>>> I'm asking is -- "dear kernel, please don't advance this process even >>> if you otherwise can". All I need is a frozen state so that I can >> >> not so easy on a multiprocessor. (unless you turn all but one >> processor off.) > > Hm. May be its getting late, but I can't quite see why that would > be the case (or may be I didn't quite communicate the intent > in my plea to the kernel ;-)) > > The target process is *already* waiting for the IO stuck inside the > kernel. It is not on a runqueue, not it is considered to be places > there.
since procwrite doesn't acquire anything other than the debug lock, how do you know? the proc could start up again before you notice. you could start grabbing locks, stealing stuff off queues or adding if(up->procctl) statements here and there, but i have a strong feeling thair be dragons in that direction. the place to catch processes is on syscall entry and/or exit. stop messages are only checked on syscall entry. i have a feeling that you want something other than notes for your problem. cpu arranges that del works. - erik
