Re: [RFC][PATCH] introduce task cgroup (#task restrictioon for prevent fork bomb by cgroup)

[KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>]

> > I create new cgroup of number task restriction.
> > Please any comments!
> 
> Would it make more sense to implement this as part of an rlimit subsystem,
> which also supports limiting e.g. address space, CPU time, number of open
> files, etc.? If we create one subsystem per resource, I'm afraid we're
> going to see quite some time spent in all those loops, and the options for
> cgroupfs is going to become pretty long if you want to exclude just one or
> two of the subsystems for one particular mount point.

Good quistion.
task cgroup often different scope against memory, cputime, etc..

example.
	(<> mean cgroup name)

   +-----------------------------------------------------+
   | <interactive>  |         <service>                  |
   |   #task = 1000 |            #task = 5000            |
   +----------------+------------------+-----------------+
                    |  <serviceA>      |  <serviceB>     |
                    |    vaddr = 100GB |    vaddr = 200B |
                    +------------------+-----------------+

tus, we have 2 choice.

1. separate 2 cgroup.
2. implement hierarchy.

I afraid to 2 cause perfomance degression.
tus, I choiced 1.