1 /*
2 * Copyright (C) 2012 The Android Open Source Project
3 *
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
7 *
8 * http://www.apache.org/licenses/LICENSE-2.0
9 *
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
15 */
16
17 #include "gc/heap.h"
18 #include "gc/space/large_object_space.h"
19 #include "gc/space/space-inl.h"
20 #include "sticky_mark_sweep.h"
21 #include "thread-inl.h"
22
23 namespace art {
24 namespace gc {
25 namespace collector {
26
StickyMarkSweep(Heap * heap,bool is_concurrent,const std::string & name_prefix)27 StickyMarkSweep::StickyMarkSweep(Heap* heap, bool is_concurrent, const std::string& name_prefix)
28 : PartialMarkSweep(heap, is_concurrent, name_prefix.empty() ? "sticky " : name_prefix) {
29 cumulative_timings_.SetName(GetName());
30 }
31
BindBitmaps()32 void StickyMarkSweep::BindBitmaps() {
33 PartialMarkSweep::BindBitmaps();
34 WriterMutexLock mu(Thread::Current(), *Locks::heap_bitmap_lock_);
35 // For sticky GC, we want to bind the bitmaps of all spaces as the allocation stack lets us
36 // know what was allocated since the last GC. A side-effect of binding the allocation space mark
37 // and live bitmap is that marking the objects will place them in the live bitmap.
38 for (const auto& space : GetHeap()->GetContinuousSpaces()) {
39 if (space->IsContinuousMemMapAllocSpace() &&
40 space->GetGcRetentionPolicy() == space::kGcRetentionPolicyAlwaysCollect) {
41 DCHECK(space->IsContinuousMemMapAllocSpace());
42 space->AsContinuousMemMapAllocSpace()->BindLiveToMarkBitmap();
43 }
44 }
45 for (const auto& space : GetHeap()->GetDiscontinuousSpaces()) {
46 CHECK(space->IsLargeObjectSpace());
47 space->AsLargeObjectSpace()->CopyLiveToMarked();
48 }
49 }
50
MarkReachableObjects()51 void StickyMarkSweep::MarkReachableObjects() {
52 // All reachable objects must be referenced by a root or a dirty card, so we can clear the mark
53 // stack here since all objects in the mark stack will Get scanned by the card scanning anyways.
54 // TODO: Not put these objects in the mark stack in the first place.
55 mark_stack_->Reset();
56 RecursiveMarkDirtyObjects(false, accounting::CardTable::kCardDirty - 1);
57 }
58
MarkConcurrentRoots(VisitRootFlags flags)59 void StickyMarkSweep::MarkConcurrentRoots(VisitRootFlags flags) {
60 TimingLogger::ScopedTiming t(__FUNCTION__, GetTimings());
61 // Visit all runtime roots and clear dirty flags including class loader. This is done to prevent
62 // incorrect class unloading since the GC does not card mark when storing store the class during
63 // object allocation. Doing this for each allocation would be slow.
64 // Since the card is not dirty, it means the object may not get scanned. This can cause class
65 // unloading to occur even though the class and class loader are reachable through the object's
66 // class.
67 Runtime::Current()->VisitConcurrentRoots(
68 this,
69 static_cast<VisitRootFlags>(flags | kVisitRootFlagClassLoader));
70 }
71
Sweep(bool swap_bitmaps ATTRIBUTE_UNUSED)72 void StickyMarkSweep::Sweep(bool swap_bitmaps ATTRIBUTE_UNUSED) {
73 SweepArray(GetHeap()->GetLiveStack(), false);
74 }
75
76 } // namespace collector
77 } // namespace gc
78 } // namespace art
79