On Fri, 6 Jul 2018, Paolo Bonzini wrote:
> On 06/07/2018 11:45, Thomas Gleixner wrote:
> >> One possibility is to introduce another layer of indirection: in
> >> addition to the percpu pvclock data, add a percpu pointer to the pvclock
> >> data and initialize it to point to a page-aligned variable in BSS. CPU0
> >> (used by vDSO) doesn't touch the pointer and keeps using the BSS
> >> variable, APs instead redirect the pointer to the percpu data.
> > Yeah, thought about that, but the extra indirection is ugly. Instead of
> > using per cpu data, I just can allocate the memory _after_ the allocators
> > are up and running and use a single page sized static __initdata for the
> > early boot.
>
> Either works for me. Assembly-wise, the indirection should be more or
> less the same as what we have now; even more efficient because it
> accesses a percpu pointer instead of computing it based on
> smp_processor_id().
Good point. Let me try that.
Thanks,
tglx
