On 16/2/07 10:54, "Andrew Morton" [off-list ref] wrote:

OK, you're screwed.  I agree that the process freezer is the way out of that
one.

Ingo said that he's clocked the freezer at a few milliseconds.  But if it's
any higher than that it'll need to get sped up once we convert cpu hotplug
to use it.

A few milliseconds is acceptable. Presumably that is under some stress
workload? What we'd really like is to be able to gang-hotplug CPUs to
amortise the freezer overhead.

This initial patchset does not include save/restore support anyway, so in
fact it would be consistent to have CONFIG_PREEMPT configurable. I'm sure
that we are going to have some nasty bugs to fix up as a result, but we
can't fix them until we find them! Then we can convert our save/restore code
to use the freezer before submitting it for inclusion.

 -- Keir