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    SubjectRe: What is the limit size of tmpfs /dev/shm ?
    Hugh Dickins wrote:
    >
    > In theory, yes, and should be true in practice before it hits swap.
    > But I think you'll find our swap handling is too primitive for tmpfs
    > to perform well once we hit swap. Most filesystems pay considerable
    > attention to good performance within their constraints of correctness.
    > Whereas with tmpfs we've just never worried about the performance once
    > swapping. It's used so you don't lose your data, but if you're really
    > expecting to be going to disk very much, better start with a filesystem
    > really designed for that.
    >

    That sounds like a problem in our overall swap handling, not
    specifically in tmpfs. Now, I can't say anything concrete about heavy
    swap conditions, but in light swap conditions I have measured a 20x
    performance improvement(!) over ext3 on real workloads.

    -hpa


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