linux-kernel - Re: ima: use of radix tree cache indexing == massive waste of memory?

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Message-ID: <1287323960.1998.360.camel@laptop>
Date:	Sun, 17 Oct 2010 15:59:20 +0200
From:	Peter Zijlstra <peterz@...radead.org>
To:	Eric Paris <eparis@...isplace.org>
Cc:	eparis@...hat.com, Mimi Zohar <zohar@...ux.vnet.ibm.com>,
	Christoph Hellwig <hch@...radead.org>,
	Dave Chinner <david@...morbit.com>,
	linux-kernel@...r.kernel.org, Mimi Zohar <zohar@...ibm.com>,
	warthog9@...nel.org, hpa@...or.com, devel@...ts.fedoraprojet.org
Subject: Re: ima: use of radix tree cache indexing == massive waste of
 memory?

On Sun, 2010-10-17 at 09:12 -0400, Eric Paris wrote:
> We could split this into 2 structures, thus greatly shrinking the size
> of the structure needed for the default/disabled case,

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.

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

>  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.


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