1 /*
2  * Copyright (C) 2011 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 package com.android.internal.util;
18 
19 import android.compat.annotation.UnsupportedAppUsage;
20 import android.os.Debug;
21 import android.os.StrictMode;
22 
23 public final class MemInfoReader {
24     final long[] mInfos = new long[Debug.MEMINFO_COUNT];
25 
26     @UnsupportedAppUsage
MemInfoReader()27     public MemInfoReader() {
28     }
29 
30     @UnsupportedAppUsage
readMemInfo()31     public void readMemInfo() {
32         // Permit disk reads here, as /proc/meminfo isn't really "on
33         // disk" and should be fast.  TODO: make BlockGuard ignore
34         // /proc/ and /sys/ files perhaps?
35         StrictMode.ThreadPolicy savedPolicy = StrictMode.allowThreadDiskReads();
36         try {
37             Debug.getMemInfo(mInfos);
38         } finally {
39             StrictMode.setThreadPolicy(savedPolicy);
40         }
41     }
42 
43     /**
44      * Total amount of RAM available to the kernel.
45      */
46     @UnsupportedAppUsage
getTotalSize()47     public long getTotalSize() {
48         return mInfos[Debug.MEMINFO_TOTAL] * 1024;
49     }
50 
51     /**
52      * Amount of RAM that is not being used for anything.
53      */
54     @UnsupportedAppUsage
getFreeSize()55     public long getFreeSize() {
56         return mInfos[Debug.MEMINFO_FREE] * 1024;
57     }
58 
59     /**
60      * Amount of RAM that the kernel is being used for caches, not counting caches
61      * that are mapped in to processes.
62      */
63     @UnsupportedAppUsage
getCachedSize()64     public long getCachedSize() {
65         return getCachedSizeKb() * 1024;
66     }
67 
68     /**
69      * Amount of RAM that is in use by the kernel for actual allocations.
70      */
getKernelUsedSize()71     public long getKernelUsedSize() {
72         return getKernelUsedSizeKb() * 1024;
73     }
74 
75     /**
76      * Total amount of RAM available to the kernel.
77      */
getTotalSizeKb()78     public long getTotalSizeKb() {
79         return mInfos[Debug.MEMINFO_TOTAL];
80     }
81 
82     /**
83      * Amount of RAM that is not being used for anything.
84      */
getFreeSizeKb()85     public long getFreeSizeKb() {
86         return mInfos[Debug.MEMINFO_FREE];
87     }
88 
89     /**
90      * Amount of RAM that the kernel is being used for caches, not counting caches
91      * that are mapped in to processes.
92      */
getCachedSizeKb()93     public long getCachedSizeKb() {
94         long kReclaimable = mInfos[Debug.MEMINFO_KRECLAIMABLE];
95 
96         // Note: MEMINFO_KRECLAIMABLE includes MEMINFO_SLAB_RECLAIMABLE and ION pools.
97         // Fall back to using MEMINFO_SLAB_RECLAIMABLE in case of older kernels that do
98         // not include KReclaimable meminfo field.
99         if (kReclaimable == 0) {
100             kReclaimable = mInfos[Debug.MEMINFO_SLAB_RECLAIMABLE];
101         }
102         return mInfos[Debug.MEMINFO_BUFFERS] + kReclaimable
103                 + mInfos[Debug.MEMINFO_CACHED] - mInfos[Debug.MEMINFO_MAPPED];
104     }
105 
106     /**
107      * Amount of RAM that is in use by the kernel for actual allocations.
108      */
getKernelUsedSizeKb()109     public long getKernelUsedSizeKb() {
110         long size = mInfos[Debug.MEMINFO_SHMEM] + mInfos[Debug.MEMINFO_SLAB_UNRECLAIMABLE]
111                 + mInfos[Debug.MEMINFO_VM_ALLOC_USED] + mInfos[Debug.MEMINFO_PAGE_TABLES];
112         if (!Debug.isVmapStack()) {
113             size += mInfos[Debug.MEMINFO_KERNEL_STACK];
114         }
115         return size;
116     }
117 
getSwapTotalSizeKb()118     public long getSwapTotalSizeKb() {
119         return mInfos[Debug.MEMINFO_SWAP_TOTAL];
120     }
121 
getSwapFreeSizeKb()122     public long getSwapFreeSizeKb() {
123         return mInfos[Debug.MEMINFO_SWAP_FREE];
124     }
125 
getZramTotalSizeKb()126     public long getZramTotalSizeKb() {
127         return mInfos[Debug.MEMINFO_ZRAM_TOTAL];
128     }
129 
130     @UnsupportedAppUsage
getRawInfo()131     public long[] getRawInfo() {
132         return mInfos;
133     }
134 }
135