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1 /*
2  * Copyright (c) 2023 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 __WAITQUEUE_H__
17 #define __WAITQUEUE_H__
18 #include "sync/sync.h"
19 #include "cpp/mutex.h"
20 #include "sched/execute_ctx.h"
21 #include "util/IntrusiveList.h"
22 #include "sync/mutex_private.h"
23 #include "dfx/log/ffrt_log_api.h"
24 
25 namespace ffrt {
26 class TaskBase;
27 struct TaskWithNode;
28 using TaskListNode = ListNode;
29 using TaskList = List<TaskWithNode, TaskListNode>;
30 
31 struct TaskWithNode : public TaskListNode {
32     TaskWithNode();
33     TaskBase* task = nullptr;
34     std::mutex lk;
35     std::condition_variable cv;
36 };
37 
38 class WaitQueue {
39 public:
40     using TimePoint = std::chrono::steady_clock::time_point;
41     void SuspendAndWait(mutexPrivate* lk);
42     int SuspendAndWaitUntil(mutexPrivate* lk, const TimePoint& tp) noexcept;
NotifyAll()43     void NotifyAll() noexcept { Notify(false); }
NotifyOne()44     void NotifyOne() noexcept { Notify(true); }
45 
WaitQueue()46     WaitQueue()
47     {
48         whead = new WaitUntilEntry();
49         whead->next = whead;
50         whead->prev = whead;
51     }
52     WaitQueue(WaitQueue const&) = delete;
53     void operator=(WaitQueue const&) = delete;
54 
~WaitQueue()55     ~WaitQueue()
56     {
57         std::lock_guard lg(wqlock);
58         ReleaseAll();
59         delete whead;
60         whead = nullptr;
61     }
62 
63 private:
64     fast_mutex wqlock;
65     WaitUntilEntry* whead;
66 
67 private:
68     void WeNotifyProc(WaitUntilEntry* we);
69     void ThreadWait(WaitUntilEntry* wn, mutexPrivate* lk, TaskBase* task);
70     bool ThreadWaitUntil(WaitUntilEntry* wn, mutexPrivate* lk, const TimePoint& tp, TaskBase* task);
71     void Notify(bool one) noexcept;
72 
empty()73     inline bool empty() const
74     {
75         if (whead == nullptr) {
76             return true;
77         }
78         return (whead->next == whead);
79     }
80 
ReleaseAll()81     void ReleaseAll()
82     {
83         while (!empty()) {
84             FFRT_LOGE("There are still tasks in cv that have not been awakened");
85             WaitUntilEntry *wue = pop_front();
86             WeNotifyProc(wue);
87         }
88     }
89 
push_back(WaitUntilEntry * we)90     inline void push_back(WaitUntilEntry* we)
91     {
92         if ((we == nullptr) || (whead == nullptr) || (whead->prev == nullptr)) {
93             FFRT_LOGE("we or whead or whead->prev is nullptr");
94             return;
95         }
96         we->next = whead;
97         we->prev = whead->prev;
98         whead->prev->next = we;
99         whead->prev = we;
100     }
101 
pop_front()102     inline WaitUntilEntry* pop_front()
103     {
104         if ((whead->next == nullptr) || (whead->next->next == nullptr)) {
105             FFRT_LOGE("whead->next or whead->next->next is nullptr");
106             return nullptr;
107         }
108         WaitEntry *we = whead->next;
109         whead->next = we->next;
110         we->next->prev = whead;
111         we->next = nullptr;
112         we->prev = nullptr;
113         return static_cast<WaitUntilEntry*>(we);
114     }
115 
remove(WaitUntilEntry * we)116     inline void remove(WaitUntilEntry* we)
117     {
118         if ((we->next == nullptr) || (we->prev == nullptr)) {
119             return;
120         }
121         we->prev->next = we->next;
122         we->next->prev = we->prev;
123         we->next = nullptr;
124         we->prev = nullptr;
125         return;
126     }
127     friend bool WeTimeoutProc(WaitQueue* wq, WaitUntilEntry* wue);
128 };
129 } // namespace ffrt
130 #endif // _WAITQUEUE_H_
131