linux-kernel - [PATCH 2/4] tick/sched: Set last

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Date:   Mon, 16 Dec 2019 18:22:23 -0500
From:   Scott Wood <swood@...hat.com>
To:     Peter Zijlstra <peterz@...radead.org>,
        Frederic Weisbecker <fweisbec@...il.com>,
        Thomas Gleixner <tglx@...utronix.de>,
        Ingo Molnar <mingo@...nel.org>
Cc:     linux-kernel@...r.kernel.org, Scott Wood <swood@...hat.com>
Subject: [PATCH 2/4] tick/sched: Set last_tick in init paths

This eliminates the need to save last_tick on nohz entry.

Signed-off-by: Scott Wood <swood@...hat.com>
---
 kernel/time/tick-sched.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/kernel/time/tick-sched.c b/kernel/time/tick-sched.c
index 8936b604dd6c..59e663e240fc 100644
--- a/kernel/time/tick-sched.c
+++ b/kernel/time/tick-sched.c
@@ -794,7 +794,6 @@ static void tick_nohz_stop_tick(struct tick_sched *ts, int cpu)
 		calc_load_nohz_start();
 		quiet_vmstat();
 
-		ts->last_tick = hrtimer_get_expires(&ts->sched_timer);
 		ts->tick_stopped = 1;
 		trace_tick_stop(1, TICK_DEP_MASK_NONE);
 	}
@@ -1248,6 +1247,7 @@ static void tick_nohz_switch_to_nohz(void)
 
 	hrtimer_set_expires(&ts->sched_timer, next);
 	hrtimer_forward_now(&ts->sched_timer, tick_period);
+	ts->last_tick = hrtimer_get_expires(&ts->sched_timer);
 	tick_program_event(hrtimer_get_expires(&ts->sched_timer), 1);
 	tick_nohz_activate(ts, NOHZ_MODE_LOWRES);
 }
@@ -1355,6 +1355,7 @@ void tick_setup_sched_timer(void)
 	}
 
 	hrtimer_forward(&ts->sched_timer, now, tick_period);
+	ts->last_tick = hrtimer_get_expires(&ts->sched_timer);
 	hrtimer_start_expires(&ts->sched_timer, HRTIMER_MODE_ABS_PINNED_HARD);
 	tick_nohz_activate(ts, NOHZ_MODE_HIGHRES);
 }
-- 
1.8.3.1