linux-kernel - Re: [PATCH v2] sched/fair: avoid redundant hrtimer check

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Date:   Sun, 19 Jun 2022 01:54:25 +0800
From:   Huichun Feng <foxhoundsk.tw@...il.com>
To:     Peter Zijlstra <peterz@...radead.org>
Cc:     Ingo Molnar <mingo@...hat.com>, Juri Lelli <juri.lelli@...hat.com>,
        Vincent Guittot <vincent.guittot@...aro.org>,
        Dietmar Eggemann <dietmar.eggemann@....com>,
        Steven Rostedt <rostedt@...dmis.org>,
        Ben Segall <bsegall@...gle.com>, Mel Gorman <mgorman@...e.de>,
        Daniel Bristot de Oliveira <bristot@...hat.com>,
        Valentin Schneider <vschneid@...hat.com>,
        "open list:SCHEDULER" <linux-kernel@...r.kernel.org>,
        jserv@...s.ncku.edu.tw, Chin-En Lin <shiyn.lin@...il.com>
Subject: Re: [PATCH v2] sched/fair: avoid redundant hrtimer check

The check is required iff HRTICK is enabled and DOUBLE_TICK is disabled,
don't do that then.

Signed-off-by: Huichun Feng <foxhoundsk.tw@...il.com>
---

Changes since v1:
- Refine commit message

 kernel/sched/fair.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
index 77b2048a9..80cc1a924 100644
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -4668,7 +4668,7 @@ entity_tick(struct cfs_rq *cfs_rq, struct sched_entity *curr, int queued)
        /*
         * don't let the period tick interfere with the hrtick preemption
         */
-       if (!sched_feat(DOUBLE_TICK) &&
+       if (sched_feat(HRTICK) && !sched_feat(DOUBLE_TICK) &&
                        hrtimer_active(&rq_of(cfs_rq)->hrtick_timer))
                return;
 #endif
-- 
2.36.1