[tip:timers/core] x86: Use tick broadcast expired check - tip-bot for Thomas Gleixner

From: tip-bot for Thomas Gleixner <tipbot@zytor.com>
To: linux-tip-commits@vger.kernel.org
Cc: linux-kernel@vger.kernel.org, arjan@infradead.org,
	john.stultz@linaro.org, hpa@zytor.com, mingo@kernel.org,
	tglx@linutronix.de
Subject: [tip:timers/core] x86: Use tick broadcast expired check
Date: Tue, 19 Mar 2013 04:40:40 -0700	[thread overview]
Message-ID: <tip-35b61edb41ffee58711850e76215b852386ddb10@git.kernel.org> (raw)
In-Reply-To: <20130306111537.702278273@linutronix.de>

Commit-ID:  35b61edb41ffee58711850e76215b852386ddb10
Gitweb:     http://git.kernel.org/tip/35b61edb41ffee58711850e76215b852386ddb10
Author:     Thomas Gleixner <tglx@linutronix.de>
AuthorDate: Wed, 6 Mar 2013 11:18:37 +0000
Committer:  Thomas Gleixner <tglx@linutronix.de>
CommitDate: Wed, 13 Mar 2013 11:39:40 +0100

x86: 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@linutronix.de>
Cc: John Stultz <john.stultz@linaro.org>
Cc: Arjan van de Veen <arjan@infradead.org>
Cc: x86@kernel.org
Link: http://lkml.kernel.org/r/20130306111537.702278273@linutronix.de
---
 arch/x86/kernel/process.c | 12 ++++++++++++
 1 file changed, 12 insertions(+)

diff --git a/arch/x86/kernel/process.c b/arch/x86/kernel/process.c
index 14ae100..aa524da 100644
--- a/arch/x86/kernel/process.c
+++ b/arch/x86/kernel/process.c
@@ -336,6 +336,18 @@ void cpu_idle(void)
 			local_touch_nmi();
 			local_irq_disable();
 
+			/*
+			 * We detected in the wakeup path that the
+			 * tick broadcast device expired for us, but
+			 * we raced with the other CPU and came back
+			 * here before it was able to fire the IPI.
+			 * No point in going idle.
+			 */
+			if (tick_check_broadcast_expired()) {
+				local_irq_enable();
+				continue;
+			}
+
 			enter_idle();
 
 			/* Don't trace irqs off for idle */
