| /* |
| * Copyright (c) 2001, 2011, Oracle and/or its affiliates. All rights reserved. |
| * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. |
| * |
| * This code is free software; you can redistribute it and/or modify it |
| * under the terms of the GNU General Public License version 2 only, as |
| * published by the Free Software Foundation. |
| * |
| * This code is distributed in the hope that it will be useful, but WITHOUT |
| * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or |
| * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License |
| * version 2 for more details (a copy is included in the LICENSE file that |
| * accompanied this code). |
| * |
| * You should have received a copy of the GNU General Public License version |
| * 2 along with this work; if not, write to the Free Software Foundation, |
| * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. |
| * |
| * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA |
| * or visit www.oracle.com if you need additional information or have any |
| * questions. |
| * |
| */ |
| |
| #ifndef SHARE_VM_GC_IMPLEMENTATION_G1_G1COLLECTEDHEAP_HPP |
| #define SHARE_VM_GC_IMPLEMENTATION_G1_G1COLLECTEDHEAP_HPP |
| |
| #include "gc_implementation/g1/concurrentMark.hpp" |
| #include "gc_implementation/g1/g1RemSet.hpp" |
| #include "gc_implementation/g1/heapRegionSets.hpp" |
| #include "gc_implementation/parNew/parGCAllocBuffer.hpp" |
| #include "memory/barrierSet.hpp" |
| #include "memory/memRegion.hpp" |
| #include "memory/sharedHeap.hpp" |
| |
| // A "G1CollectedHeap" is an implementation of a java heap for HotSpot. |
| // It uses the "Garbage First" heap organization and algorithm, which |
| // may combine concurrent marking with parallel, incremental compaction of |
| // heap subsets that will yield large amounts of garbage. |
| |
| class HeapRegion; |
| class HeapRegionSeq; |
| class HRRSCleanupTask; |
| class PermanentGenerationSpec; |
| class GenerationSpec; |
| class OopsInHeapRegionClosure; |
| class G1ScanHeapEvacClosure; |
| class ObjectClosure; |
| class SpaceClosure; |
| class CompactibleSpaceClosure; |
| class Space; |
| class G1CollectorPolicy; |
| class GenRemSet; |
| class G1RemSet; |
| class HeapRegionRemSetIterator; |
| class ConcurrentMark; |
| class ConcurrentMarkThread; |
| class ConcurrentG1Refine; |
| |
| typedef OverflowTaskQueue<StarTask> RefToScanQueue; |
| typedef GenericTaskQueueSet<RefToScanQueue> RefToScanQueueSet; |
| |
| typedef int RegionIdx_t; // needs to hold [ 0..max_regions() ) |
| typedef int CardIdx_t; // needs to hold [ 0..CardsPerRegion ) |
| |
| enum GCAllocPurpose { |
| GCAllocForTenured, |
| GCAllocForSurvived, |
| GCAllocPurposeCount |
| }; |
| |
| class YoungList : public CHeapObj { |
| private: |
| G1CollectedHeap* _g1h; |
| |
| HeapRegion* _head; |
| |
| HeapRegion* _survivor_head; |
| HeapRegion* _survivor_tail; |
| |
| HeapRegion* _curr; |
| |
| size_t _length; |
| size_t _survivor_length; |
| |
| size_t _last_sampled_rs_lengths; |
| size_t _sampled_rs_lengths; |
| |
| void empty_list(HeapRegion* list); |
| |
| public: |
| YoungList(G1CollectedHeap* g1h); |
| |
| void push_region(HeapRegion* hr); |
| void add_survivor_region(HeapRegion* hr); |
| |
| void empty_list(); |
| bool is_empty() { return _length == 0; } |
| size_t length() { return _length; } |
| size_t survivor_length() { return _survivor_length; } |
| |
| void rs_length_sampling_init(); |
| bool rs_length_sampling_more(); |
| void rs_length_sampling_next(); |
| |
| void reset_sampled_info() { |
| _last_sampled_rs_lengths = 0; |
| } |
| size_t sampled_rs_lengths() { return _last_sampled_rs_lengths; } |
| |
| // for development purposes |
| void reset_auxilary_lists(); |
| void clear() { _head = NULL; _length = 0; } |
| |
| void clear_survivors() { |
| _survivor_head = NULL; |
| _survivor_tail = NULL; |
| _survivor_length = 0; |
| } |
| |
| HeapRegion* first_region() { return _head; } |
| HeapRegion* first_survivor_region() { return _survivor_head; } |
| HeapRegion* last_survivor_region() { return _survivor_tail; } |
| |
| // debugging |
| bool check_list_well_formed(); |
| bool check_list_empty(bool check_sample = true); |
| void print(); |
| }; |
| |
| class RefineCardTableEntryClosure; |
| class G1CollectedHeap : public SharedHeap { |
| friend class VM_G1CollectForAllocation; |
| friend class VM_GenCollectForPermanentAllocation; |
| friend class VM_G1CollectFull; |
| friend class VM_G1IncCollectionPause; |
| friend class VMStructs; |
| |
| // Closures used in implementation. |
| friend class G1ParCopyHelper; |
| friend class G1IsAliveClosure; |
| friend class G1EvacuateFollowersClosure; |
| friend class G1ParScanThreadState; |
| friend class G1ParScanClosureSuper; |
| friend class G1ParEvacuateFollowersClosure; |
| friend class G1ParTask; |
| friend class G1FreeGarbageRegionClosure; |
| friend class RefineCardTableEntryClosure; |
| friend class G1PrepareCompactClosure; |
| friend class RegionSorter; |
| friend class RegionResetter; |
| friend class CountRCClosure; |
| friend class EvacPopObjClosure; |
| friend class G1ParCleanupCTTask; |
| |
| // Other related classes. |
| friend class G1MarkSweep; |
| |
| private: |
| // The one and only G1CollectedHeap, so static functions can find it. |
| static G1CollectedHeap* _g1h; |
| |
| static size_t _humongous_object_threshold_in_words; |
| |
| // Storage for the G1 heap (excludes the permanent generation). |
| VirtualSpace _g1_storage; |
| MemRegion _g1_reserved; |
| |
| // The part of _g1_storage that is currently committed. |
| MemRegion _g1_committed; |
| |
| // The maximum part of _g1_storage that has ever been committed. |
| MemRegion _g1_max_committed; |
| |
| // The master free list. It will satisfy all new region allocations. |
| MasterFreeRegionList _free_list; |
| |
| // The secondary free list which contains regions that have been |
| // freed up during the cleanup process. This will be appended to the |
| // master free list when appropriate. |
| SecondaryFreeRegionList _secondary_free_list; |
| |
| // It keeps track of the humongous regions. |
| MasterHumongousRegionSet _humongous_set; |
| |
| // The number of regions we could create by expansion. |
| size_t _expansion_regions; |
| |
| // The block offset table for the G1 heap. |
| G1BlockOffsetSharedArray* _bot_shared; |
| |
| // Move all of the regions off the free lists, then rebuild those free |
| // lists, before and after full GC. |
| void tear_down_region_lists(); |
| void rebuild_region_lists(); |
| |
| // The sequence of all heap regions in the heap. |
| HeapRegionSeq* _hrs; |
| |
| // The region from which normal-sized objects are currently being |
| // allocated. May be NULL. |
| HeapRegion* _cur_alloc_region; |
| |
| // Postcondition: cur_alloc_region == NULL. |
| void abandon_cur_alloc_region(); |
| void abandon_gc_alloc_regions(); |
| |
| // The to-space memory regions into which objects are being copied during |
| // a GC. |
| HeapRegion* _gc_alloc_regions[GCAllocPurposeCount]; |
| size_t _gc_alloc_region_counts[GCAllocPurposeCount]; |
| // These are the regions, one per GCAllocPurpose, that are half-full |
| // at the end of a collection and that we want to reuse during the |
| // next collection. |
| HeapRegion* _retained_gc_alloc_regions[GCAllocPurposeCount]; |
| // This specifies whether we will keep the last half-full region at |
| // the end of a collection so that it can be reused during the next |
| // collection (this is specified per GCAllocPurpose) |
| bool _retain_gc_alloc_region[GCAllocPurposeCount]; |
| |
| // A list of the regions that have been set to be alloc regions in the |
| // current collection. |
| HeapRegion* _gc_alloc_region_list; |
| |
| // Determines PLAB size for a particular allocation purpose. |
| static size_t desired_plab_sz(GCAllocPurpose purpose); |
| |
| // When called by par thread, requires the FreeList_lock to be held. |
| void push_gc_alloc_region(HeapRegion* hr); |
| |
| // This should only be called single-threaded. Undeclares all GC alloc |
| // regions. |
| void forget_alloc_region_list(); |
| |
| // Should be used to set an alloc region, because there's other |
| // associated bookkeeping. |
| void set_gc_alloc_region(int purpose, HeapRegion* r); |
| |
| // Check well-formedness of alloc region list. |
| bool check_gc_alloc_regions(); |
| |
| // Outside of GC pauses, the number of bytes used in all regions other |
| // than the current allocation region. |
| size_t _summary_bytes_used; |
| |
| // This is used for a quick test on whether a reference points into |
| // the collection set or not. Basically, we have an array, with one |
| // byte per region, and that byte denotes whether the corresponding |
| // region is in the collection set or not. The entry corresponding |
| // the bottom of the heap, i.e., region 0, is pointed to by |
| // _in_cset_fast_test_base. The _in_cset_fast_test field has been |
| // biased so that it actually points to address 0 of the address |
| // space, to make the test as fast as possible (we can simply shift |
| // the address to address into it, instead of having to subtract the |
| // bottom of the heap from the address before shifting it; basically |
| // it works in the same way the card table works). |
| bool* _in_cset_fast_test; |
| |
| // The allocated array used for the fast test on whether a reference |
| // points into the collection set or not. This field is also used to |
| // free the array. |
| bool* _in_cset_fast_test_base; |
| |
| // The length of the _in_cset_fast_test_base array. |
| size_t _in_cset_fast_test_length; |
| |
| volatile unsigned _gc_time_stamp; |
| |
| size_t* _surviving_young_words; |
| |
| void setup_surviving_young_words(); |
| void update_surviving_young_words(size_t* surv_young_words); |
