Re: [PATCH] Expose the statistics in blkio.time and blkio.sectors for the root cgroup

[Vivek Goyal <vgoyal@redhat.com>]

On Wed, Mar 24, 2010 at 04:35:56PM -0700, Ricky Benitez wrote:
> Currently, the io statistics for the root cgroup are maintained, but
> they are not shown because the device information is not available at
> the point that the root blkio cgroup is created. This patch updates
> the device information when the statistics are updated so that the
> statistics become visible.
> 

Ok, root group is created when request queue is being initialized and
device information like major/minor number is not available. This is
not the cleanest solution but can't think of something better right now.

Acked-by: Vivek Goyal <vgoyal@redhat.com>

Thanks
Vivek

> Signed-off-by: Ricky Benitez <rickyb@google.com>
> ---
>  block/cfq-iosched.c |    5 +++++
>  1 files changed, 5 insertions(+), 0 deletions(-)
> 
> diff --git a/block/cfq-iosched.c b/block/cfq-iosched.c
> index dee9d93..4a3579a 100644
> --- a/block/cfq-iosched.c
> +++ b/block/cfq-iosched.c
> @@ -947,6 +947,11 @@ cfq_find_alloc_cfqg(struct cfq_data *cfqd, struct cgroup *cgroup, int create)
>  	unsigned int major, minor;
>  
>  	cfqg = cfqg_of_blkg(blkiocg_lookup_group(blkcg, key));
> +	if (cfqg && !cfqg->blkg.dev && bdi->dev && dev_name(bdi->dev)) {
> +		sscanf(dev_name(bdi->dev), "%u:%u", &major, &minor);
> +		cfqg->blkg.dev = MKDEV(major, minor);
> +		goto done;
> +	}
>  	if (cfqg || !create)
>  		goto done;
>  
> -- 
> 1.7.0.1