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    SubjectRe: Frontswap [PATCH 0/4] (was Transcendent Memory): overview
    On 04/30/2010 04:45 AM, Dave Hansen wrote:
    > A large portion of CMM2's gain came from the fact that you could take
    > memory away from guests without _them_ doing any work. If the system is
    > experiencing a load spike, you increase load even more by making the
    > guests swap. If you can just take some of their memory away, you can
    > smooth that spike out. CMM2 and frontswap do that. The guests
    > explicitly give up page contents that the hypervisor does not have to
    > first consult with the guest before discarding.

    Frontswap does not do this. Once a page has been frontswapped, the host
    is committed to retaining it until the guest releases it. It's really
    not very different from a synchronous swap device.

    I think cleancache allows the hypervisor to drop pages without the
    guest's immediate knowledge, but I'm not sure.

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

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      Last update: 2010-04-30 20:41    [W:0.025 / U:0.032 seconds]
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