Running Android with low RAM

Question

I am looking at this webpage that describes several optimizations that were made to Android, to run on low RAM devices:

http://source.android.com/devices/low-ram.html

One of them is trimmed system_server. Where can I find the specific changes that optimize the system_server (from this aspect) ? Is doing diff of each java file the only way ?

Answer 1

AFAIK diff of related java files with any particular module is the only way to know the specific changes. if there's any other possible way i would also be interested to know that..

And about "trimmed system_server"... there are few optimizations are made like:

1. Previously system server performing all work in a separate thread started by main process i.e. Zygote, but Now in Android 4.4 System Server is not making any separate thread, and performs it's all work in the same Main thread with the optimization through Looper support, so that it is easy to put large number of Loopers in the monitor efficiently. (see here: https://android.googlesource.com/platform/frameworks/base.git/+/efa92b2182ab581873aa8e75d596e2e363bd5e6d)

2. Previously system server was starting all system services by default, but now in Android 4.4 as an optimization, a set of on/off switches are introduced which are used to control startup of individual services.means if any System feature is disabled in configuration than respective System service is not started, for example if Bluetooth is disabled in System config, System server checks it like below :
   boolean disableBluetooth = SystemProperties.getBoolean("config.disable_bluetooth", false);
   and if disableBluetooth is false than BluetoothManagerService is not started and same logic is also applied for all other system feature and system services also.

(see here https://android.googlesource.com/platform/frameworks/base.git/+/e4d9a01bfc7451afff1ed399a5801c7aa2af2831)

So with these two optimizations, SystemServer is trimmed for optimizations.