[maemo-developers] Out Of Memory handling in Maemo

[From: Eero Tamminen]

Hi,

ext Karthik Murugesan wrote:
> Hello all,
>     I am trying to understand Out of Memory Handling in Maemo for my
> thesis. As per the my understanding (based on the documentation  and
> browsing through libosso code). some module raises the  Dbus signals
> com.nokia.ke_recv.lowmem_on/lowmem_off  which is dispatched via DBUS
> to some other module( WM or AS) which does the actual termination of
> the LRU application based on the hibernation mode.
> 
>    But I am not able to correlate on who raises the lowmem_on/off dbus
> signal and which function/module actually kills the application.
> 
>    Is "/proc/sys/vm/lowmem_notify_high" used to listen for low memory
> conditions? If yes, How (by polling?) and which module does it.

I think ke-recv and AFAIK it doesn't use polling.


>    Whats the purpose of "/proc/sys/vm/lowmem_deny_watermark"? Is it to
> prevent launching new applications?

It tells at which point kernel should start denying memory allocations
from processes.  Processes exempted from OOM-killing are exempted
also from this.


>    I will really thankful, if someone can provide me some pointers in
> the code/guidance regarding this.


	- Eero