Re: [PATCH 2.5.66-mm2] Fix page_convert_anon locking issues

Andrew Morton (akpm@digeo.com)
Thu, 3 Apr 2003 12:06:11 -0800


Dave McCracken <dmccr@us.ibm.com> wrote:
>
>
> --On Wednesday, April 02, 2003 17:58:08 -0600 Dave McCracken
> <dmccr@us.ibm.com> wrote:
>
> > It's looking more and more like we should use your other suggestion. It's
> > definitely simpler if we can make it failsafe. I'll code it up tomorrow.
>
> I thought of a big hole in the simpler scheme you suggested. It occurred
> to me that try_to_unmap will fail. It will see the PageAnon flag so it'll
> just walk the pte_chain and assume it doesn't have to walk the vmas. This
> will leave the page with some stranded mappings. Actually
> page_convert_anon will then finish, and we'll have a page where
> try_to_unmap claims it has succeeded but still has mappings.
>

page_referenced() has the same problem, so refill_inactive_zone() will need
to lock pages too.

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