Messages in this thread | | | Date | Mon, 26 Oct 2020 14:29:56 -0400 | From | Steven Rostedt <> | Subject | Re: [PATCH] sched/rt.c: use list_is_singular() instead of '->prev != ->next' |
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On Tue, 27 Oct 2020 01:41:52 +0800 Hui Su <sh_def@163.com> wrote:
> Use the list_is_singular(&rt_se->run_list) api instead of > 'rt_se->run_list.prev != rt_se->run_list.next'. > Fix a comment by the way, and make the comment more clearly. > > Signed-off-by: Hui Su <sh_def@163.com> > --- > kernel/sched/rt.c | 8 ++++---- > 1 file changed, 4 insertions(+), 4 deletions(-) > > diff --git a/kernel/sched/rt.c b/kernel/sched/rt.c > index 49ec096a8aa1..1479d00656b4 100644 > --- a/kernel/sched/rt.c > +++ b/kernel/sched/rt.c > @@ -2381,7 +2381,7 @@ static inline void watchdog(struct rq *rq, struct task_struct *p) { } > * > * NOTE: This function can be called remotely by the tick offload that > * goes along full dynticks. Therefore no local assumption can be made > - * and everything must be accessed through the @rq and @curr passed in > + * and everything must be accessed through the @rq and @p passed in > * parameters. > */ > static void task_tick_rt(struct rq *rq, struct task_struct *p, int queued) > @@ -2406,11 +2406,11 @@ static void task_tick_rt(struct rq *rq, struct task_struct *p, int queued) > p->rt.time_slice = sched_rr_timeslice; > > /* > - * Requeue to the end of queue if we (and all of our ancestors) are not > - * the only element on the queue > + * Requeue to the end of rt_prio_array queue if we (and all of our > + * ancestors) are not the only element on the rt_prio_array queue. > */ > for_each_sched_rt_entity(rt_se) { > - if (rt_se->run_list.prev != rt_se->run_list.next) { > + if (!list_is_singular(&rt_se->run_list)) {
Perhaps there should be a list_has_more_than_one() API, as list_is_singular requires two checks, and the "more_than_one" only requires a single check.
list_is_singular() is:
return !list_empty(list) && (list->next == list->prev);
which is more work than what you are replacing.
-- Steve
> requeue_task_rt(rq, p, 0); > resched_curr(rq); > return;
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