampled_rs_lengths; }
1.143 +
1.144 + // for development purposes
1.145 + void reset_auxilary_lists();
1.146 + void clear() { _head = NULL; _length = 0; }
1.147 +
1.148 + void clear_survivors() {
1.149 + _survivor_head = NULL;
1.150 + _survivor_tail = NULL;
1.151 + _survivor_length = 0;
1.152 + }
1.153 +
1.154 + HeapRegion* first_region() { return _head; }
1.155 + HeapRegion* first_survivor_region() { return _survivor_head; }
1.156 + HeapRegion* last_survivor_region() { return _survivor_tail; }
1.157 +
1.158 + // debugging
1.159 + bool check_list_well_formed();
1.160 + bool check_list_empty(bool check_sample = true);
1.161 + void print();
1.162 +};
1.163 +
1.164 +class MutatorAllocRegion : public G1AllocRegion {
1.165 +protected:
1.166 + virtual HeapRegion* allocate_new_region(size_t word_size, bool force);
1.167 + virtual void retire_region(HeapRegion* alloc_region, size_t allocated_bytes);
1.168 +public:
1.169 + MutatorAllocRegion()
1.170 + : G1AllocRegion("Mutator Alloc Region", false /* bot_updates */) { }
1.171 +};
1.172 +
1.173 +class SurvivorGCAllocRegion : public G1AllocRegion {
1.174 +protected:
1.175 + virtual HeapRegion* allocate_new_region(size_t word_size, bool force);
1.176 + virtual void retire_region(HeapRegion* alloc_region, size_t allocated_bytes);
1.177 +public:
1.178 + SurvivorGCAllocRegion()
1.179 + : G1AllocRegion("Survivor GC Alloc Region", false /* bot_updates */) { }
1.180 +};
1.181 +
1.182 +class OldGCAllocRegion : public G1AllocRegion {
1.183 +protected:
1.184 + virtual HeapRegion* allocate_new_region(size_t word_size, bool force);
1.185 + virtual void retire_region(HeapRegion* alloc_region, size_t allocated_bytes);
1.186 +public:
1.187 + OldGCAllocRegion()
1.188 + : G1AllocRegion("Old GC Alloc Region", true /* bot_updates */) { }
1.189 +};
1.190 +
1.191 +// The G1 STW is alive closure.
1.192 +// An instance is embedded into the G1CH and used as the
1.193 +// (optional) _is_alive_non_header closure in the STW
1.194 +// reference processor. It is also extensively used during
1.195 +// reference processing during STW evacuation pauses.
1.196 +class G1STWIsAliveClosure: public BoolObjectClosure {
1.197 + G1CollectedHeap* _g1;
1.198 +public:
1.199 + G1STWIsAliveClosure(G1CollectedHeap* g1) : _g1(g1) {}
1.200 + bool do_object_b(oop p);
1.201 +};
1.202 +
1.203 +class RefineCardTableEntryClosure;
1.204 +
1.205 +class G1CollectedHeap : public SharedHeap {
1.206 + friend class VM_G1CollectForAllocation;
1.207 + friend class VM_G1CollectFull;
1.208 + friend class VM_G1IncCollectionPause;
1.209 + friend class VMStructs;
1.210 + friend class MutatorAllocRegion;
1.211 + friend class SurvivorGCAllocRegion;
1.212 + friend class OldGCAllocRegion;
1.213 +
1.214 + // Closures used in implementation.
1.215 + template <G1Barrier barrier, bool do_mark_object>
1.216 + friend class G1ParCopyClosure;
1.217 + friend class G1IsAliveClosure;
1.218 + friend class G1EvacuateFollowersClosure;
1.219 + friend class G1ParScanThreadState;
1.220 + friend class G1ParScanClosureSuper;
1.221 + friend class G1ParEvacuateFollowersClosure;
1.222 + friend class G1ParTask;
1.223 + friend class G1FreeGarbageRegionClosure;
1.224 + friend class RefineCardTableEntryClosure;
1.225 + friend class G1PrepareCompactClosure;
1.226 + friend class RegionSorter;
1.227 + friend class RegionResetter;
1.228 + friend class CountRCClosure;
1.229 + friend class EvacPopObjClosure;
1.230 + friend class G1ParCleanupCTTask;
1.231 +
1.232 + // Other related classes.
1.233 + friend class G1MarkSweep;
1.234 +
1.235 +private:
1.236 + // The one and only G1CollectedHeap, so static functions can find it.
1.237 + static G1CollectedHeap* _g1h;
1.238 +
1.239 + static size_t _humongous_object_threshold_in_words;
1.240 +
1.241 + // Storage for the G1 heap.
1.242 + VirtualSpace _g1_storage;
1.243 + MemRegion _g1_reserved;
1.244 +
1.245 + // The part of _g1_storage that is currently committed.
1.246 + MemRegion _g1_committed;
1.247 +
1.248 + // The master free list. It will satisfy all new region allocations.
1.249 + FreeRegionList _free_list;
1.250 +
1.251 + // The secondary free list which contains regions that have been
1.252 + // freed up during the cleanup process. This will be appended to the
1.253 + // master free list when appropriate.
1.254 + FreeRegionList _secondary_free_list;
1.255 +
1.256 + // It keeps track of the old regions.
1.257 + HeapRegionSet _old_set;
1.258 +
1.259 + // It keeps track of the humongous regions.
1.260 + HeapRegionSet _humongous_set;
1.261 +
1.262 + // The number of regions we could create by expansion.
1.263 + uint _expansion_regions;
1.264 +
1.265 + // The block offset table for the G1 heap.
1.266 + G1BlockOffsetSharedArray* _bot_shared;
1.267 +
1.268 + // Tears down the region sets / lists so that they are empty and the
1.269 + // regions on the heap do not belong to a region set / list. The
1.270 + // only exception is the humongous set which we leave unaltered. If
1.271 + // free_list_only is true, it will only tear down the master free
1.272 + // list. It is called before a Full GC (free_list_only == false) or
1.273 + // before heap shrinking (free_list_only == true).
1.274 + void tear_down_region_sets(bool free_list_only);
1.275 +
1.276 + // Rebuilds the region sets / lists so that they are repopulated to
1.277 + // reflect the contents of the heap. The only exception is the
1.278 + // humongous set which was not torn down in the first place. If
1.279 + // free_list_only is true, it will only rebuild the master free
1.280 + // list. It is called after a Full GC (free_list_only == false) or
1.281 + // after heap shrinking (free_list_only == true).
1.282 + void rebuild_region_sets(bool free_list_only);
1.283 +
1.284 + // The sequence of all heap regions in the heap.
1.285 + HeapRegionSeq _hrs;
1.286 +
1.287 + // Alloc region used to satisfy mutator allocation requests.
1.288 + MutatorAllocRegion _mutator_alloc_region;
1.289 +
1.290 + // Alloc region used to satisfy allocation requests by the GC for
1.291 + // survivor objects.
1.292 + SurvivorGCAllocRegion _survivor_gc_alloc_region;
1.293 +
1.294 + // PLAB sizing policy for survivors.
1.295 + PLABStats _survivor_plab_stats;
1.296 +
1.297 + // Alloc region used to satisfy allocation requests by the GC for
1.298 + // old objects.
1.299 + OldGCAllocRegion _old_gc_alloc_region;
1.300 +
1.301 + // PLAB sizing policy for tenured objects.
1.302 + PLABStats _old_plab_stats;
1.303 +
1.304 + PLABStats* stats_for_purpose(GCAllocPurpose purpose) {
1.305 + PLABStats* stats = NULL;
1.306 +
1.307 + switch (purpose) {
1.308 + case GCAllocForSurvived:
1.309 + stats = &_survivor_plab_stats;
1.310 + break;
1.311 + case GCAllocForTenured:
1.312 + stats = &_old_plab_stats;
1.313 + break;
1.314 + default:
1.315 + assert(false, "unrecognized GCAllocPurpose");
1.316 + }
1.317 +
1.318 + return stats;
1.319 + }
1.320 +
1.321 + // The last old region we allocated to during the last GC.
1.322 + // Typically, it is not full so we should re-use it during the next GC.
1.323 + HeapRegion* _retained_old_gc_alloc_region;
1.324 +
1.325 + // It specifies whether we should attempt to expand the heap after a
1.326 + // region allocation failure. If heap expansion fails we set this to
1.327 + // false so that we don't re-attempt the heap expansion (it's likely
1.328 + // that subsequent expansion attempts will also fail if one fails).
1.329 + // Currently, it is only consulted during GC and it's reset at the
1.330 + // start of each GC.
1.331 + bool _expand_heap_after_alloc_failure;
1.332 +
1.333 + // It resets the mutator alloc region before new allocations can take place.
1.334 + void init_mutator_alloc_region();
1.335 +
1.336 + // It releases the mutator alloc region.
1.337 + void release_mutator_alloc_region();
1.338 +
1.339 + // It initializes the GC alloc regions at the start of a GC.
1.340 + void init_gc_alloc_regions(EvacuationInfo& evacuation_info);
1.341 +
1.342 + // It releases the GC alloc regions at the end of a GC.
1.343 + void release_gc_alloc_regions(uint no_of_gc_workers, EvacuationInfo& evacuation_info);
1.344 +
1.345 + // It does any cleanup that needs to be done on the GC alloc regions
1.346 + // before a Full GC.
1.347 + void abandon_gc_alloc_regions();
1.348 +
1.349 + // Helper for monitoring and management support.
1.350 + G1MonitoringSupport* _g1mm;
1.351 +
1.352 + // Determines PLAB size for a particular allocation purpose.
1.353 + size_t desired_plab_sz(GCAllocPurpose purpose);
1.354 +
1.355 + // Outside of GC pauses, the number of bytes used in all regions other
1.356 + // than the current allocation region.
1.357 + size_t _summary_bytes_used;
1.358 +
1.359 + // This is used for a quick test on whether a reference points into
1.360 + // the collection set or not. Basically, we have an array, with one
1.361 + // byte per region, and that byte denotes whether the corresponding
1.362 + // region is in the collection set or not. The entry corresponding
1.363 + // the bottom of the heap, i.e., region 0, is pointed to by
1.364 + // _in_cset_fast_test_base. The _in_cset_fast_test field has been
1.365 + // biased so that it actually points to address 0 of the address
1.366 + // space, to make the test as fast as possible (we can simply shift
1.367 + // the address to address into it, instead of having to subtract the
1.368 + // bottom of the heap from the address before shifting it; basically
1.369 + // it works in the same way the card table works).
1.370 + bool* _in_cset_fast_test;
1.371 +
1.372 + // The allocated array used for the fast test on whether a reference
1.373 + // points into the collection set or not. This field is also used to
1.374 + // free the array.
1.375 + bool* _in_cset_fast_test_base;
1.376 +
1.377 + // The length of the _in_cset_fast_test_base array.
1.378 + uint _in_cset_fast_test_length;
1.379 +
1.380 + volatile unsigned _gc_time_stamp;
1.381 +
1.382 + size_t* _surviving_young_words;
1.383 +
1.384 + G1HRPrinter _hr_printer;
1.385 +
1.386 + void setup_surviving_young_words();
1.387 + void update_surviving_young_words(size_t* surv_young_words);
1.388 + void cleanup_surviving_young_words();
1.389 +
1.390 + // It decides whether an explicit GC should start a concurrent cycle
1.391 + // instead of doing a STW GC. Currently, a concurrent cycle is
1.392 + // explicitly started if:
1.393 + // (a) cause == _gc_locker and +GCLockerInvokesConcurrent, or
1.394 + // (b) cause == _java_lang_system_gc and +ExplicitGCInvokesConcurrent.
