Hi! > This patch allows "hotplugging" of CPUs on G5 machines. CPUs that are > disabled are put into an idle loop with interrupts hard-disabled, to wake > them up again we kick them just like when bringing them up. > > Maybe there's some way to actually turn off those CPUs even more? > > Cc: Benjamin Herrenschmidt <benh at kernel.crashing.org> > --- mb-wireless.orig/arch/powerpc/kernel/smp.c 2007-02-05 16:07:09.274524763 +0100 > +++ mb-wireless/arch/powerpc/kernel/smp.c 2007-02-05 18:15:51.114524763 +0100 > @@ -558,6 +558,11 @@ int __devinit start_secondary(void *unus > > local_irq_enable(); > > + /* it seems to be possible that we died from within > + * an interrupt ... reset the in-irq counts */ > + task_thread_info(paca[cpu].__current)->preempt_count &= > + ~(SOFTIRQ_MASK|HARDIRQ_MASK); > + > cpu_idle(); > return 0; This is quite a nasty hack. Are you sure? I've seen similar weirdness on pc, and it was caused by swsusp-copying-code using FPU and incrementing preempt_count... Pavel -- (english) http://www.livejournal.com/~pavelmachek (cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html
