[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] Re: [Xen-devel] Re: [PATCH] xen: always handle VIRQ_TIMER first.
>>> On 17.10.10 at 08:11, Jeremy Fitzhardinge <jeremy@xxxxxxxx> wrote: > I think (but I haven't spelunked into that code lately) that after a > tickless idle period it will update jiffies N ticks based on the > clocksource, and then run any other interrupt handler code, so jiffies > will always appear to be up to date. > > Ah, yes, here it is: > > /** > * tick_nohz_update_jiffies - update jiffies when idle was interrupted > * > * Called from interrupt entry when the CPU was idle > * > * In case the sched_tick was stopped on this CPU, we have to check if > jiffies > * must be updated. Otherwise an interrupt handler could use a stale jiffy > * value. We do this unconditionally on any cpu, as we don't know whether > the > * cpu, which has the update task assigned is in a long sleep. > */ > static void tick_nohz_update_jiffies(ktime_t now) > { > ... > } But this is available only with CONFIG_NO_HZ, which is a freely selectable option. So perhaps the code should still be added inside an #ifndef CONFIG_NO_HZ? Jan _______________________________________________ Xen-devel mailing list Xen-devel@xxxxxxxxxxxxxxxxxxx http://lists.xensource.com/xen-devel
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