1.395 + // (c) cause == _g1_humongous_allocation
1.396 + bool should_do_concurrent_full_gc(GCCause::Cause cause);
1.397 +
1.398 + // Keeps track of how many "old marking cycles" (i.e., Full GCs or
1.399 + // concurrent cycles) we have started.
1.400 + volatile unsigned int _old_marking_cycles_started;
1.401 +
1.402 + // Keeps track of how many "old marking cycles" (i.e., Full GCs or
1.403 + // concurrent cycles) we have completed.
1.404 + volatile unsigned int _old_marking_cycles_completed;
1.405 +
1.406 + bool _concurrent_cycle_started;
1.407 +
1.408 + // This is a non-product method that is helpful for testing. It is
1.409 + // called at the end of a GC and artificially expands the heap by
1.410 + // allocating a number of dead regions. This way we can induce very
1.411 + // frequent marking cycles and stress the cleanup / concurrent
1.412 + // cleanup code more (as all the regions that will be allocated by
1.413 + // this method will be found dead by the marking cycle).
1.414 + void allocate_dummy_regions() PRODUCT_RETURN;
1.415 +
1.416 + // Clear RSets after a compaction. It also resets the GC time stamps.
1.417 + void clear_rsets_post_compaction();
1.418 +
1.419 + // If the HR printer is active, dump the state of the regions in the
1.420 + // heap after a compaction.
1.421 + void print_hrs_post_compaction();
1.422 +
1.423 + double verify(bool guard, const char* msg);
1.424 + void verify_before_gc();
1.425 + void verify_after_gc();
1.426 +
1.427 + void log_gc_header();
1.428 + void log_gc_footer(double pause_time_sec);
1.429 +
1.430 + // These are macros so that, if the assert fires, we get the correct
1.431 + // line number, file, etc.
1.432 +
1.433 +#define heap_locking_asserts_err_msg(_extra_message_) \
1.434 + err_msg("%s : Heap_lock locked: %s, at safepoint: %s, is VM thread: %s", \
1.435 + (_extra_message_), \
1.436 + BOOL_TO_STR(Heap_lock->owned_by_self()), \
1.437 + BOOL_TO_STR(SafepointSynchronize::is_at_safepoint()), \
1.438 + BOOL_TO_STR(Thread::current()->is_VM_thread()))
1.439 +
1.440 +#define assert_heap_locked() \
1.441 + do { \
1.442 + assert(Heap_lock->owned_by_self(), \
1.443 + heap_locking_asserts_err_msg("should be holding the Heap_lock")); \
1.444 + } while (0)
1.445 +
1.446 +#define assert_heap_locked_or_at_safepoint(_should_be_vm_thread_) \
1.447 + do { \
1.448 + assert(Heap_lock->owned_by_self() || \
1.449 + (SafepointSynchronize::is_at_safepoint() && \
1.450 + ((_should_be_vm_thread_) == Thread::current()->is_VM_thread())), \
1.451 + heap_locking_asserts_err_msg("should be holding the Heap_lock or " \
1.452 + "should be at a safepoint")); \
1.453 + } while (0)
1.454 +
1.455 +#define assert_heap_locked_and_not_at_safepoint() \
1.456 + do { \
1.457 + assert(Heap_lock->owned_by_self() && \
1.458 + !SafepointSynchronize::is_at_safepoint(), \
1.459 + heap_locking_asserts_err_msg("should be holding the Heap_lock and " \
1.460 + "should not be at a safepoint")); \
1.461 + } while (0)
1.462 +
1.463 +#define assert_heap_not_locked() \
1.464 + do { \
1.465 + assert(!Heap_lock->owned_by_self(), \
1.466 + heap_locking_asserts_err_msg("should not be holding the Heap_lock")); \
1.467 + } while (0)
1.468 +
1.469 +#define assert_heap_not_locked_and_not_at_safepoint() \
1.470 + do { \
1.471 + assert(!Heap_lock->owned_by_self() && \
1.472 + !SafepointSynchronize::is_at_safepoint(), \
1.473 + heap_locking_asserts_err_msg("should not be holding the Heap_lock and " \
1.474 + "should not be at a safepoint")); \
1.475 + } while (0)
1.476 +
1.477 +#define assert_at_safepoint(_should_be_vm_thread_) \
1.478 + do { \
1.479 + assert(SafepointSynchronize::is_at_safepoint() && \
1.480 + ((_should_be_vm_thread_) == Thread::current()->is_VM_thread()), \
1.481 + heap_locking_asserts_err_msg("should be at a safepoint")); \
1.482 + } while (0)
1.483 +
1.484 +#define assert_not_at_safepoint() \
1.485 + do { \
1.486 + assert(!SafepointSynchronize::is_at_safepoint(), \
1.487 + heap_locking_asserts_err_msg("should not be at a safepoint")); \
1.488 + } while (0)
1.489 +
1.490 +protected:
1.491 +
1.492 + // The young region list.
1.493 + YoungList* _young_list;
1.494 +
1.495 + // The current policy object for the collector.
1.496 + G1CollectorPolicy* _g1_policy;
1.497 +
1.498 + // This is the second level of trying to allocate a new region. If
1.499 + // new_region() didn't find a region on the free_list, this call will
1.500 + // check whether there's anything available on the
1.501 + // secondary_free_list and/or wait for more regions to appear on
1.502 + // that list, if _free_regions_coming is set.
1.503 + HeapRegion* new_region_try_secondary_free_list(bool is_old);
1.504 +
1.505 + // Try to allocate a single non-humongous HeapRegion sufficient for
1.506 + // an allocation of the given word_size. If do_expand is true,
1.507 + // attempt to expand the heap if necessary to satisfy the allocation
1.508 + // request. If the region is to be used as an old region or for a
1.509 + // humongous object, set is_old to true. If not, to false.
1.510 + HeapRegion* new_region(size_t word_size, bool is_old, bool do_expand);
1.511 +
1.512 + // Attempt to satisfy a humongous allocation request of the given
1.513 + // size by finding a contiguous set of free regions of num_regions
1.514 + // length and remove them from the master free list. Return the
1.515 + // index of the first region or G1_NULL_HRS_INDEX if the search
1.516 + // was unsuccessful.
1.517 + uint humongous_obj_allocate_find_first(uint num_regions,
1.518 + size_t word_size);
1.519 +
1.520 + // Initialize a contiguous set of free regions of length num_regions
1.521 + // and starting at index first so that they appear as a single
1.522 + // humongous region.
1.523 + HeapWord* humongous_obj_allocate_initialize_regions(uint first,
1.524 + uint num_regions,
1.525 + size_t word_size);
1.526 +
1.527 + // Attempt to allocate a humongous object of the given size. Return
1.528 + // NULL if unsuccessful.
1.529 + HeapWord* humongous_obj_allocate(size_t word_size);
1.530 +
1.531 + // The following two methods, allocate_new_tlab() and
1.532 + // mem_allocate(), are the two main entry points from the runtime
1.533 + // into the G1's allocation routines. They have the following
1.534 + // assumptions:
1.535 + //
1.536 + // * They should both be called outside safepoints.
1.537 + //
1.538 + // * They should both be called without holding the Heap_lock.
1.539 + //
1.540 + // * All allocation requests for new TLABs should go to
1.541 + // allocate_new_tlab().
1.542 + //
1.543 + // * All non-TLAB allocation requests should go to mem_allocate().
1.544 + //
1.545 + // * If either call cannot satisfy the allocation request using the
1.546 + // current allocating region, they will try to get a new one. If
1.547 + // this fails, they will attempt to do an evacuation pause and
1.548 + // retry the allocation.
1.549 + //
1.550 + // * If all allocation attempts fail, even after trying to schedule
1.551 + // an evacuation pause, allocate_new_tlab() will return NULL,
1.552 + // whereas mem_allocate() will attempt a heap expansion and/or
1.553 + // schedule a Full GC.
1.554 + //
1.555 + // * We do not allow humongous-sized TLABs. So, allocate_new_tlab
1.556 + // should never be called with word_size being humongous. All
1.557 + // humongous allocation requests should go to mem_allocate() which
1.558 + // will satisfy them with a special path.
1.559 +
1.560 + virtual HeapWord* allocate_new_tlab(size_t word_size);
1.561 +
1.562 + virtual HeapWord* mem_allocate(size_t word_size,
1.563 + bool* gc_overhead_limit_was_exceeded);
1.564 +
1.565 + // The following three methods take a gc_count_before_ret
1.566 + // parameter which is used to return the GC count if the method
1.567 + // returns NULL. Given that we are required to read the GC count
1.568 + // while holding the Heap_lock, and these paths will take the
1.569 + // Heap_lock at some point, it's easier to get them to read the GC
1.570 + // count while holding the Heap_lock before they return NULL instead
1.571 + // of the caller (namely: mem_allocate()) having to also take the
1.572 + // Heap_lock just to read the GC count.
1.573 +
1.574 + // First-level mutator allocation attempt: try to allocate out of
1.575 + // the mutator alloc region without taking the Heap_lock. This
1.576 + // should only be used for non-humongous allocations.
1.577 + inline HeapWord* attempt_allocation(size_t word_size,
1.578 + unsigned int* gc_count_before_ret,
1.579 + int* gclocker_retry_count_ret);
1.580 +
1.581 + // Second-level mutator allocation attempt: take the Heap_lock and
1.582 + // retry the allocation attempt, potentially scheduling a GC
1.583 + // pause. This should only be used for non-humongous allocations.
1.584 + HeapWord* attempt_allocation_slow(size_t word_size,
1.585 + unsigned int* gc_count_before_ret,
1.586 + int* gclocker_retry_count_ret);
1.587 +
1.588 + // Takes the Heap_lock and attempts a humongous allocation. It can
1.589 + // potentially schedule a GC pause.
1.590 + HeapWord* attempt_allocation_humongous(size_t word_size,
1.591 + unsigned int* gc_count_before_ret,
1.592 + int* gclocker_retry_count_ret);
1.593 +
1.594 + // Allocation attempt that should be called during safepoints (e.g.,
1.595 + // at the end of a successful GC). expect_null_mutator_alloc_region
1.596 + // specifies whether the mutator alloc region is expected to be NULL
1.597 + // or not.
1.598 + HeapWord* attempt_allocation_at_safepoint(size_t word_size,
1.599 + bool expect_null_mutator_alloc_region);
1.600 +
1.601 + // It dirties the cards that cover the block so that so that the post
1.602 + // write barrier never queues anything when updating objects on this
1.603 + // block. It is assumed (and in fact we assert) that the block
1.604 + // belongs to a young region.
1.605 + inline void dirty_young_block(HeapWord* start, size_t word_size);
1.606 +
1.607 + // Allocate blocks during garbage collection. Will ensure an
1.608 + // allocation region, either by picking one or expanding the
1.609 + // heap, and then allocate a block of the given size. The block
1.610 + // may not be a humongous - it must fit into a single heap region.
