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[Xen-devel] Re: [PATCH v3] [linux-3.0+ for xen] tmem: self-ballooning an

To: Dan Magenheimer <dan.magenheimer@xxxxxxxxxx>
Subject: [Xen-devel] Re: [PATCH v3] [linux-3.0+ for xen] tmem: self-ballooning and frontswap-selfshrinking
From: Konrad Rzeszutek Wilk <konrad.wilk@xxxxxxxxxx>
Date: Thu, 30 Jun 2011 17:50:10 -0400
Cc: Daniel Kiper <dkiper@xxxxxxxxxxxx>, jeremy@xxxxxxxx, xen-devel@xxxxxxxxxxxxxxxxxxx, Ian Campbell <Ian.Campbell@xxxxxxxxxx>, JBeulich@xxxxxxxxxx
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> ("tmem") functionality that complement cleancache and frontswap.  Both
> use control theory to dynamically adjust and optimize memory utilization.
> Selfballooning controls the in-kernel Xen balloon driver, targeting a goal
> value (vm_committed_as), thus pushing less frequently used clean
> page cache pages (through the cleancache code) into Xen tmem where
> Xen can balance needs across all VMs residing on the physical machine.

Can this be used by KVM or HyperV code? Can it be made generic? If so, why not?
If only Xen can use this, what would it entail for other balloon drivers
to use this? Or is it that they really don't need to b/c none of them
use the clean cache code?

> Frontswap-selfshrinking controls the number of pages in frontswap,
> driving it towards zero (effectively doing a partial swapoff) when
> in-kernel memory pressure subsides, freeing up RAM for other VMs.

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