Best practise to deal with killed services?

[Mariano Kamp]

Hi,

I often see that services are killed and then "restarted".

I can force this behavior when opening many applications.

"Low Memory" or "OutOfMemory" are not problems per se, are they? This is
just the normal behavior due to Android not closing applications, but
killing the least important processes when more memory is needed, right? The
terminology "crashed service" at least sounds very serious...

D/dalvikvm( 112): GC freed 272 objects / 12256 bytes in 648ms
D/dalvikvm( 55): GC freed 4021 objects / 156072 bytes in 897ms
I/ActivityManager( 55): Process com.google.process.gapps (pid 1886) has
died.
W/ActivityManager( 55): Scheduling restart of crashed service
com.google.android.apps.gtalkservice/com.google.android.gtalkservice.service.GTalkService
in 5000ms
I/ActivityManager( 55): Low Memory: No more background processes.
I/ActivityManager( 55): Process com.tmobile.myfaves (pid 2156) has died.
W/ActivityManager( 55): Scheduling restart of crashed service
com.tmobile.myfaves/.MyFavesService in 5000ms
I/ActivityManager( 55): Low Memory: No more background processes.



D/LocationManager( 6830): removeUpdates: intent = PendingIntent{4318eb18
target ***@4318e870}
D/HTTPService( 5812): Calling: GET http://brightkite.com/me/config.jsonHTTP/1.1
W/InputManagerService( 55): Starting input on non-focused client
com.android.internal.view.IInputMethodClient$Stub$***@4333df90 (uid=10016
pid=6825)
W/InputManagerService( 55): Client not active, ignoring focus gain of:
com.android.internal.view.IInputMethodClient$Stub$***@43303ae0
W/ActivityManager( 55): Activity pause timeout for HistoryRecord{43593020
{com.android.vending/com.android.vending.AssetBrowserActivity}}
D/dalvikvm( 5812): GC freed 1254 objects / 258832 bytes in 331ms
I/WindowManager( 55): WIN DEATH: Window{4348c1b8
com.newsrob/com.newsrob.DashboardListActivity paused=false}
I/ActivityManager( 55): Process com.newsrob (pid 6207) has died.
W/ActivityManager( 55): Scheduling restart of crashed service
com.newsrob/.SynchronizationService in 5000ms
I/ActivityManager( 55): Low Memory: No more background processes.
W/InputManagerService( 55): Window already focused, ignoring focus gain
of: com.android.internal.view.IInputMethodClient$Stub$***@43450e48
W/System.err( 6830): OutOfMemory
D/dalvikvm( 5812): GC freed 181 objects / 190288 bytes in 625ms
D/dalvikvm(10389): GC freed 114 objects / 5184 bytes in 679ms
D/dalvikvm( 268): GC freed 12 objects / 368 bytes in 1096ms
D/InetAddress( 6825): android.clients.google.com: 74.125.43.101 (family 2,
proto 6)


Is there any guaranteed call back available to clean up first before being
killed?

I set an ongoing notification when the service starts and clear it when it
finishes. Unfortunately the notification isn't cleared when the service is
just killed and it hangs around until the service is the next time
triggered.

Why are those services restarted? Are they always restarted? And what
exactly happens when a service is restarted? Should I just clear the
notification in the service's onCreate() method.
To avoid the overhead of two processes I just use a
single process for my UI and the service. Should I rework my code
(stop sharing static variables) and use two separate processes?

What are you guys doing in that situations?

Cheers,
Mariano

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[Mariano Kamp]

Also, what is the best way to deal with wake locks in these situations?

Post by Mariano Kamp
Hi,
I often see that services are killed and then "restarted".
I can force this behavior when opening many applications.
"Low Memory" or "OutOfMemory" are not problems per se, are they? This is
just the normal behavior due to Android not closing applications, but
killing the least important processes when more memory is needed, right? The
terminology "crashed service" at least sounds very serious...
D/dalvikvm( 112): GC freed 272 objects / 12256 bytes in 648ms
D/dalvikvm( 55): GC freed 4021 objects / 156072 bytes in 897ms
I/ActivityManager( 55): Process com.google.process.gapps (pid 1886) has
died.
W/ActivityManager( 55): Scheduling restart of crashed service
com.google.android.apps.gtalkservice/com.google.android.gtalkservice.service.GTalkService
in 5000ms
I/ActivityManager( 55): Low Memory: No more background processes.
I/ActivityManager( 55): Process com.tmobile.myfaves (pid 2156) has died.
W/ActivityManager( 55): Scheduling restart of crashed service
com.tmobile.myfaves/.MyFavesService in 5000ms
I/ActivityManager( 55): Low Memory: No more background processes.
D/LocationManager( 6830): removeUpdates: intent = PendingIntent{4318eb18
D/HTTPService( 5812): Calling: GET http://brightkite.com/me/config.jsonHTTP/1.1
W/InputManagerService( 55): Starting input on non-focused client
W/ActivityManager( 55): Activity pause timeout for HistoryRecord{43593020
{com.android.vending/com.android.vending.AssetBrowserActivity}}
D/dalvikvm( 5812): GC freed 1254 objects / 258832 bytes in 331ms
I/WindowManager( 55): WIN DEATH: Window{4348c1b8
com.newsrob/com.newsrob.DashboardListActivity paused=false}
I/ActivityManager( 55): Process com.newsrob (pid 6207) has died.
W/ActivityManager( 55): Scheduling restart of crashed service
com.newsrob/.SynchronizationService in 5000ms
I/ActivityManager( 55): Low Memory: No more background processes.
W/InputManagerService( 55): Window already focused, ignoring focus gain
W/System.err( 6830): OutOfMemory
D/dalvikvm( 5812): GC freed 181 objects / 190288 bytes in 625ms
D/dalvikvm(10389): GC freed 114 objects / 5184 bytes in 679ms
D/dalvikvm( 268): GC freed 12 objects / 368 bytes in 1096ms
D/InetAddress( 6825): android.clients.google.com: 74.125.43.101 (family 2,
proto 6)
Is there any guaranteed call back available to clean up first before being
killed?
I set an ongoing notification when the service starts and clear it when it
finishes. Unfortunately the notification isn't cleared when the service is
just killed and it hangs around until the service is the next time
triggered.
Why are those services restarted? Are they always restarted? And what
exactly happens when a service is restarted? Should I just clear the
notification in the service's onCreate() method.
To avoid the overhead of two processes I just use a
single process for my UI and the service. Should I rework my code (stop sharing static variables) and use two separate processes?
What are you guys doing in that situations?
Cheers,
Mariano

