Re: [RFC PATCH] Bio Throttling support for block IO controller

[Vivek Goyal <vgoyal@redhat.com>]

On Fri, Sep 03, 2010 at 05:50:55PM +0800, Gui Jianfeng wrote:
> Vivek Goyal wrote:
> > Hi,
> > 
> > Currently CFQ provides the weight based proportional division of bandwidth.
> > People also have been looking at extending block IO controller to provide
> > throttling/max bandwidth control.
> > 
> > I have started to write the support for throttling in block layer on 
> > request queue so that it can be used both for higher level logical
> > devices as well as leaf nodes. This patch is still work in progress but
> > I wanted to post it for early feedback.
> > 
> > Basically currently I have hooked into __make_request() function to 
> > check which cgroup bio belongs to and if it is exceeding the specified
> > BW rate. If no, thread can continue to dispatch bio as it is otherwise
> > bio is queued internally and dispatched later with the help of a worker
> 
> Hi Vivek,
> 
> I'd like to give it a try.
> In what manner the worker dispatch bios? FIFO? I have yet gone throught the patch.
> 

Hi Gui,

Yes, the dispatch of throttled bios is FIFO with-in group.

Thanks
Vivek