| void cleanup_surviving_young_words(); |
| |
| // It decides whether an explicit GC should start a concurrent cycle |
| // instead of doing a STW GC. Currently, a concurrent cycle is |
| // explicitly started if: |
| // (a) cause == _gc_locker and +GCLockerInvokesConcurrent, or |
| // (b) cause == _java_lang_system_gc and +ExplicitGCInvokesConcurrent. |
| bool should_do_concurrent_full_gc(GCCause::Cause cause); |
| |
| // Keeps track of how many "full collections" (i.e., Full GCs or |
| // concurrent cycles) we have completed. The number of them we have |
| // started is maintained in _total_full_collections in CollectedHeap. |
| volatile unsigned int _full_collections_completed; |
| |
| // These are macros so that, if the assert fires, we get the correct |
| // line number, file, etc. |
| |
| #define heap_locking_asserts_err_msg(_extra_message_) \ |
| err_msg("%s : Heap_lock locked: %s, at safepoint: %s, is VM thread: %s", \ |
| (_extra_message_), \ |
| BOOL_TO_STR(Heap_lock->owned_by_self()), \ |
| BOOL_TO_STR(SafepointSynchronize::is_at_safepoint()), \ |
| BOOL_TO_STR(Thread::current()->is_VM_thread())) |
| |
| #define assert_heap_locked() \ |
| do { \ |
| assert(Heap_lock->owned_by_self(), \ |
| heap_locking_asserts_err_msg("should be holding the Heap_lock")); \ |
| } while (0) |
| |
| #define assert_heap_locked_or_at_safepoint(_should_be_vm_thread_) \ |
| do { \ |
| assert(Heap_lock->owned_by_self() || \ |
| (SafepointSynchronize::is_at_safepoint() && \ |
| ((_should_be_vm_thread_) == Thread::current()->is_VM_thread())), \ |
| heap_locking_asserts_err_msg("should be holding the Heap_lock or " \ |
| "should be at a safepoint")); \ |
| } while (0) |
| |
| #define assert_heap_locked_and_not_at_safepoint() \ |
| do { \ |
| assert(Heap_lock->owned_by_self() && \ |
| !SafepointSynchronize::is_at_safepoint(), \ |
| heap_locking_asserts_err_msg("should be holding the Heap_lock and " \ |
| "should not be at a safepoint")); \ |
| } while (0) |
| |
| #define assert_heap_not_locked() \ |
| do { \ |
| assert(!Heap_lock->owned_by_self(), \ |
| heap_locking_asserts_err_msg("should not be holding the Heap_lock")); \ |
| } while (0) |
| |
| #define assert_heap_not_locked_and_not_at_safepoint() \ |
| do { \ |
| assert(!Heap_lock->owned_by_self() && \ |
| !SafepointSynchronize::is_at_safepoint(), \ |
| heap_locking_asserts_err_msg("should not be holding the Heap_lock and " \ |
| "should not be at a safepoint")); \ |
| } while (0) |
| |
| #define assert_at_safepoint(_should_be_vm_thread_) \ |
| do { \ |
| assert(SafepointSynchronize::is_at_safepoint() && \ |
| ((_should_be_vm_thread_) == Thread::current()->is_VM_thread()), \ |
| heap_locking_asserts_err_msg("should be at a safepoint")); \ |
| } while (0) |
| |
| #define assert_not_at_safepoint() \ |
| do { \ |
| assert(!SafepointSynchronize::is_at_safepoint(), \ |
| heap_locking_asserts_err_msg("should not be at a safepoint")); \ |
| } while (0) |
| |
| protected: |
| |
| // Returns "true" iff none of the gc alloc regions have any allocations |
| // since the last call to "save_marks". |
| bool all_alloc_regions_no_allocs_since_save_marks(); |
| // Perform finalization stuff on all allocation regions. |
| void retire_all_alloc_regions(); |
| |
| // The number of regions allocated to hold humongous objects. |
| int _num_humongous_regions; |
| YoungList* _young_list; |
| |
| // The current policy object for the collector. |
| G1CollectorPolicy* _g1_policy; |
| |
| // This is the second level of trying to allocate a new region. If |
| // new_region_work didn't find a region in the free_list, this call |
| // will check whether there's anything available in the |
| // secondary_free_list and/or wait for more regions to appear in that |
| // list, if _free_regions_coming is set. |
| HeapRegion* new_region_try_secondary_free_list(); |
| |
| // Try to allocate a single non-humongous HeapRegion sufficient for |
| // an allocation of the given word_size. If do_expand is true, |
| // attempt to expand the heap if necessary to satisfy the allocation |
| // request. |
| HeapRegion* new_region_work(size_t word_size, bool do_expand); |
| |
| // Try to allocate a new region to be used for allocation by a |
| // mutator thread. Attempt to expand the heap if no region is |
| // available. |
| HeapRegion* new_alloc_region(size_t word_size) { |
| return new_region_work(word_size, false /* do_expand */); |
| } |
| |
| // Try to allocate a new region to be used for allocation by a GC |
| // thread. Attempt to expand the heap if no region is available. |
| HeapRegion* new_gc_alloc_region(int purpose, size_t word_size); |
| |
| // Attempt to satisfy a humongous allocation request of the given |
| // size by finding a contiguous set of free regions of num_regions |
| // length and remove them from the master free list. Return the |
| // index of the first region or -1 if the search was unsuccessful. |
| int humongous_obj_allocate_find_first(size_t num_regions, size_t word_size); |
| |
| // Initialize a contiguous set of free regions of length num_regions |
| // and starting at index first so that they appear as a single |
| // humongous region. |
| HeapWord* humongous_obj_allocate_initialize_regions(int first, |
| size_t num_regions, |
| size_t word_size); |
| |
| // Attempt to allocate a humongous object of the given size. Return |
| // NULL if unsuccessful. |
| HeapWord* humongous_obj_allocate(size_t word_size); |
| |
| // The following two methods, allocate_new_tlab() and |
| // mem_allocate(), are the two main entry points from the runtime |
| // into the G1's allocation routines. They have the following |
| // assumptions: |
| // |
| // * They should both be called outside safepoints. |
| // |
| // * They should both be called without holding the Heap_lock. |
| // |
| // * All allocation requests for new TLABs should go to |
| // allocate_new_tlab(). |
| // |
| // * All non-TLAB allocation requests should go to mem_allocate() |
| // and mem_allocate() should never be called with is_tlab == true. |
| // |
| // * If the GC locker is active we currently stall until we can |
| // allocate a new young region. This will be changed in the |
| // near future (see CR 6994056). |
| // |
| // * If either call cannot satisfy the allocation request using the |
| // current allocating region, they will try to get a new one. If |
| // this fails, they will attempt to do an evacuation pause and |
| // retry the allocation. |
| // |
| // * If all allocation attempts fail, even after trying to schedule |
| // an evacuation pause, allocate_new_tlab() will return NULL, |
| // whereas mem_allocate() will attempt a heap expansion and/or |
| // schedule a Full GC. |
| // |
| // * We do not allow humongous-sized TLABs. So, allocate_new_tlab |
| // should never be called with word_size being humongous. All |
| // humongous allocation requests should go to mem_allocate() which |
| // will satisfy them with a special path. |
| |
| virtual HeapWord* allocate_new_tlab(size_t word_size); |
| |
| virtual HeapWord* mem_allocate(size_t word_size, |
| bool is_noref, |
| bool is_tlab, /* expected to be false */ |
| bool* gc_overhead_limit_was_exceeded); |
| |
| // The following methods, allocate_from_cur_allocation_region(), |
| // attempt_allocation(), attempt_allocation_locked(), |
| // replace_cur_alloc_region_and_allocate(), |
| // attempt_allocation_slow(), and attempt_allocation_humongous() |
| // have very awkward pre- and post-conditions with respect to |
| // locking: |
| // |
| // If they are called outside a safepoint they assume the caller |
| // holds the Heap_lock when it calls them. However, on exit they |
| // will release the Heap_lock if they return a non-NULL result, but |
| // keep holding the Heap_lock if they return a NULL result. The |
| // reason for this is that we need to dirty the cards that span |
| // allocated blocks on young regions to avoid having to take the |
| // slow path of the write barrier (for performance reasons we don't |
| // update RSets for references whose source is a young region, so we |
| // don't need to look at dirty cards on young regions). But, doing |
| // this card dirtying while holding the Heap_lock can be a |
| // scalability bottleneck, especially given that some allocation |
| // requests might be of non-trivial size (and the larger the region |
| // size is, the fewer allocations requests will be considered |
| // humongous, as the humongous size limit is a fraction of the |
| // region size). So, when one of these calls succeeds in allocating |
| // a block it does the card dirtying after it releases the Heap_lock |
| // which is why it will return without holding it. |
| // |
| // The above assymetry is the reason why locking / unlocking is done |
| // explicitly (i.e., with Heap_lock->lock() and |
| // Heap_lock->unlocked()) instead of using MutexLocker and |
| // MutexUnlocker objects. The latter would ensure that the lock is |
| // unlocked / re-locked at every possible exit out of the basic |
| // block. However, we only want that action to happen in selected |
| // places. |
| // |
| // Further, if the above methods are called during a safepoint, then |
| // naturally there's no assumption about the Heap_lock being held or |
| // there's no attempt to unlock it. The parameter at_safepoint |
| // indicates whether the call is made during a safepoint or not (as |
| // an optimization, to avoid reading the global flag with |
| // SafepointSynchronize::is_at_safepoint()). |
| // |
| // The methods share these parameters: |
| // |
| // * word_size : the size of the allocation request in words |
| // * at_safepoint : whether the call is done at a safepoint; this |
| // also determines whether a GC is permitted |
