Re: Populating multiple ptes at fault time

From: Avi Kivity
Date: Thu Sep 18 2008 - 20:23:41 EST


Jeremy Fitzhardinge wrote:

bet there's an appropriate pvop hook you could use to force
synchronization just before the kernel actually inspects the bits
(leaving lazy mode sounds good).
It would have to be a new lazy mode, not the existing one, I think.

The only direct use of pte_young() is in zap_pte_range, within a
mmu_lazy region. So syncing the A bit state on entering lazy mmu mode
would work fine there.


Ugh, leaving lazy pte.a mode when entering lazy mmu mode?


The call via page_referenced_one() doesn't seem to have a very
convenient hook though. Perhaps putting something in
page_check_address() would do the job.


Why there?

Why not explicitly in the callers? We need more than to exit lazy pte.a mode, we also need to enter it again later.

--
I have a truly marvellous patch that fixes the bug which this
signature is too narrow to contain.

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