1.611 + HeapWord* par_allocate_during_gc(GCAllocPurpose purpose, size_t word_size);
1.612 +
1.613 + HeapWord* allocate_during_gc_slow(GCAllocPurpose purpose,
1.614 + HeapRegion* alloc_region,
1.615 + bool par,
1.616 + size_t word_size);
1.617 +
1.618 + // Ensure that no further allocations can happen in "r", bearing in mind
1.619 + // that parallel threads might be attempting allocations.
1.620 + void par_allocate_remaining_space(HeapRegion* r);
1.621 +
1.622 + // Allocation attempt during GC for a survivor object / PLAB.
1.623 + inline HeapWord* survivor_attempt_allocation(size_t word_size);
1.624 +
1.625 + // Allocation attempt during GC for an old object / PLAB.
1.626 + inline HeapWord* old_attempt_allocation(size_t word_size);
1.627 +
1.628 + // These methods are the "callbacks" from the G1AllocRegion class.
1.629 +
1.630 + // For mutator alloc regions.
1.631 + HeapRegion* new_mutator_alloc_region(size_t word_size, bool force);
1.632 + void retire_mutator_alloc_region(HeapRegion* alloc_region,
1.633 + size_t allocated_bytes);
1.634 +
1.635 + // For GC alloc regions.
1.636 + HeapRegion* new_gc_alloc_region(size_t word_size, uint count,
1.637 + GCAllocPurpose ap);
1.638 + void retire_gc_alloc_region(HeapRegion* alloc_region,
1.639 + size_t allocated_bytes, GCAllocPurpose ap);
1.640 +
1.641 + // - if explicit_gc is true, the GC is for a System.gc() or a heap
1.642 + // inspection request and should collect the entire heap
1.643 + // - if clear_all_soft_refs is true, all soft references should be
1.644 + // cleared during the GC
1.645 + // - if explicit_gc is false, word_size describes the allocation that
1.646 + // the GC should attempt (at least) to satisfy
1.647 + // - it returns false if it is unable to do the collection due to the
1.648 + // GC locker being active, true otherwise
1.649 + bool do_collection(bool explicit_gc,
1.650 + bool clear_all_soft_refs,
1.651 + size_t word_size);
1.652 +
1.653 + // Callback from VM_G1CollectFull operation.
1.654 + // Perform a full collection.
1.655 + virtual void do_full_collection(bool clear_all_soft_refs);
1.656 +
1.657 + // Resize the heap if necessary after a full collection. If this is
1.658 + // after a collect-for allocation, "word_size" is the allocation size,
1.659 + // and will be considered part of the used portion of the heap.
1.660 + void resize_if_necessary_after_full_collection(size_t word_size);
1.661 +
1.662 + // Callback from VM_G1CollectForAllocation operation.
1.663 + // This function does everything necessary/possible to satisfy a
1.664 + // failed allocation request (including collection, expansion, etc.)
1.665 + HeapWord* satisfy_failed_allocation(size_t word_size, bool* succeeded);
1.666 +
1.667 + // Attempting to expand the heap sufficiently
1.668 + // to support an allocation of the given "word_size". If
1.669 + // successful, perform the allocation and return the address of the
1.670 + // allocated block, or else "NULL".
1.671 + HeapWord* expand_and_allocate(size_t word_size);
1.672 +
1.673 + // Process any reference objects discovered during
1.674 + // an incremental evacuation pause.
1.675 + void process_discovered_references(uint no_of_gc_workers);
1.676 +
1.677 + // Enqueue any remaining discovered references
1.678 + // after processing.
1.679 + void enqueue_discovered_references(uint no_of_gc_workers);
1.680 +
1.681 +public:
1.682 +
1.683 + G1MonitoringSupport* g1mm() {
1.684 + assert(_g1mm != NULL, "should have been initialized");
1.685 + return _g1mm;
1.686 + }
1.687 +
1.688 + // Expand the garbage-first heap by at least the given size (in bytes!).
1.689 + // Returns true if the heap was expanded by the requested amount;
1.690 + // false otherwise.
1.691 + // (Rounds up to a HeapRegion boundary.)
1.692 + bool expand(size_t expand_bytes);
1.693 +
1.694 + // Do anything common to GC's.
1.695 + virtual void gc_prologue(bool full);
1.696 + virtual void gc_epilogue(bool full);
1.697 +
1.698 + // We register a region with the fast "in collection set" test. We
1.699 + // simply set to true the array slot corresponding to this region.
1.700 + void register_region_with_in_cset_fast_test(HeapRegion* r) {
1.701 + assert(_in_cset_fast_test_base != NULL, "sanity");
1.702 + assert(r->in_collection_set(), "invariant");
1.703 + uint index = r->hrs_index();
1.704 + assert(index < _in_cset_fast_test_length, "invariant");
1.705 + assert(!_in_cset_fast_test_base[index], "invariant");
1.706 + _in_cset_fast_test_base[index] = true;
1.707 + }
1.708 +
1.709 + // This is a fast test on whether a reference points into the
1.710 + // collection set or not. Assume that the reference
1.711 + // points into the heap.
1.712 + inline bool in_cset_fast_test(oop obj);
1.713 +
1.714 + void clear_cset_fast_test() {
1.715 + assert(_in_cset_fast_test_base != NULL, "sanity");
1.716 + memset(_in_cset_fast_test_base, false,
1.717 + (size_t) _in_cset_fast_test_length * sizeof(bool));
1.718 + }
1.719 +
1.720 + // This is called at the start of either a concurrent cycle or a Full
1.721 + // GC to update the number of old marking cycles started.
1.722 + void increment_old_marking_cycles_started();
1.723 +
1.724 + // This is called at the end of either a concurrent cycle or a Full
1.725 + // GC to update the number of old marking cycles completed. Those two
1.726 + // can happen in a nested fashion, i.e., we start a concurrent
1.727 + // cycle, a Full GC happens half-way through it which ends first,
1.728 + // and then the cycle notices that a Full GC happened and ends
1.729 + // too. The concurrent parameter is a boolean to help us do a bit
1.730 + // tighter consistency checking in the method. If concurrent is
1.731 + // false, the caller is the inner caller in the nesting (i.e., the
1.732 + // Full GC). If concurrent is true, the caller is the outer caller
1.733 + // in this nesting (i.e., the concurrent cycle). Further nesting is
1.734 + // not currently supported. The end of this call also notifies
1.735 + // the FullGCCount_lock in case a Java thread is waiting for a full
1.736 + // GC to happen (e.g., it called System.gc() with
1.737 + // +ExplicitGCInvokesConcurrent).
1.738 + void increment_old_marking_cycles_completed(bool concurrent);
1.739 +
1.740 + unsigned int old_marking_cycles_completed() {
1.741 + return _old_marking_cycles_completed;
1.742 + }
1.743 +
1.744 + void register_concurrent_cycle_start(const Ticks& start_time);
1.745 + void register_concurrent_cycle_end();
1.746 + void trace_heap_after_concurrent_cycle();
1.747 +
1.748 + G1YCType yc_type();
1.749 +
1.750 + G1HRPrinter* hr_printer() { return &_hr_printer; }
1.751 +
1.752 + // Frees a non-humongous region by initializing its contents and
1.753 + // adding it to the free list that's passed as a parameter (this is
1.754 + // usually a local list which will be appended to the master free
1.755 + // list later). The used bytes of freed regions are accumulated in
1.756 + // pre_used. If par is true, the region's RSet will not be freed
1.757 + // up. The assumption is that this will be done later.
1.758 + // The locked parameter indicates if the caller has already taken
1.759 + // care of proper synchronization. This may allow some optimizations.
1.760 + void free_region(HeapRegion* hr,
1.761 + FreeRegionList* free_list,
1.762 + bool par,
1.763 + bool locked = false);
1.764 +
1.765 + // Frees a humongous region by collapsing it into individual regions
1.766 + // and calling free_region() for each of them. The freed regions
1.767 + // will be added to the free list that's passed as a parameter (this
1.768 + // is usually a local list which will be appended to the master free
1.769 + // list later). The used bytes of freed regions are accumulated in
1.770 + // pre_used. If par is true, the region's RSet will not be freed
1.771 + // up. The assumption is that this will be done later.
1.772 + void free_humongous_region(HeapRegion* hr,
1.773 + FreeRegionList* free_list,
1.774 + bool par);
1.775 +protected:
1.776 +
1.777 + // Shrink the garbage-first heap by at most the given size (in bytes!).
1.778 + // (Rounds down to a HeapRegion boundary.)
1.779 + virtual void shrink(size_t expand_bytes);
1.780 + void shrink_helper(size_t expand_bytes);
1.781 +
1.782 + #if TASKQUEUE_STATS
1.783 + static void print_taskqueue_stats_hdr(outputStream* const st = gclog_or_tty);
1.784 + void print_taskqueue_stats(outputStream* const st = gclog_or_tty) const;
1.785 + void reset_taskqueue_stats();
1.786 + #endif // TASKQUEUE_STATS
1.787 +
1.788 + // Schedule the VM operation that will do an evacuation pause to
1.789 + // satisfy an allocation request of word_size. *succeeded will
1.790 + // return whether the VM operation was successful (it did do an
1.791 + // evacuation pause) or not (another thread beat us to it or the GC
1.792 + // locker was active). Given that we should not be holding the
1.793 + // Heap_lock when we enter this method, we will pass the
1.794 + // gc_count_before (i.e., total_collections()) as a parameter since
1.795 + // it has to be read while holding the Heap_lock. Currently, both
1.796 + // methods that call do_collection_pause() release the Heap_lock
1.797 + // before the call, so it's easy to read gc_count_before just before.
1.798 + HeapWord* do_collection_pause(size_t word_size,
1.799 + unsigned int gc_count_before,
1.800 + bool* succeeded,
1.801 + GCCause::Cause gc_cause);
1.802 +
1.803 + // The guts of the incremental collection pause, executed by the vm
1.804 + // thread. It returns false if it is unable to do the collection due
1.805 + // to the GC locker being active, true otherwise
1.806 + bool do_collection_pause_at_safepoint(double target_pause_time_ms);
1.807 +
1.808 + // Actually do the work of evacuating the collection set.
1.809 + void evacuate_collection_set(EvacuationInfo& evacuation_info);
1.810 +
1.811 + // The g1 remembered set of the heap.
1.812 + G1RemSet* _g1_rem_set;
1.813 +
1.814 + // A set of cards that cover the objects for which the Rsets should be updated
1.815 + // concurrently after the collection.
1.816 + DirtyCardQueueSet _dirty_card_queue_set;
1.817 +
1.818 + // The closure used to refine a single card.
1.819 + RefineCardTableEntryClosure* _refine_cte_cl;
1.820 +
1.821 + // A function to check the consistency of dirty card logs.
1.822 + void check_ct_logs_at_safepoint();
1.823 +
1.824 + // A DirtyCardQueueSet that is used to hold cards that contain
1.825 + // references into the current collection set. This is used to
1.826 + // update the remembered sets of the regions in the collection
1.827 + // set in the event of an evacuation failure.
1.828 + DirtyCardQueueSet _into_cset_dirty_card_queue_set;
1.829 +
1.830 + // After a collection pause, make the regions in the CS into free
1.831 + // regions.
1.832 + void free_collection_set(HeapRegion* cs_head, EvacuationInfo& evacuation_info);
1.833 +
1.834 + // Abandon the current collection set without recording policy
1.835 + // statistics or updating free lists.