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[Mariano Kamp]

onDestroy() seems to be called regularly before the process vanishes, but
onDestroy() is not. The process is just gone.

Post by Mariano Kamp
Also, what is the best way to deal with wake locks in these situations?

Post by Mariano Kamp
Hi,
I often see that services are killed and then "restarted".
I can force this behavior when opening many applications.
"Low Memory" or "OutOfMemory" are not problems per se, are they? This is
just the normal behavior due to Android not closing applications, but
killing the least important processes when more memory is needed, right? The
terminology "crashed service" at least sounds very serious...
D/dalvikvm( 112): GC freed 272 objects / 12256 bytes in 648ms
D/dalvikvm( 55): GC freed 4021 objects / 156072 bytes in 897ms
I/ActivityManager( 55): Process com.google.process.gapps (pid 1886) has
died.
W/ActivityManager( 55): Scheduling restart of crashed service
com.google.android.apps.gtalkservice/com.google.android.gtalkservice.service.GTalkService
in 5000ms
I/ActivityManager( 55): Low Memory: No more background processes.
I/ActivityManager( 55): Process com.tmobile.myfaves (pid 2156) has died.
W/ActivityManager( 55): Scheduling restart of crashed service
com.tmobile.myfaves/.MyFavesService in 5000ms
I/ActivityManager( 55): Low Memory: No more background processes.
D/LocationManager( 6830): removeUpdates: intent = PendingIntent{4318eb18
D/HTTPService( 5812): Calling: GET http://brightkite.com/me/config.jsonHTTP/1.1
W/InputManagerService( 55): Starting input on non-focused client
W/ActivityManager( 55): Activity pause timeout for
HistoryRecord{43593020
{com.android.vending/com.android.vending.AssetBrowserActivity}}
D/dalvikvm( 5812): GC freed 1254 objects / 258832 bytes in 331ms
I/WindowManager( 55): WIN DEATH: Window{4348c1b8
com.newsrob/com.newsrob.DashboardListActivity paused=false}
I/ActivityManager( 55): Process com.newsrob (pid 6207) has died.
W/ActivityManager( 55): Scheduling restart of crashed service
com.newsrob/.SynchronizationService in 5000ms
I/ActivityManager( 55): Low Memory: No more background processes.
W/InputManagerService( 55): Window already focused, ignoring focus gain
W/System.err( 6830): OutOfMemory
D/dalvikvm( 5812): GC freed 181 objects / 190288 bytes in 625ms
D/dalvikvm(10389): GC freed 114 objects / 5184 bytes in 679ms
D/dalvikvm( 268): GC freed 12 objects / 368 bytes in 1096ms
D/InetAddress( 6825): android.clients.google.com: 74.125.43.101 (family
2, proto 6)
Is there any guaranteed call back available to clean up first before being
killed?
I set an ongoing notification when the service starts and clear it when it
finishes. Unfortunately the notification isn't cleared when the service is
just killed and it hangs around until the service is the next time
triggered.
Why are those services restarted? Are they always restarted? And what
exactly happens when a service is restarted? Should I just clear the
notification in the service's onCreate() method.
To avoid the overhead of two processes I just use a
single process for my UI and the service. Should I rework my code (stop sharing static variables) and use two separate processes?
What are you guys doing in that situations?
Cheers,
Mariano

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To post to this group, send email to android-***@googlegroups.com
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[Dianne Hackborn]

You shouldn't really be able to force the behavior by "opening many
applications," since only one can be in the foreground at the time, and
background applications are always killed before ones actively running
services.

You can certainly force this by starting up a bunch of processes running
services, in which case yes eventually there will be no more memory and
something will need to go.

