From: Casey Schaufler <casey@schaufler-ca.com>
To: Ingo Molnar <mingo@elte.hu>
Cc: Eric Paris <eparis@redhat.com>,
Linus Torvalds <torvalds@linux-foundation.org>,
Al Viro <viro@zeniv.linux.org.uk>,
linux-kernel@vger.kernel.org,
linux-security-module@vger.kernel.org,
linux-fsdevel@vger.kernel.org, hch@infradead.org,
zohar@us.ibm.com, warthog9@kernel.org, david@fromorbit.com,
jmorris@namei.org, kyle@mcmartin.ca, hpa@zytor.com,
akpm@linux-foundation.org
Subject: Re: [PATCH 1/3] IMA: move read/write counters into struct inode
Date: Thu, 21 Oct 2010 09:15:29 -0700 [thread overview]
Message-ID: <4CC06721.8020308@schaufler-ca.com> (raw)
In-Reply-To: <20101020151555.GC22271@elte.hu>
On 10/20/2010 8:15 AM, Ingo Molnar wrote:
> * Eric Paris <eparis@redhat.com> wrote:
>
>> On Wed, 2010-10-20 at 16:38 +0200, Ingo Molnar wrote:
>>> * Eric Paris <eparis@redhat.com> wrote:
>>>
>>>> Executive summary of the day's work:
>>>> Yesterday morning: 944 bytes per inode in core
>>>> Yesterday night: 24 bytes per inode in core
>>>> Tonight: 4 bytes per inode in core.
>>>>
>>>> That's a x236 time reduction in memory usage. No I didn't even start looking
>>>> at a freezer. Which could bring that 4 down to 0, but would add a scalability
>>>> penalty on all inodes when IMA was enabled.
>>> Why not use inode->i_security intelligently? That already exists so that way
>>> it's 0 bytes.
>>>
>>> Thanks,
>> It still wouldn't be 0 bytes since there would be a 1-1 mapping from inode to
>> i_security structs. [...]
> Only for IMA-affected files, right?
>
> My point is to keep it 0 overhead for the _non IMA common case_.
>
>> The real reason I don't pursue this route is because of the litany of different
>> ways this pointer is used in different LSMs (or not used at all.) And we all know
>> that LSM authors aren't known for seeing the world the same way as each other. As
>> a maintainer of one of those LSMs even I'm scared to try pushing that forward....
> Ugh. That's a perfect reason to do it exactly like i suggested.
If you would like to make a proposal on LSM stacking other than
the traditional "rip the LSM out" I am sure that everyone in the
IMA, SELinux, TOMOYO, AppArmor and Smack communities would be
happy to have a look. Short of having a viable mechanism for
multiple LSMs to coexist IMA needs its separate space. Yes, people
do use both IMA and LSMs on the same machine at the same time.
> Thanks,
>
> Ingo
> --
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>
next prev parent reply other threads:[~2010-10-21 16:22 UTC|newest]
Thread overview: 31+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-10-19 1:16 [PATCH 1/3] IMA: move read/write counters into struct inode Eric Paris
2010-10-19 1:16 ` [PATCH 2/3] IMA: only allocate iint when needed Eric Paris
2010-10-19 1:17 ` [PATCH 3/3] IMA: use rbtree instead of radix tree for inode information cache Eric Paris
2010-10-19 1:30 ` [PATCH 1/3] IMA: move read/write counters into struct inode Christoph Hellwig
2010-10-19 2:14 ` Eric Paris
2010-10-19 7:39 ` Dave Chinner
2010-10-19 16:24 ` Eric Paris
2010-10-19 16:29 ` Christoph Hellwig
2010-10-19 8:39 ` Ingo Molnar
2010-10-19 2:46 ` Eric Paris
2010-10-19 15:52 ` Linus Torvalds
2010-10-19 16:36 ` Eric Paris
2010-10-19 16:55 ` Al Viro
2010-10-19 17:03 ` Linus Torvalds
2010-10-19 17:03 ` Linus Torvalds
2010-10-19 17:28 ` Al Viro
2010-10-19 18:16 ` Mimi Zohar
2010-10-20 13:10 ` John Stoffel
2010-10-20 13:36 ` Al Viro
2010-10-20 14:09 ` John Stoffel
2010-10-19 19:11 ` Matthew Wilcox
2010-10-20 3:15 ` Al Viro
2010-10-20 17:38 ` J. Bruce Fields
2010-10-19 22:49 ` Eric Paris
2010-10-20 14:38 ` Ingo Molnar
2010-10-20 14:46 ` Eric Paris
2010-10-20 15:15 ` Ingo Molnar
2010-10-20 15:25 ` Eric Paris
2010-10-21 16:15 ` Casey Schaufler [this message]
2010-10-22 8:48 ` Ingo Molnar
2010-10-22 17:50 ` Casey Schaufler
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