Re: [Lsf10-pc] Current MM topics for LSF10/MM Summit 8-9 August in Boston

Andrea Arcangeli
2010-06-21T14:45:20Z

On Mon, Jun 21, 2010 at 05:31:41PM +0300, Avi Kivity wrote:
> On 06/21/2010 05:29 PM, Andrea Arcangeli wrote:
> > On Mon, Jun 21, 2010 at 05:18:56PM +0300, Gleb Natapov wrote:
> >
> >> Avi did the fix. We discussed using MADV_DONTFORK for that, but calling
> >> madvise() from kernel deemed to be messy.
> >>
> > Agree that calling madvise looks messy. It's possible to set
> > VM_DONTCOPY under mmap_sem write mode and it'll work as well.
> >
>
> But we aren't guaranteed to get our own vma, yes?

Correct, one would need to call split_vma like madvise_behavior does
before setting the flag. For sure current fix is simpler ;).

> Note kvm shouldn't be calling do_mmap() in any case. I let that in
> because it was simple and because we had a userspace interface relying
> on that, but that's no longer the case, so I'll make that page kernel owned.

Agree ;).

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