Re: [patch 2/6] mmu_notifier: Callbacks to invalidate address ranges

Christoph Lameter
2008-02-29T01:08:59Z

On Fri, 29 Feb 2008, Andrea Arcangeli wrote:

> On Thu, Feb 28, 2008 at 10:43:54AM -0800, Christoph Lameter wrote:
> > What about invalidate_page()?
>
> That would just spin waiting an ack (just like the smp-tlb-flushing
> invalidates in numa already does).

And thus the device driver may stop receiving data on a UP system? It will
never get the ack.

> Thinking more about this, we could also parallelize it with an
> invalidate_page_before/end. If it takes 1usec to flush remotely,
> scheduling would be overkill, but spending 1usec in a while loop isn't
> nice if we can parallelize that 1usec with the ipi-tlb-flush. Not sure
> if it makes sense... it certainly would be quick to add it (especially
> thanks to _notify ;).

invalidate_page_before/end could be realized as an
invalidate_range_begin/end on a page sized range?