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/*
* Copyright (c) 2015, 2022, Red Hat, Inc. All rights reserved.
+ * Copyright Amazon.com Inc. 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.
#define SHARE_GC_SHENANDOAH_SHENANDOAHBARRIERSET_INLINE_HPP
#include "gc/shenandoah/shenandoahBarrierSet.hpp"
#include "gc/shared/accessBarrierSupport.inline.hpp"
+ #include "gc/shared/cardTable.hpp"
#include "gc/shenandoah/shenandoahAsserts.hpp"
+ #include "gc/shenandoah/shenandoahCardTable.hpp"
#include "gc/shenandoah/shenandoahCollectionSet.inline.hpp"
#include "gc/shenandoah/shenandoahEvacOOMHandler.inline.hpp"
#include "gc/shenandoah/shenandoahForwarding.inline.hpp"
+ #include "gc/shenandoah/shenandoahGeneration.hpp"
#include "gc/shenandoah/shenandoahHeap.inline.hpp"
#include "gc/shenandoah/shenandoahHeapRegion.hpp"
#include "gc/shenandoah/shenandoahMarkingContext.inline.hpp"
#include "gc/shenandoah/shenandoahThreadLocalData.hpp"
+ #include "gc/shenandoah/mode/shenandoahMode.hpp"
+ #include "memory/iterator.inline.hpp"
#include "oops/oop.inline.hpp"
inline oop ShenandoahBarrierSet::resolve_forwarded_not_null(oop p) {
return ShenandoahForwarding::get_forwardee(p);
}
}
// Prevent resurrection of unreachable phantom (i.e. weak-native) references.
if ((decorators & ON_PHANTOM_OOP_REF) != 0 &&
_heap->is_concurrent_weak_root_in_progress() &&
+ _heap->is_in_active_generation(obj) &&
!_heap->marking_context()->is_marked(obj)) {
return nullptr;
}
// Prevent resurrection of unreachable weak references.
if ((decorators & ON_WEAK_OOP_REF) != 0 &&
_heap->is_concurrent_weak_root_in_progress() &&
+ _heap->is_in_active_generation(obj) &&
!_heap->marking_context()->is_marked_strong(obj)) {
return nullptr;
}
// Prevent resurrection of unreachable objects that are visited during
if (!peek && !on_strong_oop_ref) {
satb_enqueue(value);
}
}
+ template <DecoratorSet decorators, typename T>
+ inline void ShenandoahBarrierSet::write_ref_field_post(T* field) {
+ assert(ShenandoahCardBarrier, "Should have been checked by caller");
+ volatile CardTable::CardValue* byte = card_table()->byte_for(field);
+ *byte = CardTable::dirty_card_val();
+ }
+
template <typename T>
inline oop ShenandoahBarrierSet::oop_load(DecoratorSet decorators, T* addr) {
oop value = RawAccess<>::oop_load(addr);
value = load_reference_barrier(decorators, value, addr);
keep_alive_if_weak(decorators, value);
}
template <DecoratorSet decorators, typename BarrierSetT>
template <typename T>
inline void ShenandoahBarrierSet::AccessBarrier<decorators, BarrierSetT>::oop_store_common(T* addr, oop value) {
- shenandoah_assert_marked_if(nullptr, value, !CompressedOops::is_null(value) && ShenandoahHeap::heap()->is_evacuation_in_progress());
+ shenandoah_assert_marked_if(nullptr, value,
+ !CompressedOops::is_null(value) && ShenandoahHeap::heap()->is_evacuation_in_progress()
+ && !(ShenandoahHeap::heap()->active_generation()->is_young()
+ && ShenandoahHeap::heap()->heap_region_containing(value)->is_old()));
shenandoah_assert_not_in_cset_if(addr, value, value != nullptr && !ShenandoahHeap::heap()->cancelled_gc());