1.836 + void abandon_collection_set(HeapRegion* cs_head);
1.837 +
1.838 + // Applies "scan_non_heap_roots" to roots outside the heap,
1.839 + // "scan_rs" to roots inside the heap (having done "set_region" to
1.840 + // indicate the region in which the root resides),
1.841 + // and does "scan_metadata" If "scan_rs" is
1.842 + // NULL, then this step is skipped. The "worker_i"
1.843 + // param is for use with parallel roots processing, and should be
1.844 + // the "i" of the calling parallel worker thread's work(i) function.
1.845 + // In the sequential case this param will be ignored.
1.846 + void g1_process_strong_roots(bool is_scavenging,
1.847 + ScanningOption so,
1.848 + OopClosure* scan_non_heap_roots,
1.849 + OopsInHeapRegionClosure* scan_rs,
1.850 + G1KlassScanClosure* scan_klasses,
1.851 + uint worker_i);
1.852 +
1.853 + // Apply "blk" to all the weak roots of the system. These include
1.854 + // JNI weak roots, the code cache, system dictionary, symbol table,
1.855 + // string table, and referents of reachable weak refs.
1.856 + void g1_process_weak_roots(OopClosure* root_closure);
1.857 +
1.858 + // Notifies all the necessary spaces that the committed space has
1.859 + // been updated (either expanded or shrunk). It should be called
1.860 + // after _g1_storage is updated.
1.861 + void update_committed_space(HeapWord* old_end, HeapWord* new_end);
1.862 +
1.863 + // The concurrent marker (and the thread it runs in.)
1.864 + ConcurrentMark* _cm;
1.865 + ConcurrentMarkThread* _cmThread;
1.866 + bool _mark_in_progress;
1.867 +
1.868 + // The concurrent refiner.
1.869 + ConcurrentG1Refine* _cg1r;
1.870 +
1.871 + // The parallel task queues
1.872 + RefToScanQueueSet *_task_queues;
1.873 +
1.874 + // True iff a evacuation has failed in the current collection.
1.875 + bool _evacuation_failed;
1.876 +
1.877 + EvacuationFailedInfo* _evacuation_failed_info_array;
1.878 +
1.879 + // Failed evacuations cause some logical from-space objects to have
1.880 + // forwarding pointers to themselves. Reset them.
1.881 + void remove_self_forwarding_pointers();
1.882 +
1.883 + // Together, these store an object with a preserved mark, and its mark value.
1.884 + Stack<oop, mtGC> _objs_with_preserved_marks;
1.885 + Stack<markOop, mtGC> _preserved_marks_of_objs;
1.886 +
1.887 + // Preserve the mark of "obj", if necessary, in preparation for its mark
1.888 + // word being overwritten with a self-forwarding-pointer.
1.889 + void preserve_mark_if_necessary(oop obj, markOop m);
1.890 +
1.891 + // The stack of evac-failure objects left to be scanned.
1.892 + GrowableArray<oop>* _evac_failure_scan_stack;
1.893 + // The closure to apply to evac-failure objects.
1.894 +
1.895 + OopsInHeapRegionClosure* _evac_failure_closure;
1.896 + // Set the field above.
1.897 + void
1.898 + set_evac_failure_closure(OopsInHeapRegionClosure* evac_failure_closure) {
1.899 + _evac_failure_closure = evac_failure_closure;
1.900 + }
1.901 +
1.902 + // Push "obj" on the scan stack.
1.903 + void push_on_evac_failure_scan_stack(oop obj);
1.904 + // Process scan stack entries until the stack is empty.
1.905 + void drain_evac_failure_scan_stack();
1.906 + // True iff an invocation of "drain_scan_stack" is in progress; to
1.907 + // prevent unnecessary recursion.
1.908 + bool _drain_in_progress;
1.909 +
1.910 + // Do any necessary initialization for evacuation-failure handling.
1.911 + // "cl" is the closure that will be used to process evac-failure
1.912 + // objects.
1.913 + void init_for_evac_failure(OopsInHeapRegionClosure* cl);
1.914 + // Do any necessary cleanup for evacuation-failure handling data
1.915 + // structures.
1.916 + void finalize_for_evac_failure();
1.917 +
1.918 + // An attempt to evacuate "obj" has failed; take necessary steps.
1.919 + oop handle_evacuation_failure_par(G1ParScanThreadState* _par_scan_state, oop obj);
1.920 + void handle_evacuation_failure_common(oop obj, markOop m);
1.921 +
1.922 +#ifndef PRODUCT
1.923 + // Support for forcing evacuation failures. Analogous to
1.924 + // PromotionFailureALot for the other collectors.
1.925 +
1.926 + // Records whether G1EvacuationFailureALot should be in effect
1.927 + // for the current GC
1.928 + bool _evacuation_failure_alot_for_current_gc;
1.929 +
1.930 + // Used to record the GC number for interval checking when
1.931 + // determining whether G1EvaucationFailureALot is in effect
1.932 + // for the current GC.
1.933 + size_t _evacuation_failure_alot_gc_number;
1.934 +
1.935 + // Count of the number of evacuations between failures.
1.936 + volatile size_t _evacuation_failure_alot_count;
1.937 +
1.938 + // Set whether G1EvacuationFailureALot should be in effect
1.939 + // for the current GC (based upon the type of GC and which
1.940 + // command line flags are set);
1.941 + inline bool evacuation_failure_alot_for_gc_type(bool gcs_are_young,
1.942 + bool during_initial_mark,
1.943 + bool during_marking);
1.944 +
1.945 + inline void set_evacuation_failure_alot_for_current_gc();
1.946 +
1.947 + // Return true if it's time to cause an evacuation failure.
1.948 + inline bool evacuation_should_fail();
1.949 +
1.950 + // Reset the G1EvacuationFailureALot counters. Should be called at
1.951 + // the end of an evacuation pause in which an evacuation failure occurred.
1.952 + inline void reset_evacuation_should_fail();
1.953 +#endif // !PRODUCT
1.954 +
1.955 + // ("Weak") Reference processing support.
1.956 + //
1.957 + // G1 has 2 instances of the reference processor class. One
1.958 + // (_ref_processor_cm) handles reference object discovery
1.959 + // and subsequent processing during concurrent marking cycles.
1.960 + //
1.961 + // The other (_ref_processor_stw) handles reference object
1.962 + // discovery and processing during full GCs and incremental
1.963 + // evacuation pauses.
1.964 + //
1.965 + // During an incremental pause, reference discovery will be
1.966 + // temporarily disabled for _ref_processor_cm and will be
1.967 + // enabled for _ref_processor_stw. At the end of the evacuation
1.968 + // pause references discovered by _ref_processor_stw will be
1.969 + // processed and discovery will be disabled. The previous
1.970 + // setting for reference object discovery for _ref_processor_cm
1.971 + // will be re-instated.
1.972 + //
1.973 + // At the start of marking:
1.974 + // * Discovery by the CM ref processor is verified to be inactive
1.975 + // and it's discovered lists are empty.
1.976 + // * Discovery by the CM ref processor is then enabled.
1.977 + //
1.978 + // At the end of marking:
1.979 + // * Any references on the CM ref processor's discovered
1.980 + // lists are processed (possibly MT).
1.981 + //
1.982 + // At the start of full GC we:
1.983 + // * Disable discovery by the CM ref processor and
1.984 + // empty CM ref processor's discovered lists
1.985 + // (without processing any entries).
1.986 + // * Verify that the STW ref processor is inactive and it's
1.987 + // discovered lists are empty.
1.988 + // * Temporarily set STW ref processor discovery as single threaded.
1.989 + // * Temporarily clear the STW ref processor's _is_alive_non_header
1.990 + // field.
1.991 + // * Finally enable discovery by the STW ref processor.
1.992 + //
1.993 + // The STW ref processor is used to record any discovered
1.994 + // references during the full GC.
1.995 + //
1.996 + // At the end of a full GC we:
1.997 + // * Enqueue any reference objects discovered by the STW ref processor
1.998 + // that have non-live referents. This has the side-effect of
1.999 + // making the STW ref processor inactive by disabling discovery.
1.1000 + // * Verify that the CM ref processor is still inactive
1.1001 + // and no references have been placed on it's discovered
1.1002 + // lists (also checked as a precondition during initial marking).
1.1003 +
1.1004 + // The (stw) reference processor...
1.1005 + ReferenceProcessor* _ref_processor_stw;
1.1006 +
1.1007 + STWGCTimer* _gc_timer_stw;
1.1008 + ConcurrentGCTimer* _gc_timer_cm;
1.1009 +
1.1010 + G1OldTracer* _gc_tracer_cm;
1.1011 + G1NewTracer* _gc_tracer_stw;
1.1012 +
1.1013 + // During reference object discovery, the _is_alive_non_header
1.1014 + // closure (if non-null) is applied to the referent object to
1.1015 + // determine whether the referent is live. If so then the
1.1016 + // reference object does not need to be 'discovered' and can
1.1017 + // be treated as a regular oop. This has the benefit of reducing
1.1018 + // the number of 'discovered' reference objects that need to
1.1019 + // be processed.
1.1020 + //
1.1021 + // Instance of the is_alive closure for embedding into the
1.1022 + // STW reference processor as the _is_alive_non_header field.
1.1023 + // Supplying a value for the _is_alive_non_header field is
1.1024 + // optional but doing so prevents unnecessary additions to
1.1025 + // the discovered lists during reference discovery.
1.1026 + G1STWIsAliveClosure _is_alive_closure_stw;
1.1027 +
1.1028 + // The (concurrent marking) reference processor...
1.1029 + ReferenceProcessor* _ref_processor_cm;
1.1030 +
1.1031 + // Instance of the concurrent mark is_alive closure for embedding
1.1032 + // into the Concurrent Marking reference processor as the
1.1033 + // _is_alive_non_header field. Supplying a value for the
1.1034 + // _is_alive_non_header field is optional but doing so prevents
1.1035 + // unnecessary additions to the discovered lists during reference
1.1036 + // discovery.
1.1037 + G1CMIsAliveClosure _is_alive_closure_cm;
1.1038 +
1.1039 + // Cache used by G1CollectedHeap::start_cset_region_for_worker().
1.1040 + HeapRegion** _worker_cset_start_region;
1.1041 +
1.1042 + // Time stamp to validate the regions recorded in the cache
1.1043 + // used by G1CollectedHeap::start_cset_region_for_worker().
1.1044 + // The heap region entry for a given worker is valid iff
1.1045 + // the associated time stamp value matches the current value
1.1046 + // of G1CollectedHeap::_gc_time_stamp.
1.1047 + unsigned int* _worker_cset_start_region_time_stamp;
1.1048 +
1.1049 + enum G1H_process_strong_roots_tasks {
1.1050 + G1H_PS_filter_satb_buffers,
1.1051 + G1H_PS_refProcessor_oops_do,
1.1052 + // Leave this one last.
