Re: RFC [patch 13/34] PID Virtualization Define new task_pid api

[ebiederm@xmission.com (Eric W. Biederman)]

Kirill Korotaev <dev@sw.ru> writes:

> In fact this is almost what OpenVZ does for half a year, both containers and
> VPIDs.
> But it is very usefull to see process tree from host system. To be able to use
> std tools to manage containers from host (i.e. ps, kill, top, etc.). So it is
> much more convinient to have 2 pids. One globally unique, and one for container.

There are two issues here.
1) Monitoring.  (ps, top etc)
2) Control (kill).

For monitoring you might need to patch ps/top a little but it is doable without
2 pids.

For kill it is extremely rude to kill processes inside of a nested pid space.
There are other solutions to the problem.

It is undesireable to make it too easy to communicate through the barrier because
then applications may start to take advantage of it and then depend on
it and you will have lost the isolation that the container gives you.

Eric
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