Re: [PATCH 0/2 V2] ksm: take dirty bit as reference to avoidvolatile pages scanning

From: Chris Wright
Date: Tue Jun 21 2011 - 20:46:34 EST

* Nai Xia (nai.xia@xxxxxxxxx) wrote:
> Compared to the first version, this patch set addresses the problem of
> dirty bit updating of virtual machines, by adding two mmu_notifier interfaces.
> So it can now track the volatile working set inside KVM guest OS.
> V1 log:
> Currently, ksm uses page checksum to detect volatile pages. Izik Eidus
> suggested that we could use pte dirty bit to optimize. This patch series
> adds this new logic.
> Preliminary benchmarks show that the scan speed is improved by up to 16
> times on volatile transparent huge pages and up to 8 times on volatile
> regular pages.

Did you run this only in the host (which would not trigger the notifiers
to kvm), or also run your test program in a guest?

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