1.1053 + G1H_PS_NumElements
1.1054 + };
1.1055 +
1.1056 + SubTasksDone* _process_strong_tasks;
1.1057 +
1.1058 + volatile bool _free_regions_coming;
1.1059 +
1.1060 +public:
1.1061 +
1.1062 + SubTasksDone* process_strong_tasks() { return _process_strong_tasks; }
1.1063 +
1.1064 + void set_refine_cte_cl_concurrency(bool concurrent);
1.1065 +
1.1066 + RefToScanQueue *task_queue(int i) const;
1.1067 +
1.1068 + // A set of cards where updates happened during the GC
1.1069 + DirtyCardQueueSet& dirty_card_queue_set() { return _dirty_card_queue_set; }
1.1070 +
1.1071 + // A DirtyCardQueueSet that is used to hold cards that contain
1.1072 + // references into the current collection set. This is used to
1.1073 + // update the remembered sets of the regions in the collection
1.1074 + // set in the event of an evacuation failure.
1.1075 + DirtyCardQueueSet& into_cset_dirty_card_queue_set()
1.1076 + { return _into_cset_dirty_card_queue_set; }
1.1077 +
1.1078 + // Create a G1CollectedHeap with the specified policy.
1.1079 + // Must call the initialize method afterwards.
1.1080 + // May not return if something goes wrong.
1.1081 + G1CollectedHeap(G1CollectorPolicy* policy);
1.1082 +
1.1083 + // Initialize the G1CollectedHeap to have the initial and
1.1084 + // maximum sizes and remembered and barrier sets
1.1085 + // specified by the policy object.
1.1086 + jint initialize();
1.1087 +
1.1088 + virtual void stop();
1.1089 +
1.1090 + // Return the (conservative) maximum heap alignment for any G1 heap
1.1091 + static size_t conservative_max_heap_alignment();
1.1092 +
1.1093 + // Initialize weak reference processing.
1.1094 + virtual void ref_processing_init();
1.1095 +
1.1096 + void set_par_threads(uint t) {
1.1097 + SharedHeap::set_par_threads(t);
1.1098 + // Done in SharedHeap but oddly there are
1.1099 + // two _process_strong_tasks's in a G1CollectedHeap
1.1100 + // so do it here too.
1.1101 + _process_strong_tasks->set_n_threads(t);
1.1102 + }
1.1103 +
1.1104 + // Set _n_par_threads according to a policy TBD.
1.1105 + void set_par_threads();
1.1106 +
1.1107 + void set_n_termination(int t) {
1.1108 + _process_strong_tasks->set_n_threads(t);
1.1109 + }
1.1110 +
1.1111 + virtual CollectedHeap::Name kind() const {
1.1112 + return CollectedHeap::G1CollectedHeap;
1.1113 + }
1.1114 +
1.1115 + // The current policy object for the collector.
1.1116 + G1CollectorPolicy* g1_policy() const { return _g1_policy; }
1.1117 +
1.1118 + virtual CollectorPolicy* collector_policy() const { return (CollectorPolicy*) g1_policy(); }
1.1119 +
1.1120 + // Adaptive size policy. No such thing for g1.
1.1121 + virtual AdaptiveSizePolicy* size_policy() { return NULL; }
1.1122 +
1.1123 + // The rem set and barrier set.
1.1124 + G1RemSet* g1_rem_set() const { return _g1_rem_set; }
1.1125 +
1.1126 + unsigned get_gc_time_stamp() {
1.1127 + return _gc_time_stamp;
1.1128 + }
1.1129 +
1.1130 + void reset_gc_time_stamp() {
1.1131 + _gc_time_stamp = 0;
1.1132 + OrderAccess::fence();
1.1133 + // Clear the cached CSet starting regions and time stamps.
1.1134 + // Their validity is dependent on the GC timestamp.
1.1135 + clear_cset_start_regions();
1.1136 + }
1.1137 +
1.1138 + void check_gc_time_stamps() PRODUCT_RETURN;
1.1139 +
1.1140 + void increment_gc_time_stamp() {
1.1141 + ++_gc_time_stamp;
1.1142 + OrderAccess::fence();
1.1143 + }
1.1144 +
1.1145 + // Reset the given region's GC timestamp. If it's starts humongous,
1.1146 + // also reset the GC timestamp of its corresponding
1.1147 + // continues humongous regions too.
1.1148 + void reset_gc_time_stamps(HeapRegion* hr);
1.1149 +
1.1150 + void iterate_dirty_card_closure(CardTableEntryClosure* cl,
1.1151 + DirtyCardQueue* into_cset_dcq,
1.1152 + bool concurrent, uint worker_i);
1.1153 +
1.1154 + // The shared block offset table array.
1.1155 + G1BlockOffsetSharedArray* bot_shared() const { return _bot_shared; }
1.1156 +
1.1157 + // Reference Processing accessors
1.1158 +
1.1159 + // The STW reference processor....
1.1160 + ReferenceProcessor* ref_processor_stw() const { return _ref_processor_stw; }
1.1161 +
1.1162 + // The Concurrent Marking reference processor...
1.1163 + ReferenceProcessor* ref_processor_cm() const { return _ref_processor_cm; }
1.1164 +
1.1165 + ConcurrentGCTimer* gc_timer_cm() const { return _gc_timer_cm; }
1.1166 + G1OldTracer* gc_tracer_cm() const { return _gc_tracer_cm; }
1.1167 +
1.1168 + virtual size_t capacity() const;
1.1169 + virtual size_t used() const;
1.1170 + // This should be called when we're not holding the heap lock. The
1.1171 + // result might be a bit inaccurate.
1.1172 + size_t used_unlocked() const;
1.1173 + size_t recalculate_used() const;
1.1174 +
1.1175 + // These virtual functions do the actual allocation.
1.1176 + // Some heaps may offer a contiguous region for shared non-blocking
1.1177 + // allocation, via inlined code (by exporting the address of the top and
1.1178 + // end fields defining the extent of the contiguous allocation region.)
1.1179 + // But G1CollectedHeap doesn't yet support this.
1.1180 +
1.1181 + // Return an estimate of the maximum allocation that could be performed
1.1182 + // without triggering any collection or expansion activity. In a
1.1183 + // generational collector, for example, this is probably the largest
1.1184 + // allocation that could be supported (without expansion) in the youngest
1.1185 + // generation. It is "unsafe" because no locks are taken; the result
1.1186 + // should be treated as an approximation, not a guarantee, for use in
1.1187 + // heuristic resizing decisions.
1.1188 + virtual size_t unsafe_max_alloc();
1.1189 +
1.1190 + virtual bool is_maximal_no_gc() const {
1.1191 + return _g1_storage.uncommitted_size() == 0;
1.1192 + }
1.1193 +
1.1194 + // The total number of regions in the heap.
1.1195 + uint n_regions() { return _hrs.length(); }
1.1196 +
1.1197 + // The max number of regions in the heap.
1.1198 + uint max_regions() { return _hrs.max_length(); }
1.1199 +
1.1200 + // The number of regions that are completely free.
1.1201 + uint free_regions() { return _free_list.length(); }
1.1202 +
1.1203 + // The number of regions that are not completely free.
1.1204 + uint used_regions() { return n_regions() - free_regions(); }
1.1205 +
1.1206 + // The number of regions available for "regular" expansion.
1.1207 + uint expansion_regions() { return _expansion_regions; }
1.1208 +
1.1209 + // Factory method for HeapRegion instances. It will return NULL if
1.1210 + // the allocation fails.
1.1211 + HeapRegion* new_heap_region(uint hrs_index, HeapWord* bottom);
1.1212 +
1.1213 + void verify_not_dirty_region(HeapRegion* hr) PRODUCT_RETURN;
1.1214 + void verify_dirty_region(HeapRegion* hr) PRODUCT_RETURN;
1.1215 + void verify_dirty_young_list(HeapRegion* head) PRODUCT_RETURN;
1.1216 + void verify_dirty_young_regions() PRODUCT_RETURN;
1.1217 +
1.1218 + // verify_region_sets() performs verification over the region
1.1219 + // lists. It will be compiled in the product code to be used when
1.1220 + // necessary (i.e., during heap verification).
1.1221 + void verify_region_sets();
1.1222 +
1.1223 + // verify_region_sets_optional() is planted in the code for
1.1224 + // list verification in non-product builds (and it can be enabled in
1.1225 + // product builds by defining HEAP_REGION_SET_FORCE_VERIFY to be 1).
1.1226 +#if HEAP_REGION_SET_FORCE_VERIFY
1.1227 + void verify_region_sets_optional() {
1.1228 + verify_region_sets();
1.1229 + }
1.1230 +#else // HEAP_REGION_SET_FORCE_VERIFY
1.1231 + void verify_region_sets_optional() { }
1.1232 +#endif // HEAP_REGION_SET_FORCE_VERIFY
1.1233 +
1.1234 +#ifdef ASSERT
1.1235 + bool is_on_master_free_list(HeapRegion* hr) {
1.1236 + return hr->containing_set() == &_free_list;
1.1237 + }
1.1238 +#endif // ASSERT
1.1239 +
1.1240 + // Wrapper for the region list operations that can be called from
1.1241 + // methods outside this class.
1.1242 +
1.1243 + void secondary_free_list_add(FreeRegionList* list) {
1.1244 + _secondary_free_list.add_ordered(list);
1.1245 + }
1.1246 +
1.1247 + void append_secondary_free_list() {
1.1248 + _free_list.add_ordered(&_secondary_free_list);
1.1249 + }
1.1250 +
1.1251 + void append_secondary_free_list_if_not_empty_with_lock() {
1.1252 + // If the secondary free list looks empty there's no reason to
1.1253 + // take the lock and then try to append it.
1.1254 + if (!_secondary_free_list.is_empty()) {
1.1255 + MutexLockerEx x(SecondaryFreeList_lock, Mutex::_no_safepoint_check_flag);
1.1256 + append_secondary_free_list();
1.1257 + }
1.1258 + }
1.1259 +
1.1260 + inline void old_set_remove(HeapRegion* hr);
1.1261 +
1.1262 + size_t non_young_capacity_bytes() {
1.1263 + return _old_set.total_capacity_bytes() + _humongous_set.total_capacity_bytes();
1.1264 + }
1.1265 +
1.1266 + void set_free_regions_coming();
1.1267 + void reset_free_regions_coming();
1.1268 + bool free_regions_coming() { return _free_regions_coming; }
1.1269 + void wait_while_free_regions_coming();
1.1270 +
1.1271 + // Determine whether the given region is one that we are using as an
1.1272 + // old GC alloc region.
1.1273 + bool is_old_gc_alloc_region(HeapRegion* hr) {
1.1274 + return hr == _retained_old_gc_alloc_region;
1.1275 + }
1.1276 +
1.1277 + // Perform a collection of the heap; intended for use in implementing
1.1278 + // "System.gc". This probably implies as full a collection as the
1.1279 + // "CollectedHeap" supports.
1.1280 + virtual void collect(GCCause::Cause cause);
1.1281 +
1.1282 + // The same as above but assume that the caller holds the Heap_lock.
1.1283 + void collect_locked(GCCause::Cause cause);
1.1284 +
1.1285 + // True iff an evacuation has failed in the most-recent collection.
1.1286 + bool evacuation_failed() { return _evacuation_failed; }
1.1287 +
1.1288 + void remove_from_old_sets(const HeapRegionSetCount& old_regions_removed, const HeapRegionSetCount& humongous_regions_removed);
1.1289 + void prepend_to_freelist(FreeRegionList* list);
1.1290 + void decrement_summary_bytes(size_t bytes);
1.1291 +
1.1292 + // Returns "TRUE" iff "p" points into the committed areas of the heap.
