Re: 10KB for the OS?
Flash is cheap in embedded devices, RAM is the expensive thing. Your microcontroller may have anything from 256 bytes to 256 kilobytes and anything beyond will need external RAM which makes is so expensive you can just as well add 16 Megabytes with no additional cost and run Linux
As far as I can tell, this page gives memory requirements for LiteOS
Google Translate does not seem to be up to the task of rendering the appropriate table into a reasonable English format, or French for that matter. Would someone who can read Chinese care to take a stab at this? I am also not sure from looking through the Googlized web page whether the network stack is part of the kernel. I hope not as something like that could bring us the IoT PoD (though that does have a nice ring to it).