获取Android应用内存信息

1 本地调试获取内存信息

1.1 获取系统内存信息

通过在 adb shell 内执行命令 cat /proc/meminfo，获取信息如下：

OP4C72L1:/ $ cat /proc/meminfo                                                                        
MemTotal:        7800948 kB
MemFree:          227700 kB
MemAvailable:    4981420 kB
Buffers:           12092 kB
Cached:          4694560 kB
SwapCached:        53148 kB
Active:          4018228 kB
Inactive:        1765996 kB
Active(anon):    1021200 kB
Inactive(anon):   269516 kB
Active(file):    2997028 kB
Inactive(file):  1496480 kB
Unevictable:      200428 kB
Mlocked:          200428 kB
SwapTotal:       4194300 kB
SwapFree:        3413924 kB
Dirty:                88 kB
Writeback:             0 kB
AnonPages:       1272280 kB
Mapped:          1445728 kB
Shmem:             15028 kB
KReclaimable:     513568 kB
Slab:             477908 kB
SReclaimable:     194116 kB
SUnreclaim:       283792 kB
KernelStack:       71008 kB
ShadowCallStack:    4441 kB
PageTables:        97700 kB
NFS_Unstable:          0 kB
Bounce:                0 kB
WritebackTmp:          0 kB
CommitLimit:    11240496 kB
Committed_AS:   126822724 kB
VmallocTotal:   263061440 kB
VmallocUsed:      141028 kB
VmallocChunk:          0 kB
CmaTotal:         208896 kB
CmaFree:           24264 kB
IonTotalCache:    134756 kB
IonTotalUsed:     108500 kB
GPUTotalUsed:     107708 kB

1.2 获取执行 App 内存信息

主要通过命令dumpsys meminfo <package name>，例如

OP4C72L1:/ $ dumpsys meminfo com.x.x.example
Applications Memory Usage (in Kilobytes):
Uptime: 16468000 Realtime: 39149166

** MEMINFO in pid 3137 [com.shopee.sszrtc.example] **
                   Pss  Private  Private  SwapPss      Rss     Heap     Heap     Heap
                 Total    Dirty    Clean    Dirty    Total     Size    Alloc     Free
                ------   ------   ------   ------   ------   ------   ------   ------
  Native Heap    53051    53016        0       22    54372    77824    56613    21210
  Dalvik Heap     8292     6656     1592       16     9536    12555     6278     6277
 Dalvik Other     4693     3320        8        0     6540                           
        Stack     2396     2396        0        0     2404                           
       Ashmem        8        0        0        0       32                           
      Gfx dev     7168     7160        8        0     7168                           
    Other dev       44        0       44        0      444                           
     .so mmap    28755      768    24144        5    74912                           
    .jar mmap     1992        0      132        0    34692                           
    .apk mmap      491        0       24        0    24076                           
    .ttf mmap      222        0      132        0      600                           
    .dex mmap    16684    16672        0        0    16812                           
    .oat mmap       31        0        0        0     2536                           
    .art mmap     9094     8688       28        0    22536                           
   Other mmap       77       36        0        0     1388                           
   EGL mtrack    61780    61780        0        0    61780                           
    GL mtrack     1152     1152        0        0     1152                           
      Unknown      543      528        4        2     1028                           
        TOTAL   196518   162172    26116       45   196518    90379    62891    27487
 
 App Summary
                       Pss(KB)                        Rss(KB)
                        ------                         ------
           Java Heap:    15372                          32072
         Native Heap:    53016                          54372
                Code:    41896                         156472
               Stack:     2396                           2404
            Graphics:    70100                          70100
       Private Other:     5508
              System:     8230
             Unknown:                                    6588
 
           TOTAL PSS:   196518            TOTAL RSS:   322008       TOTAL SWAP PSS:       45
 
 Objects
               Views:       84         ViewRootImpl:        2
         AppContexts:        8           Activities:        2
              Assets:       57        AssetManagers:        0
       Local Binders:       30        Proxy Binders:       47
       Parcel memory:       10         Parcel count:       41
    Death Recipients:        5      OpenSSL Sockets:        3
            WebViews:        0
 
 SQL
         MEMORY_USED:      578
  PAGECACHE_OVERFLOW:       92          MALLOC_SIZE:      117
 
 DATABASES
      pgsz     dbsz   Lookaside(b)          cache  Dbname
         4       24             33         2/33/3  /data/user/0/com.shopee.sszrtc.example/databases/hcc
         4       20            109       42/73/25  /data/user/0/com.shopee.sszrtc.example/databases/sszrtc
         4       20            109       12/43/13  /data/user/0/com.shopee.sszrtc.example/databases/sszrtc

2 线上获取内存信息

2.1 获取系统内存

private long getDevicePhyMemoryInKB() {
    ActivityManager manager = (ActivityManager) mContext.getSystemService(Context.ACTIVITY_SERVICE);
    ActivityManager.MemoryInfo memoryInfo = new ActivityManager.MemoryInfo();
    manager.getMemoryInfo(memoryInfo);
    long memorySizeInKB = memoryInfo.totalMem / 1024;

    Log.i(TAG, "totalMem: " + memorySizeInKB);
    return memorySizeInKB;
}

2.2 获取App内存信息

1. ActivityManager.getProcessMemoryInfo(pids: IntArray)

该接口在 Android Q 之后只能获取同 uid 进程的内存数据，而且频率受系统底层限制，默认是 300000 ms (5 min)，即5min内多次获取到的是相同的值。可通过命令查看限制时间：

OP4C72L1:/ $ dumpsys activity settings | grep "memory_info"                                              
memory_info_throttle_time=300000

2. Debug.getMemoryInfo(memInfo: Debug.MemoryInfo)

该接口获取到的当前进程内存信息会缺失 graphicis 的数值，其实最后返回的 totalPss 数值是偏小的。网上说，此接口在Android Q 之后可以频繁调用获取到当前进程的内存信息，但经测试，也是被限制了，表现与getProcessMemoryInfo() 一样，在5 min内调用获取到的值依旧不会产生变化。而经过测试，调用 Debug.getPss() 获取到的内存信息是变化的。

综上，个人认为，线上获取App 内存信息可以通过以下方法：

public long getAppMemUsageInKB() {
    long memUsageInKB = 0;
    try {
        long summaryGraphics = 0;

        /*
             * As start of Android Q, this API is significantly limited, if called faster the limit
             * (about 5 min) you will receive the same data as the previous call.
             */
        Debug.MemoryInfo[] memInfos = mActivityManager.getProcessMemoryInfo(new int[] {Process.myPid()});
        if (memInfos != null && memInfos.length > 0) {
            Debug.MemoryInfo memInfo = memInfos[0];
            memUsageInKB = memInfo.getTotalPss();
            if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.M) {
                JSONObject object = new JSONObject(memInfo.getMemoryStats());
                Log.d(TAG, "getAppMemUsageInKB, info: " + object);
                if (object.has("summary.graphics")) {
                    summaryGraphics = Integer.parseInt(object.getString("summary.graphics"));
                }
            }
        }

        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.Q) {
            /* getPss() lack of graphics used memory, need fix up */
            memUsageInKB = Debug.getPss() + summaryGraphics;
        }
        Log.i(TAG, "getAppMemUsageInKB: totalPss = " + memUsageInKB);
    } catch (Exception e) {
        Log.w(TAG, "getAppMemUsageInKB: ", e);
    }
    return memUsageInKB;
}