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Subject: Re: [RFC][PATCH 4/7] UBC: syscalls (user interface)
From: Rohit Seth <rohitseth@google.com>
Reply-To: rohitseth@google.com
To: Kirill Korotaev <dev@sw.ru>
Cc: Andrew Morton <akpm@osdl.org>,
       Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
       Alan Cox <alan@lxorguk.ukuu.org.uk>, Ingo Molnar <mingo@elte.hu>,
       Christoph Hellwig <hch@infradead.org>,
       Pavel Emelianov <xemul@openvz.org>, Andrey Savochkin <saw@sw.ru>,
       devel@openvz.org, Rik van Riel <riel@redhat.com>, hugh@veritas.com,
       ckrm-tech@lists.sourceforge.net, Andi Kleen <ak@suse.de>
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Date: Thu, 17 Aug 2006 10:05:19 -0700
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On Thu, 2006-08-17 at 16:04 +0400, Kirill Korotaev wrote:
> >>Add the following system calls for UB management:
> >>  1. sys_getluid    - get current UB id
> >>  2. sys_setluid    - changes exec_ and fork_ UBs on current
> >>  3. sys_setublimit - set limits for resources consumtions
> >>
> > 
> > 
> > Why not have another system call for getting the current limits?
> will add sys_getublimit().
> 
> > But as I said in previous mail, configfs seems like a better choice for
> > user interface.  That way user has to go to one place to read/write
> > limits, see the current usage and other stats.
> Check another email about interfaces. I have arguments against it :/
> 

...and I'm still not convinced that syscall is the right approach.

> > I think there should be a check here for seeing if the new limits are
> > lower than the current usage of a resource.  If so then take appropriate
> > action.
> any idea what exact action to add here?
> Looks like can be added when needed, agree?
> 

When you have the support of user memory, then operations like flush the
extra pages belonging to the container to disk seems reasonable.

-rohit