On Sun, 13 Jul 2003 17:22:00 -0700
Larry McVoy <lm@xxxxxxxxxxxx> wrote:
> Hey, maybe it isn't, but could you please quantify the cost of the VM
> operations? How hard is that?
So the page is in a non-uptodate state, NFS would have it locked,
and anyone else trying to get at it would sleep.
This page we have currently is "dummy" in that it is only a place
holder in case we don't get a full page from the networking.
We have all the infrastructure to do everything up to this point.
Next, if the networking gave us a full page, we'd "replace"
the dummy page with this one, which would involve:
1) delete the dummy page from the lookup, insert the networking's
2) arrange so that all sleepers on the dummy page will do a relookup
and find the new page
And when we're done with the operation we wake everyone up.
I can't see any part of this turning out to be expensive.