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    SubjectRe: cache limit
    Denis Vlasenko <> wrote:
    > There was a discussion (and patches) in the middle of 2.5 series
    > about O_STREAMING open flag which mean "do not aggressively cache
    > this file". Targeted at MP3/video playing, copying large files and such.
    > I don't know whether it actually was merged. If it was,
    > your program can use it.

    It was not. Instead we have fadvise. So it would be appropriate to change
    applications such as rsync to optionally run

    posix_fadvise(fd, 0, -1, POSIX_FADV_DONTNEED)

    against file descriptors just before closing them, so all the pagecache
    gets thrown away. (Well, most of the pagecache - dirty pages won't get
    dropped - the app must fsync the files by hand first if it wants this)

    This would be a useful addition to rsync and such applications - it is
    stronger and more specific and safer than banging on the VM for a special

    But if you want to bang on the VM for a special case, run 2.6 and set
    /proc/sys/vm/swappiness to zero during the rsync run.

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      Last update: 2005-03-22 13:47    [W:0.020 / U:1.980 seconds]
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