ShenandoahBarrierSet* const bs = ShenandoahBarrierSet::barrier_set();
bs->satb_barrier<decorators>(addr);
Raw::oop_store(addr, value);
}
inline void ShenandoahBarrierSet::AccessBarrier<decorators, BarrierSetT>::oop_store_in_heap(T* addr, oop value) {
shenandoah_assert_not_in_cset_loc_except(addr, ShenandoahHeap::heap()->cancelled_gc());
shenandoah_assert_not_forwarded_except (addr, value, value == nullptr || ShenandoahHeap::heap()->cancelled_gc() || !ShenandoahHeap::heap()->is_concurrent_mark_in_progress());
oop_store_common(addr, value);
+ if (ShenandoahCardBarrier) {
+ ShenandoahBarrierSet* bs = ShenandoahBarrierSet::barrier_set();
+ bs->write_ref_field_post<decorators>(addr);
+ }
}
template <DecoratorSet decorators, typename BarrierSetT>
inline void ShenandoahBarrierSet::AccessBarrier<decorators, BarrierSetT>::oop_store_in_heap_at(oop base, ptrdiff_t offset, oop value) {
oop_store_in_heap(AccessInternal::oop_field_addr<decorators>(base, offset), value);
template <DecoratorSet decorators, typename BarrierSetT>
template <typename T>
inline oop ShenandoahBarrierSet::AccessBarrier<decorators, BarrierSetT>::oop_atomic_cmpxchg_in_heap(T* addr, oop compare_value, oop new_value) {
assert((decorators & (AS_NO_KEEPALIVE | ON_UNKNOWN_OOP_REF)) == 0, "must be absent");
ShenandoahBarrierSet* bs = ShenandoahBarrierSet::barrier_set();
- return bs->oop_cmpxchg(decorators, addr, compare_value, new_value);
+ oop result = bs->oop_cmpxchg(decorators, addr, compare_value, new_value);
+ if (ShenandoahCardBarrier) {
+ bs->write_ref_field_post<decorators>(addr);
+ }
+ return result;
}
template <DecoratorSet decorators, typename BarrierSetT>
inline oop ShenandoahBarrierSet::AccessBarrier<decorators, BarrierSetT>::oop_atomic_cmpxchg_in_heap_at(oop base, ptrdiff_t offset, oop compare_value, oop new_value) {
assert((decorators & AS_NO_KEEPALIVE) == 0, "must be absent");
ShenandoahBarrierSet* bs = ShenandoahBarrierSet::barrier_set();
DecoratorSet resolved_decorators = AccessBarrierSupport::resolve_possibly_unknown_oop_ref_strength<decorators>(base, offset);
- return bs->oop_cmpxchg(resolved_decorators, AccessInternal::oop_field_addr<decorators>(base, offset), compare_value, new_value);
+ auto addr = AccessInternal::oop_field_addr<decorators>(base, offset);
+ oop result = bs->oop_cmpxchg(resolved_decorators, addr, compare_value, new_value);
+ if (ShenandoahCardBarrier) {
+ bs->write_ref_field_post<decorators>(addr);
+ }
+ return result;
}
template <DecoratorSet decorators, typename BarrierSetT>
template <typename T>
inline oop ShenandoahBarrierSet::AccessBarrier<decorators, BarrierSetT>::oop_atomic_xchg_not_in_heap(T* addr, oop new_value) {
template <DecoratorSet decorators, typename BarrierSetT>
template <typename T>
inline oop ShenandoahBarrierSet::AccessBarrier<decorators, BarrierSetT>::oop_atomic_xchg_in_heap(T* addr, oop new_value) {
assert((decorators & (AS_NO_KEEPALIVE | ON_UNKNOWN_OOP_REF)) == 0, "must be absent");
ShenandoahBarrierSet* bs = ShenandoahBarrierSet::barrier_set();
- return bs->oop_xchg(decorators, addr, new_value);