| // (at_safepoint == false) or not (at_safepoint == true) |
| // * do_dirtying : whether the method should dirty the allocated |
| // block before returning |
| // |
| // They all return either the address of the block, if they |
| // successfully manage to allocate it, or NULL. |
| |
| // It tries to satisfy an allocation request out of the current |
| // alloc region, which is passed as a parameter. It assumes that the |
| // caller has checked that the current alloc region is not NULL. |
| // Given that the caller has to check the current alloc region for |
| // at least NULL, it might as well pass it as the first parameter so |
| // that the method doesn't have to read it from the |
| // _cur_alloc_region field again. It is called from both |
| // attempt_allocation() and attempt_allocation_locked() and the |
| // with_heap_lock parameter indicates whether the caller was holding |
| // the heap lock when it called it or not. |
| inline HeapWord* allocate_from_cur_alloc_region(HeapRegion* cur_alloc_region, |
| size_t word_size, |
| bool with_heap_lock); |
| |
| // First-level of allocation slow path: it attempts to allocate out |
| // of the current alloc region in a lock-free manner using a CAS. If |
| // that fails it takes the Heap_lock and calls |
| // attempt_allocation_locked() for the second-level slow path. |
| inline HeapWord* attempt_allocation(size_t word_size); |
| |
| // Second-level of allocation slow path: while holding the Heap_lock |
| // it tries to allocate out of the current alloc region and, if that |
| // fails, tries to allocate out of a new current alloc region. |
| inline HeapWord* attempt_allocation_locked(size_t word_size); |
| |
| // It assumes that the current alloc region has been retired and |
| // tries to allocate a new one. If it's successful, it performs the |
| // allocation out of the new current alloc region and updates |
| // _cur_alloc_region. Normally, it would try to allocate a new |
| // region if the young gen is not full, unless can_expand is true in |
| // which case it would always try to allocate a new region. |
| HeapWord* replace_cur_alloc_region_and_allocate(size_t word_size, |
| bool at_safepoint, |
| bool do_dirtying, |
| bool can_expand); |
| |
| // Third-level of allocation slow path: when we are unable to |
| // allocate a new current alloc region to satisfy an allocation |
| // request (i.e., when attempt_allocation_locked() fails). It will |
| // try to do an evacuation pause, which might stall due to the GC |
| // locker, and retry the allocation attempt when appropriate. |
| HeapWord* attempt_allocation_slow(size_t word_size); |
| |
| // The method that tries to satisfy a humongous allocation |
| // request. If it cannot satisfy it it will try to do an evacuation |
| // pause to perhaps reclaim enough space to be able to satisfy the |
| // allocation request afterwards. |
| HeapWord* attempt_allocation_humongous(size_t word_size, |
| bool at_safepoint); |
| |
| // It does the common work when we are retiring the current alloc region. |
| inline void retire_cur_alloc_region_common(HeapRegion* cur_alloc_region); |
| |
| // It retires the current alloc region, which is passed as a |
| // parameter (since, typically, the caller is already holding on to |
| // it). It sets _cur_alloc_region to NULL. |
| void retire_cur_alloc_region(HeapRegion* cur_alloc_region); |
| |
| // It attempts to do an allocation immediately before or after an |
| // evacuation pause and can only be called by the VM thread. It has |
| // slightly different assumptions that the ones before (i.e., |
| // assumes that the current alloc region has been retired). |
| HeapWord* attempt_allocation_at_safepoint(size_t word_size, |
| bool expect_null_cur_alloc_region); |
| |
| // It dirties the cards that cover the block so that so that the post |
| // write barrier never queues anything when updating objects on this |
| // block. It is assumed (and in fact we assert) that the block |
| // belongs to a young region. |
| inline void dirty_young_block(HeapWord* start, size_t word_size); |
| |
| // Allocate blocks during garbage collection. Will ensure an |
| // allocation region, either by picking one or expanding the |
| // heap, and then allocate a block of the given size. The block |
| // may not be a humongous - it must fit into a single heap region. |
| HeapWord* par_allocate_during_gc(GCAllocPurpose purpose, size_t word_size); |
| |
| HeapWord* allocate_during_gc_slow(GCAllocPurpose purpose, |
| HeapRegion* alloc_region, |
| bool par, |
| size_t word_size); |
| |
| // Ensure that no further allocations can happen in "r", bearing in mind |
| // that parallel threads might be attempting allocations. |
| void par_allocate_remaining_space(HeapRegion* r); |
| |
| // Retires an allocation region when it is full or at the end of a |
| // GC pause. |
| void retire_alloc_region(HeapRegion* alloc_region, bool par); |
| |
| // - if explicit_gc is true, the GC is for a System.gc() or a heap |
| // inspection request and should collect the entire heap |
| // - if clear_all_soft_refs is true, all soft references should be |
| // cleared during the GC |
| // - if explicit_gc is false, word_size describes the allocation that |
| // the GC should attempt (at least) to satisfy |
| // - it returns false if it is unable to do the collection due to the |
| // GC locker being active, true otherwise |
| bool do_collection(bool explicit_gc, |
| bool clear_all_soft_refs, |
| size_t word_size); |
| |
| // Callback from VM_G1CollectFull operation. |
| // Perform a full collection. |
| void do_full_collection(bool clear_all_soft_refs); |
| |
| // Resize the heap if necessary after a full collection. If this is |
| // after a collect-for allocation, "word_size" is the allocation size, |
| // and will be considered part of the used portion of the heap. |
| void resize_if_necessary_after_full_collection(size_t word_size); |
| |
| // Callback from VM_G1CollectForAllocation operation. |
| // This function does everything necessary/possible to satisfy a |
| // failed allocation request (including collection, expansion, etc.) |
| HeapWord* satisfy_failed_allocation(size_t word_size, bool* succeeded); |
| |
| // Attempting to expand the heap sufficiently |
| // to support an allocation of the given "word_size". If |
| // successful, perform the allocation and return the address of the |
| // allocated block, or else "NULL". |
| HeapWord* expand_and_allocate(size_t word_size); |
| |
| public: |
| // Expand the garbage-first heap by at least the given size (in bytes!). |
| // Returns true if the heap was expanded by the requested amount; |
| // false otherwise. |
| // (Rounds up to a HeapRegion boundary.) |
| bool expand(size_t expand_bytes); |
| |
| // Do anything common to GC's. |
| virtual void gc_prologue(bool full); |
| virtual void gc_epilogue(bool full); |
| |
| // We register a region with the fast "in collection set" test. We |
| // simply set to true the array slot corresponding to this region. |
| void register_region_with_in_cset_fast_test(HeapRegion* r) { |
| assert(_in_cset_fast_test_base != NULL, "sanity"); |
| assert(r->in_collection_set(), "invariant"); |
| int index = r->hrs_index(); |
| assert(0 <= index && (size_t) index < _in_cset_fast_test_length, "invariant"); |
| assert(!_in_cset_fast_test_base[index], "invariant"); |
| _in_cset_fast_test_base[index] = true; |
| } |
| |
| // This is a fast test on whether a reference points into the |
| // collection set or not. It does not assume that the reference |
| // points into the heap; if it doesn't, it will return false. |
| bool in_cset_fast_test(oop obj) { |
| assert(_in_cset_fast_test != NULL, "sanity"); |
| if (_g1_committed.contains((HeapWord*) obj)) { |
| // no need to subtract the bottom of the heap from obj, |
| // _in_cset_fast_test is biased |
| size_t index = ((size_t) obj) >> HeapRegion::LogOfHRGrainBytes; |
| bool ret = _in_cset_fast_test[index]; |
| // let's make sure the result is consistent with what the slower |
| // test returns |
| assert( ret || !obj_in_cs(obj), "sanity"); |
| assert(!ret || obj_in_cs(obj), "sanity"); |
| return ret; |
| } else { |
| return false; |
| } |
| } |
| |
| void clear_cset_fast_test() { |
| assert(_in_cset_fast_test_base != NULL, "sanity"); |
| memset(_in_cset_fast_test_base, false, |
| _in_cset_fast_test_length * sizeof(bool)); |
| } |
| |
| // This is called at the end of either a concurrent cycle or a Full |
| // GC to update the number of full collections completed. Those two |
| // can happen in a nested fashion, i.e., we start a concurrent |
| // cycle, a Full GC happens half-way through it which ends first, |
| // and then the cycle notices that a Full GC happened and ends |
| // too. The concurrent parameter is a boolean to help us do a bit |
| // tighter consistency checking in the method. If concurrent is |
| // false, the caller is the inner caller in the nesting (i.e., the |
| // Full GC). If concurrent is true, the caller is the outer caller |
| // in this nesting (i.e., the concurrent cycle). Further nesting is |
| // not currently supported. The end of the this call also notifies |
| // the FullGCCount_lock in case a Java thread is waiting for a full |
| // GC to happen (e.g., it called System.gc() with |
| // +ExplicitGCInvokesConcurrent). |
| void increment_full_collections_completed(bool concurrent); |
| |
| unsigned int full_collections_completed() { |
| return _full_collections_completed; |
| } |
| |
| protected: |
| |
| // Shrink the garbage-first heap by at most the given size (in bytes!). |
| // (Rounds down to a HeapRegion boundary.) |
| virtual void shrink(size_t expand_bytes); |
| void shrink_helper(size_t expand_bytes); |
| |
| #if TASKQUEUE_STATS |
