Re: [patch v12 06/13] procfs: add per-pid task isolation state

Thomas Gleixner
2022-04-25T23:27:40Z

On Tue, Mar 15 2022 at 12:31, Marcelo Tosatti wrote:
> Add /proc/pid/task_isolation file, to query the state of
> task isolation configuration.
>
> ---

Lacks a Signed-off-by...

> fs/proc/base.c | 68 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++

> +#ifdef CONFIG_TASK_ISOLATION
> +
> +struct qoptions {
> + unsigned long mask;
> + char *name;
> +};
> +
> +static struct qoptions iopts[] = {
> + {ISOL_F_QUIESCE, "quiesce"},
> +};
> +#define ILEN (sizeof(iopts) / sizeof(struct qoptions))

Reinventing ARRAY_SIZE() just because this isolation muck is special?

> +static struct qoptions qopts[] = {
> + {ISOL_F_QUIESCE_VMSTATS, "vmstat_sync"},
> +};
> +#define QLEN (sizeof(qopts) / sizeof(struct qoptions))

Ditto.

> +static void show_isolation_state(struct seq_file *m,
> + struct qoptions *iopt,
> + int mask,
> + const char *hdr)
> +{
> + int i;
> +
> + seq_printf(m, hdr);
> + for (i = 0; i < ILEN; i++) {
> + if (mask & iopt->mask)
> + seq_printf(m, "%s ", iopt->name);
> + iopt++;
> + }
> + if (mask == 0)
> + seq_printf(m, "none ");
> + seq_printf(m, "\n");
> +}
> +
> +int proc_pid_task_isolation(struct seq_file *m, struct pid_namespace *ns,
> + struct pid *pid, struct task_struct *t)

This is required to be global without a prototype because?

> +{
> + int active_mask, quiesce_mask, conf_mask;
> + struct task_isol_info *task_isol_info;
> + struct inode *inode = m->private;
> + struct task_struct *task = get_proc_task(inode);
> +
> + task_isol_info = t->task_isol_info;
> + if (!task_isol_info)
> + active_mask = quiesce_mask = conf_mask = 0;
> + else {
> + active_mask = task_isol_info->active_mask;
> + quiesce_mask = task_isol_info->quiesce_mask;
> + conf_mask = task_isol_info->conf_mask;
> + }
> +
> + show_isolation_state(m, iopts, conf_mask, "Configured state: ");
> + show_isolation_state(m, iopts, active_mask, "Active state: ");
> + show_isolation_state(m, qopts, quiesce_mask, "Quiescing: ");

And once you have 10 features with 10 subfeature masks supported, all of
this ends up in fs/proc/base.c just because all of this nonsense is
required to be disconnected from the actual task isolation code, right?

Just because a lot of crap has been dumped over time into that file does
not justify to mindlessly dump more crap into it.

Thanks,

tglx