Re: [RFC] 2.3/4 VM queues idea

Stephen C. Tweedie
2000-05-26T14:38:21Z

Hi,

On Fri, May 26, 2000 at 04:31:29PM +0200, Jamie Lokier wrote:

> You didn't mention it, but that leaves mremap. This is a fiddly one!

Yes, we know this. :-)

> mremaps that simply expand or shrink a segment are fine by themselves.
> mremaps that move a segment are fine by themselves.

No, they are not fine. When you move a segment, you end up with pages
which have the same offset but are now at a different VA. What that
means is that you have no way of finding out, for a given physical page,
what the VA of all of the mappings of that page may be. That means that
you have no way to find all of the ptes short of scanning all the vmas
in order.

--Stephen