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    SubjectRe: ima: use of radix tree cache indexing == massive waste of memory?
    On Sun, Oct 17, 2010 at 03:59:20PM +0200, Peter Zijlstra wrote:
    > Well, it does suck it needs to bloat data and code when its effectively
    > disabled. Isn't there a way to gather this data before we enable it, eg.
    > scan the files list on enable or somesuch?
    >
    > I mean, if you mandate an external storage you might as well extend
    > struct inode, that's cheaper in each respect.

    That's in fact what it did initially. While IBM claimed it would never
    be enabled in distros and this would be fine I feared this would not be
    true and told them to not make it have overhead if compiled in but not
    used.

    Turns out I wa right in my fear that IBM pressured distros to enable
    it anyway. And turns out that I should have verified they didn't
    actually mess it up instead of expecting people to get such trivial
    things right.

    > Me, I'm henceforth making sure to have CONFIG_IMA disabled...

    Yeah.

    > > but it doesn't
    > > help the fact that the suggested structure for storage (the radix
    > > tree) is apparently quite inefficient. I'd love to hear other
    > > suggestions for a better structure....
    >
    > radix tree is efficient for dense sets, not sparse sets.

    Which actually works just fine for inodes on many filesystems if you
    use the right key.


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