+ oop result = bs->oop_xchg(decorators, addr, new_value);
+ if (ShenandoahCardBarrier) {
+ bs->write_ref_field_post<decorators>(addr);
+ }
+ return result;
}
template <DecoratorSet decorators, typename BarrierSetT>
inline oop ShenandoahBarrierSet::AccessBarrier<decorators, BarrierSetT>::oop_atomic_xchg_in_heap_at(oop base, ptrdiff_t offset, oop new_value) {
assert((decorators & AS_NO_KEEPALIVE) == 0, "must be absent");
ShenandoahBarrierSet* bs = ShenandoahBarrierSet::barrier_set();
DecoratorSet resolved_decorators = AccessBarrierSupport::resolve_possibly_unknown_oop_ref_strength<decorators>(base, offset);
- return bs->oop_xchg(resolved_decorators, AccessInternal::oop_field_addr<decorators>(base, offset), new_value);
+ auto addr = AccessInternal::oop_field_addr<decorators>(base, offset);
+ oop result = bs->oop_xchg(resolved_decorators, addr, new_value);
+ if (ShenandoahCardBarrier) {
+ bs->write_ref_field_post<decorators>(addr);
+ }
+ return result;
}
// Clone barrier support
template <DecoratorSet decorators, typename BarrierSetT>
void ShenandoahBarrierSet::AccessBarrier<decorators, BarrierSetT>::clone_in_heap(oop src, oop dst, size_t size) {
template <DecoratorSet decorators, typename BarrierSetT>
template <typename T>
bool ShenandoahBarrierSet::AccessBarrier<decorators, BarrierSetT>::oop_arraycopy_in_heap(arrayOop src_obj, size_t src_offset_in_bytes, T* src_raw,
arrayOop dst_obj, size_t dst_offset_in_bytes, T* dst_raw,
size_t length) {
+ T* src = arrayOopDesc::obj_offset_to_raw(src_obj, src_offset_in_bytes, src_raw);
+ T* dst = arrayOopDesc::obj_offset_to_raw(dst_obj, dst_offset_in_bytes, dst_raw);
+
ShenandoahBarrierSet* bs = ShenandoahBarrierSet::barrier_set();
- bs->arraycopy_barrier(arrayOopDesc::obj_offset_to_raw(src_obj, src_offset_in_bytes, src_raw),
- arrayOopDesc::obj_offset_to_raw(dst_obj, dst_offset_in_bytes, dst_raw),
- length);
- return Raw::oop_arraycopy_in_heap(src_obj, src_offset_in_bytes, src_raw, dst_obj, dst_offset_in_bytes, dst_raw, length);
+ bs->arraycopy_barrier(src, dst, length);
+ bool result = Raw::oop_arraycopy_in_heap(src_obj, src_offset_in_bytes, src_raw, dst_obj, dst_offset_in_bytes, dst_raw, length);
+ if (ShenandoahCardBarrier) {
+ bs->write_ref_array((HeapWord*) dst, length);
+ }
+ return result;
}
template <class T, bool HAS_FWD, bool EVAC, bool ENQUEUE>
void ShenandoahBarrierSet::arraycopy_work(T* src, size_t count) {
- assert(HAS_FWD == _heap->has_forwarded_objects(), "Forwarded object status is sane");
+ // Young cycles are allowed to run when old marking is in progress. When old marking is in progress,
+ // this barrier will be called with ENQUEUE=true and HAS_FWD=false, even though the young generation
+ // may have forwarded objects. In this case, the `arraycopy_work` is first called with HAS_FWD=true and
+ // ENQUEUE=false.
+ assert(HAS_FWD == _heap->has_forwarded_objects() || (_heap->gc_state() & ShenandoahHeap::OLD_MARKING) != 0,
+ "Forwarded object status is sane");
+ // This function cannot be called to handle marking and evacuation at the same time (they operate on
+ // different sides of the copy).