| static void print_taskqueue_stats_hdr(outputStream* const st = gclog_or_tty); |
| void print_taskqueue_stats(outputStream* const st = gclog_or_tty) const; |
| void reset_taskqueue_stats(); |
| #endif // TASKQUEUE_STATS |
| |
| // Schedule the VM operation that will do an evacuation pause to |
| // satisfy an allocation request of word_size. *succeeded will |
| // return whether the VM operation was successful (it did do an |
| // evacuation pause) or not (another thread beat us to it or the GC |
| // locker was active). Given that we should not be holding the |
| // Heap_lock when we enter this method, we will pass the |
| // gc_count_before (i.e., total_collections()) as a parameter since |
| // it has to be read while holding the Heap_lock. Currently, both |
| // methods that call do_collection_pause() release the Heap_lock |
| // before the call, so it's easy to read gc_count_before just before. |
| HeapWord* do_collection_pause(size_t word_size, |
| unsigned int gc_count_before, |
| bool* succeeded); |
| |
| // The guts of the incremental collection pause, executed by the vm |
| // thread. It returns false if it is unable to do the collection due |
| // to the GC locker being active, true otherwise |
| bool do_collection_pause_at_safepoint(double target_pause_time_ms); |
| |
| // Actually do the work of evacuating the collection set. |
| void evacuate_collection_set(); |
| |
| // The g1 remembered set of the heap. |
| G1RemSet* _g1_rem_set; |
| // And it's mod ref barrier set, used to track updates for the above. |
| ModRefBarrierSet* _mr_bs; |
| |
| // A set of cards that cover the objects for which the Rsets should be updated |
| // concurrently after the collection. |
| DirtyCardQueueSet _dirty_card_queue_set; |
| |
| // The Heap Region Rem Set Iterator. |
| HeapRegionRemSetIterator** _rem_set_iterator; |
| |
| // The closure used to refine a single card. |
| RefineCardTableEntryClosure* _refine_cte_cl; |
| |
| // A function to check the consistency of dirty card logs. |
| void check_ct_logs_at_safepoint(); |
| |
| // A DirtyCardQueueSet that is used to hold cards that contain |
| // references into the current collection set. This is used to |
| // update the remembered sets of the regions in the collection |
| // set in the event of an evacuation failure. |
| DirtyCardQueueSet _into_cset_dirty_card_queue_set; |
| |
| // After a collection pause, make the regions in the CS into free |
| // regions. |
| void free_collection_set(HeapRegion* cs_head); |
| |
| // Abandon the current collection set without recording policy |
| // statistics or updating free lists. |
| void abandon_collection_set(HeapRegion* cs_head); |
| |
| // Applies "scan_non_heap_roots" to roots outside the heap, |
| // "scan_rs" to roots inside the heap (having done "set_region" to |
| // indicate the region in which the root resides), and does "scan_perm" |
| // (setting the generation to the perm generation.) If "scan_rs" is |
| // NULL, then this step is skipped. The "worker_i" |
| // param is for use with parallel roots processing, and should be |
| // the "i" of the calling parallel worker thread's work(i) function. |
| // In the sequential case this param will be ignored. |
| void g1_process_strong_roots(bool collecting_perm_gen, |
| SharedHeap::ScanningOption so, |
| OopClosure* scan_non_heap_roots, |
| OopsInHeapRegionClosure* scan_rs, |
| OopsInGenClosure* scan_perm, |
| int worker_i); |
| |
| // Apply "blk" to all the weak roots of the system. These include |
| // JNI weak roots, the code cache, system dictionary, symbol table, |
| // string table, and referents of reachable weak refs. |
| void g1_process_weak_roots(OopClosure* root_closure, |
| OopClosure* non_root_closure); |
| |
| // Invoke "save_marks" on all heap regions. |
| void save_marks(); |
| |
| // Frees a non-humongous region by initializing its contents and |
| // adding it to the free list that's passed as a parameter (this is |
| // usually a local list which will be appended to the master free |
| // list later). The used bytes of freed regions are accumulated in |
| // pre_used. If par is true, the region's RSet will not be freed |
| // up. The assumption is that this will be done later. |
| void free_region(HeapRegion* hr, |
| size_t* pre_used, |
| FreeRegionList* free_list, |
| bool par); |
| |
| // Frees a humongous region by collapsing it into individual regions |
| // and calling free_region() for each of them. The freed regions |
| // will be added to the free list that's passed as a parameter (this |
| // is usually a local list which will be appended to the master free |
| // list later). The used bytes of freed regions are accumulated in |
| // pre_used. If par is true, the region's RSet will not be freed |
| // up. The assumption is that this will be done later. |
| void free_humongous_region(HeapRegion* hr, |
| size_t* pre_used, |
| FreeRegionList* free_list, |
| HumongousRegionSet* humongous_proxy_set, |
| bool par); |
| |
| // The concurrent marker (and the thread it runs in.) |
| ConcurrentMark* _cm; |
| ConcurrentMarkThread* _cmThread; |
| bool _mark_in_progress; |
| |
| // The concurrent refiner. |
| ConcurrentG1Refine* _cg1r; |
| |
| // The parallel task queues |
| RefToScanQueueSet *_task_queues; |
| |
| // True iff a evacuation has failed in the current collection. |
| bool _evacuation_failed; |
| |
| // Set the attribute indicating whether evacuation has failed in the |
| // current collection. |
| void set_evacuation_failed(bool b) { _evacuation_failed = b; } |
| |
| // Failed evacuations cause some logical from-space objects to have |
| // forwarding pointers to themselves. Reset them. |
| void remove_self_forwarding_pointers(); |
| |
| // When one is non-null, so is the other. Together, they each pair is |
| // an object with a preserved mark, and its mark value. |
| GrowableArray<oop>* _objs_with_preserved_marks; |
| GrowableArray<markOop>* _preserved_marks_of_objs; |
| |
| // Preserve the mark of "obj", if necessary, in preparation for its mark |
| // word being overwritten with a self-forwarding-pointer. |
| void preserve_mark_if_necessary(oop obj, markOop m); |
| |
| // The stack of evac-failure objects left to be scanned. |
| GrowableArray<oop>* _evac_failure_scan_stack; |
| // The closure to apply to evac-failure objects. |
| |
| OopsInHeapRegionClosure* _evac_failure_closure; |
| // Set the field above. |
| void |
| set_evac_failure_closure(OopsInHeapRegionClosure* evac_failure_closure) { |
| _evac_failure_closure = evac_failure_closure; |
| } |
| |
| // Push "obj" on the scan stack. |
| void push_on_evac_failure_scan_stack(oop obj); |
| // Process scan stack entries until the stack is empty. |
| void drain_evac_failure_scan_stack(); |
| // True iff an invocation of "drain_scan_stack" is in progress; to |
| // prevent unnecessary recursion. |
| bool _drain_in_progress; |
| |
| // Do any necessary initialization for evacuation-failure handling. |
| // "cl" is the closure that will be used to process evac-failure |
| // objects. |
| void init_for_evac_failure(OopsInHeapRegionClosure* cl); |
| // Do any necessary cleanup for evacuation-failure handling data |
| // structures. |
| void finalize_for_evac_failure(); |
| |
| // An attempt to evacuate "obj" has failed; take necessary steps. |
| oop handle_evacuation_failure_par(OopsInHeapRegionClosure* cl, oop obj); |
| void handle_evacuation_failure_common(oop obj, markOop m); |
| |
| |
| // Ensure that the relevant gc_alloc regions are set. |
| void get_gc_alloc_regions(); |
| // We're done with GC alloc regions. We are going to tear down the |
| // gc alloc list and remove the gc alloc tag from all the regions on |
| // that list. However, we will also retain the last (i.e., the one |
| // that is half-full) GC alloc region, per GCAllocPurpose, for |
| // possible reuse during the next collection, provided |
| // _retain_gc_alloc_region[] indicates that it should be the |
| // case. Said regions are kept in the _retained_gc_alloc_regions[] |
| // array. If the parameter totally is set, we will not retain any |
| // regions, irrespective of what _retain_gc_alloc_region[] |
| // indicates. |
| void release_gc_alloc_regions(bool totally); |
| #ifndef PRODUCT |
| // Useful for debugging. |
| void print_gc_alloc_regions(); |
| #endif // !PRODUCT |
| |
| // Instance of the concurrent mark is_alive closure for embedding |
| // into the reference processor as the is_alive_non_header. This |
| // prevents unnecessary additions to the discovered lists during |
| // concurrent discovery. |
| G1CMIsAliveClosure _is_alive_closure; |
| |
| // ("Weak") Reference processing support |
| ReferenceProcessor* _ref_processor; |
| |
| enum G1H_process_strong_roots_tasks { |
| G1H_PS_mark_stack_oops_do, |
| G1H_PS_refProcessor_oops_do, |
| // Leave this one last. |
| G1H_PS_NumElements |
| }; |
| |
| SubTasksDone* _process_strong_tasks; |
| |
| volatile bool _free_regions_coming; |
| |
| public: |
| |
| SubTasksDone* process_strong_tasks() { return _process_strong_tasks; } |
| |
| void set_refine_cte_cl_concurrency(bool concurrent); |
| |
| RefToScanQueue *task_queue(int i) const; |
| |
| // A set of cards where updates happened during the GC |
| DirtyCardQueueSet& dirty_card_queue_set() { return _dirty_card_queue_set; } |
| |
| // A DirtyCardQueueSet that is used to hold cards that contain |
| // references into the current collection set. This is used to |
| // update the remembered sets of the regions in the collection |
| // set in the event of an evacuation failure. |
| DirtyCardQueueSet& into_cset_dirty_card_queue_set() |
| { return _into_cset_dirty_card_queue_set; } |
| |
| // Create a G1CollectedHeap with the specified policy. |
| // Must call the initialize method afterwards. |
