Re: cpusets vs. mempolicy and how to get interleaving

[Paul Jackson <pj@sgi.com>]

Ethan wrote:
> 	And what happens when the weight then goes back up? e.g. at first the 
> mems_allowed specifies nodes 0 and 1, and the user sets a 
> MPOL_INTERLEAVE policy across nodes 0 and 1. At some point the "cpuset 
> manager" shrinks the number of nodes to just node 0, then later it adds 
> back node 1. What nodes are in my MPOL_INTERLEAVE policy?
> 
> 	As I read the code, I'll only have one node in the mempolicy. If that's 
> true, this doesn't do what I want.

I read the code the same way.

Sounds to me like you want a new and different MPOL_* mempolicy, that
interleaves over whatever nodes are available (allowed) to the task.

The existing MPOL_INTERLEAVE mempolicy interleaves over some specified
nodemask, so we do the best we can to remap that set when it changes.

You want a mempolicy that interleaves over all available nodes, not over
some specified subset of them.

-- 
                  I won't rest till it's the best ...
                  Programmer, Linux Scalability
                  Paul Jackson <pj@sgi.com> 1.925.600.0401

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