+ assert((HAS_FWD || EVAC) != ENQUEUE, "Cannot evacuate and mark both sides of copy.");
Thread* thread = Thread::current();
SATBMarkQueue& queue = ShenandoahThreadLocalData::satb_mark_queue(thread);
ShenandoahMarkingContext* ctx = _heap->marking_context();
const ShenandoahCollectionSet* const cset = _heap->collection_set();
if (EVAC && obj == fwd) {
fwd = _heap->evacuate_object(obj, thread);
}
shenandoah_assert_forwarded_except(elem_ptr, obj, _heap->cancelled_gc());
ShenandoahHeap::atomic_update_oop(fwd, elem_ptr, o);
- obj = fwd;
}
- if (ENQUEUE && !ctx->is_marked_strong(obj)) {
+ if (ENQUEUE && !ctx->is_marked_strong_or_old(obj)) {
_satb_mark_queue_set.enqueue_known_active(queue, obj);
}
}
}
}
void ShenandoahBarrierSet::arraycopy_barrier(T* src, T* dst, size_t count) {
if (count == 0) {
return;
}
int gc_state = _heap->gc_state();
- if ((gc_state & ShenandoahHeap::MARKING) != 0) {
- arraycopy_marking(src, dst, count);
- } else if ((gc_state & ShenandoahHeap::EVACUATION) != 0) {
+ if ((gc_state & ShenandoahHeap::YOUNG_MARKING) != 0) {
+ arraycopy_marking(src, dst, count, false);
+ return;
+ }
+
+ if ((gc_state & ShenandoahHeap::EVACUATION) != 0) {
arraycopy_evacuation(src, count);
} else if ((gc_state & ShenandoahHeap::UPDATEREFS) != 0) {
arraycopy_update(src, count);
}
+
+ if (_heap->mode()->is_generational()) {
+ assert(ShenandoahSATBBarrier, "Generational mode assumes SATB mode");
+ if ((gc_state & ShenandoahHeap::OLD_MARKING) != 0) {
+ // Note that we can't do the arraycopy marking using the 'src' array when
+ // SATB mode is enabled (so we can't do this as part of the iteration for
+ // evacuation or update references).
+ arraycopy_marking(src, dst, count, true);
+ }
+ }
}
template <class T>
- void ShenandoahBarrierSet::arraycopy_marking(T* src, T* dst, size_t count) {
+ void ShenandoahBarrierSet::arraycopy_marking(T* src, T* dst, size_t count, bool is_old_marking) {
assert(_heap->is_concurrent_mark_in_progress(), "only during marking");
- T* array = ShenandoahSATBBarrier ? dst : src;
- if (!_heap->marking_context()->allocated_after_mark_start(reinterpret_cast<HeapWord*>(array))) {
- arraycopy_work<T, false, false, true>(array, count);
+ /*
+ * Note that an old-gen object is considered live if it is live at the start of OLD marking or if it is promoted
+ * following the start of OLD marking.
+ *
+ * 1. Every object promoted following the start of OLD marking will be above TAMS within its old-gen region
+ * 2. Every object live at the start of OLD marking will be referenced from a "root" or it will be referenced from
+ * another live OLD-gen object. With regards to old-gen, roots include stack locations and all of live young-gen.
+ * All root references to old-gen are identified during a bootstrap young collection. All references from other
+ * old-gen objects will be marked during the traversal of all old objects, or will be marked by the SATB barrier.
+ *
+ * During old-gen marking (which is interleaved with young-gen collections), call arraycopy_work() if:
+ *
+ * 1. The overwritten array resides in old-gen and it is below TAMS within its old-gen region
+ * 2. Do not call arraycopy_work for any array residing in young-gen because young-gen collection is idle at this time
+ *
+ * During young-gen marking, call arraycopy_work() if:
+ *
+ * 1. The overwritten array resides in young-gen and is below TAMS within its young-gen region
+ * 2. Additionally, if array resides in old-gen, regardless of its relationship to TAMS because this old-gen array
+ * may hold references to young-gen
+ */
+ if (ShenandoahSATBBarrier) {
+ T* array = dst;
+ HeapWord* array_addr = reinterpret_cast<HeapWord*>(array);
+ ShenandoahHeapRegion* r = _heap->heap_region_containing(array_addr);
+ if (is_old_marking) {
+ // Generational, old marking
+ assert(_heap->mode()->is_generational(), "Invariant");
+ if (r->is_old() && (array_addr < _heap->marking_context()->top_at_mark_start(r))) {
+ arraycopy_work<T, false, false, true>(array, count);
+ }
+ } else if (_heap->mode()->is_generational()) {
+ // Generational, young marking
+ if (r->is_old() || (array_addr < _heap->marking_context()->top_at_mark_start(r))) {
+ arraycopy_work<T, false, false, true>(array, count);
+ }
+ } else if (array_addr < _heap->marking_context()->top_at_mark_start(r)) {
+ // Non-generational, marking
+ arraycopy_work<T, false, false, true>(array, count);
+ }
}
}
inline bool ShenandoahBarrierSet::need_bulk_update(HeapWord* ary) {
return ary < _heap->heap_region_containing(ary)->get_update_watermark();
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