[dm-devel] Re: [PATCH 21/25] io-controller: Per cgroup request descriptor support

[Vivek Goyal <vgoyal redhat com>]

On Wed, Jul 08, 2009 at 11:27:25AM +0800, Gui Jianfeng wrote:
> Vivek Goyal wrote:
> ...
> >  }
> > +#ifdef CONFIG_GROUP_IOSCHED
> > +static ssize_t queue_group_requests_show(struct request_queue *q, char *page)
> > +{
> > +	return queue_var_show(q->nr_group_requests, (page));
> > +}
> > +
> > +static ssize_t
> > +queue_group_requests_store(struct request_queue *q, const char *page,
> > +					size_t count)
> > +{
> > +	unsigned long nr;
> > +	int ret = queue_var_store(&nr, page, count);
> > +	if (nr < BLKDEV_MIN_RQ)
> > +		nr = BLKDEV_MIN_RQ;
> > +
> > +	spin_lock_irq(q->queue_lock);
> > +	q->nr_group_requests = nr;
> > +	spin_unlock_irq(q->queue_lock);
> > +	return ret;
> > +}
> > +#endif
> 
> Hi Vivek,
> 
> Do we need to update the congestion thresholds for allocated io groups?
> 

Good catch Gui. Thanks. I will test the patch and queue up for next posting.

Vivek

> Signed-off-by: Gui Jianfeng <guijianfeng cn fujitsu com>
> ---
>  block/blk-sysfs.c |   15 +++++++++++++++
>  1 files changed, 15 insertions(+), 0 deletions(-)
> 
> diff --git a/block/blk-sysfs.c b/block/blk-sysfs.c
> index 577ed42..92b9f25 100644
> --- a/block/blk-sysfs.c
> +++ b/block/blk-sysfs.c
> @@ -83,17 +83,32 @@ static ssize_t queue_group_requests_show(struct request_queue *q, char *page)
>  	return queue_var_show(q->nr_group_requests, (page));
>  }
>  
> +extern void elv_io_group_congestion_threshold(struct request_queue *q,
> +					      struct io_group *iog);
> +
>  static ssize_t
>  queue_group_requests_store(struct request_queue *q, const char *page,
>  					size_t count)
>  {
> +	struct hlist_node *n;
> +	struct io_group *iog;
> +	struct elv_fq_data *efqd;
>  	unsigned long nr;
>  	int ret = queue_var_store(&nr, page, count);
> +
>  	if (nr < BLKDEV_MIN_RQ)
>  		nr = BLKDEV_MIN_RQ;
>  
>  	spin_lock_irq(q->queue_lock);
> +
>  	q->nr_group_requests = nr;
> +
> +	efqd = &q->elevator->efqd;
> +
> +	hlist_for_each_entry(iog, n, &efqd->group_list, elv_data_node) {
> +		elv_io_group_congestion_threshold(q, iog);
> +	}
> +
>  	spin_unlock_irq(q->queue_lock);
>  	return ret;
>  }
> -- 
> 1.5.4.rc3