1 /*
2  * Copyright (C) 2019 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 #ifndef ANDROID_SYSTEM_SUSPEND_WAKE_LOCK_ENTRY_LIST_H
18 #define ANDROID_SYSTEM_SUSPEND_WAKE_LOCK_ENTRY_LIST_H
19 
20 #include <android-base/unique_fd.h>
21 #include <android/system/suspend/internal/WakeLockInfo.h>
22 #include <utils/Mutex.h>
23 
24 #include <list>
25 #include <mutex>
26 #include <unordered_map>
27 #include <utility>
28 #include <vector>
29 
30 using ::android::system::suspend::internal::WakeLockInfo;
31 
32 namespace android {
33 namespace system {
34 namespace suspend {
35 namespace V1_0 {
36 
37 using android::base::unique_fd;
38 using TimestampType = int64_t;
39 
40 TimestampType getTimeNow();
41 
42 /*
43  * WakeLockEntryList to collect wake lock stats.
44  * This class is thread safe.
45  */
46 class WakeLockEntryList {
47    public:
48     WakeLockEntryList(size_t capacity, unique_fd kernelWakelockStatsFd);
49     void updateOnAcquire(const std::string& name, int pid, TimestampType timeNow);
50     void updateOnRelease(const std::string& name, int pid, TimestampType timeNow);
51     // updateNow() should be called before getWakeLockStats() to ensure stats are
52     // updated wrt the current time.
53     void updateNow();
54     void getWakeLockStats(std::vector<WakeLockInfo>* aidl_return) const;
55     friend std::ostream& operator<<(std::ostream& out, const WakeLockEntryList& list);
56 
57    private:
58     void evictIfFull() REQUIRES(mStatsLock);
59     void insertEntry(WakeLockInfo entry) REQUIRES(mStatsLock);
60     void deleteEntry(std::list<WakeLockInfo>::iterator entry) REQUIRES(mStatsLock);
61     WakeLockInfo createNativeEntry(const std::string& name, int pid, TimestampType timeNow) const;
62     WakeLockInfo createKernelEntry(const std::string& name) const;
63     void getKernelWakelockStats(std::vector<WakeLockInfo>* aidl_return) const;
64 
65     // Hash for WakeLockEntry key (pair<std::string, int>)
66     struct LockHash {
operatorLockHash67         std::size_t operator()(const std::pair<std::string, int>& key) const {
68             return std::hash<std::string>()(key.first) ^ std::hash<int>()(key.second);
69         }
70     };
71 
72     size_t mCapacity;
73     unique_fd mKernelWakelockStatsFd;
74 
75     mutable std::mutex mStatsLock;
76 
77     // std::list and std::unordered map are used to support both inserting a stat
78     // and eviction of the LRU stat in O(1) time. The LRU stat is maintained at
79     // the back of the list.
80     std::list<WakeLockInfo> mStats GUARDED_BY(mStatsLock);
81     std::unordered_map<std::pair<std::string, int>, std::list<WakeLockInfo>::iterator, LockHash>
82         mLookupTable GUARDED_BY(mStatsLock);
83 };
84 
85 }  // namespace V1_0
86 }  // namespace suspend
87 }  // namespace system
88 }  // namespace android
89 
90 #endif  // ANDROID_SYSTEM_SUSPEND_WAKE_LOCK_ENTRY_LIST_H
91