| // May not return if something goes wrong. |
| G1CollectedHeap(G1CollectorPolicy* policy); |
| |
| // Initialize the G1CollectedHeap to have the initial and |
| // maximum sizes, permanent generation, and remembered and barrier sets |
| // specified by the policy object. |
| jint initialize(); |
| |
| virtual void ref_processing_init(); |
| |
| void set_par_threads(int t) { |
| SharedHeap::set_par_threads(t); |
| _process_strong_tasks->set_n_threads(t); |
| } |
| |
| virtual CollectedHeap::Name kind() const { |
| return CollectedHeap::G1CollectedHeap; |
| } |
| |
| // The current policy object for the collector. |
| G1CollectorPolicy* g1_policy() const { return _g1_policy; } |
| |
| // Adaptive size policy. No such thing for g1. |
| virtual AdaptiveSizePolicy* size_policy() { return NULL; } |
| |
| // The rem set and barrier set. |
| G1RemSet* g1_rem_set() const { return _g1_rem_set; } |
| ModRefBarrierSet* mr_bs() const { return _mr_bs; } |
| |
| // The rem set iterator. |
| HeapRegionRemSetIterator* rem_set_iterator(int i) { |
| return _rem_set_iterator[i]; |
| } |
| |
| HeapRegionRemSetIterator* rem_set_iterator() { |
| return _rem_set_iterator[0]; |
| } |
| |
| unsigned get_gc_time_stamp() { |
| return _gc_time_stamp; |
| } |
| |
| void reset_gc_time_stamp() { |
| _gc_time_stamp = 0; |
| OrderAccess::fence(); |
| } |
| |
| void increment_gc_time_stamp() { |
| ++_gc_time_stamp; |
| OrderAccess::fence(); |
| } |
| |
| void iterate_dirty_card_closure(CardTableEntryClosure* cl, |
| DirtyCardQueue* into_cset_dcq, |
| bool concurrent, int worker_i); |
| |
| // The shared block offset table array. |
| G1BlockOffsetSharedArray* bot_shared() const { return _bot_shared; } |
| |
| // Reference Processing accessor |
| ReferenceProcessor* ref_processor() { return _ref_processor; } |
| |
| virtual size_t capacity() const; |
| virtual size_t used() const; |
| // This should be called when we're not holding the heap lock. The |
| // result might be a bit inaccurate. |
| size_t used_unlocked() const; |
| size_t recalculate_used() const; |
| #ifndef PRODUCT |
| size_t recalculate_used_regions() const; |
| #endif // PRODUCT |
| |
| // These virtual functions do the actual allocation. |
| // Some heaps may offer a contiguous region for shared non-blocking |
| // allocation, via inlined code (by exporting the address of the top and |
| // end fields defining the extent of the contiguous allocation region.) |
| // But G1CollectedHeap doesn't yet support this. |
| |
| // Return an estimate of the maximum allocation that could be performed |
| // without triggering any collection or expansion activity. In a |
| // generational collector, for example, this is probably the largest |
| // allocation that could be supported (without expansion) in the youngest |
| // generation. It is "unsafe" because no locks are taken; the result |
| // should be treated as an approximation, not a guarantee, for use in |
| // heuristic resizing decisions. |
| virtual size_t unsafe_max_alloc(); |
| |
| virtual bool is_maximal_no_gc() const { |
| return _g1_storage.uncommitted_size() == 0; |
| } |
| |
| // The total number of regions in the heap. |
| size_t n_regions(); |
| |
| // The number of regions that are completely free. |
| size_t max_regions(); |
| |
| // The number of regions that are completely free. |
| size_t free_regions() { |
| return _free_list.length(); |
| } |
| |
| // The number of regions that are not completely free. |
| size_t used_regions() { return n_regions() - free_regions(); } |
| |
| // The number of regions available for "regular" expansion. |
| size_t expansion_regions() { return _expansion_regions; } |
| |
| // verify_region_sets() performs verification over the region |
| // lists. It will be compiled in the product code to be used when |
| // necessary (i.e., during heap verification). |
| void verify_region_sets(); |
| |
| // verify_region_sets_optional() is planted in the code for |
| // list verification in non-product builds (and it can be enabled in |
| // product builds by definning HEAP_REGION_SET_FORCE_VERIFY to be 1). |
| #if HEAP_REGION_SET_FORCE_VERIFY |
| void verify_region_sets_optional() { |
| verify_region_sets(); |
| } |
| #else // HEAP_REGION_SET_FORCE_VERIFY |
| void verify_region_sets_optional() { } |
| #endif // HEAP_REGION_SET_FORCE_VERIFY |
| |
| #ifdef ASSERT |
| bool is_on_master_free_list(HeapRegion* hr) { |
| return hr->containing_set() == &_free_list; |
| } |
| |
| bool is_in_humongous_set(HeapRegion* hr) { |
| return hr->containing_set() == &_humongous_set; |
| } |
| #endif // ASSERT |
| |
| // Wrapper for the region list operations that can be called from |
| // methods outside this class. |
| |
| void secondary_free_list_add_as_tail(FreeRegionList* list) { |
| _secondary_free_list.add_as_tail(list); |
| } |
| |
| void append_secondary_free_list() { |
| _free_list.add_as_tail(&_secondary_free_list); |
| } |
| |
| void append_secondary_free_list_if_not_empty_with_lock() { |
| // If the secondary free list looks empty there's no reason to |
| // take the lock and then try to append it. |
| if (!_secondary_free_list.is_empty()) { |
| MutexLockerEx x(SecondaryFreeList_lock, Mutex::_no_safepoint_check_flag); |
| append_secondary_free_list(); |
| } |
| } |
| |
| void set_free_regions_coming(); |
| void reset_free_regions_coming(); |
| bool free_regions_coming() { return _free_regions_coming; } |
| void wait_while_free_regions_coming(); |
| |
| // Perform a collection of the heap; intended for use in implementing |
| // "System.gc". This probably implies as full a collection as the |
| // "CollectedHeap" supports. |
| virtual void collect(GCCause::Cause cause); |
| |
| // The same as above but assume that the caller holds the Heap_lock. |
| void collect_locked(GCCause::Cause cause); |
| |
| // This interface assumes that it's being called by the |
| // vm thread. It collects the heap assuming that the |
| // heap lock is already held and that we are executing in |
| // the context of the vm thread. |
| virtual void collect_as_vm_thread(GCCause::Cause cause); |
| |
| // True iff a evacuation has failed in the most-recent collection. |
| bool evacuation_failed() { return _evacuation_failed; } |
| |
| // It will free a region if it has allocated objects in it that are |
| // all dead. It calls either free_region() or |
| // free_humongous_region() depending on the type of the region that |
| // is passed to it. |
| void free_region_if_empty(HeapRegion* hr, |
| size_t* pre_used, |
| FreeRegionList* free_list, |
| HumongousRegionSet* humongous_proxy_set, |
| HRRSCleanupTask* hrrs_cleanup_task, |
| bool par); |
| |
| // It appends the free list to the master free list and updates the |
| // master humongous list according to the contents of the proxy |
| // list. It also adjusts the total used bytes according to pre_used |
| // (if par is true, it will do so by taking the ParGCRareEvent_lock). |
| void update_sets_after_freeing_regions(size_t pre_used, |
| FreeRegionList* free_list, |
| HumongousRegionSet* humongous_proxy_set, |
| bool par); |
| |
| // Returns "TRUE" iff "p" points into the allocated area of the heap. |
| virtual bool is_in(const void* p) const; |
| |
| // Return "TRUE" iff the given object address is within the collection |
| // set. |
| inline bool obj_in_cs(oop obj); |
| |
| // Return "TRUE" iff the given object address is in the reserved |
| // region of g1 (excluding the permanent generation). |
| bool is_in_g1_reserved(const void* p) const { |
| return _g1_reserved.contains(p); |
| } |
| |
| // Returns a MemRegion that corresponds to the space that has been |
| // committed in the heap |
| MemRegion g1_committed() { |
| return _g1_committed; |
| } |
| |
| virtual bool is_in_closed_subset(const void* p) const; |
| |
| // Dirty card table entries covering a list of young regions. |
| void dirtyCardsForYoungRegions(CardTableModRefBS* ct_bs, HeapRegion* list); |
| |
| // This resets the card table to all zeros. It is used after |
| // a collection pause which used the card table to claim cards. |
| void cleanUpCardTable(); |
| |
| // Iteration functions. |
| |
| // Iterate over all the ref-containing fields of all objects, calling |
| // "cl.do_oop" on each. |
| virtual void oop_iterate(OopClosure* cl) { |
| oop_iterate(cl, true); |
| } |
| void oop_iterate(OopClosure* cl, bool do_perm); |
| |
| // Same as above, restricted to a memory region. |
| virtual void oop_iterate(MemRegion mr, OopClosure* cl) { |
| oop_iterate(mr, cl, true); |
| } |
| void oop_iterate(MemRegion mr, OopClosure* cl, bool do_perm); |
| |
| // Iterate over all objects, calling "cl.do_object" on each. |
| virtual void object_iterate(ObjectClosure* cl) { |
| object_iterate(cl, true); |
| } |
| virtual void safe_object_iterate(ObjectClosure* cl) { |
| object_iterate(cl, true); |
| } |
| void object_iterate(ObjectClosure* cl, bool do_perm); |
| |
| // Iterate over all objects allocated since the last collection, calling |
| // "cl.do_object" on each. The heap must have been initialized properly |
| // to support this function, or else this call will fail. |
| virtual void object_iterate_since_last_GC(ObjectClosure* cl); |
| |
| // Iterate over all spaces in use in the heap, in ascending address order. |
| virtual void space_iterate(SpaceClosure* cl); |
| |
| // Iterate over heap regions, in address order, terminating the |
| // iteration early if the "doHeapRegion" method returns "true". |
| void heap_region_iterate(HeapRegionClosure* blk); |
| |
| // Iterate over heap regions starting with r (or the first region if "r" |
| // is NULL), in address order, terminating early if the "doHeapRegion" |
| // method returns "true". |
| void heap_region_iterate_from(HeapRegion* r, HeapRegionClosure* blk); |
