Re: [RFC] respect the referenced bit of KVM guest pages?

From: Avi Kivity
Date: Wed Aug 05 2009 - 11:20:56 EST


On 08/05/2009 06:15 PM, Rik van Riel wrote:
Avi Kivity wrote:

If so, we could unmap them when they get moved from the
active to the inactive list, and soft fault them back in
on access, emulating the referenced bit for EPT pages and
making page replacement on them work like it should.

It should be easy to implement via the mmu notifier callback: when the mm calls clear_flush_young(), mark it as young, and unmap it from the EPT pagetable.

You mean "mark it as old"?

I meant 'return young, and drop it from the EPT pagetable'.

If we use the present bit as a replacement for the accessed bit, present means young, and clear_flush_young means "if present, return young and unmap, otherwise return old'.

See kvm_age_rmapp() in arch/x86/kvm/mmu.c.

--
error compiling committee.c: too many arguments to function

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