Re: [ckrm-tech] [PATCH 0/2] resource control file system - aka containers on top of nsproxy!

[Srivatsa Vaddagiri <vatsa@in.ibm.com>]

On Sat, Mar 10, 2007 at 07:32:20AM +0530, Srivatsa Vaddagiri wrote:
> Ok, let me see if I can convey what I had in mind better:
> 
> 	    uts_ns pid_ns ipc_ns
> 		\    |    /
> 		---------------
> 	       | nsproxy  	|
> 	        ----------------
>                  /  |   \    \ <-- 'nsproxy' pointer
> 		T1  T2  T3 ...T1000
> 		|   |   |      | <-- 'containers' pointer (4/8 KB for 1000 task)
> 	       -------------------
> 	      | container_group	  |
> 	       ------------------	
> 		/
> 	     ----------
> 	    | container |
> 	     ----------
> 		|
> 	     ----------
> 	    | cpu_limit |
> 	     ---------- 

[snip]

> We save on 4/8 KB (for 1000 tasks) by avoiding the 'containers' pointer
> in each task_struct (just to get to the resource limit information).

Having the 'containers' pointer in each task-struct is great from a
non-container res mgmt perspective. It lets you dynamically decide what
is the fundamental unit of res mgmt. 

It could be {T1, T5} tasks/threads of a process, or {T1, T3, T8, T10} tasks of 
a session (for limiting login time per session), or {T1, T2 ..T10, T18, T27} 
tasks of a user etc.

But from a vserver/container pov, this level flexibility (at a -task- level) of 
deciding the unit of res mgmt is IMHO not needed. The
vserver/container/namespace (tsk->nsproxy->some_ns) to which a task 
belongs automatically defines that unit of res mgmt.


-- 
Regards,
vatsa