| |
| // As above but starting from the region at index idx. |
| void heap_region_iterate_from(int idx, HeapRegionClosure* blk); |
| |
| HeapRegion* region_at(size_t idx); |
| |
| // Divide the heap region sequence into "chunks" of some size (the number |
| // of regions divided by the number of parallel threads times some |
| // overpartition factor, currently 4). Assumes that this will be called |
| // in parallel by ParallelGCThreads worker threads with discinct worker |
| // ids in the range [0..max(ParallelGCThreads-1, 1)], that all parallel |
| // calls will use the same "claim_value", and that that claim value is |
| // different from the claim_value of any heap region before the start of |
| // the iteration. Applies "blk->doHeapRegion" to each of the regions, by |
| // attempting to claim the first region in each chunk, and, if |
| // successful, applying the closure to each region in the chunk (and |
| // setting the claim value of the second and subsequent regions of the |
| // chunk.) For now requires that "doHeapRegion" always returns "false", |
| // i.e., that a closure never attempt to abort a traversal. |
| void heap_region_par_iterate_chunked(HeapRegionClosure* blk, |
| int worker, |
| jint claim_value); |
| |
| // It resets all the region claim values to the default. |
| void reset_heap_region_claim_values(); |
| |
| #ifdef ASSERT |
| bool check_heap_region_claim_values(jint claim_value); |
| #endif // ASSERT |
| |
| // Iterate over the regions (if any) in the current collection set. |
| void collection_set_iterate(HeapRegionClosure* blk); |
| |
| // As above but starting from region r |
| void collection_set_iterate_from(HeapRegion* r, HeapRegionClosure *blk); |
| |
| // Returns the first (lowest address) compactible space in the heap. |
| virtual CompactibleSpace* first_compactible_space(); |
| |
| // A CollectedHeap will contain some number of spaces. This finds the |
| // space containing a given address, or else returns NULL. |
| virtual Space* space_containing(const void* addr) const; |
| |
| // A G1CollectedHeap will contain some number of heap regions. This |
| // finds the region containing a given address, or else returns NULL. |
| HeapRegion* heap_region_containing(const void* addr) const; |
| |
| // Like the above, but requires "addr" to be in the heap (to avoid a |
| // null-check), and unlike the above, may return an continuing humongous |
| // region. |
| HeapRegion* heap_region_containing_raw(const void* addr) const; |
| |
| // A CollectedHeap is divided into a dense sequence of "blocks"; that is, |
| // each address in the (reserved) heap is a member of exactly |
| // one block. The defining characteristic of a block is that it is |
| // possible to find its size, and thus to progress forward to the next |
| // block. (Blocks may be of different sizes.) Thus, blocks may |
| // represent Java objects, or they might be free blocks in a |
| // free-list-based heap (or subheap), as long as the two kinds are |
| // distinguishable and the size of each is determinable. |
| |
| // Returns the address of the start of the "block" that contains the |
| // address "addr". We say "blocks" instead of "object" since some heaps |
| // may not pack objects densely; a chunk may either be an object or a |
| // non-object. |
| virtual HeapWord* block_start(const void* addr) const; |
| |
| // Requires "addr" to be the start of a chunk, and returns its size. |
| // "addr + size" is required to be the start of a new chunk, or the end |
| // of the active area of the heap. |
| virtual size_t block_size(const HeapWord* addr) const; |
| |
| // Requires "addr" to be the start of a block, and returns "TRUE" iff |
| // the block is an object. |
| virtual bool block_is_obj(const HeapWord* addr) const; |
| |
| // Does this heap support heap inspection? (+PrintClassHistogram) |
| virtual bool supports_heap_inspection() const { return true; } |
| |
| // Section on thread-local allocation buffers (TLABs) |
| // See CollectedHeap for semantics. |
| |
| virtual bool supports_tlab_allocation() const; |
| virtual size_t tlab_capacity(Thread* thr) const; |
| virtual size_t unsafe_max_tlab_alloc(Thread* thr) const; |
| |
| // Can a compiler initialize a new object without store barriers? |
| // This permission only extends from the creation of a new object |
| // via a TLAB up to the first subsequent safepoint. If such permission |
| // is granted for this heap type, the compiler promises to call |
| // defer_store_barrier() below on any slow path allocation of |
| // a new object for which such initializing store barriers will |
| // have been elided. G1, like CMS, allows this, but should be |
| // ready to provide a compensating write barrier as necessary |
| // if that storage came out of a non-young region. The efficiency |
| // of this implementation depends crucially on being able to |
| // answer very efficiently in constant time whether a piece of |
| // storage in the heap comes from a young region or not. |
| // See ReduceInitialCardMarks. |
| virtual bool can_elide_tlab_store_barriers() const { |
| // 6920090: Temporarily disabled, because of lingering |
| // instabilities related to RICM with G1. In the |
| // interim, the option ReduceInitialCardMarksForG1 |
| // below is left solely as a debugging device at least |
| // until 6920109 fixes the instabilities. |
| return ReduceInitialCardMarksForG1; |
| } |
| |
| virtual bool card_mark_must_follow_store() const { |
| return true; |
| } |
| |
| bool is_in_young(oop obj) { |
| HeapRegion* hr = heap_region_containing(obj); |
| return hr != NULL && hr->is_young(); |
| } |
| |
| // We don't need barriers for initializing stores to objects |
| // in the young gen: for the SATB pre-barrier, there is no |
| // pre-value that needs to be remembered; for the remembered-set |
| // update logging post-barrier, we don't maintain remembered set |
| // information for young gen objects. Note that non-generational |
| // G1 does not have any "young" objects, should not elide |
| // the rs logging barrier and so should always answer false below. |
| // However, non-generational G1 (-XX:-G1Gen) appears to have |
| // bit-rotted so was not tested below. |
| virtual bool can_elide_initializing_store_barrier(oop new_obj) { |
| // Re 6920090, 6920109 above. |
| assert(ReduceInitialCardMarksForG1, "Else cannot be here"); |
| assert(G1Gen || !is_in_young(new_obj), |
| "Non-generational G1 should never return true below"); |
| return is_in_young(new_obj); |
| } |
| |
| // Can a compiler elide a store barrier when it writes |
| // a permanent oop into the heap? Applies when the compiler |
| // is storing x to the heap, where x->is_perm() is true. |
| virtual bool can_elide_permanent_oop_store_barriers() const { |
| // At least until perm gen collection is also G1-ified, at |
| // which point this should return false. |
| return true; |
| } |
| |
| // The boundary between a "large" and "small" array of primitives, in |
| // words. |
| virtual size_t large_typearray_limit(); |
| |
| // Returns "true" iff the given word_size is "very large". |
| static bool isHumongous(size_t word_size) { |
| // Note this has to be strictly greater-than as the TLABs |
| // are capped at the humongous thresold and we want to |
| // ensure that we don't try to allocate a TLAB as |
| // humongous and that we don't allocate a humongous |
| // object in a TLAB. |
| return word_size > _humongous_object_threshold_in_words; |
| } |
| |
| // Update mod union table with the set of dirty cards. |
| void updateModUnion(); |
| |
| // Set the mod union bits corresponding to the given memRegion. Note |
| // that this is always a safe operation, since it doesn't clear any |
| // bits. |
| void markModUnionRange(MemRegion mr); |
| |
| // Records the fact that a marking phase is no longer in progress. |
| void set_marking_complete() { |
| _mark_in_progress = false; |
| } |
| void set_marking_started() { |
| _mark_in_progress = true; |
| } |
| bool mark_in_progress() { |
| return _mark_in_progress; |
| } |
| |
| // Print the maximum heap capacity. |
| virtual size_t max_capacity() const; |
| |
| virtual jlong millis_since_last_gc(); |
| |
| // Perform any cleanup actions necessary before allowing a verification. |
| virtual void prepare_for_verify(); |
| |
| // Perform verification. |
| |
| // use_prev_marking == true -> use "prev" marking information, |
| // use_prev_marking == false -> use "next" marking information |
| // NOTE: Only the "prev" marking information is guaranteed to be |
| // consistent most of the time, so most calls to this should use |
| // use_prev_marking == true. Currently, there is only one case where |
| // this is called with use_prev_marking == false, which is to verify |
| // the "next" marking information at the end of remark. |
| void verify(bool allow_dirty, bool silent, bool use_prev_marking); |
| |
| // Override; it uses the "prev" marking information |
| virtual void verify(bool allow_dirty, bool silent); |
| // Default behavior by calling print(tty); |
| virtual void print() const; |
| // This calls print_on(st, PrintHeapAtGCExtended). |
| virtual void print_on(outputStream* st) const; |
| // If extended is true, it will print out information for all |
| // regions in the heap by calling print_on_extended(st). |
| virtual void print_on(outputStream* st, bool extended) const; |
| virtual void print_on_extended(outputStream* st) const; |
| |
| virtual void print_gc_threads_on(outputStream* st) const; |
| virtual void gc_threads_do(ThreadClosure* tc) const; |
| |
| // Override |
| void print_tracing_info() const; |
| |
| // If "addr" is a pointer into the (reserved?) heap, returns a positive |
| // number indicating the "arena" within the heap in which "addr" falls. |
