Messages in this thread |  | | Subject | Re: proc fs and shared pids | Date | Tue, 30 Jul 1996 16:26:36 +0200 | From | Michiel Boland <> |
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>Kernelthreads? They dont shre the same pid. Userthreads are not visible to >the kernel at all and therefore there is no proc entry.
As I understand it, kernel threads are implemented in linux with clone(), and hence they *can* share the same PID. Whether this is a good idea is perhaps another matter.
Just did some experimenting with clone() and the CLONE_PID flag.
This creates a new process with the same process ID as the original process. The proc fs has two directory entries for this with the same i-number. (!) So I guess the status of one of the two processes can never be retrieved.
IMHO this is yet another severe shortcoming of /proc. It would perhaps be better to create a device which you can read and then returns the status of all processes. I just wrote a module that does exactly that. -- Michiel Boland <boland@sci.kun.nl> University of Nijmegen The Netherlands
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