[lxc-devel] /proc/cpuinfo per cgroup

[Daniel P. Berrange]

On Mon, Nov 25, 2013 at 09:09:40AM -0600, Serge Hallyn wrote:
> Quoting Marian Marinov (mm at yuhu.biz):
> > Hi guys,
> > I'm using LXC containers for some of my teaching and I want to have /proc/cpuinfo and /proc/memory based on the cgroup 
> > limits that I have set.
> > 
> > The idea is that if one container is limited to a cpuset of 0-1 it should see only the first two cores and not all the 
> > cores on the machine.
> > 
> > The same thing is needed for the memory.
> > 
> > I simply want my students see the actual resources that they have.
> > 
> > Does any of you have any suggestions?
> > 
> > I'm planning to patch the kernel. As far as I can see it, I need to patch the following files:
> > ./tile/kernel/proc.c
> > ./sh/kernel/cpu/proc.c
> > ./x86/kernel/cpu/proc.c
> > ./mips/kernel/proc.c
> > 
> > Actually the c_start function.
> 
> Hi,
> 
> patching the kernel would be a good exercise.  Historically that hasn't
> been acceptable upstream - but then tastes and politics change pretty
> frequently, and what was nacked one year can be enthusiastically
> accepted two years later...
> 
> now the alternative is to use fuse to have userspace change what is
> shown in those files.  Daniel Lezcano years ago had one working.  The
> code for that is up at https://github.com/hallyn/procfs, however it
> won't work or even compile as is.  But if you can whip that into a
> working shape we could hopefully figure out how to ship it with lxc.

In libvirt we went the FUSE route for /proc/meminfo, given the
kernel guys resistance to changing kernel code for this use case.

Regards,
Daniel
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