Re: [PATCH 15/20] io-controller: map async requests to appropriate cgroup

Vivek Goyal
2009-06-22T15:40:29Z

On Mon, Jun 22, 2009 at 09:45:41AM +0800, Gui Jianfeng wrote:
> Vivek Goyal wrote:
> > o So far we were assuming that a bio/rq belongs to the task who is submitting
> > it. It did not hold good in case of async writes. This patch makes use of
> > blkio_cgroup pataches to attribute the aysnc writes to right group instead
> > of task submitting the bio.
> >
> > o For sync requests, we continue to assume that io belongs to the task
> > submitting it. Only in case of async requests, we make use of io tracking
> > patches to track the owner cgroup.
> >
> > o So far cfq always caches the async queue pointer. With async requests now
> > not necessarily being tied to submitting task io context, caching the
> > pointer will not help for async queues. This patch introduces a new config
> > option CONFIG_TRACK_ASYNC_CONTEXT. If this option is not set, cfq retains
> > old behavior where async queue pointer is cached in task context. If it
> > is not set, async queue pointer is not cached and we take help of bio
>
> Here "If it is not set" should be "If it is set".

Yes, in last line it should be "If it is set". Thanks Gui. Will fix the
comment.

Vivek