Re: [PATCH 1/3] i/o bandwidth controller documentation

["Carl Henrik Lunde" <chlunde@ping.uio.no>]

On Sat, Jun 7, 2008 at 00:27, Andrea Righi <righi.andrea@gmail.com> wrote:
[...]
> +3. Advantages of providing this feature
> +
> +* Allow QoS for block device I/O among different cgroups

I'm not sure if this can be called QoS, as it does not guarantee
anything but throttling?

> +* The bandwidth limitations are guaranteed both for synchronous and
> +  asynchronous operations, even the I/O passing through the page cache or
> +  buffers and not only direct I/O (see below for details)

The throttling does not seem to cover the I/O path for XFS?
I was unable to throttle processes reading from an XFS file system.

Also I think the name of the function cgroup_io_account is a bit too innocent?
It sounds like a inline function "{ io += bytes; }", not like
something which may sleep.

-- 
Carl Henrik