1 /*
2  * Copyright (c) 2024 Huawei Device Co., Ltd.
3  * Licensed under the Apache License, Version 2.0 (the "License");
4  * you may not use this file except in compliance with the License.
5  * You may obtain a copy of the License at
6  *
7  *     http://www.apache.org/licenses/LICENSE-2.0
8  *
9  * Unless required by applicable law or agreed to in writing, software
10  * distributed under the License is distributed on an "AS IS" BASIS,
11  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
12  * See the License for the specific language governing permissions and
13  * limitations under the License.
14  */
15 
16 #ifndef ECMASCRIPT_MEM_RSET_WORKLIST_HANDLER_H
17 #define ECMASCRIPT_MEM_RSET_WORKLIST_HANDLER_H
18 
19 #include "ecmascript/platform/mutex.h"
20 
21 namespace panda::ecmascript {
22 class Heap;
23 class Region;
24 class RememberedSet;
25 
26 class RSetItem {
27 public:
RSetItem(Region *region, RememberedSet *rSet)28     explicit RSetItem(Region *region, RememberedSet *rSet) : region_(region), rSet_(rSet) {}
29     ~RSetItem() = default;
30 
31     template<class Visitor>
32     inline void Process(const Visitor &visitor);
33 
34     inline void MergeBack();
35 
36 private:
37     Region *region_ {nullptr};
38     RememberedSet *rSet_ {nullptr};
39 };
40 
41 class RSetWorkListHandler {
42 public:
43     explicit RSetWorkListHandler(Heap *heap);
44     ~RSetWorkListHandler() = default;
45 
46     inline void Initialize();
47 
48     template<class Visitor>
49     inline void ProcessAll(const Visitor &visitor);
50 
51     // Only called from the bound js thread in RUNNING state.
52     inline void WaitFinishedThenMergeBack();
53 
54     inline bool MergeBack();
55 
56     inline Heap *GetHeap();
57 
58     inline void EnumerateRegions(const Heap *heap);
59 
60     template<class Visitor>
61     inline void ProcessAllVisitor(const Visitor &visitor, int done);
62 
63     inline void MergeBackForAllItem();
64 
65 private:
66     inline void CollectRSetItemsInHeap(const Heap *heap);
67 
68     template<class Visitor>
69     inline bool ProcessNext(const Visitor &visitor);
70 
71     inline bool TryMergeBack();
72 
73     Heap *heap_ {nullptr};
74     /**
75      * This value represent whether there are some items to process, this is set to true in Initialize when collecting
76      * the RSet in heap(call from daemon thread in SuspendAll), and use CAS to set to false when try to merge back and
77      * clear(call maybe from daemon thread in SuspendAll, or from bound js thread in RUNNING state).
78      * Only two ways to modify this value:
79      * 1. Initialzie, from daemon thread in SuspendAll, and the modification must be visible to the bound js thread.
80      * 2. MergeBackAndReset, maybe from daemon thread when SuspendAll, or from js thread which region
81      * belonged to in RUNNING state.
82      * So the bound js thread can always see the lastest value without using atomic.
83      * And thus WaitFinishedThenMergeBack should ONLY be called from the bound js thread in RUNNING state.
84     */
85     bool initialized_ {false};
86     std::vector<RSetItem> items_;
87     std::atomic<int> nextItemIndex_ {-1};
88     int remainItems_ {0};
89     Mutex mutex_;
90     ConditionVariable cv_;
91 };
92 }  // namespace panda::ecmascript
93 
94 #endif  // ECMASCRIPT_MEM_RSET_WORKLIST_HANDLER_H
95