Re: [RFC 2.6.11-rc2-mm2 7/7] mm: manual page migration -- sys_page_migrate

[Paul Jackson <pj@sgi.com>]

Robin wrote:
> Then how do you handle overlapping nodes.  If I am doing a 5->4, 4->3,
> 3->2, 2->1 shift ...

Then do the shifts in the other order, first 2->1, then 3->2, ...

So now you ask, what if you are doing a rotation?  Use a temporary
node: 2->tmp, 3->2, ..., N->(N-1), tmp->N.

So now you ask, what if you are doing a rotation involving _all_
nodes, and have nothing you can use as a temporary node?

Argh I say ... would anyone really do that?  Or perhaps it makes
sense to have the system call take a virtual address range (and
hence a pid).  In which case, you can do one page at a time, if
need be, and get any foolhardy migration possible.

Or perhaps some integration with Andi's mbind/mempolicy make sense.
I'm not quite following Andi's comments on this, so I can't say
one way or the other if this is good.

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                  Paul Jackson <pj@sgi.com> 1.650.933.1373, 1.925.600.0401