[patch 7/7] x86: Use tick broadcast expired check

From: Thomas Gleixner <tglx@linutronix.de>
To: LKML <linux-kernel@vger.kernel.org>
Cc: LAK <linux-arm-kernel@lists.infradead.org>,
	John Stultz <john.stultz@linaro.org>,
	Arjan van de Veen <arjan@infradead.org>,
	Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>,
	Santosh Shilimkar <santosh.shilimkar@ti.com>,
	Jason Liu <liu.h.jason@gmail.com>,
	x86@kernel.org
Subject: [patch 7/7] x86: Use tick broadcast expired check
Date: Wed, 06 Mar 2013 11:18:37 -0000	[thread overview]
Message-ID: <20130306111537.702278273@linutronix.de> (raw)
In-Reply-To: 20130306111351.883117670@linutronix.de

[-- Attachment #1: x86-use-broadcast-expired-check.patch --]
[-- Type: text/plain, Size: 894 bytes --]

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

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: x86@kernel.org
---
 arch/x86/kernel/process.c |   12 ++++++++++++
 1 file changed, 12 insertions(+)

Index: tip/arch/x86/kernel/process.c
===================================================================

--- tip.orig/arch/x86/kernel/process.c
+++ tip/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 */


