[guardian-dev] developer sneak peak: CacheWord

[G. Blake Meike]

Hi.  I just stumbled into this discussion.  This may be of use:

Android does, in fact SIGKILL processes by priority.  Priorities are values between 15 and -16, smaller is more persistent.  You can find the priority of any given process by looking at the file /proc/<process id>/oom_adj.

It is the process that is being killed, not the DVM. Native code is no help.

Android can kill off any process in an attempt to free memory.  Each device has a build-time table that associates memory conditions with the priorities that should be killed in those conditions.  It is unlikely that things with oom_adm < 0 will ever be killed.  It is also difficult to get an oom_adj < 0 unless your app is signed with the same key as Android itself.

The discussion below concerns the use of the android:persistent flag.  Karim claims that the flag may work for any app.  I have only a little familiarity with the flag: I don't know if it affects priority.  I do know that if a persistent app is killed off, it will restart automagically.

https://groups.google.com/forum/?fromgroups=#!topic/android-platform/nU0e3aoBlSY

-blake

On Mar 27, 2013, at 7:52 AM, Michael Rogers wrote:

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> On 26/03/13 18:10, Hans-Christoph Steiner wrote:
>> But my guess is that if Android kills a process without even
>> calling onDestroy(), then its probably sending SIGKILL, and then
>> native code won't help.  In that case, sounds like the permanent
>> notification is required to guarantee that the zeroification will
>> be run.
> 
> Even a process that's showing a permanent notification may be killed
> if there's not enough memory to keep all such processes running.
> 
> https://developer.android.com/guide/components/processes-and-threads.html#Lifecycle
> 
> Cheers,
> Michael
> 
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