linux-kernel - [tip:timers/core] arm: Use tick broadcast expired check

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Date:	Tue, 19 Mar 2013 04:39:29 -0700
From:	tip-bot for Thomas Gleixner <tipbot@...or.com>
To:	linux-tip-commits@...r.kernel.org
Cc:	linux-kernel@...r.kernel.org, hpa@...or.com, mingo@...nel.org,
	linux-arm-kernel@...ts.infradead.org, santosh.shilimkar@...com,
	john.stultz@...aro.org, arjan@...radead.org, liu.h.jason@...il.com,
	tglx@...utronix.de, lorenzo.pieralisi@....com
Subject: [tip:timers/core] arm: Use tick broadcast expired check

Commit-ID:  80bbe9f273a38f83ecfc50fe384a57f8428887bd
Gitweb:     http://git.kernel.org/tip/80bbe9f273a38f83ecfc50fe384a57f8428887bd
Author:     Thomas Gleixner <tglx@...utronix.de>
AuthorDate: Wed, 6 Mar 2013 11:18:37 +0000
Committer:  Thomas Gleixner <tglx@...utronix.de>
CommitDate: Wed, 13 Mar 2013 11:39:40 +0100

arm: Use tick broadcast expired check

Avoid going back into deep idle if the tick broadcast IPI is about to
fire.

Signed-off-by: Thomas Gleixner <tglx@...utronix.de>
Cc: LAK <linux-arm-kernel@...ts.infradead.org>
Cc: John Stultz <john.stultz@...aro.org>
Cc: Arjan van de Veen <arjan@...radead.org>
Cc: Lorenzo Pieralisi <lorenzo.pieralisi@....com>
Tested-by: Santosh Shilimkar <santosh.shilimkar@...com>
Cc: Jason Liu <liu.h.jason@...il.com>
Link: http://lkml.kernel.org/r/20130306111537.640722922@linutronix.de

---
 arch/arm/kernel/process.c | 11 ++++++++++-
 1 file changed, 10 insertions(+), 1 deletion(-)

diff --git a/arch/arm/kernel/process.c b/arch/arm/kernel/process.c
index 047d3e4..db4ffd0 100644
--- a/arch/arm/kernel/process.c
+++ b/arch/arm/kernel/process.c
@@ -199,7 +199,16 @@ void cpu_idle(void)
 #ifdef CONFIG_PL310_ERRATA_769419
 			wmb();
 #endif
-			if (hlt_counter) {
+			/*
+			 * In poll mode we reenable interrupts and spin.
+			 *
+			 * Also if we detected in the wakeup from idle
+			 * path that the tick broadcast device expired
+			 * for us, we don't want to go deep idle as we
+			 * know that the IPI is going to arrive right
+			 * away
+			 */
+			if (hlt_counter || tick_check_broadcast_expired()) {
 				local_irq_enable();
 				cpu_relax();
 			} else if (!need_resched()) {
--
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