On Wed, Jul 30, 2014 at 02:24:15AM -0400, Chen, Gong wrote:
> On Wed, Jul 23, 2014 at 10:36:28PM +0200, Borislav Petkov wrote:
> > /*
> > * At CPU state changes, update the x2apic cluster sibling info.
> > */
> > @@ -151,9 +166,14 @@ static int
> > update_clusterinfo(struct notifier_block *nfb, unsigned long action, void
> > *hcpu)
> > {
> > unsigned int this_cpu = (unsigned long)hcpu;
> > - unsigned int cpu;
> > int err = 0;
> >
> > + if (action & CPU_TASKS_FROZEN) {
> > + if ((action & ~CPU_TASKS_FROZEN) == CPU_UP_CANCELED)
> > + __update_clusterinfo(this_cpu);
> > + return NOTIFY_OK;
> > + }
> > +
> Hi, Boris
>
> Here you assume once the action contains FROZEN flag, it will return
> NOTIFY_OK.
Well, look at the original code. What do you think happens if another
_FROZEN action comes in which we don't handle in the switch-case?
Take a piece of paper and play it through slowly if you don't see it.
Hint: err = 0.
> It looks like not quite comply with original logic. Once
> new FROZEN logic is added, we have to update this code again. How
> about using following code snippet:
>
> + if ((action & CPU_TASKS_FROZEN) &&
> + ((action & ~CPU_TASKS_FROZEN) == CPU_UP_CANCELED)) {
> + __update_clusterinfo(this_cpu);
> + return NOTIFY_OK;
No, this is different now from the original logic.
--
Regards/Gruss,
Boris.
Sent from a fat crate under my desk. Formatting is fine.
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