1.1293 + virtual bool is_in(const void* p) const;
1.1294 +
1.1295 + // Return "TRUE" iff the given object address is within the collection
1.1296 + // set.
1.1297 + inline bool obj_in_cs(oop obj);
1.1298 +
1.1299 + // Return "TRUE" iff the given object address is in the reserved
1.1300 + // region of g1.
1.1301 + bool is_in_g1_reserved(const void* p) const {
1.1302 + return _g1_reserved.contains(p);
1.1303 + }
1.1304 +
1.1305 + // Returns a MemRegion that corresponds to the space that has been
1.1306 + // reserved for the heap
1.1307 + MemRegion g1_reserved() {
1.1308 + return _g1_reserved;
1.1309 + }
1.1310 +
1.1311 + // Returns a MemRegion that corresponds to the space that has been
1.1312 + // committed in the heap
1.1313 + MemRegion g1_committed() {
1.1314 + return _g1_committed;
1.1315 + }
1.1316 +
1.1317 + virtual bool is_in_closed_subset(const void* p) const;
1.1318 +
1.1319 + G1SATBCardTableModRefBS* g1_barrier_set() {
1.1320 + return (G1SATBCardTableModRefBS*) barrier_set();
1.1321 + }
1.1322 +
1.1323 + // This resets the card table to all zeros. It is used after
1.1324 + // a collection pause which used the card table to claim cards.
1.1325 + void cleanUpCardTable();
1.1326 +
1.1327 + // Iteration functions.
1.1328 +
1.1329 + // Iterate over all the ref-containing fields of all objects, calling
1.1330 + // "cl.do_oop" on each.
1.1331 + virtual void oop_iterate(ExtendedOopClosure* cl);
1.1332 +
1.1333 + // Same as above, restricted to a memory region.
1.1334 + void oop_iterate(MemRegion mr, ExtendedOopClosure* cl);
1.1335 +
1.1336 + // Iterate over all objects, calling "cl.do_object" on each.
1.1337 + virtual void object_iterate(ObjectClosure* cl);
1.1338 +
1.1339 + virtual void safe_object_iterate(ObjectClosure* cl) {
1.1340 + object_iterate(cl);
1.1341 + }
1.1342 +
1.1343 + // Iterate over all spaces in use in the heap, in ascending address order.
1.1344 + virtual void space_iterate(SpaceClosure* cl);
1.1345 +
1.1346 + // Iterate over heap regions, in address order, terminating the
1.1347 + // iteration early if the "doHeapRegion" method returns "true".
1.1348 + void heap_region_iterate(HeapRegionClosure* blk) const;
1.1349 +
1.1350 + // Return the region with the given index. It assumes the index is valid.
1.1351 + inline HeapRegion* region_at(uint index) const;
1.1352 +
1.1353 + // Divide the heap region sequence into "chunks" of some size (the number
1.1354 + // of regions divided by the number of parallel threads times some
1.1355 + // overpartition factor, currently 4). Assumes that this will be called
1.1356 + // in parallel by ParallelGCThreads worker threads with discinct worker
1.1357 + // ids in the range [0..max(ParallelGCThreads-1, 1)], that all parallel
1.1358 + // calls will use the same "claim_value", and that that claim value is
1.1359 + // different from the claim_value of any heap region before the start of
1.1360 + // the iteration. Applies "blk->doHeapRegion" to each of the regions, by
1.1361 + // attempting to claim the first region in each chunk, and, if
1.1362 + // successful, applying the closure to each region in the chunk (and
1.1363 + // setting the claim value of the second and subsequent regions of the
1.1364 + // chunk.) For now requires that "doHeapRegion" always returns "false",
1.1365 + // i.e., that a closure never attempt to abort a traversal.
1.1366 + void heap_region_par_iterate_chunked(HeapRegionClosure* blk,
1.1367 + uint worker,
1.1368 + uint no_of_par_workers,
1.1369 + jint claim_value);
1.1370 +
1.1371 + // It resets all the region claim values to the default.
1.1372 + void reset_heap_region_claim_values();
1.1373 +
1.1374 + // Resets the claim values of regions in the current
1.1375 + // collection set to the default.
1.1376 + void reset_cset_heap_region_claim_values();
1.1377 +
1.1378 +#ifdef ASSERT
1.1379 + bool check_heap_region_claim_values(jint claim_value);
1.1380 +
1.1381 + // Same as the routine above but only checks regions in the
1.1382 + // current collection set.
1.1383 + bool check_cset_heap_region_claim_values(jint claim_value);
1.1384 +#endif // ASSERT
1.1385 +
1.1386 + // Clear the cached cset start regions and (more importantly)
1.1387 + // the time stamps. Called when we reset the GC time stamp.
1.1388 + void clear_cset_start_regions();
1.1389 +
1.1390 + // Given the id of a worker, obtain or calculate a suitable
1.1391 + // starting region for iterating over the current collection set.
1.1392 + HeapRegion* start_cset_region_for_worker(uint worker_i);
1.1393 +
1.1394 + // This is a convenience method that is used by the
1.1395 + // HeapRegionIterator classes to calculate the starting region for
1.1396 + // each worker so that they do not all start from the same region.
1.1397 + HeapRegion* start_region_for_worker(uint worker_i, uint no_of_par_workers);
1.1398 +
1.1399 + // Iterate over the regions (if any) in the current collection set.
1.1400 + void collection_set_iterate(HeapRegionClosure* blk);
1.1401 +
1.1402 + // As above but starting from region r
1.1403 + void collection_set_iterate_from(HeapRegion* r, HeapRegionClosure *blk);
1.1404 +
1.1405 + // Returns the first (lowest address) compactible space in the heap.
1.1406 + virtual CompactibleSpace* first_compactible_space();
1.1407 +
1.1408 + // A CollectedHeap will contain some number of spaces. This finds the
1.1409 + // space containing a given address, or else returns NULL.
1.1410 + virtual Space* space_containing(const void* addr) const;
1.1411 +
1.1412 + // A G1CollectedHeap will contain some number of heap regions. This
1.1413 + // finds the region containing a given address, or else returns NULL.
1.1414 + template <class T>
1.1415 + inline HeapRegion* heap_region_containing(const T addr) const;
1.1416 +
1.1417 + // Like the above, but requires "addr" to be in the heap (to avoid a
1.1418 + // null-check), and unlike the above, may return an continuing humongous
1.1419 + // region.
1.1420 + template <class T>
1.1421 + inline HeapRegion* heap_region_containing_raw(const T addr) const;
1.1422 +
1.1423 + // A CollectedHeap is divided into a dense sequence of "blocks"; that is,
1.1424 + // each address in the (reserved) heap is a member of exactly
1.1425 + // one block. The defining characteristic of a block is that it is
1.1426 + // possible to find its size, and thus to progress forward to the next
1.1427 + // block. (Blocks may be of different sizes.) Thus, blocks may
1.1428 + // represent Java objects, or they might be free blocks in a
1.1429 + // free-list-based heap (or subheap), as long as the two kinds are
1.1430 + // distinguishable and the size of each is determinable.
1.1431 +
1.1432 + // Returns the address of the start of the "block" that contains the
1.1433 + // address "addr". We say "blocks" instead of "object" since some heaps
1.1434 + // may not pack objects densely; a chunk may either be an object or a
1.1435 + // non-object.
1.1436 + virtual HeapWord* block_start(const void* addr) const;
1.1437 +
1.1438 + // Requires "addr" to be the start of a chunk, and returns its size.
1.1439 + // "addr + size" is required to be the start of a new chunk, or the end
1.1440 + // of the active area of the heap.
1.1441 + virtual size_t block_size(const HeapWord* addr) const;
1.1442 +
1.1443 + // Requires "addr" to be the start of a block, and returns "TRUE" iff
1.1444 + // the block is an object.
1.1445 + virtual bool block_is_obj(const HeapWord* addr) const;
1.1446 +
1.1447 + // Does this heap support heap inspection? (+PrintClassHistogram)
1.1448 + virtual bool supports_heap_inspection() const { return true; }
1.1449 +
1.1450 + // Section on thread-local allocation buffers (TLABs)
1.1451 + // See CollectedHeap for semantics.
1.1452 +
1.1453 + bool supports_tlab_allocation() const;
1.1454 + size_t tlab_capacity(Thread* ignored) const;
1.1455 + size_t tlab_used(Thread* ignored) const;
1.1456 + size_t max_tlab_size() const;
1.1457 + size_t unsafe_max_tlab_alloc(Thread* ignored) const;
1.1458 +
1.1459 + // Can a compiler initialize a new object without store barriers?
1.1460 + // This permission only extends from the creation of a new object
1.1461 + // via a TLAB up to the first subsequent safepoint. If such permission
1.1462 + // is granted for this heap type, the compiler promises to call
1.1463 + // defer_store_barrier() below on any slow path allocation of
1.1464 + // a new object for which such initializing store barriers will
1.1465 + // have been elided. G1, like CMS, allows this, but should be
1.1466 + // ready to provide a compensating write barrier as necessary
1.1467 + // if that storage came out of a non-young region. The efficiency
1.1468 + // of this implementation depends crucially on being able to
1.1469 + // answer very efficiently in constant time whether a piece of
1.1470 + // storage in the heap comes from a young region or not.
1.1471 + // See ReduceInitialCardMarks.
1.1472 + virtual bool can_elide_tlab_store_barriers() const {
1.1473 + return true;
1.1474 + }
1.1475 +
1.1476 + virtual bool card_mark_must_follow_store() const {
1.1477 + return true;
1.1478 + }
1.1479 +
1.1480 + inline bool is_in_young(const oop obj);
1.1481 +
1.1482 +#ifdef ASSERT
1.1483 + virtual bool is_in_partial_collection(const void* p);
1.1484 +#endif
1.1485 +
1.1486 + virtual bool is_scavengable(const void* addr);
1.1487 +
1.1488 + // We don't need barriers for initializing stores to objects
1.1489 + // in the young gen: for the SATB pre-barrier, there is no
1.1490 + // pre-value that needs to be remembered; for the remembered-set
1.1491 + // update logging post-barrier, we don't maintain remembered set
1.1492 + // information for young gen objects.
1.1493 + virtual inline bool can_elide_initializing_store_barrier(oop new_obj);
1.1494 +
1.1495 + // Returns "true" iff the given word_size is "very large".
1.1496 + static bool isHumongous(size_t word_size) {
1.1497 + // Note this has to be strictly greater-than as the TLABs
1.1498 + // are capped at the humongous thresold and we want to
1.1499 + // ensure that we don't try to allocate a TLAB as
1.1500 + // humongous and that we don't allocate a humongous
1.1501 + // object in a TLAB.
1.1502 + return word_size > _humongous_object_threshold_in_words;
1.1503 + }
1.1504 +
1.1505 + // Update mod union table with the set of dirty cards.
1.1506 + void updateModUnion();
1.1507 +
1.1508 + // Set the mod union bits corresponding to the given memRegion. Note
1.1509 + // that this is always a safe operation, since it doesn't clear any
1.1510 + // bits.
1.1511 + void markModUnionRange(MemRegion mr);
1.1512 +
1.1513 + // Records the fact that a marking phase is no longer in progress.
