Re: [RFC][PATCH 4/5] hugetlb: fix cpuset-constrained pool resizing

[Christoph Lameter <clameter@sgi.com>]

On Mon, 6 Aug 2007, Nishanth Aravamudan wrote:

> I understand what you mean, that root should be able to do whatever it
> wants, but at the same time, if a root-owned process is running in a
> cpuset, it's constrained for a reason.

Yes but the constraint is for an application running under a regular 
user id not for the root user.
 
> More importantly, let's say your process (owned by root or not) is
> running in a restricted cpuset on  nodes 2 and 3 of a 4-node system and
> wants to use 100 hugepages. Using the global sysctl, presuming an equal
> distribution of free memory on all nodes, said process would need to
> allocate 200 hugepages on the system (50 on each node), to get 100
> hugepages on nodes 2 and 3. With this patch, it only needs to allocate
> 100 hugepages.

The app is not able to use the sysctl. The root user must be able to do 
whatever desired. Does not make sense to impose restrictions on sysctls.

> Become dependent on the *proccess* context, which is, to me, what would
> be expected. If a process is restricted in some way, I would expect it
> to be restricted in that way across the board.

Nope these values are global. Cpuset relative data belongs in /dev/cpuset.

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