Re: [PATCH V4 1/6] Sched: Scheduler time slice extension

[Mathieu Desnoyers <mathieu.desnoyers@efficios.com>]

On 2025-05-13 17:45, Prakash Sangappa wrote:
[...]
> diff --git a/kernel/rseq.c b/kernel/rseq.c
> index b7a1ec327e81..dba44ca9f624 100644
> --- a/kernel/rseq.c
> +++ b/kernel/rseq.c
> @@ -448,6 +448,62 @@ void __rseq_handle_notify_resume(struct ksignal *ksig, struct pt_regs *regs)
>   	force_sigsegv(sig);
>   }
>   
> +bool rseq_delay_resched(void)
> +{
> +	struct task_struct *t = current;
> +	u32 flags;
> +
> +	if (!IS_ENABLED(CONFIG_SCHED_HRTICK))
> +		return false;
> +
> +	if (!t->rseq)
> +		return false;
> +
> +	if (t->sched_time_delay)
> +		return false;
> +
> +	if (copy_from_user_nofault(&flags, &t->rseq->flags, sizeof(flags)))
> +		return false;

This considers rseq->flags, but not rseq->rseq_cs->flags. Am I missing
something ?

Thanks,

Mathieu

> +
> +	if (!(flags & RSEQ_CS_FLAG_DELAY_RESCHED))
> +		return false;
> +
> +	flags &= ~RSEQ_CS_FLAG_DELAY_RESCHED;
> +	if (copy_to_user_nofault(&t->rseq->flags, &flags, sizeof(flags)))
> +		return false;
> +
> +	t->sched_time_delay = 1;
> +
> +	return true;
> +}
> +


-- 
Mathieu Desnoyers
EfficiOS Inc.
https://www.efficios.com