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

Avi Kivity
2010-06-21T14:31:41Z

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?

> But surely we can as well keep this quicker fix until the fork vs gup
> race is fixed, and back it out later.
>

Right.

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.

--
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