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    SubjectRe: [00/41] Large Blocksize Support V7 (adds memmap support)
    On Thursday 13 September 2007 23:03, David Chinner wrote:
    > On Thu, Sep 13, 2007 at 03:23:21AM +1000, Nick Piggin wrote:

    > > Well, it may not be easy to _fix_, but it's easy to try a few
    > > improvements ;)
    > >
    > > How do I make an image and run a workload that will coerce XFS into
    > > doing a significant number of vmaps?
    > # mkfs.xfs -n size=16384 <dev>
    > to create a filesystem with a 16k directory block size on a 4k page
    > machine.
    > Then just do operations on directories with lots of files in them
    > (tens of thousands). Every directory operation will require at
    > least one vmap in this situation - e.g. a traversal will result in
    > lots and lots of blocks being read that will require vmap() for every
    > directory block read from disk and an unmap almost immediately
    > afterwards when the reference is dropped....

    Ah, wow, thanks: I can reproduce it.
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      Last update: 2007-09-13 19:45    [W:0.026 / U:4.180 seconds]
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