Messages in this thread | | | Date | Sun, 17 Oct 2010 14:52:03 -0400 | From | Christoph Hellwig <> | Subject | Re: ima: use of radix tree cache indexing == massive waste of memory? |
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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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