Exactly.
> In that case, why can't we just take the next mm from
> init_mm and just "roll over" our mm to the back of the
> list once we're done with it ?
No. That's how it used to be, that's what I changed it from.
fork and exec are well ordered in how they add to the mmlist,
and that ordering (children after parent) suited swapoff nicely,
to minimize duplication of a swapent while it's being unused;
except swap_out randomized the order by cycling init_mm around it.
I agree that mmput would look nicer without the reference to swap_mm.
If you want to make a change here, I'd suggest replacing swap_mm
pointer by full dummy marker swap_mm, then mmput wouldn't need to
worry about it at all.
I didn't do it that way because I couldn't see where to initialize
the swap_mm structure without touching each architecture separately;
and I also wondered if there might be some stats gathering utility
out there which would get confused by finding a non-mm in the mmlist.
Hugh
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