| // Or else returns 0. |
| virtual int addr_to_arena_id(void* addr) const; |
| |
| // Convenience function to be used in situations where the heap type can be |
| // asserted to be this type. |
| static G1CollectedHeap* heap(); |
| |
| void empty_young_list(); |
| |
| void set_region_short_lived_locked(HeapRegion* hr); |
| // add appropriate methods for any other surv rate groups |
| |
| YoungList* young_list() { return _young_list; } |
| |
| // debugging |
| bool check_young_list_well_formed() { |
| return _young_list->check_list_well_formed(); |
| } |
| |
| bool check_young_list_empty(bool check_heap, |
| bool check_sample = true); |
| |
| // *** Stuff related to concurrent marking. It's not clear to me that so |
| // many of these need to be public. |
| |
| // The functions below are helper functions that a subclass of |
| // "CollectedHeap" can use in the implementation of its virtual |
| // functions. |
| // This performs a concurrent marking of the live objects in a |
| // bitmap off to the side. |
| void doConcurrentMark(); |
| |
| // This is called from the marksweep collector which then does |
| // a concurrent mark and verifies that the results agree with |
| // the stop the world marking. |
| void checkConcurrentMark(); |
| void do_sync_mark(); |
| |
| bool isMarkedPrev(oop obj) const; |
| bool isMarkedNext(oop obj) const; |
| |
| // use_prev_marking == true -> use "prev" marking information, |
| // use_prev_marking == false -> use "next" marking information |
| bool is_obj_dead_cond(const oop obj, |
| const HeapRegion* hr, |
| const bool use_prev_marking) const { |
| if (use_prev_marking) { |
| return is_obj_dead(obj, hr); |
| } else { |
| return is_obj_ill(obj, hr); |
| } |
| } |
| |
| // Determine if an object is dead, given the object and also |
| // the region to which the object belongs. An object is dead |
| // iff a) it was not allocated since the last mark and b) it |
| // is not marked. |
| |
| bool is_obj_dead(const oop obj, const HeapRegion* hr) const { |
| return |
| !hr->obj_allocated_since_prev_marking(obj) && |
| !isMarkedPrev(obj); |
| } |
| |
| // This is used when copying an object to survivor space. |
| // If the object is marked live, then we mark the copy live. |
| // If the object is allocated since the start of this mark |
| // cycle, then we mark the copy live. |
| // If the object has been around since the previous mark |
| // phase, and hasn't been marked yet during this phase, |
| // then we don't mark it, we just wait for the |
| // current marking cycle to get to it. |
| |
| // This function returns true when an object has been |
| // around since the previous marking and hasn't yet |
| // been marked during this marking. |
| |
| bool is_obj_ill(const oop obj, const HeapRegion* hr) const { |
| return |
| !hr->obj_allocated_since_next_marking(obj) && |
| !isMarkedNext(obj); |
| } |
| |
| // Determine if an object is dead, given only the object itself. |
| // This will find the region to which the object belongs and |
| // then call the region version of the same function. |
| |
| // Added if it is in permanent gen it isn't dead. |
| // Added if it is NULL it isn't dead. |
| |
| // use_prev_marking == true -> use "prev" marking information, |
| // use_prev_marking == false -> use "next" marking information |
| bool is_obj_dead_cond(const oop obj, |
| const bool use_prev_marking) { |
| if (use_prev_marking) { |
| return is_obj_dead(obj); |
| } else { |
| return is_obj_ill(obj); |
| } |
| } |
| |
| bool is_obj_dead(const oop obj) { |
| const HeapRegion* hr = heap_region_containing(obj); |
| if (hr == NULL) { |
| if (Universe::heap()->is_in_permanent(obj)) |
| return false; |
| else if (obj == NULL) return false; |
| else return true; |
| } |
| else return is_obj_dead(obj, hr); |
| } |
| |
| bool is_obj_ill(const oop obj) { |
| const HeapRegion* hr = heap_region_containing(obj); |
| if (hr == NULL) { |
| if (Universe::heap()->is_in_permanent(obj)) |
| return false; |
| else if (obj == NULL) return false; |
| else return true; |
| } |
| else return is_obj_ill(obj, hr); |
| } |
| |
| // The following is just to alert the verification code |
| // that a full collection has occurred and that the |
| // remembered sets are no longer up to date. |
| bool _full_collection; |
| void set_full_collection() { _full_collection = true;} |
| void clear_full_collection() {_full_collection = false;} |
| bool full_collection() {return _full_collection;} |
| |
| ConcurrentMark* concurrent_mark() const { return _cm; } |
| ConcurrentG1Refine* concurrent_g1_refine() const { return _cg1r; } |
| |
| // The dirty cards region list is used to record a subset of regions |
| // whose cards need clearing. The list if populated during the |
| // remembered set scanning and drained during the card table |
| // cleanup. Although the methods are reentrant, population/draining |
| // phases must not overlap. For synchronization purposes the last |
| // element on the list points to itself. |
| HeapRegion* _dirty_cards_region_list; |
| void push_dirty_cards_region(HeapRegion* hr); |
| HeapRegion* pop_dirty_cards_region(); |
| |
| public: |
| void stop_conc_gc_threads(); |
| |
| // <NEW PREDICTION> |
| |
| double predict_region_elapsed_time_ms(HeapRegion* hr, bool young); |
| void check_if_region_is_too_expensive(double predicted_time_ms); |
| size_t pending_card_num(); |
| size_t max_pending_card_num(); |
| size_t cards_scanned(); |
| |
| // </NEW PREDICTION> |
| |
| protected: |
| size_t _max_heap_capacity; |
| }; |
| |
| #define use_local_bitmaps 1 |
| #define verify_local_bitmaps 0 |
| #define oop_buffer_length 256 |
| |
| #ifndef PRODUCT |
| class GCLabBitMap; |
| class GCLabBitMapClosure: public BitMapClosure { |
| private: |
| ConcurrentMark* _cm; |
| GCLabBitMap* _bitmap; |
| |
| public: |
| GCLabBitMapClosure(ConcurrentMark* cm, |
| GCLabBitMap* bitmap) { |
| _cm = cm; |
| _bitmap = bitmap; |
| } |
| |
| virtual bool do_bit(size_t offset); |
| }; |
| #endif // !PRODUCT |
| |
| class GCLabBitMap: public BitMap { |
| private: |
| ConcurrentMark* _cm; |
| |
| int _shifter; |
| size_t _bitmap_word_covers_words; |
| |
| // beginning of the heap |
| HeapWord* _heap_start; |
| |
| // this is the actual start of the GCLab |
| HeapWord* _real_start_word; |
| |
| // this is the actual end of the GCLab |
| HeapWord* _real_end_word; |
| |
| // this is the first word, possibly located before the actual start |
| // of the GCLab, that corresponds to the first bit of the bitmap |
| HeapWord* _start_word; |
| |
| // size of a GCLab in words |
| size_t _gclab_word_size; |
| |
| static int shifter() { |
| return MinObjAlignment - 1; |
| } |
| |
| // how many heap words does a single bitmap word corresponds to? |
| static size_t bitmap_word_covers_words() { |
| return BitsPerWord << shifter(); |
| } |
| |
| size_t gclab_word_size() const { |
| return _gclab_word_size; |
| } |
| |
| // Calculates actual GCLab size in words |
| size_t gclab_real_word_size() const { |
| return bitmap_size_in_bits(pointer_delta(_real_end_word, _start_word)) |
| / BitsPerWord; |
| } |
| |
| static size_t bitmap_size_in_bits(size_t gclab_word_size) { |
| size_t bits_in_bitmap = gclab_word_size >> shifter(); |
| // We are going to ensure that the beginning of a word in this |
| // bitmap also corresponds to the beginning of a word in the |
| // global marking bitmap. To handle the case where a GCLab |
| // starts from the middle of the bitmap, we need to add enough |
| // space (i.e. up to a bitmap word) to ensure that we have |
| // enough bits in the bitmap. |
| return bits_in_bitmap + BitsPerWord - 1; |
| } |
| public: |
| GCLabBitMap(HeapWord* heap_start, size_t gclab_word_size) |
| : BitMap(bitmap_size_in_bits(gclab_word_size)), |
| _cm(G1CollectedHeap::heap()->concurrent_mark()), |
| _shifter(shifter()), |
| _bitmap_word_covers_words(bitmap_word_covers_words()), |
| _heap_start(heap_start), |
| _gclab_word_size(gclab_word_size), |
| _real_start_word(NULL), |
| _real_end_word(NULL), |
| _start_word(NULL) |
| { |
| guarantee( size_in_words() >= bitmap_size_in_words(), |
| "just making sure"); |
| } |
| |
| inline unsigned heapWordToOffset(HeapWord* addr) { |
| unsigned offset = (unsigned) pointer_delta(addr, _start_word) >> _shifter; |
| assert(offset < size(), "offset should be within bounds"); |
| return offset; |
| } |
| |
| inline HeapWord* offsetToHeapWord(size_t offset) { |
| HeapWord* addr = _start_word + (offset << _shifter); |
| assert(_real_start_word <= addr && addr < _real_end_word, "invariant"); |
| return addr; |
| } |
| |
| bool fields_well_formed() { |
| bool ret1 = (_real_start_word == NULL) && |
| (_real_end_word == NULL) && |
| (_start_word == NULL); |
| if (ret1) |
| return true; |
| |
| bool ret2 = _real_start_word >= _start_word && |
| _start_word < _real_end_word && |
| (_real_start_word + _gclab_word_size) == _real_end_word && |
| (_start_word + _gclab_word_size + _bitmap_word_covers_words) |
| > _real_end_word; |
| return ret2; |
| } |
| |
| inline bool mark(HeapWord* addr) { |
| guarantee(use_local_bitmaps, "invariant"); |
| assert(fields_well_formed(), "invariant"); |
| |
| if (addr >= _real_start_word && addr < _real_end_word) { |
| assert(!isMarked(addr), "should not have already been marked"); |
| |
| // first mark it on the bitmap |
| at_put(heapWordToOffset(addr), true); |
| |
| return true; |
| } else { |
| return false; |
| } |
| } |
| |
| inline bool isMarked(HeapWord* addr) { |
| guarantee(use_local_bitmaps, "invariant"); |
| assert(fields_well_formed(), "invariant"); |
| |
| return at(heapWordToOffset(addr)); |
| } |
| |
| void set_buffer(HeapWord* start) { |
| guarantee(use_local_bitmaps, "invariant"); |
| clear(); |
| |
| assert(start != NULL, "invariant"); |