1.1514 + void set_marking_complete() {
1.1515 + _mark_in_progress = false;
1.1516 + }
1.1517 + void set_marking_started() {
1.1518 + _mark_in_progress = true;
1.1519 + }
1.1520 + bool mark_in_progress() {
1.1521 + return _mark_in_progress;
1.1522 + }
1.1523 +
1.1524 + // Print the maximum heap capacity.
1.1525 + virtual size_t max_capacity() const;
1.1526 +
1.1527 + virtual jlong millis_since_last_gc();
1.1528 +
1.1529 +
1.1530 + // Convenience function to be used in situations where the heap type can be
1.1531 + // asserted to be this type.
1.1532 + static G1CollectedHeap* heap();
1.1533 +
1.1534 + void set_region_short_lived_locked(HeapRegion* hr);
1.1535 + // add appropriate methods for any other surv rate groups
1.1536 +
1.1537 + YoungList* young_list() const { return _young_list; }
1.1538 +
1.1539 + // debugging
1.1540 + bool check_young_list_well_formed() {
1.1541 + return _young_list->check_list_well_formed();
1.1542 + }
1.1543 +
1.1544 + bool check_young_list_empty(bool check_heap,
1.1545 + bool check_sample = true);
1.1546 +
1.1547 + // *** Stuff related to concurrent marking. It's not clear to me that so
1.1548 + // many of these need to be public.
1.1549 +
1.1550 + // The functions below are helper functions that a subclass of
1.1551 + // "CollectedHeap" can use in the implementation of its virtual
1.1552 + // functions.
1.1553 + // This performs a concurrent marking of the live objects in a
1.1554 + // bitmap off to the side.
1.1555 + void doConcurrentMark();
1.1556 +
1.1557 + bool isMarkedPrev(oop obj) const;
1.1558 + bool isMarkedNext(oop obj) const;
1.1559 +
1.1560 + // Determine if an object is dead, given the object and also
1.1561 + // the region to which the object belongs. An object is dead
1.1562 + // iff a) it was not allocated since the last mark and b) it
1.1563 + // is not marked.
1.1564 +
1.1565 + bool is_obj_dead(const oop obj, const HeapRegion* hr) const {
1.1566 + return
1.1567 + !hr->obj_allocated_since_prev_marking(obj) &&
1.1568 + !isMarkedPrev(obj);
1.1569 + }
1.1570 +
1.1571 + // This function returns true when an object has been
1.1572 + // around since the previous marking and hasn't yet
1.1573 + // been marked during this marking.
1.1574 +
1.1575 + bool is_obj_ill(const oop obj, const HeapRegion* hr) const {
1.1576 + return
1.1577 + !hr->obj_allocated_since_next_marking(obj) &&
1.1578 + !isMarkedNext(obj);
1.1579 + }
1.1580 +
1.1581 + // Determine if an object is dead, given only the object itself.
1.1582 + // This will find the region to which the object belongs and
1.1583 + // then call the region version of the same function.
1.1584 +
1.1585 + // Added if it is NULL it isn't dead.
1.1586 +
1.1587 + inline bool is_obj_dead(const oop obj) const;
1.1588 +
1.1589 + inline bool is_obj_ill(const oop obj) const;
1.1590 +
1.1591 + bool allocated_since_marking(oop obj, HeapRegion* hr, VerifyOption vo);
1.1592 + HeapWord* top_at_mark_start(HeapRegion* hr, VerifyOption vo);
1.1593 + bool is_marked(oop obj, VerifyOption vo);
1.1594 + const char* top_at_mark_start_str(VerifyOption vo);
1.1595 +
1.1596 + ConcurrentMark* concurrent_mark() const { return _cm; }
1.1597 +
1.1598 + // Refinement
1.1599 +
1.1600 + ConcurrentG1Refine* concurrent_g1_refine() const { return _cg1r; }
1.1601 +
1.1602 + // The dirty cards region list is used to record a subset of regions
1.1603 + // whose cards need clearing. The list if populated during the
1.1604 + // remembered set scanning and drained during the card table
1.1605 + // cleanup. Although the methods are reentrant, population/draining
1.1606 + // phases must not overlap. For synchronization purposes the last
1.1607 + // element on the list points to itself.
1.1608 + HeapRegion* _dirty_cards_region_list;
1.1609 + void push_dirty_cards_region(HeapRegion* hr);
1.1610 + HeapRegion* pop_dirty_cards_region();
1.1611 +
1.1612 + // Optimized nmethod scanning support routines
1.1613 +
1.1614 + // Register the given nmethod with the G1 heap
1.1615 + virtual void register_nmethod(nmethod* nm);
1.1616 +
1.1617 + // Unregister the given nmethod from the G1 heap
1.1618 + virtual void unregister_nmethod(nmethod* nm);
1.1619 +
1.1620 + // Migrate the nmethods in the code root lists of the regions
1.1621 + // in the collection set to regions in to-space. In the event
1.1622 + // of an evacuation failure, nmethods that reference objects
1.1623 + // that were not successfullly evacuated are not migrated.
1.1624 + void migrate_strong_code_roots();
1.1625 +
1.1626 + // Free up superfluous code root memory.
1.1627 + void purge_code_root_memory();
1.1628 +
1.1629 + // During an initial mark pause, mark all the code roots that
1.1630 + // point into regions *not* in the collection set.
1.1631 + void mark_strong_code_roots(uint worker_id);
1.1632 +
1.1633 + // Rebuild the stong code root lists for each region
1.1634 + // after a full GC
1.1635 + void rebuild_strong_code_roots();
1.1636 +
1.1637 + // Delete entries for dead interned string and clean up unreferenced symbols
1.1638 + // in symbol table, possibly in parallel.
1.1639 + void unlink_string_and_symbol_table(BoolObjectClosure* is_alive, bool unlink_strings = true, bool unlink_symbols = true);
1.1640 +
1.1641 + // Redirty logged cards in the refinement queue.
1.1642 + void redirty_logged_cards();
1.1643 + // Verification
1.1644 +
1.1645 + // The following is just to alert the verification code
1.1646 + // that a full collection has occurred and that the
1.1647 + // remembered sets are no longer up to date.
1.1648 + bool _full_collection;
1.1649 + void set_full_collection() { _full_collection = true;}
1.1650 + void clear_full_collection() {_full_collection = false;}
1.1651 + bool full_collection() {return _full_collection;}
1.1652 +
1.1653 + // Perform any cleanup actions necessary before allowing a verification.
1.1654 + virtual void prepare_for_verify();
1.1655 +
1.1656 + // Perform verification.
1.1657 +
1.1658 + // vo == UsePrevMarking -> use "prev" marking information,
1.1659 + // vo == UseNextMarking -> use "next" marking information
1.1660 + // vo == UseMarkWord -> use the mark word in the object header
1.1661 + //
1.1662 + // NOTE: Only the "prev" marking information is guaranteed to be
1.1663 + // consistent most of the time, so most calls to this should use
1.1664 + // vo == UsePrevMarking.
1.1665 + // Currently, there is only one case where this is called with
1.1666 + // vo == UseNextMarking, which is to verify the "next" marking
1.1667 + // information at the end of remark.
1.1668 + // Currently there is only one place where this is called with
1.1669 + // vo == UseMarkWord, which is to verify the marking during a
1.1670 + // full GC.
1.1671 + void verify(bool silent, VerifyOption vo);
1.1672 +
1.1673 + // Override; it uses the "prev" marking information
1.1674 + virtual void verify(bool silent);
1.1675 +
1.1676 + // The methods below are here for convenience and dispatch the
1.1677 + // appropriate method depending on value of the given VerifyOption
1.1678 + // parameter. The values for that parameter, and their meanings,
1.1679 + // are the same as those above.
1.1680 +
1.1681 + bool is_obj_dead_cond(const oop obj,
1.1682 + const HeapRegion* hr,
1.1683 + const VerifyOption vo) const;
1.1684 +
1.1685 + bool is_obj_dead_cond(const oop obj,
1.1686 + const VerifyOption vo) const;
1.1687 +
1.1688 + // Printing
1.1689 +
1.1690 + virtual void print_on(outputStream* st) const;
1.1691 + virtual void print_extended_on(outputStream* st) const;
1.1692 + virtual void print_on_error(outputStream* st) const;
1.1693 +
1.1694 + virtual void print_gc_threads_on(outputStream* st) const;
1.1695 + virtual void gc_threads_do(ThreadClosure* tc) const;
1.1696 +
1.1697 + // Override
1.1698 + void print_tracing_info() const;
1.1699 +
1.1700 + // The following two methods are helpful for debugging RSet issues.
1.1701 + void print_cset_rsets() PRODUCT_RETURN;
1.1702 + void print_all_rsets() PRODUCT_RETURN;
1.1703 +
1.1704 +public:
1.1705 + size_t pending_card_num();
1.1706 + size_t cards_scanned();
1.1707 +
1.1708 +protected:
1.1709 + size_t _max_heap_capacity;
1.1710 +};
1.1711 +
1.1712 +class G1ParGCAllocBuffer: public ParGCAllocBuffer {
1.1713 +private:
1.1714 + bool _retired;
1.1715 +
1.1716 +public:
1.1717 + G1ParGCAllocBuffer(size_t gclab_word_size);
1.1718 +
1.1719 + void set_buf(HeapWord* buf) {
1.1720 + ParGCAllocBuffer::set_buf(buf);
1.1721 + _retired = false;
1.1722 + }
1.1723 +
1.1724 + void retire(bool end_of_gc, bool retain) {
1.1725 + if (_retired)
1.1726 + return;
1.1727 + ParGCAllocBuffer::retire(end_of_gc, retain);
1.1728 + _retired = true;
1.1729 + }
1.1730 +};
1.1731 +
1.1732 +class G1ParScanThreadState : public StackObj {
1.1733 +protected:
1.1734 + G1CollectedHeap* _g1h;
1.1735 + RefToScanQueue* _refs;
1.1736 + DirtyCardQueue _dcq;
1.1737 + G1SATBCardTableModRefBS* _ct_bs;
1.1738 + G1RemSet* _g1_rem;
1.1739 +
1.1740 + G1ParGCAllocBuffer _surviving_alloc_buffer;
1.1741 + G1ParGCAllocBuffer _tenured_alloc_buffer;
1.1742 + G1ParGCAllocBuffer* _alloc_buffers[GCAllocPurposeCount];
1.1743 + ageTable _age_table;
1.1744 +
1.1745 + G1ParScanClosure _scanner;
1.1746 +
1.1747 + size_t _alloc_buffer_waste;
1.1748 + size_t _undo_waste;
1.1749 +
1.1750 + OopsInHeapRegionClosure* _evac_failure_cl;
1.1751 +
1.1752 + int _hash_seed;
1.1753 + uint _queue_num;
1.1754 +
1.1755 + size_t _term_attempts;
1.1756 +
1.1757 + double _start;
1.1758 + double _start_strong_roots;
1.1759 + double _strong_roots_time;
1.1760 + double _start_term;
1.1761 + double _term_time;
1.1762 +
1.1763 + // Map from young-age-index (0 == not young, 1 is youngest) to
1.1764 + // surviving words. base is what we get back from the malloc call
1.1765 + size_t* _surviving_young_words_base;
1.1766 + // this points into the array, as we use the first few entries for padding
1.1767 + size_t* _surviving_young_words;
1.1768 +
1.1769 +#define PADDING_ELEM_NUM (DEFAULT_CACHE_LINE_SIZE / sizeof(size_t))
1.1770 +
1.1771 + void add_to_alloc_buffer_waste(size_t waste) { _alloc_buffer_waste += waste; }
1.1772 +
1.1773 + void add_to_undo_waste(size_t waste) { _undo_waste += waste; }
1.1774 +
1.1775 + DirtyCardQueue& dirty_card_queue() { return _dcq; }
1.1776 + G1SATBCardTableModRefBS* ctbs() { return _ct_bs; }
1.1777 +
1.1778 + template <class T> inline void immediate_rs_update(HeapRegion* from, T* p, int tid);
1.1779 +
1.1780 + template <class T> void deferred_rs_update(HeapRegion* from, T* p, int tid) {
1.1781 + // If the new value of the field points to the same region or
1.1782 + // is the to-space, we don't need to include it in the Rset updates.
