Re: [RFC 2/2] x86_64, mm: Reinsert the absent memory

From: Ingo Molnar
Date: Tue Jun 25 2013 - 03:31:34 EST



* H. Peter Anvin <hpa@xxxxxxxxx> wrote:

> On 06/24/2013 12:39 PM, Ingo Molnar wrote:
> >
> > That might be a bit too granular: if we hit such an uninitialized block of
> > memory we'd have to process 262,144 pages - potentially from an IRQ
> > handler that does GFP_ATOMIC... or other latency critical code.
> >
> > With 2MB we'd have to on-demand initialize 512 pages, which shouldn't show
> > up during normal use.
> >
>
> No... you split the gigabyte page into 511 2M pages and 512 4K pages.

Oh, double deferred initialization. That should solve the 32 exabyte
problem as well I guess ;-)

Thanks,

Ingo
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