1 /*
2 * Copyright (c) 2021, 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 #pragma once
18
19 #include <android-base/result.h>
20 #include <android-base/stringprintf.h>
21 #include <android-base/strings.h>
22 #include <utils/Mutex.h>
23 #include <utils/RefBase.h>
24
25 #include <string>
26 #include <unordered_set>
27 #include <vector>
28
29 namespace android {
30 namespace automotive {
31 namespace watchdog {
32
33 constexpr const char* kProcDiskStatsPath = "/proc/diskstats";
34
recordStatsForDevice(const std::string & deviceName)35 inline constexpr bool recordStatsForDevice(const std::string& deviceName) {
36 for (const auto& prefix : {"zram", "ram"}) {
37 if (android::base::StartsWith(deviceName, prefix)) {
38 return false;
39 }
40 }
41 return true;
42 }
43
44 // Struct that represents the stats from |kUidIoStatsPath|.
45 struct DiskStats {
46 int major = 0;
47 int minor = 0;
48 std::string deviceName;
49 uint64_t numReadsCompleted = 0;
50 uint64_t numReadsMerged = 0;
51 uint64_t numKibRead = 0;
52 uint64_t readTimeInMillis = 0;
53 uint64_t numWritesCompleted = 0;
54 uint64_t numWritesMerged = 0;
55 uint64_t numKibWritten = 0;
56 uint64_t writeTimeInMillis = 0;
57 uint64_t totalIoTimeInMillis = 0;
58 uint64_t weightedTotalIoTimeInMillis = 0;
59 uint64_t numFlushCompleted = 0;
60 uint64_t flushTimeInMillis = 0;
61
62 DiskStats& operator-=(const DiskStats& rhs);
63 DiskStats& operator+=(const DiskStats& rhs);
64 struct HashByPartition {
65 size_t operator()(const DiskStats& stats) const;
66 };
67 struct EqualByPartition {
68 bool operator()(const DiskStats& lhs, const DiskStats& rhs) const;
69 };
70 };
71
72 /*
73 * Contains methods that should be implemented by the /proc/diskstats reader or any mock reader
74 * used in tests.
75 */
76 class ProcDiskStatsCollectorInterface : virtual public android::RefBase {
77 public:
78 using PerPartitionDiskStats = ::std::unordered_set<DiskStats, DiskStats::HashByPartition,
79 DiskStats::EqualByPartition>;
80 // Initializes the collector.
81 virtual void init() = 0;
82
83 // Collects the system-wide block devices statistics.
84 virtual android::base::Result<void> collect() = 0;
85
86 // Returns the latest per-disk stats.
87 virtual PerPartitionDiskStats latestPerPartitionDiskStats() const = 0;
88
89 // Returns the aggregated delta stats since the last before collection.
90 virtual DiskStats deltaSystemWideDiskStats() const = 0;
91
92 // Returns true when the proc diskstats file is accessible. Otherwise, returns false.
93 virtual bool enabled() const = 0;
94
95 // Path to the disk stats file.
96 virtual std::string filePath() const = 0;
97 };
98
99 class ProcDiskStatsCollector final : public ProcDiskStatsCollectorInterface {
100 public:
kPath(path)101 explicit ProcDiskStatsCollector(const std::string& path = kProcDiskStatsPath) : kPath(path) {}
102
~ProcDiskStatsCollector()103 ~ProcDiskStatsCollector() {}
104
init()105 void init() {
106 Mutex::Autolock lock(mMutex);
107 // Note: Verify proc file access outside the constructor. Otherwise, the unittests of
108 // dependent classes would call the constructor before mocking and get killed due to
109 // sepolicy violation.
110 mEnabled = access(kPath.c_str(), R_OK) == 0;
111 }
112
113 android::base::Result<void> collect();
114
latestPerPartitionDiskStats()115 PerPartitionDiskStats latestPerPartitionDiskStats() const {
116 Mutex::Autolock lock(mMutex);
117 return mLatestPerPartitionDiskStats;
118 }
119
deltaSystemWideDiskStats()120 DiskStats deltaSystemWideDiskStats() const {
121 Mutex::Autolock lock(mMutex);
122 return mDeltaSystemWideDiskStats;
123 }
124
enabled()125 bool enabled() const {
126 Mutex::Autolock lock(mMutex);
127 return mEnabled;
128 }
129
filePath()130 std::string filePath() const { return kPath; }
131
132 private:
133 // Path to disk stats file.
134 const std::string kPath;
135
136 // Makes sure only one collection is running at any given time.
137 mutable Mutex mMutex;
138
139 // True if |kPath| is accessible.
140 bool mEnabled GUARDED_BY(mMutex);
141
142 // Delta of per-UID I/O usage since last before collection.
143 DiskStats mDeltaSystemWideDiskStats GUARDED_BY(mMutex);
144
145 /*
146 * Latest per-disk stats from the file at |kPath|. Per-disk stats is required for calculating
147 * per-disk delta since last collection. Because the stats reported in |kPath| may overflow,
148 * storing the stats per-disk helps to deal with this issue.
149 */
150 PerPartitionDiskStats mLatestPerPartitionDiskStats GUARDED_BY(mMutex);
151 };
152
153 } // namespace watchdog
154 } // namespace automotive
155 } // namespace android
156