On Tue, 2011-01-18 at 07:31 +1100, Benjamin Herrenschmidt wrote: > > Beware of false positive, I've used "fake" reschedule IPIs in the past > for other things (like kicking a CPU out of sleep state for unrelated > reasons). Nothing that I know that is upstream today but some of that > might come back. I'd like to avoid having to add an atomic to know if > it's a real reschedule, will the scheduler be smart enough to not bother > with false positives ? Yes it can deal with that, some will be for reschedules, some will be for ttwu tail ends and x86 too uses this ipi for a few random other things like kicking kvm out of guest context..