linux-kernel - [PATCH] nohz: Remove ts->inidle checks before restarting the tick

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Message-Id: <1323181843-12144-1-git-send-email-fweisbec@gmail.com>
Date:	Tue,  6 Dec 2011 15:30:43 +0100
From:	Frederic Weisbecker <fweisbec@...il.com>
To:	Thomas Gleixner <tglx@...utronix.de>
Cc:	LKML <linux-kernel@...r.kernel.org>,
	Frederic Weisbecker <fweisbec@...il.com>,
	Peter Zijlstra <a.p.zijlstra@...llo.nl>,
	Ingo Molnar <mingo@...e.hu>
Subject: [PATCH] nohz: Remove ts->inidle checks before restarting the tick

ts->inidle is set by tick_nohz_stop_sched_tick(1) and unset
by tick_nohz_restart_sched_tick(). These two calls are assumed
to be always paired. This means that by the time we call
tick_nohz_restart_sched_tick(), ts->inidle is supposed to
be always set to 1.

Remove the checks for ts->inidle in tick_nohz_restart_sched_tick().
This simplifies a bit the code and improves its debuggability
(ie: ensure the call is paired with a tick_nohz_stop_sched_tick() call).

Signed-off-by: Frederic Weisbecker <fweisbec@...il.com>
Cc: Peter Zijlstra <a.p.zijlstra@...llo.nl>
Cc: Ingo Molnar <mingo@...e.hu>
---
 kernel/time/tick-sched.c |   12 +++++++-----
 1 files changed, 7 insertions(+), 5 deletions(-)

diff --git a/kernel/time/tick-sched.c b/kernel/time/tick-sched.c
index 4042064..0f7c5e5 100644
--- a/kernel/time/tick-sched.c
+++ b/kernel/time/tick-sched.c
@@ -529,20 +529,22 @@ void tick_nohz_restart_sched_tick(void)
 	ktime_t now;
 
 	local_irq_disable();
-	if (ts->idle_active || (ts->inidle && ts->tick_stopped))
+
+	WARN_ON_ONCE(!ts->inidle);
+
+	ts->inidle = 0;
+
+	if (ts->idle_active || ts->tick_stopped)
 		now = ktime_get();
 
 	if (ts->idle_active)
 		tick_nohz_stop_idle(cpu, now);
 
-	if (!ts->inidle || !ts->tick_stopped) {
-		ts->inidle = 0;
+	if (!ts->tick_stopped) {
 		local_irq_enable();
 		return;
 	}
 
-	ts->inidle = 0;
-
 	rcu_exit_nohz();
 
 	/* Update jiffies first */
-- 
1.7.5.4

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