Hi,
On 19/11/14 08:35, Wanpeng Li wrote:
> There is no need to dequeue/enqueue and push/pull if there are
> no scheduling parameters changed for dl class, actually both
> fair and rt class have already check if parameters changed for
> them to avoid unnecessary overhead. This patch add the parameters
> changed verify for dl class in order to reduce overhead.
>
> Signed-off-by: Wanpeng Li <[email protected]>
> ---
> kernel/sched/core.c | 17 ++++++++++++++++-
> 1 file changed, 16 insertions(+), 1 deletion(-)
>
> diff --git a/kernel/sched/core.c b/kernel/sched/core.c
> index 603c462..f361867 100644
> --- a/kernel/sched/core.c
> +++ b/kernel/sched/core.c
> @@ -3402,6 +3402,21 @@ static bool check_same_owner(struct task_struct *p)
> return match;
> }
>
> +static bool dl_param_changed(struct task_struct *p,
> + const struct sched_attr *attr)
Please check alignment.
> +{
> + struct sched_dl_entity *dl_se = &p->dl;
> +
> + if (dl_se->dl_runtime != attr->sched_runtime ||
> + dl_se->dl_deadline != attr->sched_deadline ||
> + dl_se->dl_period != attr->sched_period ||
> + dl_se->flags != attr->sched_flags ||
> + p->rt_priority != attr->sched_priority)
This last one is useless, as we fail above if
attr->sched_priority != 0 when task has !rt_policy.
Thanks,
- Juri
> + return true;
> +
> + return false;
> +}
> +
> static int __sched_setscheduler(struct task_struct *p,
> const struct sched_attr *attr,
> bool user)
> @@ -3530,7 +3545,7 @@ recheck:
> goto change;
> if (rt_policy(policy) && attr->sched_priority != p->rt_priority)
> goto change;
> - if (dl_policy(policy))
> + if (dl_policy(policy) && dl_param_changed(p, attr))
> goto change;
>
> p->sched_reset_on_fork = reset_on_fork;
>
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