Re: [PATCH 2/9] Containers (V9): Example CPU accounting subsystem

[Balbir Singh <balbir@linux.vnet.ibm.com>]

menage@google.com wrote:
> +
> +/* Lazily update the load calculation if necessary. Called with ca locked */
> +static void cpuusage_update(struct cpuacct *ca)
> +{
> +	u64 now = get_jiffies_64();
> +	/* If we're not due for an update, return */
> +	if (ca->next_interval_check > now)
> +		return;
> +
> +	if (ca->next_interval_check <= (now - INTERVAL)) {

These two conditions seem a little confusing.

If ca->next_interval_check > (now - INTERVAL), the else part
is executed, but if ca->next_interval_check > (now - INTERVAL)
then ca->next_interval_check > now, which implies we return
and never enter the else part. It's been quite sometime since
I looked at this code, so I might have gotten it wrong.
I see a load of 0% on my powerpc box. I think it is because
last_interval_time is always 0, I'll debug further


-- 
	Warm Regards,
	Balbir Singh
	Linux Technology Center
	IBM, ISTL