Re: [patch 1/2] x86_64 page fault NMI-safe

Linus Torvalds
2010-07-15T15:47:10Z

On Thu, Jul 15, 2010 at 7:51 AM, Linus Torvalds
<torvalds@linux-foundation.org> wrote:
>
> So it's not the lazy page table fill that is the problem. Never has
> been. We've been doing the lazy fill for a long time, and it was
> simple and useful way back when.

Btw, this is true to the degree that I would _much_ rather just get
rid of the crazy "vmalloc_sync_all()" crap entirely, and make it clear
that non-lazy vmalloc page table fill is a bug.

Because quite frankly, it _is_ a bug to depend on non-lazy vmalloc.
The whole function is only implemented on 32-bit x86, so any code that
thinks it needs it is either just wrong, or will only work on 32-bit
x86 anyway (and on other architectures by pure chance, likely because
their VM fill granularity is so big that they never saw the problem).

So getting rid of vmalloc_sync_all() entirely would be a good thing.
Then we wouldn't have that silly and pointless interface, and we
wouldn't have that crazy "this only does something on x86-32,
everywhere else it's a placebo".

Linus