On Thu, 16 Nov 2006, Thomas Gleixner wrote: > On Thu, 2006-11-16 at 16:26 -0500, Alan Stern wrote: > > On Thu, 16 Nov 2006, Thomas Gleixner wrote: > > > > > There is another issue with this SRCU change: > > > > > > The notification comes actually after the real change, which is bad. We > > > try to make the TSC usable by backing it with pm_timer accross such > > > states, but this behaviour breaks the safety code. > > > > I don't understand. Sending notifications is completely separate from > > setting up the notifier chain's head. The patch you mentioned didn't > > touch the code that sends the notifications. > > Yeah, my bad. It just uses rcu based locking, but its still synchronous. > > I have to dig deeper, why the change of the frequency happens _before_ > the notifier arrives.
There are supposed to be _two_ notifier calls: one before the frequency change and one after. Check the callers of cpufreq_notify_transition(). Alan Stern - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