| _real_start_word = start; |
| _real_end_word = start + _gclab_word_size; |
| |
| size_t diff = |
| pointer_delta(start, _heap_start) % _bitmap_word_covers_words; |
| _start_word = start - diff; |
| |
| assert(fields_well_formed(), "invariant"); |
| } |
| |
| #ifndef PRODUCT |
| void verify() { |
| // verify that the marks have been propagated |
| GCLabBitMapClosure cl(_cm, this); |
| iterate(&cl); |
| } |
| #endif // PRODUCT |
| |
| void retire() { |
| guarantee(use_local_bitmaps, "invariant"); |
| assert(fields_well_formed(), "invariant"); |
| |
| if (_start_word != NULL) { |
| CMBitMap* mark_bitmap = _cm->nextMarkBitMap(); |
| |
| // this means that the bitmap was set up for the GCLab |
| assert(_real_start_word != NULL && _real_end_word != NULL, "invariant"); |
| |
| mark_bitmap->mostly_disjoint_range_union(this, |
| 0, // always start from the start of the bitmap |
| _start_word, |
| gclab_real_word_size()); |
| _cm->grayRegionIfNecessary(MemRegion(_real_start_word, _real_end_word)); |
| |
| #ifndef PRODUCT |
| if (use_local_bitmaps && verify_local_bitmaps) |
| verify(); |
| #endif // PRODUCT |
| } else { |
| assert(_real_start_word == NULL && _real_end_word == NULL, "invariant"); |
| } |
| } |
| |
| size_t bitmap_size_in_words() const { |
| return (bitmap_size_in_bits(gclab_word_size()) + BitsPerWord - 1) / BitsPerWord; |
| } |
| |
| }; |
| |
| class G1ParGCAllocBuffer: public ParGCAllocBuffer { |
| private: |
| bool _retired; |
| bool _during_marking; |
| GCLabBitMap _bitmap; |
| |
| public: |
| G1ParGCAllocBuffer(size_t gclab_word_size) : |
| ParGCAllocBuffer(gclab_word_size), |
| _during_marking(G1CollectedHeap::heap()->mark_in_progress()), |
| _bitmap(G1CollectedHeap::heap()->reserved_region().start(), gclab_word_size), |
| _retired(false) |
| { } |
| |
| inline bool mark(HeapWord* addr) { |
| guarantee(use_local_bitmaps, "invariant"); |
| assert(_during_marking, "invariant"); |
| return _bitmap.mark(addr); |
| } |
| |
| inline void set_buf(HeapWord* buf) { |
| if (use_local_bitmaps && _during_marking) |
| _bitmap.set_buffer(buf); |
| ParGCAllocBuffer::set_buf(buf); |
| _retired = false; |
| } |
| |
| inline void retire(bool end_of_gc, bool retain) { |
| if (_retired) |
| return; |
| if (use_local_bitmaps && _during_marking) { |
| _bitmap.retire(); |
| } |
| ParGCAllocBuffer::retire(end_of_gc, retain); |
| _retired = true; |
| } |
| }; |
| |
| class G1ParScanThreadState : public StackObj { |
| protected: |
| G1CollectedHeap* _g1h; |
| RefToScanQueue* _refs; |
| DirtyCardQueue _dcq; |
| CardTableModRefBS* _ct_bs; |
| G1RemSet* _g1_rem; |
| |
| G1ParGCAllocBuffer _surviving_alloc_buffer; |
| G1ParGCAllocBuffer _tenured_alloc_buffer; |
| G1ParGCAllocBuffer* _alloc_buffers[GCAllocPurposeCount]; |
| ageTable _age_table; |
| |
| size_t _alloc_buffer_waste; |
| size_t _undo_waste; |
| |
| OopsInHeapRegionClosure* _evac_failure_cl; |
| G1ParScanHeapEvacClosure* _evac_cl; |
| G1ParScanPartialArrayClosure* _partial_scan_cl; |
| |
| int _hash_seed; |
| int _queue_num; |
| |
| size_t _term_attempts; |
| |
| double _start; |
| double _start_strong_roots; |
| double _strong_roots_time; |
| double _start_term; |
| double _term_time; |
| |
| // Map from young-age-index (0 == not young, 1 is youngest) to |
| // surviving words. base is what we get back from the malloc call |
| size_t* _surviving_young_words_base; |
| // this points into the array, as we use the first few entries for padding |
| size_t* _surviving_young_words; |
| |
| #define PADDING_ELEM_NUM (DEFAULT_CACHE_LINE_SIZE / sizeof(size_t)) |
| |
| void add_to_alloc_buffer_waste(size_t waste) { _alloc_buffer_waste += waste; } |
| |
| void add_to_undo_waste(size_t waste) { _undo_waste += waste; } |
| |
| DirtyCardQueue& dirty_card_queue() { return _dcq; } |
| CardTableModRefBS* ctbs() { return _ct_bs; } |
| |
| template <class T> void immediate_rs_update(HeapRegion* from, T* p, int tid) { |
| if (!from->is_survivor()) { |
| _g1_rem->par_write_ref(from, p, tid); |
| } |
| } |
| |
| template <class T> void deferred_rs_update(HeapRegion* from, T* p, int tid) { |
| // If the new value of the field points to the same region or |
| // is the to-space, we don't need to include it in the Rset updates. |
| if (!from->is_in_reserved(oopDesc::load_decode_heap_oop(p)) && !from->is_survivor()) { |
| size_t card_index = ctbs()->index_for(p); |
| // If the card hasn't been added to the buffer, do it. |
| if (ctbs()->mark_card_deferred(card_index)) { |
| dirty_card_queue().enqueue((jbyte*)ctbs()->byte_for_index(card_index)); |
| } |
| } |
| } |
| |
| public: |
| G1ParScanThreadState(G1CollectedHeap* g1h, int queue_num); |
| |
| ~G1ParScanThreadState() { |
| FREE_C_HEAP_ARRAY(size_t, _surviving_young_words_base); |
| } |
| |
| RefToScanQueue* refs() { return _refs; } |
| ageTable* age_table() { return &_age_table; } |
| |
| G1ParGCAllocBuffer* alloc_buffer(GCAllocPurpose purpose) { |
| return _alloc_buffers[purpose]; |
| } |
| |
| size_t alloc_buffer_waste() const { return _alloc_buffer_waste; } |
| size_t undo_waste() const { return _undo_waste; } |
| |
| #ifdef ASSERT |
| bool verify_ref(narrowOop* ref) const; |
| bool verify_ref(oop* ref) const; |
| bool verify_task(StarTask ref) const; |
| #endif // ASSERT |
| |
| template <class T> void push_on_queue(T* ref) { |
| assert(verify_ref(ref), "sanity"); |
| refs()->push(ref); |
| } |
| |
| template <class T> void update_rs(HeapRegion* from, T* p, int tid) { |
| if (G1DeferredRSUpdate) { |
| deferred_rs_update(from, p, tid); |
| } else { |
| immediate_rs_update(from, p, tid); |
| } |
| } |
| |
| HeapWord* allocate_slow(GCAllocPurpose purpose, size_t word_sz) { |
| |
| HeapWord* obj = NULL; |
| size_t gclab_word_size = _g1h->desired_plab_sz(purpose); |
| if (word_sz * 100 < gclab_word_size * ParallelGCBufferWastePct) { |
| G1ParGCAllocBuffer* alloc_buf = alloc_buffer(purpose); |
| assert(gclab_word_size == alloc_buf->word_sz(), |
| "dynamic resizing is not supported"); |
| add_to_alloc_buffer_waste(alloc_buf->words_remaining()); |
| alloc_buf->retire(false, false); |
| |
| HeapWord* buf = _g1h->par_allocate_during_gc(purpose, gclab_word_size); |
| if (buf == NULL) return NULL; // Let caller handle allocation failure. |
| // Otherwise. |
| alloc_buf->set_buf(buf); |
| |
| obj = alloc_buf->allocate(word_sz); |
| assert(obj != NULL, "buffer was definitely big enough..."); |
| } else { |
| obj = _g1h->par_allocate_during_gc(purpose, word_sz); |
| } |
| return obj; |
| } |
| |
| HeapWord* allocate(GCAllocPurpose purpose, size_t word_sz) { |
| HeapWord* obj = alloc_buffer(purpose)->allocate(word_sz); |
| if (obj != NULL) return obj; |
| return allocate_slow(purpose, word_sz); |
| } |
| |
| void undo_allocation(GCAllocPurpose purpose, HeapWord* obj, size_t word_sz) { |
| if (alloc_buffer(purpose)->contains(obj)) { |
| assert(alloc_buffer(purpose)->contains(obj + word_sz - 1), |
| "should contain whole object"); |
| alloc_buffer(purpose)->undo_allocation(obj, word_sz); |
| } else { |
| CollectedHeap::fill_with_object(obj, word_sz); |
| add_to_undo_waste(word_sz); |
| } |
| } |
| |
| void set_evac_failure_closure(OopsInHeapRegionClosure* evac_failure_cl) { |
| _evac_failure_cl = evac_failure_cl; |
| } |
| OopsInHeapRegionClosure* evac_failure_closure() { |
| return _evac_failure_cl; |
| } |
| |
| void set_evac_closure(G1ParScanHeapEvacClosure* evac_cl) { |
| _evac_cl = evac_cl; |
| } |
| |
| void set_partial_scan_closure(G1ParScanPartialArrayClosure* partial_scan_cl) { |
| _partial_scan_cl = partial_scan_cl; |
| } |
| |
| int* hash_seed() { return &_hash_seed; } |
| int queue_num() { return _queue_num; } |
| |
| size_t term_attempts() const { return _term_attempts; } |
| void note_term_attempt() { _term_attempts++; } |
| |
| void start_strong_roots() { |
| _start_strong_roots = os::elapsedTime(); |
| } |
| void end_strong_roots() { |
| _strong_roots_time += (os::elapsedTime() - _start_strong_roots); |
| } |
| double strong_roots_time() const { return _strong_roots_time; } |
| |
| void start_term_time() { |
| note_term_attempt(); |
| _start_term = os::elapsedTime(); |
| } |
| void end_term_time() { |
| _term_time += (os::elapsedTime() - _start_term); |
| } |
| double term_time() const { return _term_time; } |
| |
| double elapsed_time() const { |
| return os::elapsedTime() - _start; |
| } |
| |
| static void |
| print_termination_stats_hdr(outputStream* const st = gclog_or_tty); |
| void |
| print_termination_stats(int i, outputStream* const st = gclog_or_tty) const; |
| |
| size_t* surviving_young_words() { |
| // We add on to hide entry 0 which accumulates surviving words for |
| // age -1 regions (i.e. non-young ones) |
| return _surviving_young_words; |
| } |
| |
| void retire_alloc_buffers() { |
| for (int ap = 0; ap < GCAllocPurposeCount; ++ap) { |
| size_t waste = _alloc_buffers[ap]->words_remaining(); |
| add_to_alloc_buffer_waste(waste); |
| _alloc_buffers[ap]->retire(true, false); |
| } |
| } |
| |
| template <class T> void deal_with_reference(T* ref_to_scan) { |
| if (has_partial_array_mask(ref_to_scan)) { |
| _partial_scan_cl->do_oop_nv(ref_to_scan); |
| } else { |
| // Note: we can use "raw" versions of "region_containing" because |
| // "obj_to_scan" is definitely in the heap, and is not in a |
| // humongous region. |
| HeapRegion* r = _g1h->heap_region_containing_raw(ref_to_scan); |
| _evac_cl->set_region(r); |
| _evac_cl->do_oop_nv(ref_to_scan); |
| } |
| } |
| |
| void deal_with_reference(StarTask ref) { |
| assert(verify_task(ref), "sanity"); |
| if (ref.is_narrow()) { |
| deal_with_reference((narrowOop*)ref); |
| } else { |
| deal_with_reference((oop*)ref); |
| } |
| } |
| |
| public: |
| void trim_queue(); |
| }; |
| |
| #endif // SHARE_VM_GC_IMPLEMENTATION_G1_G1COLLECTEDHEAP_HPP |