How do I discover memory usage of my application in Android?

Question

How can I find the memory used on my Android application, programmatically?

I hope there is a way to do it. Plus, how do I get the free memory of the phone too?

Answer 1

We found out that all the standard ways of getting the total memory of the current process have some issues.

• Runtime.getRuntime().totalMemory(): returns JVM memory only
• ActivityManager.getMemoryInfo(), Process.getFreeMemory() and anything else based on /proc/meminfo - returns memory info about all the processes combined (e.g. android_util_Process.cpp)
• Debug.getNativeHeapAllocatedSize() - uses mallinfo() which return information about memory allocations performed by malloc() and related functions only (see android_os_Debug.cpp)
• Debug.getMemoryInfo() - does the job but it's too slow. It takes about 200ms on Nexus 6 for a single call. The performance overhead makes this function useless for us as we call it regularly and every call is quite noticeable (see android_os_Debug.cpp)
• ActivityManager.getProcessMemoryInfo(int[]) - calls Debug.getMemoryInfo() internally (see ActivityManagerService.java)

Finally, we ended up using the following code:

const long pageSize = 4 * 1024; //`sysconf(_SC_PAGESIZE)`
string stats = File.ReadAllText("/proc/self/statm");
var statsArr = stats.Split(new [] {' ', '\t', '\n'}, 3);

if( statsArr.Length < 2 )
    throw new Exception("Parsing error of /proc/self/statm: " + stats);

return long.Parse(statsArr[1]) * pageSize;

It returns VmRSS metric. You can find more details about it here: one, two and three.

---

P.S. I noticed that the theme still has a lack of an actual and simple code snippet of how to estimate the private memory usage of the process if the performance isn't a critical requirement:

Debug.MemoryInfo memInfo = new Debug.MemoryInfo();
Debug.getMemoryInfo(memInfo);
long res = memInfo.getTotalPrivateDirty();

if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.KITKAT) 
    res += memInfo.getTotalPrivateClean(); 

return res * 1024L;