The onLowMemory() callback happens a fair amount before any services are
started -- currently it is sent when the system is not able to keep around
any background processes. The next process to go will be a service, but
there is a bit of a hump in memory use before that happens.

The crashed service message is because all the activity manager knows is the
process goes away -- this may be because the kernel killed it, or its
process crashed, it can't tell between the two.

As with everything else, there is no callback that happens before a service
is killed, since this is done deep down in the kernel when it finds that it
is getting low on memory.

In general the management of running services is tricky because developers
have a tendency to leave them running for longer than needed, or even just
forgetting to stop them. They also often have memory leaks so as they
continue to run they eat more and more memory, leaving no room for other
things. So at this point the system is pretty heavy-handed with them. One
thing in particular is that after a service has been running for a while, we
will reclassify it as a background process, allowing it to be killed much
more aggressively.

As far as wake locks, the system automatically releases them when your
process goes away so there is no need to worry about them when you are
killed.

Finally, if you are indeed showing an ongoing notification while your
service is running, so the user is directly aware of what you are doing, and
can explicitly stop your service when they want, then you have one
additional facility available to you: Service.setForeground() will tell the
system that you count as a foreground application, something the user is
directly aware of, so your process will be killed much less aggressively.

Please use this API only in this case (look at the media playback service as
a the typical kind of behavior that should be associated with it). Actually
I am starting to see apps abuse this API just to force themselves to run
without those semantics, so we'll probably have to do something about it --
my current thought is to turn it into a no-op and add a new API that
requires you have an ongoing notification to be counted as foreground.

Post by Mariano Kamp
onDestroy() seems to be called regularly before the process vanishes, but
onDestroy() is not. The process is just gone.

Post by Mariano Kamp
Also, what is the best way to deal with wake locks in these situations?

Post by Mariano Kamp
Hi,
I often see that services are killed and then "restarted".
I can force this behavior when opening many applications.
"Low Memory" or "OutOfMemory" are not problems per se, are they? This
is just the normal behavior due to Android not closing applications, but
killing the least important processes when more memory is needed, right? The
terminology "crashed service" at least sounds very serious...
D/dalvikvm( 112): GC freed 272 objects / 12256 bytes in 648ms
D/dalvikvm( 55): GC freed 4021 objects / 156072 bytes in 897ms
I/ActivityManager( 55): Process com.google.process.gapps (pid 1886) has
died.
W/ActivityManager( 55): Scheduling restart of crashed service
com.google.android.apps.gtalkservice/com.google.android.gtalkservice.service.GTalkService
in 5000ms
I/ActivityManager( 55): Low Memory: No more background processes.
I/ActivityManager( 55): Process com.tmobile.myfaves (pid 2156) has died.
W/ActivityManager( 55): Scheduling restart of crashed service
com.tmobile.myfaves/.MyFavesService in 5000ms
I/ActivityManager( 55): Low Memory: No more background processes.
D/LocationManager( 6830): removeUpdates: intent = PendingIntent{4318eb18
D/HTTPService( 5812): Calling: GET http://brightkite.com/me/config.jsonHTTP/1.1
W/InputManagerService( 55): Starting input on non-focused client
W/ActivityManager( 55): Activity pause timeout for
HistoryRecord{43593020
{com.android.vending/com.android.vending.AssetBrowserActivity}}
D/dalvikvm( 5812): GC freed 1254 objects / 258832 bytes in 331ms
I/WindowManager( 55): WIN DEATH: Window{4348c1b8
com.newsrob/com.newsrob.DashboardListActivity paused=false}
I/ActivityManager( 55): Process com.newsrob (pid 6207) has died.
W/ActivityManager( 55): Scheduling restart of crashed service
com.newsrob/.SynchronizationService in 5000ms
I/ActivityManager( 55): Low Memory: No more background processes.
W/InputManagerService( 55): Window already focused, ignoring focus gain
W/System.err( 6830): OutOfMemory
D/dalvikvm( 5812): GC freed 181 objects / 190288 bytes in 625ms
D/dalvikvm(10389): GC freed 114 objects / 5184 bytes in 679ms
D/dalvikvm( 268): GC freed 12 objects / 368 bytes in 1096ms
D/InetAddress( 6825): android.clients.google.com: 74.125.43.101 (family
2, proto 6)
Is there any guaranteed call back available to clean up first before
being killed?
I set an ongoing notification when the service starts and clear it when
it finishes. Unfortunately the notification isn't cleared when the service
is just killed and it hangs around until the service is the next time
triggered.
Why are those services restarted? Are they always restarted? And what
exactly happens when a service is restarted? Should I just clear the
notification in the service's onCreate() method.
To avoid the overhead of two processes I just use a
single process for my UI and the service. Should I rework my code (stop sharing static variables) and use two separate processes?
What are you guys doing in that situations?
Cheers,
Mariano

--
Dianne Hackborn
Android framework engineer
***@android.com

Note: please don't send private questions to me, as I don't have time to
provide private support, and so won't reply to such e-mails. All such
questions should be posted on public forums, where I and others can see and
answer them.

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