Re: [PATCH] cgroups: Do not show inactive devices in cgroups statistics

[Tejun Heo <tj-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>]

(cc'ing Vivek and Jens)

On Wed, Jun 26, 2013 at 12:26:10PM -0700, Anatol Pomozov wrote:
> @@ -548,6 +548,9 @@ u64 __blkg_prfill_u64(struct seq_file *sf, struct blkg_policy_data *pd, u64 v)
>  	if (!dname)
>  		return 0;
>  
> +	if (!v)
> +		return 0;
> +

I don't think it'd be a good idea to filter out 0 by default from
__blkg_prfill_u64().  It'd probably be a better idea to do the
filtering from the users of __blkg_prfill_u64().  Would that be a lot
more churn?

> @@ -571,19 +574,23 @@ u64 __blkg_prfill_rwstat(struct seq_file *sf, struct blkg_policy_data *pd,
>  		[BLKG_RWSTAT_ASYNC]	= "Async",
>  	};
>  	const char *dname = blkg_dev_name(pd->blkg);
> -	u64 v;
> +	u64 total;
>  	int i;
>  
>  	if (!dname)
>  		return 0;
>  
> +	total = rwstat->cnt[BLKG_RWSTAT_READ] + rwstat->cnt[BLKG_RWSTAT_WRITE];
> +	/* skip devices with no activity */
> +	if (!total)
> +		return 0;
> +

Doing it from rwstat is fine as it's always printing "stats" and
suppressing 0 stats by default should be fine, I think.  Can you
please update the function comment accordingly tho?

Vivek, any objections?

Thanks.

-- 
tejun