1.1783 + if (!from->is_in_reserved(oopDesc::load_decode_heap_oop(p)) && !from->is_survivor()) {
1.1784 + size_t card_index = ctbs()->index_for(p);
1.1785 + // If the card hasn't been added to the buffer, do it.
1.1786 + if (ctbs()->mark_card_deferred(card_index)) {
1.1787 + dirty_card_queue().enqueue((jbyte*)ctbs()->byte_for_index(card_index));
1.1788 + }
1.1789 + }
1.1790 + }
1.1791 +
1.1792 +public:
1.1793 + G1ParScanThreadState(G1CollectedHeap* g1h, uint queue_num, ReferenceProcessor* rp);
1.1794 +
1.1795 + ~G1ParScanThreadState() {
1.1796 + FREE_C_HEAP_ARRAY(size_t, _surviving_young_words_base, mtGC);
1.1797 + }
1.1798 +
1.1799 + RefToScanQueue* refs() { return _refs; }
1.1800 + ageTable* age_table() { return &_age_table; }
1.1801 +
1.1802 + G1ParGCAllocBuffer* alloc_buffer(GCAllocPurpose purpose) {
1.1803 + return _alloc_buffers[purpose];
1.1804 + }
1.1805 +
1.1806 + size_t alloc_buffer_waste() const { return _alloc_buffer_waste; }
1.1807 + size_t undo_waste() const { return _undo_waste; }
1.1808 +
1.1809 +#ifdef ASSERT
1.1810 + bool verify_ref(narrowOop* ref) const;
1.1811 + bool verify_ref(oop* ref) const;
1.1812 + bool verify_task(StarTask ref) const;
1.1813 +#endif // ASSERT
1.1814 +
1.1815 + template <class T> void push_on_queue(T* ref) {
1.1816 + assert(verify_ref(ref), "sanity");
1.1817 + refs()->push(ref);
1.1818 + }
1.1819 +
1.1820 + template <class T> inline void update_rs(HeapRegion* from, T* p, int tid);
1.1821 +
1.1822 + HeapWord* allocate_slow(GCAllocPurpose purpose, size_t word_sz) {
1.1823 + HeapWord* obj = NULL;
1.1824 + size_t gclab_word_size = _g1h->desired_plab_sz(purpose);
1.1825 + if (word_sz * 100 < gclab_word_size * ParallelGCBufferWastePct) {
1.1826 + G1ParGCAllocBuffer* alloc_buf = alloc_buffer(purpose);
1.1827 + add_to_alloc_buffer_waste(alloc_buf->words_remaining());
1.1828 + alloc_buf->retire(false /* end_of_gc */, false /* retain */);
1.1829 +
1.1830 + HeapWord* buf = _g1h->par_allocate_during_gc(purpose, gclab_word_size);
1.1831 + if (buf == NULL) return NULL; // Let caller handle allocation failure.
1.1832 + // Otherwise.
1.1833 + alloc_buf->set_word_size(gclab_word_size);
1.1834 + alloc_buf->set_buf(buf);
1.1835 +
1.1836 + obj = alloc_buf->allocate(word_sz);
1.1837 + assert(obj != NULL, "buffer was definitely big enough...");
1.1838 + } else {
1.1839 + obj = _g1h->par_allocate_during_gc(purpose, word_sz);
1.1840 + }
1.1841 + return obj;
1.1842 + }
1.1843 +
1.1844 + HeapWord* allocate(GCAllocPurpose purpose, size_t word_sz) {
1.1845 + HeapWord* obj = alloc_buffer(purpose)->allocate(word_sz);
1.1846 + if (obj != NULL) return obj;
1.1847 + return allocate_slow(purpose, word_sz);
1.1848 + }
1.1849 +
1.1850 + void undo_allocation(GCAllocPurpose purpose, HeapWord* obj, size_t word_sz) {
1.1851 + if (alloc_buffer(purpose)->contains(obj)) {
1.1852 + assert(alloc_buffer(purpose)->contains(obj + word_sz - 1),
1.1853 + "should contain whole object");
1.1854 + alloc_buffer(purpose)->undo_allocation(obj, word_sz);
1.1855 + } else {
1.1856 + CollectedHeap::fill_with_object(obj, word_sz);
1.1857 + add_to_undo_waste(word_sz);
1.1858 + }
1.1859 + }
1.1860 +
1.1861 + void set_evac_failure_closure(OopsInHeapRegionClosure* evac_failure_cl) {
1.1862 + _evac_failure_cl = evac_failure_cl;
1.1863 + }
1.1864 + OopsInHeapRegionClosure* evac_failure_closure() {
1.1865 + return _evac_failure_cl;
1.1866 + }
1.1867 +
1.1868 + int* hash_seed() { return &_hash_seed; }
1.1869 + uint queue_num() { return _queue_num; }
1.1870 +
1.1871 + size_t term_attempts() const { return _term_attempts; }
1.1872 + void note_term_attempt() { _term_attempts++; }
1.1873 +
1.1874 + void start_strong_roots() {
1.1875 + _start_strong_roots = os::elapsedTime();
1.1876 + }
1.1877 + void end_strong_roots() {
1.1878 + _strong_roots_time += (os::elapsedTime() - _start_strong_roots);
1.1879 + }
1.1880 + double strong_roots_time() const { return _strong_roots_time; }
1.1881 +
1.1882 + void start_term_time() {
1.1883 + note_term_attempt();
1.1884 + _start_term = os::elapsedTime();
1.1885 + }
1.1886 + void end_term_time() {
1.1887 + _term_time += (os::elapsedTime() - _start_term);
1.1888 + }
1.1889 + double term_time() const { return _term_time; }
1.1890 +
1.1891 + double elapsed_time() const {
1.1892 + return os::elapsedTime() - _start;
1.1893 + }
1.1894 +
1.1895 + static void
1.1896 + print_termination_stats_hdr(outputStream* const st = gclog_or_tty);
1.1897 + void
1.1898 + print_termination_stats(int i, outputStream* const st = gclog_or_tty) const;
1.1899 +
1.1900 + size_t* surviving_young_words() {
1.1901 + // We add on to hide entry 0 which accumulates surviving words for
1.1902 + // age -1 regions (i.e. non-young ones)
1.1903 + return _surviving_young_words;
1.1904 + }
1.1905 +
1.1906 + void retire_alloc_buffers() {
1.1907 + for (int ap = 0; ap < GCAllocPurposeCount; ++ap) {
1.1908 + size_t waste = _alloc_buffers[ap]->words_remaining();
1.1909 + add_to_alloc_buffer_waste(waste);
1.1910 + _alloc_buffers[ap]->flush_stats_and_retire(_g1h->stats_for_purpose((GCAllocPurpose)ap),
1.1911 + true /* end_of_gc */,
1.1912 + false /* retain */);
1.1913 + }
1.1914 + }
1.1915 +private:
1.1916 + #define G1_PARTIAL_ARRAY_MASK 0x2
1.1917 +
1.1918 + inline bool has_partial_array_mask(oop* ref) const {
1.1919 + return ((uintptr_t)ref & G1_PARTIAL_ARRAY_MASK) == G1_PARTIAL_ARRAY_MASK;
1.1920 + }
1.1921 +
1.1922 + // We never encode partial array oops as narrowOop*, so return false immediately.
1.1923 + // This allows the compiler to create optimized code when popping references from
1.1924 + // the work queue.
1.1925 + inline bool has_partial_array_mask(narrowOop* ref) const {
1.1926 + assert(((uintptr_t)ref & G1_PARTIAL_ARRAY_MASK) != G1_PARTIAL_ARRAY_MASK, "Partial array oop reference encoded as narrowOop*");
1.1927 + return false;
1.1928 + }
1.1929 +
1.1930 + // Only implement set_partial_array_mask() for regular oops, not for narrowOops.
1.1931 + // We always encode partial arrays as regular oop, to allow the
1.1932 + // specialization for has_partial_array_mask() for narrowOops above.
1.1933 + // This means that unintentional use of this method with narrowOops are caught
1.1934 + // by the compiler.
1.1935 + inline oop* set_partial_array_mask(oop obj) const {
1.1936 + assert(((uintptr_t)(void *)obj & G1_PARTIAL_ARRAY_MASK) == 0, "Information loss!");
1.1937 + return (oop*) ((uintptr_t)(void *)obj | G1_PARTIAL_ARRAY_MASK);
1.1938 + }
1.1939 +
1.1940 + inline oop clear_partial_array_mask(oop* ref) const {
1.1941 + return cast_to_oop((intptr_t)ref & ~G1_PARTIAL_ARRAY_MASK);
1.1942 + }
1.1943 +
1.1944 + inline void do_oop_partial_array(oop* p);
1.1945 +
1.1946 + // This method is applied to the fields of the objects that have just been copied.
1.1947 + template <class T> void do_oop_evac(T* p, HeapRegion* from) {
1.1948 + assert(!oopDesc::is_null(oopDesc::load_decode_heap_oop(p)),
1.1949 + "Reference should not be NULL here as such are never pushed to the task queue.");
1.1950 + oop obj = oopDesc::load_decode_heap_oop_not_null(p);
1.1951 +
1.1952 + // Although we never intentionally push references outside of the collection
1.1953 + // set, due to (benign) races in the claim mechanism during RSet scanning more
1.1954 + // than one thread might claim the same card. So the same card may be
1.1955 + // processed multiple times. So redo this check.
1.1956 + if (_g1h->in_cset_fast_test(obj)) {
1.1957 + oop forwardee;
1.1958 + if (obj->is_forwarded()) {
1.1959 + forwardee = obj->forwardee();
1.1960 + } else {
1.1961 + forwardee = copy_to_survivor_space(obj);
1.1962 + }
1.1963 + assert(forwardee != NULL, "forwardee should not be NULL");
1.1964 + oopDesc::encode_store_heap_oop(p, forwardee);
1.1965 + }
1.1966 +
1.1967 + assert(obj != NULL, "Must be");
1.1968 + update_rs(from, p, queue_num());
1.1969 + }
1.1970 +public:
1.1971 +
1.1972 + oop copy_to_survivor_space(oop const obj);
1.1973 +
1.1974 + template <class T> inline void deal_with_reference(T* ref_to_scan);
1.1975 +
1.1976 + inline void deal_with_reference(StarTask ref);
1.1977 +
1.1978 +public:
1.1979 + void trim_queue();
1.1980 +};
1.1981 +
1.1982 +#endif // SHARE_VM_GC_IMPLEMENTATION_G1_G1COLLECTEDHEAP_HPP
