linux-kernel - [PATCH 3/5] Do not wait till next cpu online and abort early if lead cpu do not wait for us anymore

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Date:	Wed,  9 May 2012 12:25:00 +0200
From:	Igor Mammedov <imammedo@...hat.com>
To:	linux-kernel@...r.kernel.org
Cc:	rob@...dley.net, tglx@...utronix.de, mingo@...hat.com,
	hpa@...or.com, x86@...nel.org, luto@....edu,
	suresh.b.siddha@...el.com, avi@...hat.com, imammedo@...hat.com,
	a.p.zijlstra@...llo.nl, johnstul@...ibm.com, arjan@...ux.intel.com,
	linux-doc@...r.kernel.org
Subject: [PATCH 3/5] Do not wait till next cpu online and abort early if lead cpu do not wait for us anymore

Use cpu_callout_mask for checking if boot cpu is still waiting on us

Signed-off-by: Igor Mammedov <imammedo@...hat.com>
---
 arch/x86/kernel/tsc_sync.c |    7 +++++--
 1 files changed, 5 insertions(+), 2 deletions(-)

diff --git a/arch/x86/kernel/tsc_sync.c b/arch/x86/kernel/tsc_sync.c
index 5f06138..1741385 100644
--- a/arch/x86/kernel/tsc_sync.c
+++ b/arch/x86/kernel/tsc_sync.c
@@ -188,10 +188,13 @@ void __cpuinit check_tsc_sync_target(void)
 	/*
 	 * Wait for the source CPU to start the measurement
 	 */
-	while (!atomic_read(&start_tsc_sync))
+	while (!atomic_read(&start_tsc_sync)) {
+		if (!cpumask_test_cpu(smp_processor_id(), cpu_callout_mask))
+			return;
 		cpu_relax();
+	}
 
-	if (!cpumask_test_cpu(smp_processor_id(), cpu_initialized_mask))
+	if (!cpumask_test_cpu(smp_processor_id(), cpu_callout_mask))
 		return;
 
 	atomic_set(&start_tsc_sync, 0);
-- 
1.7.1

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