Message-ID: <47D793AB.6070008@openvz.org>
Date: Wed, 12 Mar 2008 11:26:19 +0300
From: Pavel Emelyanov <xemul@openvz.org>
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To: Greg KH <greg@kroah.com>, serue@us.ibm.com
CC: Andrew Morton <akpm@linux-foundation.org>, linux-kernel@vger.kernel.org,
       menage@google.com, sukadev@us.ibm.com,
       Al Viro <viro@zeniv.linux.org.uk>
Subject: Re: [PATCH 5/9] Make use of permissions, returned by kobj_lookup
References: <47CED717.60406@openvz.org> <47CEDA64.1070506@openvz.org> <20080305171304.f686f6de.akpm@linux-foundation.org> <47D10939.6020806@openvz.org> <20080307013553.7ed35f91.akpm@linux-foundation.org> <47D11068.9010704@openvz.org> <20080307155921.GB28439@kroah.com> <47D16F9B.6050008@openvz.org> <20080307170104.GA24746@kroah.com> <47D657A3.5080801@openvz.org> <20080311173646.GA26931@kroah.com>
In-Reply-To: <20080311173646.GA26931@kroah.com>
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Greg KH wrote:
> On Tue, Mar 11, 2008 at 12:57:55PM +0300, Pavel Emelyanov wrote:
>> Besides, I've measured some things - the lat_syscall test for open from 
>> lmbench test suite and the nptl perf test. Here are the results:
>>
>>         sec     nosec
>> open    3.0980s  3.0709s
>> nptl    2.7746s  2.7710s
>>
>> So we have 0.88% loss in open and ~0.15% with nptl. I know, this is not that
>> much, but it is noticeable. Besides, this is only two tests, digging deeper
>> may reveal more.
> 
> I think that is in the noise of sampling if you run that test many more
> times.

These numbers are average values of 20 runs of each test. I didn't
provide the measurement accuracy, but the abs(open.sec - open.nosec)
is greater than it.

>> Let alone the fact that simply turning the CONFIG_SECURITY to 'y' puts +8Kb 
>> to the vmlinux...
>>
>> I think, I finally agree with you and Al Viro, that the kobj mapper is 
>> not the right place to put the filtering, but taking the above numbers 
>> into account, can we put the "hooks" into the #else /* CONFIG_SECURITY */
>> versions of security_inode_permission/security_file_permission/etc?
> 
> Ask the security module interface maintainers about this, not me :)

OK :) Thanks for your time, Greg.

So, Serge, since you already have a LSM-based version, maybe you can
change it with the proposed "fix" and send it to LSM maintainers for
review?

> good luck,
> 
> greg k-h
> 

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