[Serdev] SER-wide IPC/RPC, how?

[Maxim Sobolev]

Folks,

We are currently investigating possibility to enhance database support 
in usrloc module to make it more robust. The idea is that when the 
database goes down for some reason, ser should be able to detect it and 
switch automatically to memory-only mode. When in this mode it should 
from time to time try to re-connect to the db. Once the connection is 
restored it syncs in-memory contacts table with that in the db and 
switches back to the previous mode.

Unfortunately current architecture makes almost impossible to do it 
correctly since both timer thread and listening threads perform database 
operations. My plan is to restructure the code somehow, so that only 
timer thread is allowed to perform db operations, which would require 
some way in which listening threads can "wake up" timer thread and ask 
it to insert or update specific contact. This brings up question in the 
subject: is there any existing way for the listening thread to perform 
remote procedure call or queue task for the timer thread and wake it up? 
I guess that it can be done using shared memory and semaphores, just 
wonder if there any existing APIs that can be re-used or similar code, 
so that I will not be re-inventing the wheel.

Any ideas or suggestions are highly appreciated.

Regards,

Maxim