On Mon, Oct 22, 2007 at 05:49:39PM -0700, Paul Menage wrote:
> +static u64 cpu_usage_read(struct cgroup *cgrp, struct cftype *cft)
> +{
> + struct task_group *tg = cgroup_tg(cgrp);
> + int i;
> + u64 res = 0;
> + for_each_possible_cpu(i) {
> + unsigned long flags;
> + spin_lock_irqsave(&tg->cfs_rq[i]->rq->lock, flags);
Is the lock absolutely required here?
Hmm .. I hope the cgroup code prevents a task group from being destroyed while
we are still reading a task group's cpu usage. Is that so?
> + res += tg->se[i]->sum_exec_runtime;
> + spin_unlock_irqrestore(&tg->cfs_rq[i]->rq->lock, flags);
> + }
> + /* Convert from ns to ms */
> + do_div(res, 1000000);
> + return res;
> +}
--
Regards,
vatsa
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