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/*
* Copyright (C) 2012 The Android Open Source Project
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#include "sticky_mark_sweep.h"
#include "gc/accounting/atomic_stack.h"
#include "gc/accounting/card_table.h"
#include "gc/heap.h"
#include "gc/space/large_object_space.h"
#include "gc/space/space-inl.h"
#include "runtime.h"
#include "thread-current-inl.h"
namespace art {
namespace gc {
namespace collector {
StickyMarkSweep::StickyMarkSweep(Heap* heap, bool is_concurrent, const std::string& name_prefix)
: PartialMarkSweep(heap, is_concurrent, name_prefix.empty() ? "sticky " : name_prefix) {
cumulative_timings_.SetName(GetName());
}
void StickyMarkSweep::BindBitmaps() {
PartialMarkSweep::BindBitmaps();
WriterMutexLock mu(Thread::Current(), *Locks::heap_bitmap_lock_);
// For sticky GC, we want to bind the bitmaps of all spaces as the allocation stack lets us
// know what was allocated since the last GC. A side-effect of binding the allocation space mark
// and live bitmap is that marking the objects will place them in the live bitmap.
for (const auto& space : GetHeap()->GetContinuousSpaces()) {
if (space->IsContinuousMemMapAllocSpace() &&
space->GetGcRetentionPolicy() == space::kGcRetentionPolicyAlwaysCollect) {
DCHECK(space->IsContinuousMemMapAllocSpace());
space->AsContinuousMemMapAllocSpace()->BindLiveToMarkBitmap();
}
}
for (const auto& space : GetHeap()->GetDiscontinuousSpaces()) {
CHECK(space->IsLargeObjectSpace());
space->AsLargeObjectSpace()->CopyLiveToMarked();
}
}
void StickyMarkSweep::MarkReachableObjects() {
// All reachable objects must be referenced by a root or a dirty card, so we can clear the mark
// stack here since all objects in the mark stack will get scanned by the card scanning anyways.
// TODO: Not put these objects in the mark stack in the first place.
mark_stack_->Reset();
RecursiveMarkDirtyObjects(false, accounting::CardTable::kCardDirty - 1);
}
void StickyMarkSweep::MarkConcurrentRoots(VisitRootFlags flags) {
TimingLogger::ScopedTiming t(__FUNCTION__, GetTimings());
// Visit all runtime roots and clear dirty flags including class loader. This is done to prevent
// incorrect class unloading since the GC does not card mark when storing the class during
// object allocation. Doing this for each allocation would be slow.
// Since the card is not dirty, it means the object may not get scanned. This can cause class
// unloading to occur even though the class and class loader are reachable through the object's
// class.
Runtime::Current()->VisitConcurrentRoots(
this,
static_cast<VisitRootFlags>(flags | kVisitRootFlagClassLoader));
}
void StickyMarkSweep::Sweep(bool swap_bitmaps ATTRIBUTE_UNUSED) {
SweepArray(GetHeap()->GetLiveStack(), false);
}
} // namespace collector
} // namespace gc
} // namespace art