(Disclaimer: what follows is just my understanding of things and may be quite wrong)
Bitmap memory management is complicated by the fact that the memory for bitmaps is allocated in a separate native heap. The amount of memory available in this native heap is the total memory allocation limit minus the java heap size. This is reasonable but has a subtle consequence which I can best explain by a simple example (the byte sizes have been chosen for simplicity): 1) Process starts up, generating a java heap allocation of 2MB. 2) Application initializes its state and allocates 2MB in the java heap. 3) Application creates a 2MB Bitmap which is allocated in the native heap 4) Application updates its state by crunching a 10MB byte array 5) Garbage collector kicks in and reclaims the 10MB byte array 6) Application attempts to a create a new 2MB Bitmap 7) An OutOfMemoryException is raised. At first sight it looks as though the total memory usage at (6) is 6MB (4MB java and 2MB native) so the allocation should succeed. BUT (4) raised the Java heap size to 14MB, and though most of that is no longer in use, the java heap does not shrink. So the actual allocation to the native heap is only 2MB and that is already used by the first bitmap. I hope this is correct, perhaps someone else could corroborate it, I don't want to spread my misunderstandings. Tom 2009/10/7 Mariano Kamp <mariano.k...@gmail.com> > Hi, > > I very often get bug reports about out-of-memory errors. > > Those errors are caught bei the default exception handler where I then > ask how much memory is left (see below). Very often, like in the case from > below, there is plenty of memory left though. > > I am wondering why this is? > Of course, it might be that the bitmap (bitmap size exceeds VM budget) is > actually megabytes and megabytes, but as these are resources that are small > (and used by all the other users that don't get ooms) I would say that's not > the case. > Maybe the memory has been freed between the error and the measurement. That > would be unfortunate. Any better wetter to measure the current memory > consumption? > > Or am I missing something and there is a completely different > explanation? That would be wonderful and maybe give me a completely new > attack vector against those bugs. > > FWIW. I embed WebView and it is one of my top candidates for huge memory > consumption. Maybe there is something I can measure? > > Cheers, > Mariano > > -- Time: Sat Oct 03 11:19:00 GMT+01:00 2009 > -- Android Version: sdk=3, release=1.5, inc=150879 > -- Memory free: 12.27MB total: 15.44MB max: 16.00MB > -- NewsRob Version: 3.1.0/310 > -- Stacktrace:(3390) > android.view.InflateException: Binary XML file line #29: Error inflating > class java.lang.reflect.Constructor > at android.view.LayoutInflater. > > createView(LayoutInflater.java:512) > at > com.android.internal.policy.impl.PhoneLayoutInflater.onCreateView(PhoneLayoutInflater.java:56) > at android.view.LayoutInflater.createViewFromTag(LayoutInflater.java:562) > at android.view.LayoutInflater.rInflate(LayoutInflater.java:617) > at android.view.LayoutInflater.inflate(LayoutInflater.java:407) > at android.view.LayoutInflater.inflate(LayoutInflater.java:320) > at > android.widget.ResourceCursorAdapter.newView(ResourceCursorAdapter.java:79) > at android.widget.SimpleCursorAdapter.newView(SimpleCursorAdapter.java:93) > at android.widget.CursorAdapter.getView(CursorAdapter.java:182) > at android.widget.AbsListView.obtainView(AbsListView.java:1269) > at android.widget.ListView.makeAndAddView(ListView.java:1623) > at android.widget.ListView.fillDown(ListView.java:607) > at android.widget.ListView.fillSpecific(ListView.java:1194) > at android.widget.ListView.layoutChildren(ListView.java:1459) > at android.widget.AbsListView.onLayout(AbsListView.java:1113) > at android.view.View.layout(View.java:6133) > at android.widget.FrameLayout.onLayout(FrameLayout.java:333) > at android.view.View.layout(View.java:6133) > at android.widget.FrameLayout.onLayout(FrameLayout.java:333) > at android.view.View.layout(View.java:6133) > at android.widget.LinearLayout.setChildFrame(LinearLayout.java:1119) > at android.widget.LinearLayout.layoutVertical(LinearLayout.java:998) > at android.widget.LinearLayout.onLayout(LinearLayout.java:918) > at android.view.View.layout(View.java:6133) > at android.widget.FrameLayout.onLayout(FrameLayout.java:333) > at android.view.View.layout(View.java:6133) > at android.widget.FrameLayout.onLayout(FrameLayout.java:333) > at android.view.View.layout(View.java:6133) > at android.view.ViewRoot.performTraversals(ViewRoot.java:929) > at android.view.ViewRoot.handleMessage(ViewRoot.java:1482) > at android.os.Handler.dispatchMessage(Handler.java:99) > at android.os.Looper.loop(Looper.java:123) > at android.app.ActivityThread.main(ActivityThread.java:3948) > at java.lang.reflect.Method.invokeNative(Native Method) > at java.lang.reflect.Method.invoke(Method.java:521) > at > com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:782) > at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:540) > at dalvik.system.NativeStart.main(Native Method) > Caused by: java.lang.reflect.InvocationTargetException > at android.widget.TextView.<init>(TextView.java:308) > at java.lang.reflect.Constructor.constructNative(Native Method) > at java.lang.reflect.Constructor.newInstance(Constructor.java:446) > at android.view.LayoutInflater.createView(LayoutInflater.java:499) > ... 37 more > Caused by: java.lang.OutOfMemoryError: bitmap size exceeds VM budget > at android.graphics.BitmapFactory.nativeDecodeAsset(Native Method) > at android.graphics.BitmapFactory.decodeStream(BitmapFactory.java:363) > at android.graphics.BitmapFactory.decodeStream(BitmapFactory.java:212) > at > android.graphics.drawable.Drawable.createFromResourceStream(Drawable.java:663) > at android.content.res.Resources.loadDrawable(Resources.java:1637) > at android.content.res.TypedArray.getDrawable(TypedArray.java:548) > at android.view.View.<init>(View.java:1725) > at android.widget.TextView.<init>(TextView.java:314) > ... 41 more > > > > --~--~---------~--~----~------------~-------~--~----~ You received this message because you are subscribed to the Google Groups "Android Developers" group. 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