Hello,
On Mon, Jun 13, 2016 at 10:44:09PM +0300, Topi Miettinen wrote:
> Track maximum pids in the cgroup, present it in cgroup pids.current_max.
"max" is often used for maximum limits in cgroup. I think "watermark"
or "high_watermark" would be a lot clearer.
> @@ -236,6 +246,14 @@ static void pids_free(struct task_struct *task)
> pids_uncharge(pids, 1);
> }
>
> +static void pids_fork(struct task_struct *task)
> +{
> + struct pids_cgroup *pids = css_pids(task_css(task, pids_cgrp_id));
> +
> + if (atomic64_read(&pids->cur_max) < atomic64_read(&pids->counter))
> + atomic64_set(&pids->cur_max, atomic64_read(&pids->counter));
> +}
Wouldn't it make more sense to track high watermark from the charge
functions instead? I don't get why this requires a separate fork
callback. Also, racing atomic64_set's are racy. The counter can end
up with a lower number than it should be.
> @@ -300,6 +326,11 @@ static struct cftype pids_files[] = {
> .read_s64 = pids_current_read,
> .flags = CFTYPE_NOT_ON_ROOT,
> },
> + {
> + .name = "current_max",
Please make this "high_watermark" field in pids.stats file.
Thanks.
--
tejun
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