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    SubjectRe: [PATCH 0/7] Kill PF_MEMALLOC abuse
    > On Tue, 2009-11-17 at 17:33 +0900, KOSAKI Motohiro wrote:
    > >
    > > if there is so such reason. we might need to implement another MM trick.
    > > but keeping this strage usage is not a option. All memory freeing activity
    > > (e.g. page out, task killing) need some memory. we need to protect its
    > > emergency memory. otherwise linux reliability decrease dramatically when
    > > the system face to memory stress.
    > In general PF_MEMALLOC is a particularly bad idea, even for the VM when
    > not coupled with limiting the consumption. That is one should make an
    > upper-bound estimation of the memory needed for a writeout-path per
    > page, and reserve a small multiple thereof, and limit the number of
    > pages written out so as to never exceed this estimate.
    > If the current mempool interface isn't sufficient (not hard to imagine),
    > look at the swap over NFS patch-set, that includes a much more able
    > reservation scheme, and accounting framework.

    Yes, I agree.

    In this discussion, some people explained why their subsystem need
    emergency memory, but nobody claim sharing memory pool against VM and
    surely want to stop reclaim (PF_MEMALLOC's big side effect).

    OK. I try to review your patch carefully and remake this patch series on top
    your reservation framework in swap-over-nfs patch series.

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      Last update: 2009-11-18 06:59    [W:2.247 / U:0.304 seconds]
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