linux-kernel - Re: [PATCH 2/3] i/o bandwidth controller infrastructure

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [day] [month] [year] [list]

Message-ID: <4869058E.7060605@gmail.com>
Date:	Mon, 30 Jun 2008 18:10:54 +0200
From:	Andrea Righi <righi.andrea@...il.com>
To:	Andrew Morton <akpm@...ux-foundation.org>
CC:	balbir@...ux.vnet.ibm.com, menage@...gle.com, chlunde@...g.uio.no,
	axboe@...nel.dk, matt@...ehost.com, roberto@...it.it,
	randy.dunlap@...cle.com, dpshah@...gle.com,
	containers@...ts.linux-foundation.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH 2/3] i/o bandwidth controller infrastructure

Andrea Righi wrote:
> Andrew Morton wrote:
>> On Fri, 27 Jun 2008 00:36:46 +0200
>> Andrea Righi <righi.andrea@...il.com> wrote:
>>
>>>> Does all this code treat /dev/sda1 as a separate device from /dev/sda2?
>>>>  If so, that would be broken.
>>> Yes, all the partitions are treated as separate devices with
>>> (potentially) different limiting rules, but I don't understand why it
>>> would be broken... dev_t has both minor and major numbers, so it would
>>> be possible to select single partitions as well.
>> Well it's functionally broken, isn't it?  A physical disk has a fixed
>> IO bandwidth and when the administrator wants to partition that
>> bandwidth amongst control groups he will need to consider the entire
>> device when doing so?
>>
>> I mean, the whole point of this feature and of control groups as a
>> whole is isolation.  But /dev/sda1 and /dev/sda2 are very much _not_
>> isolated.  Whereas /dev/sda and /dev/sdb are (to a large degree)
>> isolated.
> 
> well... yes, sounds reasonable. In this case we could just ignore the
> minor number and consider only major number as the key to identify a
> specific block device (both for userspace<->kernel interface and when
> accounting/throttling i/o requests).

oops.. no, this is obviously wrong. So, I dunno if it would be better to
add complexity in cgroup_io_throttle() to identify the disk a partition
belongs or to just use the struct block_device as key, instead of dev_t,
as you intially suggested. I'll investigate.

-Andrea
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/