Re: [PATCH v0.9.1 3/6] sched/umcg: implement UMCG syscalls

Thomas Gleixner
2021-11-26T21:16:29Z

On Fri, Nov 26 2021 at 18:09, Peter Zijlstra wrote:
> +
> + if (timo) {
> + hrtimer_init_sleeper_on_stack(&timeout, tsk->umcg_clock,
> + HRTIMER_MODE_ABS);
> + hrtimer_set_expires_range_ns(&timeout.timer, (s64)timo,
> + tsk->timer_slack_ns);
> + }
> +
> + for (;;) {
> + set_current_state(TASK_INTERRUPTIBLE);
> +
> + ret = -EINTR;
> + if (signal_pending(current))
> + break;
> +
> + /*
> + * Faults can block and scribble our wait state.
> + */
> + pagefault_disable();
> + if (get_user(state, &self->state)) {
> + pagefault_enable();
> +
> + ret = -EFAULT;
> + if (page) {
> + unpin_user_page(page);
> + page = NULL;
> + break;
> + }
> +
> + if (pin_user_pages_fast((unsigned long)self, 1, 0, &page) != 1) {
> + page = NULL;
> + break;
> + }
> +
> + continue;
> + }
> +
> + if (page) {
> + unpin_user_page(page);
> + page = NULL;
> + }
> + pagefault_enable();
> +
> + state &= UMCG_TASK_MASK;
> + if (state != UMCG_TASK_RUNNABLE) {
> + ret = 0;
> + if (state == UMCG_TASK_RUNNING)
> + break;
> +
> + ret = -EINVAL;
> + break;
> + }
> +
> + if (timo)
> + hrtimer_sleeper_start_expires(&timeout, HRTIMER_MODE_ABS);
> +
> + freezable_schedule();

You can replace the whole hrtimer foo with

if (!schedule_hrtimeout_range_clock(timo ? &timo : NULL,
tsk->timer_slack_ns,
HRTIMER_MODE_ABS,
tsk->umcg_clock)) {
ret = -ETIMEOUT;
break;
}

Thanks,

tglx