Re: [PATCH] sched: don't call task_group() many times in set_task_rq()

Paul Turner
2011-11-11T21:26:12Z

On 11/11/2011 06:04 AM, Andrew Vagin wrote:
> It improves perfomance, especially if autogroup enabled.
>
> The size of set_task_rq() was 0x180 and now it is 0xa0.

A slightly more verbose commit message would be helpful here.

>
> Signed-off-by: Andrew Vagin<avagin@openvz.org>

Signed-off-by: Paul Turner <pjt@google.com>

> ---
> kernel/sched.c | 12 ++++++++----
> 1 files changed, 8 insertions(+), 4 deletions(-)
>
> diff --git a/kernel/sched.c b/kernel/sched.c
> index d87c6e5..a740eec 100644
> --- a/kernel/sched.c
> +++ b/kernel/sched.c
> @@ -766,14 +766,18 @@ static inline struct task_group *task_group(struct task_struct *p)
> /* Change a task's cfs_rq and parent entity if it moves across CPUs/groups */
> static inline void set_task_rq(struct task_struct *p, unsigned int cpu)
> {
> +#if defined(CONFIG_FAIR_GROUP_SCHED) || defined(CONFIG_RT_GROUP_SCHED)
> + struct task_group *tg = task_group(p);
> +#endif
> +
> #ifdef CONFIG_FAIR_GROUP_SCHED
> - p->se.cfs_rq = task_group(p)->cfs_rq[cpu];
> - p->se.parent = task_group(p)->se[cpu];
> + p->se.cfs_rq = tg->cfs_rq[cpu];
> + p->se.parent = tg->se[cpu];
> #endif
>
> #ifdef CONFIG_RT_GROUP_SCHED
> - p->rt.rt_rq = task_group(p)->rt_rq[cpu];
> - p->rt.parent = task_group(p)->rt_se[cpu];
> + p->rt.rt_rq = tg->rt_rq[cpu];
> + p->rt.parent = tg->rt_se[cpu];
> #endif
> }
>